Here is the article from my last round of testing: http://www.hotrod.com/articles/dyno-tested-vacuum-pump-help-engine-make-power/

Peak power with the vacuum pump and the Wilson ported intake was 775 hp. That is running unleaded premium with out of box Trick Flow 270 heads. I'm sure that more compression would make more power but we're getting close to the limits of a stock block so no reason to turn up the wick anymore.

Great article. I want that Manifold. I’ll trade you my untouched one LOL.

Good info Andy, this makes for an interesting comparison to the Wet sump Flat Tappet Chapman (Engine Masters) 470 that Steve Dulcich did back in 2004, Nearly Identical power!

http://www.hotrod.com/articles/mopp-0405-stage-vi-manifold-casting/

Wonder how the Chapmans would have worked with either the Dry or VP, your Wilson manifold and solid roller? Probably enough to break the block!

Andy: could you supply a part number for this cam? "Comp Cams 264/268 solid roller with HXL and HXX lobes"
Thanks Birdtracker

Yes the power is about the same as Dulcich's Engine Master engine. The big difference is that you can order these heads from Summit and bolt them on. (and they don't cost that much)

It is a custom cam. If you want to duplicate it just ask for 264/268 with HXL and HXX lobes. You'll also need to pick a lobe center.

do you know what the lobe center was on the one dynoed? thanks Birdtracker

Andy how much vacuum did the dry sump pump pull?

Don

True....but how much did the manifold porting cost? or the Dry sump Vaccuum system...or the roller and lifters, or the Pan?

I was just stating power to power, but if someone wants to open the discussion up to "Cherry Picking" the costs. Which dyno ready motor cost more for the 775 HP?

There was nothing wrong with the Chapman heads...other than the Overpriced MP Marketing. Finally Mopar produced n awesome head out of the box...but they blew it with the exorbinate pricing.

The only other "custom" cost vs any other offset intake rocker head (as far as I know) is the $150 billet rocker stands which are arguably well-worth the expense. I think I paid $2400 for my set new but second hand.

I mean I get it, there are "promotional considerations" with every new product testing and we're all happy to have solid tech articles to read, but this is Moparts where we should talk "Apples to Apples"....fairly and objectively.

Ground 108, installed 104

Not a lot, somewhere around 10 to 12 inches. Neither the dry sump or the vacuum pump were set up to pull a ton of vacuum.

The Cam in my 517 is also 264/268 on 108, but it's a Bullet Hydraulic Roller, makes mad torque and pulls to 6800+ It's been in the motor 10 years now, trouble free.

Thinking of Switching to a Solid roller just so I can run the BAM lightweight pressure fed lifters, save on some of that valvetrain mass.

My suggestion to birdtracker is to contact Dwayne Porter (fast68plymouth) for the cam, especially since he may have a different recommendation for lobes, depending upon the application.

I plan on calling Comp this coming week. I would of already but I figured with the holiday I should wait. This is my ideal build for my engine this winter. I have a low deck Indy block that I plan to put Trick flow Max Wedge CNC ported heads on. Would like to run it on pump gas or E-85 and 800-900 hp.
The Comp Cam that I have right now is 2226B 4134B which is a custom grind on 108 center.Lift is 663 on intake and 645 on exhaust with 1.5 rockers. 1.6 rockers would net 703 on intake and 685 on exhaust. Duration is 264 at .050 on intake and 268 on exhaust at .050. Birdtracker

A 2226B/4134B should be 260/266@ .050

There's usually a few thousand extra $$$$$ to get from 800hp to 900hp.

Of course, "low deck Indy block" doesn't really narrow things down too much.
It could be a 451....... Or a 557.

2226 is a HXL lobe that is just a few degrees smaller than the lobe I used. Your 4134 exhaust lobe is a different family. That is an RT lobe with 266 duration.

If you replaced your cam with my cam I doubt you would see much difference. Maybe pick up a little power but I don't think it would be worth the hassle.

800 hp with the Trick Flow 270 heads will take some work. With E85 you can run more compression so you'll want to run as much as possible. If it is a race only deal you'll probably want to throw more cam at it than I'm using. Especially if you have more compression. Don't forget to get the intake ported, that is the key to unlocking some power.

Just an Idea....

So in a post a year or so ago it was mentioned that someone in the Engine Masters comp had used a windowed block to reduce effects of pumping losses by increasing the cubic volume of the sump area (no vac pumps in engine masters?)

So if using a vac pump, its got to pull vs a set volume, if you could reduce that volume, it would work better?

So if you put a big sealed triangular wedge under the valley cover you could take out a bunch of CI from the internal space of the motor and make the pump work better?

Years ago I had a customer bring me his 1968 383 C.I. Charger that he had put a set of after market cast aluminum valve covers on with the stock type PVC and twist on oil filler cap with no vent. It would start and idle fine for a short while(1 1/2 to 2 1/2 minutes) and then slow down by several hundred RPM, the motor was sealed up tight enough that the PCV was making a vacuum in the motor after it suck the pressure out of the motor I put a breather cap on it and he was happy after that
A vacuum pump will do the same thing on a leak free motor
The pumping action of the pistons and rods going up and down and ring blow by will cause crankcase pressure, especially at high RPM

That was my build in 2014 and you are correct-No vac pumps in EMC. I agree with your theory about reducing volume the vac pump has to act on. I also know how theories often pan out. J.Rob

Andy: a few people have shown interest with this topic in reguards to the article. Am I wrong that the 270 heads with your cam and ported intake made 775 hp or did you use a different head? What compression height and ratio were you using with the J.E pistons? Are these a shelf piston? The pump gas is what really interests me cause alot of us still drive ours. Thanks Birdtracker

Basically a shelf piston but I added some options such as lateral gas ports, max lightening, coated skirts, etc. It isn't a super trick setup, Molnar crank and rods and semi-custom pistons. Pistons have a very small dish in them to make the compression 10.8 to one. Heads are Trick Flow 270 right out of the box. No porting or machine work on the heads. They were inspected and cleaned and bolted on.

Andy,
Were any other Camshafts tested during any of the trick flow head tests? I am getting the 270 heads and they are going on a 12:1 511. So I am curious if another 5-10 degrees would be worth it.

Wow Andy you do know how to get awesome power from your Mopars !! Ron

Just curious Andy if you know the flow #'s on the OOB 270 Trick Flow heads you used on the eng ? Thanks , Ron

Ron trick flow site advertises these numbers ootb intake
.100- 72
.200- 154
.300- 230
.400- 288
.500- 322
.600- 343
.700- 352

exhaust
.100-58
.200-130
.300-186
.400-222
.500-243
.600-253
.700-262

I have not done any cam testing with the 270 heads. The cam I used for the 270 heads is the one that was best with the 240 heads. I'm pretty sure I can find some more power if I start testing cams. Now that I have the 270 heads and the ported intake I'm sure the engine would respond to a little more area under the curve. I'm kind of busy building the Duster at the moment but if I get a little free time I'll research some cams for this engine and then see if I can get it back on the dyno.

Thanks Ron. Not sure I really know in advance how to make power but if you try enough things eventually some stuff works. I chased my tail with rocker arm ratios and cam grinds and crappy intake manifolds and spacers that didn't work and all of that stuff. First pull with the 470 was 620 hp so we've found 150 hp over the past 18 months.

I'm sure that motor combo could benefit from more duration, provided the car has the right pieces to make use of it.



Exhaust numbers are with a flow tube attached.

Nice work, thats what should happen when one keeps testing and testing and re-testing stuff. I think a lot of guys on here would be supprised how much they could gain from trying some different manifolds, carbs, spacers, rocer geometry, rocker ratio... vs the typical just throw more cylinder head, cam, and compression at it.

Regarding the crankcase. While the pistons are going up and down they are disp[lacing volume on the top of the piston but it cannot nbe any different on the bottom of the piston. The pistons are moving a lot of air in the crankcase and it takes energy to compress that air. Then when it expands back all of the energy doesn't come back. There's also the fact that air has to rush around the spinning crank, connecting rods, etc. So by adding cubic inches of volume to the crankcase, the air doesn't have to be compressed that much because the piston is working with a larger volume.
The vacuum pump attacks the problem another way by making the crankcase air much less dense. It doesn't take as much energy to move around this less dense air. The vacuum might also assist in ring loading but I'm not sure how big the effect is.

One problem will pop up with decreased crankcase pressure, and that's technically called Net Positive Suction Head (NPSH). The oil pump doesn't suck oil in, it's the absolute pressure of the atmosphere that pushes the oil into the pump inlet. When you decrease the absolute pressure in the crankcase, it reduces the pressure available to push the oil into the oil pump inlet. I have a friend who had problems with oil pressure at the end of the track because his vacuum pump was so effective.

R.

When I first heard of the oil starvation problems with motors running vacuum pumps I thought it was due to tight of clearances on the wrist pins to rod and pistons due to most pin oiling being splash oiling.
The oil pump is a suction pump also but it forces liquid through a restrictor, the engine oiling system and has a high pressure bypass system built into the pump so the motor will have a maximum oil pressure at the higher RPM. The oil pump has to battle the negative pressures above the oil level to suck oil into it, or does it
Using a vacuum pump does allow thinner rings to seal better which allows the motor to make more power with less oil contamination in the combustion chambers
As well as stop some of those pesky tiny oil leaks

That's funny Cab , 20 or so years ago I had similar issues on a customers stock 308ci Holden , after 20 minutes the motor would stall . Took a little while to work that one out , vented oil filler cap solved it .

Tex

I modified a PCV so it would flow slightly under vacuum and then put it on the vent side. I now have 2ish inches of crankcase vacuum and it has made a world of difference in throttle response and power/mpg.

I think the PCV has been on the wrong end of the crankcase vent sequence.

Wow thats some nice #'s. I believe they do come CNC ported right out of the box ? Thanks Viperblue72. Ron

And us Mopar people do thank you as you do alot of work in testing parts and letting us know what works in many combo's and myself I thank you. I really enjoy reading about your dyno' runs. Ron

Can you explain this "wrong side" theory please...........

i am guessing to position the valve where the air inters the engine?

Is this referring to using manifold vacuum via pvc to pull a vacuum on the crankcase ?

I used some home depot parts to install a PCV in the breather line. However I opened up a passage so the PCV flows backwards.

Restricting the vent flow creates negative CC pressure. I couldn't believe how off idle throttle response and street manners improved. Mileage is up as well.

I have pics but my brand new phone and antique PC won't link, so I am working to get that fixed.

varunner:
I'm just harnessing the vacuum energy pulling air through the crankcase already.

A PCV is a one way valve right? The spring shoves it closed with no vacuum and opens with around 2 + inches of vacuum, correct?
If you apply vacuum to the ball side of the valve doesn't that suck it closed?

Cab I removed the idle circuit ball, and the cruise circuit spring. Vacuum closes the cruise ball, and can only flow through the idle side. When CC goes positive, the valve can fully vent into the aircleaner.

I did it with the Wagner adjustable PCV. It works really good.
You have a PM

Heres pics of my setup

Not sure if I completely understand what you have here. Is that a "normal" breather in the top picture ? Bottom picture shows (2) adjustable pvc valves ? thanks for sharing this.

The top pic is the driver side, and the vent is from the 70s. The original elbow was causing oil to weep at the grommet, and the new vent solved that.

The hose goes to the air intake tube, and thats where I cut in the 2nd valve.

Bottom pic is the PS to show how that 2nd valve is setup. I'm still tinkering with it though cause I think 1 valve should work.

Does the hose from the PVC on the valve cover go to a port on the intake ? Is there a particular rpm range you're trying to get this to work at. IIRC, some stock eliminator guys did some type of trick like this.....which I'd like to know about

I had issues on my old street pump gas 518 C.I. 400 stroker motor with the original six pack blowing oil out of the breather caps with two caps and one PVC valve when I raced it shifting at or above 7000 RPM, I added another PVC valve with a T to the vacuum side and that stop the problem That also made the motor idle better which allowed me to lean down the idle mixture screws on all three carbs. a tiny bit

The VC PVC hooks to a port on the manifold, near the plenum floor. Its kinda cluttered, and hard to get a clear pic.

I have no idea what it's done power wise. A lot of dyno time would be needed. Next spring I intend to go to the track and test this setup out.

I'm guessing this will mainly affect 60 foot time.

Cab these Wagner valves are really impressive because they manage the vacuum signal so well. I'm convinced a lot of carb idle issues are caused by PCVs not metering correctly.

Have the new grind from Comp for this engine. They stepped it up with some new QRI and HXX HL lobes so now it is very aggressive. They also sent me some new dual conical springs to try. These springs are pretty trick. They are lightweight and they don't have the friction of an interference fit damper. I'll get the new parts installed on the 470 and back up on the dyno within the next few weeks. Should be interesting.

Andy,are the retainers Ti or tool steel and do you know the gram weight? Thanks

Oh boy, conical springs A big no no here



Those springs are very nice 👍🇺🇸

The retainers I have are tool steel. Comp has Ti retainers for these springs but didn't think they were needed for my combo. This engine only spins to 7000.

The conical springs save about 1 pound of weight over the existing dual springs. Also, the conical springs get rid of the interference fit damper. The damper in my existing springs is showing a clear wear pattern after just a few dyno pulls. Those wear marks took power to make and the ground up steel went into the oil system.....

Not only do they save weight, they also help cancel valve train harmonics, require less pressure to control the valves than traditional duel springs and are made from better material.

Yep, I'm looking forward to this round of dyno testing just to see if the new cam design and the new springs make any difference. I'm hoping we'll pick up 10 or 15 hp but it might not be that big of a difference.

Andy, I loved the comment that the wear marks on the valve springs took energy to make. Wow!

Folks, if you're pondering how AndyF makes power, it's because of understanding things like this.

Conical springs? It just freaks me out how the Spintron has pushed the understanding of valve train dynamics.
Years ago Isky made a spring for smallblock Chevies that had a small end to fit in the spring pockets, and then ballooned out to 1.55or so for the rest of the way up to the retainer. They were beehive springs, but they were upside down.

BTW I need one new Isky 2005 valve spring to round out a set.

R.

Along with taking power to make the witness marks, it created HEAT in the valve train.
Andy this should be an interesting test!
Thanks for your info!
Don

Andy do you have part #s for the springs? Do they have them for solid flat tappets also?
Thanks, Don

The springs I'm using are 7245. Comp has a variety of these dual conical springs in their new catalog. Shouldn't be a problem finding a set that would work with a flat tappet cam.

Try this link. This isn't all of the conical springs but it might get you going.

http://www.compperformancegroupstores.co...ory_Code=SPRNGC

Thanks.

I second that.

The springs installed into the Trick Flow heads without any issues. The spring locator drops right in place without any machine work. Installed height in my heads was 1.975 and the seat pressure was 205 lbs. Open pressure at 0.750 lift is 660 lbs.

The conical spring is smaller at the top so there is a ton of clearance around the rocker arm. I had clearance issues with the T&D rocker arms with the dual springs that were in there but now there is plenty of space.

I also test fitted some 7/16 dual taper pushrods. They almost fit but rubbed a little bit so we'll pull the heads and do a little machine work. Should have the engine back on the dyno around the end of the month.

It's too bad the pressures aren't more in line with the advertised specs.
I was looking forward to seeing if that spring design could really keep everything under control with only 150 on the seat.

At 205/660, while that's still less than I would normally use with that new cam, it's not as low as its "supposed" to be.

But if all goes well...... I could see trying them in something.

Yeah I think they are a great spring, only issue is that they are little on the expensive side. I don't fully understand the difference between 150 in the catalog and 205 when measured. I think it is due to the step on the locator and the retainer but Comp should know about that.

Comp does say that conical springs can be run with much less pressure than normal straight springs but they don't provide any more guidance than that. The engineer I talked to said these springs would work just fine with this cam profile but he didn't say why he felt that way. I know they have done a lot of Spintron testing with these conical springs so I'm guessing that someone knows what works and what doesn't but they didn't pass that knowledge on to me!

Still a lot of uncertainty and doubts with both beehive and conical springs. I have seen these new era springs being used on LS platforms making north of 700 horsepower with ZERO issues. I hope the springs perform well for you in that if they exceed your expectations some of the uncertainty and doubts will slowly disappear because these new spring designs are way better than traditional dual springs.

It seems that the 150 lb seat pressure that is listed in the catalog is incorrect. I exchanged emails with some engineers from Comp today and they said the seat pressure should be higher. They agreed with my 205 lb measurement and verified it on their end.

Geez - a catalog error. Imagine that.

Starting to get the top end back together. Dialed in the new cam and did a bunch of clearance checking. Everything appears to fit just fine. Valve lift is a little over 0.800 with checking springs. Should be lower than that with the real springs.

Ran the engine on the dyno on Friday. Having some problems with the vacuum pump filling up with oil. It seems that when we changed the rocker arms over to pushrod oiling we ended up sending a ton more oil thru the rocker arms. I'm not sure exactly why, but the oil is now shooting right up the valve cover wall and inside the baffle for the vacuum pump. You can see it in this video: https://youtu.be/p4SO73Xu13c

Here is another video showing a little more of the engine. We only got a couple of pulls in all day and neither one made good power. So I need to re-engineer the vacuum pump system this weekend and we'll try again on Monday.

https://youtu.be/S4AbomE1lis

Do you have any pulls with the current heads/intake/carb with the previous cam and no vacuum pump?

Probably, I'd have to look thru the test matrix from the last test. We're basically around the same power level as it was before without the vacuum pump so the new cam isn't making anymore power. Might even be down a little bit of power from the previous cam.

If we can get the vacuum pump setup sorted out then we'll make some pulls on Monday and try advancing the cam and maybe opening up the lash a bit. I think this new cam might be a touch too large for the engine. Or maybe it is just too aggressive. This new cam has very aggressive lobes so maybe the engine doesn't want that.

In general terms, faster is bigger.....as far as how the motor sees it.

At least, that's how I always looked at it.

So....... If you would have thought a "bigger" cam than the previous one would have been better with the motor in its current configuration ...... Then "faster" is a step in that direction.

If you wanted to see if the combo will respond to more (hi lift)area under the curve, without really going bigger....... Then a commensurate reduction in duration would accompany the added rate.

You probably haven't really made any representative pulls yet though, so the jury is still out on the new cam.
It might be safe to say though, that "big gains" aren't in the cards.

I know this engine is a little touchy about overcamming it but this new cam is only 1 degree bigger on the rated duration. It is a couple of degrees larger at 200 and has a bunch more lift.

We'll add 3 or 4 thou on the lash and see how it responds. I'm also going to try it 4 degrees advanced. Right now it is straight up at 108.

What RPM is the motor seeing peak HP at?
I had one roller cam motor that would stop gaining HP for three hundred RPM and then take off again and finally peak at 800 RPM higher

My “armchair quarterback” response is........I would have installed the new cam at the same c/l as the previous cam.

I watched the video.......and that does look like a ton of oil coming to the top.
Although, in all fairness.......I’ve never run anything with a clear v/c.......so I don’t really have anything to compare to.
It just “seems” like that’s a lot of oil up top.

I typically install cams at 4 degrees advanced unless told otherwise. In this case the engineer at Comp who I was working with told me to install the cam straight up.

It seems like an excessive amount of oil to me. Maybe next time I buy pushrods I'll order a set with restrictors to see how it works.

I’ll be a bit surprised if a little cam advance doesn’t help to some degree.

Though, when the heads have low lift flow as good as TF heads do, it’s easier to open the valve too early.

My starting point still would have been to use the same c/l, just to eliminate the variable.

Advancing the cam 4 degrees added some area under the curve and picked up peak power by a small amount. I'll need to spend some time looking at the data but I think this cam is just a few degrees larger than the engine wants.

I can go back to my 264/268 cam or I could get a smaller version of the new cam with the more aggressive QRI lobes. Haven't decided which way to go yet.

Never did figure out the vacuum pump issue. Appears that the switch to pushrod oiling changed the amount of oil in the valve covers enough that it overwhelmed the baffles. I added a Moroso oil separator tank and that still didn't work. So I need to pull the stuff apart and see if I can figure out what is going on.

Andy, any thoughts on how much the pushrods will need to be restricted? Size of oil holes??

Haven't thought about it much. Wouldn't need to be very big, 0.020 should work but holes that small can get plugged up with any RTV that is floating around in the oil so it isn't a perfect solution.

Sounds like the QRI lobe wasn't the best choice for this engine. Billy G. at Comp says the QRI lobes are designed for a smaller journal cam and with a Mopar large journal cam I would have better results with a DGO or LRW lobe. Which are lobes I've never heard of and are not in the master lobe catalog. Mr. G was kind enough to send me the new lobes so I'll attach them here. Just in case anyone feels the need to have the latest and greatest solid roller lobes.

Thanks Andy.
Guess its "onward" on cam choices for that 470.
you test- we learn.

I think there might be "some" gains to be had by (as Grumpy said in his 1975 SBC book) "fiddling with the cam".
But, the fact that the motor didn't respond at all to a pretty big swing in rocker ratio changes....... I don't think there's any "easy 25hp" to be gleaned from only swapping the cam at this point.

I'd be looking towards the EM builds for inspiration as far as the cam goes.

Btw...... Did you mess with the lash?

We'll loosen up the lash and make some runs today.

Comp engineer said to tighten up the LSA until we run out of valve clearance. My calculations say we can go to a 104 LCA before we start to run out of room with the existing lobes.

Thats the test i would like to see results with. LSA.

You can probably find a good number of LSA-type tests searching online. No real mystery, other than making sure the LSA, duration & lift actually suit the combination.

Well, maybe it's a mystery to a lot of people, still.

Yes you can. I have read a few. Seems 108 works pretty good on a small block. I would like to see first hand what Andy finds with that BB.

Were the 270 heads otb or ported?

TF 270 heads have out of the box ports and valve job. The springs have been changed and we did a little bit of machine work so 7/16 inch pushrods would fit.

TF 270's are fully ported OOTB.

Sure, some may be porting them more, but there are no "unported" TF 270's.

Opening up the lash by 0.005 didn't change the peak power but it did add a little big of area under the curve. So I'm fairly well convinced that this particular cam wasn't what the engine needed. Maybe just a little too big.

It worked better advanced 4 degrees and with looser lash. To be fair, I did not do a lash test with teh 264/268 cam and I never tried anything other than 4 degrees advanced so I don't know if that cam is "perfect" or just closer to the target.

So, peak to peak, what was the difference between the two cams?

Not trying to bust your chops, but 108 works where 108 is the right LSA for the combination, regardless of small block, big block, or whatever. Four of my last five BB cams have all been 108, because that's been a good choice for those combinations. If I made significant changes, I'd expect the LSA and/or duration might need to change, too. I've got a nice 109 LSA solid roller that I never tried because I didn't have the right rocker ratios on hand to show its true potential. That cam grinder wanted to put it on 110, but we split the difference on his preference for 110 and mine for 108.


I can't ready Andy's mind (nor my wife's, even though she thinks I'm supposed to be able to), but I suspect anyone who wants to send him a $1000 to offset parts / teardown / dyno expenses might "influence" what he's interested or willing to test. I've got enough first-hand experience now from multiple dyno sessions to know that stuff gets spendy fast, especially if it turns into more of an R&D session than a straight test & tune of a single combination.

Turns out I don't have a clean A to B test with the same exact parts on both engine due to the problems I had with the vacuum pump. I wasn't able to run the QRI cam with a vacuum pump since I had issues with it so all of my current testing is with breathers. The engine is making right around 750 hp with the QRI cam using breathers.

I made 775 hp with the HXL cam using a vacuum pump and Wilson Indy. I made 745 hp with the HXL cam using breathers but with the M1 Wilson intake. (std port intake) I never tested the HXL cam with breathers and the Indy Wilson intake so I don't have that as a baseline.

My guess is that the HXL cam with breathers and the Indy Wilson intake would hit 755 or 760 hp in an A to B test but I wouldn't be surprised to be wrong.

Another thing is the weather. The last few days have had cold air so the correction factor is negative. Even thought the correction factor is only a few percent different than the previous tests, that is enough difference to throw some doubt on the comparison.

Yeah no doubt about that. I'm fortunate to be in a position where I have the resources to do this type of testing but still there are limits. I might have the time to dink around with engine testing but people around me don't have the time so I have to respectful of them. The guy who runs the dyno has to make a living and he can't just play engines with me all day since he needs to get work out the door in order to feed his family. Given that, I can only squeak in some dyno testing "fun" about 4 or 5 times a year. So I have to pick and choose what I'll test.

Did you A/B the vacuum pump last time, so you have a pretty good idea on what that was worth?

Sounds like you're thinking 10-15hp.

Yes, the vacuum pump was worth 15 hp and the Indy Wilson was worth 15 hp. The M1 with breathers was 745, then went to 760 with the vacuum pump and then went to 775 with the Indy intake.

I'll attach a chart with the lash test. There is enough "noise" in the testing results that it is hard to see a clear change but my guess is that the looser lash is making a little more area under the curve. So the cam might be a little too big.

Brad, it sounded to me that Andy was going to experiment with lobe sep angles. I did not suggest he do that or tell him too. My comment was about my curiosity of what he finds in that test. No one has to remind me of the expenses of this hobby as i understand that as well. My 410 that came apart on the dyno was a real good education of the expenses of this hobby. About a $5000 education.

David Vizard has a graph for selecting lobe sep angles. He says its the best way to do it as he finds more power in big blocks than most anyone else. I have never seen anyone use it. Looking at his graph shows my 511 would need a lob sep of 100*. I have never seen anyone use a cam with those kind of lobe sep angles. Anyone know if Vizards gragh is BS or is there some validity to it. I am assuming his engines are race only.

are you talking LSA or LCA ? two different things .

There have been some very long threads on SpeedTalk about Vizard's LSA chart. Most engine builders think he is nuts although not everyone. I think the trick is that Vizard's chart was really only designed for 23 degree head SBC engines but I'm not sure. I do know that if you follow his advice you end up with cams that seem very strange and the cores might not even exist to make them. However, as Dwayne hinted at, some of the EMC guys had success running a super narrow LSA. I recall engines with 99, 100 and 101 lobe angles. That kind of stuff is way off the chart in my world. I used to have an old Crower cam that was 103 or something like that. I never ran it so now idea how well it worked. It must have worked at some point for someone though.

I'm not sure what I'm going to do with this engine. I might just put my old cam back in it or I might try one of these new lobes that Comp has released. The DGO 14669 looks like it would work on the intake for my engine or perhaps the DSP 12177. I think the DSS lobe might be pushing the lift just a tad too far.

Lobe displacement angle LDA. Lobe seperation angle LSA or lobe sep as i call it.

Ouch. Sorry to hear that...

It's not as simple as they make it out to be, but it's better than some crap I've seen published on the subject.

Many years ago the late Joe Sherman (who only recently passed away) had an article in Car Craft or Hot Rod where he did a 106 / 108 / 110 LSA comparison on a fairly hot (close to 600 HP) SBC 23* build with a solid flat-tappet cam. The 106 made more power & torque everywhere except the last couple of hundred RPM. The 110 never made as much anywhere as the 106; the 108 was the cam that made a little bit more than the 106 only at the very top of the RPM range.

It was valid for that specific build, but the YMMV caveat always comes into play.

There's my suggestion... but you have more time & $ than I do at this point.

Same kind of test i mentioned earlier, but with a sb mopar, i believe it was a 408. It was in enginemasters 2008 oct i believe. Ill have to look that up, but they found in that test of several different lsa spec'ed cams that the 108 was best in that combo. Best avg power. It was an interesting read as well.

You should always cam for the build, but with that said.

I think one of the reasons the old MP .590 does so well for A lot of people Even to this Day, is its 106 LSA, and its 271 @ .050. The 106 LSA helps in the lower torque range, and the 271 @ .050 gives it some upper HP range. A pretty broad range race cam IMO.

Ive even heard some early racers refer the Mp 590 cam torque cam compared to others in the race environment.

I see. I think it would interesting to go to one of davids seminars just to see his theories first hand . Thanks Andy.

Do you have all the specs of the .590 cam for BB? Open/close and lift both valves?

I've read that article a few times and I think it needs some editing for clarity. I don't think the author ever says how the cams were installed. Were they all installed straight up? He also doesn't talk about the big effect that LSA can have on valve to piston clearance. And I think some of his conclusions are wrong. He says the 101 LSA cam has a wider powerband but I think that is wrong. Looks to me like the 101 cam falls off faster than the others.

It is a spare engine so I'm not in any hurry to figure it out. I can leave it sit until I come up with another idea.

The thing about a wide lsa cam is they retard the intake lobe, & that will affect low end TQ, I have advanced a wide 112 lsa cam from 111 Intake LCA to 106 & it pick up lots of low end & still pulled on the top end, yes this was tested on a dyno.

The 101 does Fall off faster at the Top of the rpm, past 5600. I guess it depends on where you start and stop your power band measurements.

If you look at his dyno graphs, the 101 LSA did have the Wider Stronger power band up to 5600 rpm

Now if you compared the 101 LSA from say 5000 to 6500, clearly the other two cams had the wider power band. In this case, if you had a 5000 stall vert, the wider LSA cams would be the better choice. A 4000 stall vert, probably the 101, just by the visual of the graph. Didn't spec the numbers out. 1500 vert, the 101 Blows the wider LSA cams away.

With that said, wouldn't want the 101 LSA cam in my race car.



Edit, And Dave, yes I have the specs for the MP 590. I will post them up for you later.

Thanks. I know the dynomation 5 program is not very reliable to real world results, but just for giggles i input alot of cams in it using my 511 specs and nothing has had as nice tq/hp curves as the cam Dwayne spec'ed for and is in it. 270/276@50 .644/.624 on a 110LSA. I use a 1.6 rocker on int. and a 1.5 on ex.

Some measure the cam at 271 @ .050, mine measured 272 @ .050, that makes the math more simple.

But, for Strait up at a 106 ICL

--------open------ close-------
int: 30* BTDC, 62* ABDC
exh: 62* BBDC, 30* ATDC


But, as MP suggests a 104 ICL

-------open------ close-------
int: 32* BTDC, 60* ABDC
exh: 64* BBDC, 28* ATDC


But, Racers in the know, set it around a 100 ICL

-------open------ close-------
int: 36* BTDC, 56* ABDC
exh: 68* BBDC, 24* ATDC


See how Strait up works with symmetrical cams. With the Piston ATDC, the cams intake and exhaust lobes are centered as well between Max lift so the opening and closing numbers events match but on opposite sides of the pistons TDC