Rocker ratio questions

What are the benefits of going to a 1.6 or 1.7 rocker ratio versus just getting the correct cam to start with. Is there some sort of mechanical advantage with a higher ratio rocker?
It seems that hardly anyone runs a 1.5 rocker anymore judging from some of the builds I've seen here.

Gus

Never mind

The higher rocker arm ratio gets the valve off the seat faster. (higher acceleration for the valve)

The question is do you need to get the valve off the seat faster for your build? If you don't then there isn't any point in the higher rocker ratio. You'll just be beating on the parts harder without making more power.

Most of the builds on here do not need a high ratio rocker arm but there isn't necessarily anything wrong with using them as long as they matched with the correct cam. A typical Mopar bracket type big block engine can easily make 600 or 700 hp with the factory style 1.50 shaft rocker arm setup.

If you're looking for 1000 hp then you'll most likely need to ditch the shaft rockers and use a higher ratio.

The only way to know for sure if you could use
a bigger ratio is to test it by tightening
the intake lash some.. I run a tighter lash
on my engines.. thats cheaper than buying new
intake rockers.. I have never seen the engine
make more power changing the exhaust ratio
unless its WAY off

I see this consistently from guys that have a lot of experience, so I trust it to be true. But it begs the question: why does every split pattern cam I’ve ever looked at feature more lift and duration on the exhaust side of the equation?

I’m planning on going from my current 1.5 to 1.6 rockers this winter for the following reason: last year I had my heads ported and prepped, and the flow sheet says they continue offering more flow well past .650 lift while my current cam offers net .555 lift. My theory is that in my case more lift and effective ramp speed should benefit me (??). The rest of the combo (carb/intake/exhaust) should also adequately support more flow. Hopefully we’ll see if I’m correct.

My W-9 heads were known for having good exhaust flow and
I had the rockers to change over so I did.. the car didnt
show any change with just the exhaust.. all I can say is
test it and see

First, most split pattern cams I have used may have more exhaust duration than intake, but always have less lift. Second, if your heads can handle more flow than what you are creating now, than a 1.6 rocker will help. Higher ratio rockers not only give you more lift, they also give you more duration at valve, without creating more motion from lifter or pushrod. Most "Other" brand engines, and even later Magnum engines all use ratios higher than 1.5 these days on production engines. So there is something to be said for higher ratios. My last 500 cid build had Indy -1's with Jesel 1.7 rockers. The cam I chose was based on a BBC grind, that also used factory 1.7 rocker ratio.

I spent a bunch of time and money last year testing rocker arm ratios. The answer is that your engine only needs what it needs. Adding more rocker arm ratio or more duration to the cam doesn't add any power if the engine doesn't need it.

Based on my testing I'm pretty confident that a person can build a 700 or 800 hp BB Mopar with 1.50 shaft mount rocker arms and cam lobes right out of the catalog.

https://www.hotrod.com/articles/trying-find-extra-power-rocker-arm-testing/

This is definitely one of those “ it depends” items.

My flat tappet cam lobes are worn and I'm replacing the cam with a hydraulic roller. There aren't many off the shelf grinds available and before I either get one custom ground or buy off the shelf I wan't to know if I should add new rockers to the build. My current rockers are some good old 1.5 Isky's with the premium service from RAS. They are working perfect on my old cam but will they be good with my new cam?
My combo
493 10.9 compression Wiseco Pro-Tru flattops
Indy EZ heads std. port with some clean-up and valve job by Nick Wilson. They flow 319 at 600.
My car is a street/strip deal that runs 10.91 124.6 at 3640#
I wouldn't mind a 10.50 time slip in my glovebox. I think I can get more out of my combo with just a valvetrain change.
My old cam was a Comp XTQ series 292-312 grind.

Thanks
Gus

If you liked how it ran with that 292/312 flat tappet then you could swap in a XR292HR-10 hyd roller and it should be close. If it was me I'd probably go down one size on the cam for street driving and use the XR286HR-10 but it really depends on how you drive the car as well as gears and weight and how well the carb is dialed in.

For street cars we've been using the XR280HR cam in the 500 inch stroker engines. That cam is a little small for drag racing, but it sure makes them run nice on the street. 600+ ft-lbs of torque down low and they'll still make 550 hp at peak. In your case you might want a little more top end power for drag racing.

I think your existing rocker arms will be just fine with a hyd roller cam.

IMO, your rockers are fine for what you’re looking to do.

Hyd roller vs solid flat tappet for an ET improvement?
I guess we’ll see how that works out for you.

I am not saying to run a hydro roller, BUT, I went from a solid FT to one in my 512, used one from Hughes, 9.7to one, 4050lb street car,
solid cam was 248@.050 116 mph 12.03 2200 DA
Hyd roller 255,258 @ .050 121 11.33 mph 1750 DA Short shifting 5500, easy pass
but I used the expensive High RPM Morel.
Still need to do some track tuning.
also had better rear tires for the faster pass

Your Rockers are great, BUT I also went from 1.5, to 1.6, not saying it had anything to do with more power

Well I wish I didn't have to do this deal at all but my old cam gave up after about 5 years and I don't want to go flat again.
I checked on Morel rollers and they were over a grand and that's just a little much for my build budget.
I'm probably going with a Howards cam and lifters they have better reviews than Comp Cams do.

Gus

Morel has 2 versions, I think the Howards are the less cost Morel from what I have been told

Check with Gaterman for pricing. They have really nice looking hyd roller lifters.

Considering the RT weight, it would be nice to fit a 3/4" pushrod in there for the extra spring load...

Maybe I am just too old school, but I don't see the advantage of going HR versus FT solid cam. A solid cam may be a tic noiser, but a few thou tighter on lash helps. plus they are cheaper by a bunch, and allow you to see any problem early on in the valvetrain. Valve lash changed a bit? OK, what caused that? Something is wearing. Easy to find. HR adds two areas for failure; the roller wheels, and the hydraulics.

I agreed with everything you just said, until the tool steel solid FT lifters started eating up my camshaft lobes & I had to go back through the engine, I just hope the hydro roller holds up, so far over 2k miles & all is good.

Thats exactly how I found two of my lobes were going round as my lash went wide after the engine got pretty hot.
People tried telling me to go roller when I built this engine but I wanted to keep it simple. Roller technology has come a long way in the last 5 years with so many people putting them in street cars now.
Going back to a flat tappet cam would really save me a TON of money and work and it's not completely off the table yet.
I have considered getting a nitrided cam and EDM lifters then I could keep my oil pump drive,timing chain and cover,pushrods,springs,and retainers.
Those are the ancillary costs of switching to a roller.
So still trying to talk myself into it or out of it

Gus

Gus I run these Hughes roller tip rockers that are 1.6's. But I only went with them because I got them in a trade with my brother and they were like new when I got them. The FT cam I run that Dwayne built for me was perfect and I would have run the 1.5 rockers if that's what I had. That said these Hughes rockers have been flawless as I have run them since 2011 and rarely do I need to adjust them when I check my lash once a year. I like the ductile Isky rockers you run now. Good luck with her Gus what ever rockers you decide on. Ron

What RPM do you turn the engine? If you aren't spinning it past 6200 or so then the hyd roller should work just fine. If you have deep gears and are running it thru the lights at 6800 or higher then you might want to stay with a flat tappet cam. The EDM lifters might solve your problem and/or add the nitrided cam.

Gus, Just curious...... what are the springs pressures you were running with that cam, and what kind of oil?

Any idea of how many miles you put on those parts during those 5 years they were in the motor?

I just got off the phone with Bill Gaterman and he answered a lot of my questions about his lifters. They are making a new run of improved lifters that should be done by the end of next month.
He also confirmed Howard's Cams uses their lifters under the Howard's name.
I shift the car at 6000 and usually trap at 6500. I still use the Edelbrock Performer RPM so I really don't feel it pulling much over 6500. The thing I still don't understand is why do roller lifters with a bronze bushing cost more than roller bearings.

Gus

Did he tell you which part number Howard’s lifter for a BB Mopar application are made by him?

I am running a set of Crower springs 177-486 and I have been running Brad Penn since I broke it in about 5 years ago.
I was hot lapping the car trying to dial in an Edelbrock carb to run in NSS and it went over 260 degrees and thats when I noticed the clattering from the valvetrain. Pulled the valve covers off and confirmed #4 intake and #8 ex lobes going flat with a dial indicator.
Maybe the oil got thin when it got hot

Gus

No but he did say they were the same as the AMC lifters.

Gus

Sooo, 177lbs on the seat, 486lbs open?

That’s way too much for a street strip car if you’re trying to make the cam live...... especially if you’re only turning it 6500.
Those are mid-level street roller pressures.

And, that’s more than what most of the street/strip type hyd roller lifters are rated for.

I read a very scary article about how oil viscosity affects engine life at start-up: 20W50 takes about a week to reach that last tappet...

http://tinyurl.com/ycbdktsg

WOW that was a lot to process The engines I deal with at work with VVTI have a high volume oil pump with large galleys and that 0-20 synthetic oil really does the job.

Still have to sleep on this flat versus hyd.roller cam debate in my head.

Gus

These are the lifters I have, note the spring pressure




Return to Parts List

Category : D- Big Block (Low Deck) : Lifters

HUG 6074

BB RACE HYDRAULIC ROLLER LIFTER SET

GOOD FOR UP TO 225# SEAT PRESSURE & 550# OPEN

$919.47

Set of 16 Big Block Hydraulic Race Roller Lifters. These are oil thru lifters and will oil through the pushrods if you need them to.

Suggested maximum spring pressure: 225# on the seat 550# full lift

DO NOT RUN OIL THICKER THAN 5W40 WITH THESE LIFTERS.

.810" roller

* The lifter bores do not need to be bushed to run these lifters.
* DO NOT use these lifters with a flat tappet cam!



Note: These lifters also fit the AMC V8 engines.

These are the less money ones

HUG 5319

BIG BLOCK HYD ROLLER LIFTER SET

GOOD FOR UP TO 160# SEAT PRESSURE & 380# OPEN

$449.95

Set of 16 Big Block Hydraulic STREET Roller Lifters. These are oil thru lifters and will oil through the pushrods if you need them to.

Suggested maximum spring pressure: 160# on the seat 380# full lift.

For race applications with heavier spring pressures use part # 6074

10W30 oil recommended.

.700" roller

* The lifter bores do not need to be bushed to run these lifters.
* DO NOT use these lifters with a flat tappet cam!



Note: These lifters also fit the AMC V8 engines.

If you stay with a solid, and stick with spring loads like you posted....... expect cam life to not be all that great.

I read that article. Love the fact the author pointed out oil doesn't have a "weight" but has a "grade".

One thing I read that I'm not sure of is the author said that synthetic oils don't have VI improvers. I'm not sure that is correct. If I have time tomorrow I may make some phone calls and ask around about that.


Other than that, that was a great article.

On your deal I would of look for between 140 to 170 lbs. on the seats sand from 325 to 375 Lbs. open

Avoid nitriding your cam .
I had mine nitrided brand new at start of 2017 , block split May 2018 . When I pulled cam I was going to reuse it . BUPBOW , surface failed . This was with about 3-5000 street miles and a lot of racing . I was told the heat process softened the core so the surface was hard but brittle. It started to breakup .
got a new cam last week ,not nitrided
will post a pic off my phone if possible

Tex

By the way the lifters were still like new , Howards EDM

Tex

Dwayne had my FT cam nitrided and I use the Comp EDM lifters he sent me with it. Its been flawless as the cam and lifters are still working great after almost 8 years. Ron

Mike Jones posted some stuff about nitriding cams and IIRC he wasn't much for it because as was mentioned it cause the core to soften.

I don't have issues and I don't even run lifters with holes in them. I think idle speed and oil flow have a lot to do with cams going bad after surviving break in.

I see guys letting their stuff idle down to 700-750 and that's just too slow for fast ramp cams IMHO. My cam will most easily idle at 750 but I cringe if it drops below 900. There is just no reason to let the lifter drag over the lobe.

That's what kills the lobes when new if not started correctly. That slow lifter rotation (or none at all) kills them. Prolonged slow idle is not good for them.

Also, the oil pressure and flow is way down at those engine speeds, even if you use a HV pump.

I have my idle about 1000 in gear because with my converter it drops to much if I lower it much more. I had Dwayne nitride my cam because he did recommend it and I felt the EDM lifters with the oil hole on the bottom sounded like a good idea. And so far its worked great since I first fired her up in June 2011 . Dwayne also recommended I stay with the flat tappet since I told him I plan to drive it a lot on the street and did not want to pull my lifters at 3000 or more miles to have them checked over if I had gone with a solid roller. And of course I don't have to run all that spring pressure and change my springs as often as a solid roller as my springs are about 140 on the seat and around 350 open. I admit as I get older I like having to do less maintenance on my car. In my younger years I enjoyed it more. Now my mind enjoys it as much but my body not as much. Its a bummer getting older. LoL. Ron

https://www.bizol.com/company/education/lubricant-knowledge-base/why-synthetic-motor-oil/

If the synthetic oil has a viscosity index that is high enough, VI improvers need not be added. In any case, synthetic oils need much less VI improver than mineral oils.

The problem with VI improvers is they tend to shear down with use and lose viscosity at high temperatures. Years and years ago GM had a problem with people using 10W-40 with subsequent engine failure. That was late '70s early '80s. They determined that the VI improvers were coming apart under high stress loads, like in the 350 Diesel, and the oil would lose viscosity and allow metal-to-metal contact. I believe there was even a warning put in owners manuals that if using 10W-40 oil, the warranty was void.

R.

I just read the first bit as I don't have time to read it all right now.

The curious thing is in Germany it's agains the law to palm off as synthetic oil stuff that is NOT synthetic. I've never seen a real Group IV synthetic oil work with alcohol fuels, but the group III oils will. That's because they are not really synthetic oils.

It also stated that Group IV oils (PAO's) are gasoline based. I thought they were natural gas based or alcohol based. Again, I have to check my sources. I may be confusing the Ester based stuff with PAO's.

The reason why it's legal in the US to call an oil synthetic when it isn't can be traced to a lawsuit that went to SCOTUS and a bunch of moron judges who've never lifted a hood let alone looked at a can of oil for purchase decided that refined hydrocarbons are indeed synthetic!!!

That literally makes all oil a synthetic of sorts. The courts should have stayed the hell out of it, but there was money to be made (I should say money to made by the snooker) and in the end, the big money paid enough to grease the skid and make what is not, real.

Judgments that cost an industry (Dow Corning) billions, no proof offered as to causation: silicone breast implants.

My Engle flat tappet cam is going on 10 years now with no issues. I use the matching springs from Engle, they are doubles and offer 150 & 350 lbs respectively. I’ve been using Lucas “HotRod” 10w-30 along with a zinc additive for years, after breaking it in on JoeGibs BR-30. I used to see a lot of posts about cams going flat, but not so much anymore. I think for a while the oils were not up to the task, and many of us were uneducated about it. Now most of us understand the differences in oils needed to run a flat tappet cam.

Why not a solid roller, less weight and you can still do pushrod oiling...and the cost is not through the roof. Tim

An auxiliary spring does most of what a hydraulic does: take the slack out of the valve train so the roller needles don't come crashing down constantly at idle. Getting the roller up to speed every time it touches down is a bad thing.
Don't thank me, the idea is pre-WW2. Why not now? It costs $8.00 on a production line that the stockholders don't get.

I seem to remember all the cam company having to buy imported solid flat tappet and flat tappet hydraulic lifters as the real reason for all the cam failures back then.
I heard the cam companies blaming the removal of Zinc from the oils as causing all those problem I also seem to remember hearing that those issues ended up with Jonhsion (SP?) Controls getting back into making all of those better quality type lifter back here in the U.S.A Maybe I'm mistaken again

A solid roller doesn't like to idle,I guess not enough oil to the roller from what I've read. I was on the fence when I built this engine years ago roller or solid. From what I have researched the Hydraulic roller keeps constant pressure on the lobe instead of banging the roller every time the ramp comes with a solid roller.
I could be wrong but this issue has been beat to death on many many forums. I think I may be going back to a flat solid just for the simple fact I have other uses for $1000 and I like the way a flat solid revs with a stick car.
Now I have to pick a grind or have one custom ground

Gus

And........ buy new springs.

Hydraulic roller keeps constant pressure on the lobe
That's the idea.
Is there ever a point where the lobe shape is so violent that, at idle, oil pressure cannot keep the tappet inflated and it develops lash anyway? Who knows.

I forgot what they were called (brain dead today)…...rev kit ?? Where a spring is on top of the lifter to help hold it against the cam. I saw that setup on a Pontiac Super Stock eng back around 1970. I saw one on a solid roller car some years back also. But I don't seem to see or hear much about people using them kits today as they seem like a good idea. Ron

Yes, rev kit, Comp sells a weak spring specifically for this but you need a fixture to position the spring against the bottom of the head surface. It only adds about 30 lbs. to the tappet (but adds nothing to the valve side).
OEM on the Chevy L6 pre-WW2.

Tex013
from what I see that is a metallurgical issue with the foundry. Yes the lifters would be like new. Maybe even help their life in certain situations. Oil pocket holes in the casting to provide some backup supply.

Tex

Gus, I wish I was smart enough to know how to post a picture of my cam card, but I'm not. Here are the specs of my cam. It is a Scott Brown custom grind that has worked and is still working for me after almost 9 years. SFT cam.
LOBE .398/.395
LIFT .597/.593 with 1.5 rockers .633/.626 with 1.6 rockers
DURATION 259/266
C/L 109 INSTALLED AT 105
SPRING PRESSURE 145/350
I use 1.6 stainless rockers
I use Comp Cams spring 928. They have a seat of 135 and open at 375. Double spring with damper. This combo works very well for a street/strip heavy stick car. I also use Rotilla 15w40 oil, with STP.

That is almost my exact combination. Except I'm 105 on a 105 and my springs cam from Doug Herbert and mine don't have the dampener.

What is your seat to seat timing if you don't mind????

I really don't know. I do know that this combo is working fine for the way I drive my car.

68LAR I sent you a PM.

Got it and replied

Hey Larry thanks for the reply.
I'm looking at this one from Howards http://www.summitracing.com/parts/HRS-722422-08/

I still have some time to think about it

Gus

264/272 at 050 is going to be pretty rowdy on the street in a pump gas 500 inch engine. You can make it work with a low restriction exhaust and careful carb/ignition tuning but you'll definitely hear it coming.

His current cam is 264/270-108....... so he should be used to how that’s going to behave by now.

That Howard’s cam uses faster lobes, so it might be a touch rowdier.

Gus, With your car being a good 300 pounds lighter than mine, that cam may work well. I personally would look for a cam that has a power band around 3500-7000 or so. But that's just me. We all have our preferences. Like my post about 10 second street/strip cars. Lot's of different combos that seem to be working. Why have a cam that will go to 7600 rpm that your engine will never see? Combo, combo.. If I can offer any suggestions, please feel free to PM me.

I remember when choosing the cam for my 505 i think Hughes noted go about 2 cam sizes over what you would choose for a 440 . I have 258@050 in the 440 i went 272@050 in the 505 . Both have a softer/slower ramp , definately softer than a Howards grind
Cam choice is like choosing beer , each to their own .
But to initial question i like stock ratio with appropriate cam speced

Tex

From what I’ve seen..... with stick cars in particular....... is that “usually”a cam that’s a bit too small will run quicker than one that’s a bit too big.

This is what Scott Brown told me. I was running a MP590 prior. My car picked up a bunch after the Scotty cam was installed. Heavy stick cars are a different breed from auto cars. No insult intended. Just stating what I've heard and learned. Also, with my combo, I went to the 1.6 rockers and picked up a bit more. I run the 1.6's on both valves.

This is the hydraulic roller I was looking at
With Comp's Hydraulic Roller Retrofit camshafts, you can get all the benefits of the increased power which comes from a roller cam with the low maintenance of a regular hydraulic. Plus, there's no worries of the cam going flat, having to do the correct "break in" process, etc. After helping customers through dozens and dozens of builds, we found that Comp's largest off the shelf Hydraulic Roller just wasn't big enough for the 500 inch and larger engines running a good flowing (325+ CFM) head such as our CNC Stealth heads. We had many customers who had Comp custom grind them this particular cam, and it worked so well that we decided to offer it as an "off the shelf custom," keeping them in stock at all times for our customers. The .571" lift and 252 intake and 258 exhaust duration at .050" really lets the more serious builds reach their potential, while still having enough low end for some street use. These are ground on a 110 degree lobe separation angle. We'd use about a 3500 stall, and some decent rear end gears (3.55-4.10 for the street,) and a minimum of 10:1 compression. With this setup, we recommend our 145-1008 Hydraulic roller lifters, our 145-1014 springs, our 145-1003 retainers, and our 145-1002 locks (if you are using valves with 11/32" stems.) Also, this cam uses three bolt timing chain sets. We carry them (along with the required bolts, etc.) on our timing chains page. And, since this is Comp we're talking about, you can be assured of two things: The product is 100% made in the USA, and the quality is second to none. If you're planning on using this cam, give us a quick call so we can go over your build and make sure everything sounds correct before you pull the trigger.
It's a custom deal ground for 440 Source and it looks like a decent cam.
Gus

My cam from Dwayne is 264 & 270 @ .050 with .585 & .592 lift on a 110 LSA. I have it in the eng on the recommended 106 ICL. If you watch the video when they go to the back of my car you can hear how it idles pretty good but I did have it idling a bit high in the video. But the cam works great in my 493 driving on the street. It actually sounds a bit milder to me then I thought it would but I love it. Ron

https://www.facebook.com/moparmusclemag/videos/10155914655157792/

It’s just a phone call away.

Baddest cam at the drive in

Love the sound of that motor.

Comp's largest off the shelf Hydraulic Roller just wasn't big enough for the 500 inch and larger engines?
Tighten the LSA to 104.

Me too thanks to you. Thanks Dwayne , Ron

My cam is very close to that comp cam
[video:youtube]https://youtu.be/c4jgbv98adY[/video]

Since we are doing videos...

This was before mufflers, drag radials and I had the rev limiter set way low at 5500(?) as I recall.

https://youtu.be/FcKEEDBRwno

I only posted mine because my cams duration at .050 is very close to the 264 & 272 Andy was talking about. But I enjoyed yours and csk's video's also. Thnaks for posting them, Ron

I knew the 'Drive In" reminded me of something as it was the GTO commercial around 1970 about the GTO called the "Humbler". I now remember the commercial with the Humbler GTO cruising through the drive-in and hearing the exh right at the exh tips. You have a good memory Dwayne. Ron

Well I'm looking at another Howards cam 260/268 duration and 555/574 lift with 108 separation.
The lift seems a little low but the duration is where I think would work with my car.

Gus

252@.050 Engle KV3 idle at 900rpm.

Link: Satellite Idle

Gus ,
no thought on getting a custom grind ?

Tex

Close to the 259/266 that mine is, but with less lift and 1* less C/L.

open -------- close
int.24.5 BTDC 54.5 ABDC
ext.66 BTDC 20 ATDC These are the valve events of my cam.

With this, my power band is 3200-7200. Torq comes in around 4300.
My 2 step is usually set between 4600-5200.

Gus,
It seems you are liking Howards cams. See if this one fits? part number 721602-08. 260/260 .616/.616 lift on a 108 c/l. power 35-7200 rpm.

Well I pulled the trigger and ordered Howard's flat cam 260/264 616/620 108 LS and I think I will like it. Also ordered the Direct Lube lifters and some Max ZPM break in lube.
All in for $323.48
Still looking at springs,bee-hive maybe

Gus

Tex

Why so small? I run bigger in my 440.

I like your choice on that cam Where will you install the intake lobes?

I like that choice also. I think it will work out real well for you.