572 Hemi Saga

It's been a long time since I've posted here but I feel this latest project is Moparts worthy. Especially since there are so many G2 Hemi guys in here. While I'm certainly no Hemi guru I have been working on a 572 cube Hemi as of late. The story begins with a customer that has a '70 Challenger that he wanted a big bad Hemi under the hood or in this case through the hood. He had a local builder supply him with an ex race 572 Hemi which he swapped out the high compression pistons and big solid roller for pump gas street duty. Installs it in the car with elephant ears, crank trigger, external oil pickup, aluminum oil pan, 4-5 piece headers, electric waterpump, custom fabbed aluminum valve covers, and cross ram intake with Holley carbs. The engine he is told is good for 800-900HP buy the builder and off he goes. While in the car the customer never can seem to get it running very well and I don't think it ever went above idle. The carbs seem very rich and the whole car goes to a Holley carb tuner and this guy is truly awesome with a Holley. He goes through them and while he does improve the tune, a host of other problems really prevent the car from being driven. It is suggested that the engine should be sorted out on the dyno before going any further. Here is where I enter the picture.

On the dyno the engine looks every bit the part of a believable 800-900hp piece. It sounds crazy and looks crazy. I added dual wideband O2 sensors to my dyno recently and that was one big reason it came to me in order to sort out the fuel ratio/curve with the help of the Holley expert-GB. As expected it is very rich but we have to get a baseline so the first test is from 4500-5500 rpm. The carb linkage makes it tricky to open the throttle to WOT smoothly but the engine makes 700+ tq @ 4500 rpm. What happens after that is a bit of a head scratcher. The power falls off a cliff and makes less than 500HP with the little air cleaners installed. A backup pull is performed with no air cleaners and 740tq and a 40hp gain is seen but with the same power curve. I check timing and see it is @ 36 total and back it up to 32 and it picks up another 30hp with the same cliff jumper curve. I wanted to see what cylinder pressure was and performed a quick compression test =165 psi. We could hear some misfiring through the RPM range so we thought fresh plugs would help while I checked valve lash. The engine has a Bullet solid roller and RBRE rocker system--very nice stuff. New plugs were installed and no real changes to the power or curve is observed. We try a pull to 6500 rpm just to see and right at 5600 rpm the power makes a U-turn and heads upwards as the design of the crossram starts to shine-a best of 670HP is observed. I think we tried a few more pulls but we could not really get rid of the misfiring and time was running out as well. This was my second day working on it as it took me 6 hrs to hook it up on the dyno the previous day. The engine leaked oil at multiple places, I observed more blowby than I would like and the headers leaked too. Options were discussed with the owner and he was unhappy with several things so basically we were given the green light to pretty much start over.

He never liked the headers, the elephant ears, the external oil line system, the crank trigger,the gear drive or the valve covers, the sparkplug wires and nobody present was happy about the way it ran. I was given the greenlight to go through it and make the necessary changes. As I took it apart some interesting discoveries were made. In short we are keeping the block/crank/rods/heads/rockers/camshaft and maybe the pushrods. The block has a sleeve, the head ports were raised so radically that no intake will fit without some custom spacer work, the exhaust ports are welded to radically raise the floor, the pistons featured a very small dome, the lifters are Comp's entry level rollers, the water pump would barely turn by hand, the swinging pickup in the pan was jammed up, the crossram intake had lots and lots of work on it internally etc.....

Getting very very close to putting this back on the dyno and I think it will be a much different story. Some pics for your enjoyment. J.Rob

Promised pics, J.Rob

I elected to fill the intake port roofs. If you look closely you can see the previous port shape. J.Rob

More cylinder head work. I didn't think the heads looked right without a frost plug. J.Rob

Nice Diamond pistons with Total Seal AP/Napier ring pack. J.Rob

This intake is up for grabs if anyone wants to take a shot at it. J.Rob

Nowhere to go but up with that one.

Pretty much-a lot of low hanging fruit. J.Rob

I’m trying to figure out what the shiny ring around the chamber is?

Witness mark from the pistons contacting the heads?

Is the target to have it be in the 800-900hp range when done?

Heads and intake are old Super Stock stuff. I'd say that's why it became such a turd after changing the pistons and cam for stuff that was more street friendly. Looking at the heads and intake, plus your location; I can guess where the stuff came from... and everything you said/found with the motor makes much more sense.

I think its just the photo-No contact from what I can tell.

No 800-900Hp is not really the goal--Just a properly running engine. I'm sure anything over 700HP will be a win. J.Rob

Sounds like the valve springs are shot.....When ever the power falls off a cliff like that, its always been valve springs.

Was there something bolted to the underside of the intake ports?

I was thinking valve springs didn't sound happy as well. What are the pushrod specs?

The last pump gas 572 hemi I built made 800 HP at 6500 RPM on Oregon 92 octane non ethanol pump swill. it had around 10 3/4 to 1 compression ratio and a top end kit from Stage V heads from FHO along with one of there cams for EFI, Stage V single plane dual 4150 flange with a set of 1150 CFM dry throttle bodies with a Holley EFI kit from Rich at Fastman EFI
Nothing special in the motor as the car will have air conditioning, cruise control power steering and power brakes
This motor is going into a 1971 Challenger street and local drive to the local car shows car, customer wanted a "Hemi"
I call the 426 Hemi motors Hemiroids for a reason
Good luck on yours, they are basically a internal combustion motor after all

Yeah, looks like a bunch of obsolete super stock parts. The valve springs might be shot or perhaps that cross ram was just so messed up that it shuts the power off for a big chunk of the curve. Depends what the customer wants but a good single plane intake would probably solve most of the issues. Or something like the Stage V intake. Good luck sorting it out. Customers usually aren't too happy about spending money to fix the last guy's mistakes.

It did have hacked up self tapping screws in the runners--Maybe to hold port floor fillers? I dunno but they are gone and plugged now. J.Rob

Normally I would agree but this was different. I put the air hat on to see if CFM fell off at higher RPM's it didn't. I have also never seen valvesprings go away and then come back 500rpm later and hold on a further 1000rpm. J.Rob

Looking forward to seeing how it does after you fix it up! Seems like a typical thrown together w/ leftover obsolete race parts car show hemi. Looks good and sounds mean, but won't pull a greasy string out of a hog's butt.

That's a picture...

That is a new one
I'll try and remember it to use as a good example in a proper discussion on HP and torque

I'm just sitting here looking forward to the next installment.

Thanks, It's coming along nicely but now I am in need of some .070" thick head gaskets. The flat land of the piston is .028" above deck.

Any one know of some Cometic C5447-070 available? Or I am into machining the pistons a touch. J.Rob

Call Cometic, they will make them any way you want....

Harmonic spring distortion at that particular RPM? (probably not the exact technical term I'm grasping for)

Kevin

Jegs has them

Thanks for posting...everyone knows you're a capable builder and your cust is in good hands. So even though there is low-hanging fruit he'll be happy I'd guess.

Jegs has a ship date of Dec 21 for those. I can't stall that long. J.Rob

Not sure who would have the gaskets. When I ordered cometics for mine it took a month to get them.

Getting very very close to dyno time now. Hope it runs the way it should. J.Rob

How do you stop the picture from rotating 90 when you post? I've resized, rotated, saved, renamed etc.... It looks fine until I post it..What gives? J.Rob

Hope you changed the valve springs...

Yes, Love Isky springs--9365PLUS in there now. Hope they are happy in this combo. J.Rob

More times than I can count, when a Hemi engine won't rev, its been the springs. I think all the street miles on mine is the issue. Looking to put a spray bar in the valve cover for the intake springs. I like the carb setup, what size are those?

Did you happen to flow the heads before and after the filler work?

All ears

Yes, and I would be interested to know before/after port volume as well.

Ran into dyno issues, engine is healthy. They are 600cfm, flow 720 dry @ 20.4

Didn't flow the heads but they are no anomaly, probably 350-360 cfm. I added almost 10cc of filler.
J.Rob

I see you're running the marine intake. Are you planning on trying the stage V also? Interested to see the difference since I'm running a stage V currently and have a new marine sitting in a box.

Also a picture of bottom of stage V.

Thanks Mike

As for the pic orientation...... what seems to work for me, when uploading from my phone.....

Have the pic stored in the phone so it’s oriented correctly when holding the phone vertically.
And hold the phone vertically while you’re browsing the pics to upload them.

Sometimes I’ve had to rotate and save the pics, again........ even when they were correct originally.

Let’s try it with one of yours......

No plans to try the Stage V intake although that looks like a real nice intake-thanks for the pics. This gentleman just wants a real nice Hemi that looks good, starts/idles and can drive 100 or more kms on pumpgas--I'm sure he won't mind having enough power to boil the hides when the urge strikes. Thanks again, J.Rob

Thanks Dwayne, I just tried it and we'll see with the two pics I'm gonna post.

Yesterday was a bit of a struggle--I fired the Hemi on the dyno after spending the entire day and then some hooking it up on the dyno. It fired unbelievably quickly and I start running through all of my usual checks --terrified of of oil leaks especially the rear main on the B/RB's and all seems to be going well. My carb guy Guillaume Bordeau shows up as he went through the brand new carbs a month or so ago and we proceed to attempt a pull. I set the rpm too low @ 3500 and when I load it it blows through the absorber and just hangs at 5500 rpm. The torque doesn't look right at 651 ft/lbs so I know something is up with the dyno. Long story short I spent most of today (Sat) replacing the absorber mechanical seal and we get back into business by about 1:30 p.m. First test from 5000 rpm-5500 rpm is a success and we do bunch of other stuff like a plug change (was running the old plugs)--fool around with the widebands, etc....

Long story longer the engine runs really really nice--doesn't leak a drop of anything and I'm impressed with the cam the previous builder used. It makes almost 17" of vac @1100-1150 rpm (solid roller) We ended the day with 710-715 tq (probably 750 at peak) and 708 hp with awesome manners and consistency. I'd like to load it at a lower rpm and capture the actual peak torque but I don't think I will be able. The graph shows the before and after differences nicely. J.Rob

Couldn’t pull it lower after the seal change?

No lower than 4900 rpm. Any ideas Dwayne? I know you have an SF. I have the 871 absorber, it was far better but something is still off. I think it may be the inlet assembly valve not allowing suction. J.Rob

Does yours not have the low rpm/high load “boost” line?

Not that you should need it for that combo, but using it would answer the question as to whether or not it was an inlet volume issue.

Servo valve has full range of motion?

I wonder if a pair of shear plates would help with the power any. I wish I could try it on my 572. Glad you are happy with your build. Tim

That's a nice improvement. I'm sure the owner will be much happier w/ it now!

Really nice looking engine J, that should really make your customer happy.

One question, what are the cam specs?

I'd sure like to see it pull lower as others mentioned, but glad for any info at all.

Thanks

Impressive!👍

So I've been working on it since Monday. Yesterday I machined a coil bracket, lashed the valves, re-torqued the heads, compression test all cylinders while plugs were out--205psi across the board-150 psi first crank,hooked up electric chokes to +12v, removed the electric water pump, installed the serpentine drive kit and installed the MSD 6Al2 programmable. Warmed it up and made a couple of tests--its much stronger with an ignition curve in it--It is now about 20ft/lbs stronger and making 735hp and climbing. Going to disassemble the absorber today and try and figure out what is going on. I spoke with Superflow yesterday and they weren't a whole lot of help although they said my dyno should hold 800-900 ft/lbs @ 3000 rpm--which I have NEVER been able to do. I'm starting to wonder if this absorber had tight enough tolerances to begin with--we bought it new in June 2009. All I have for cam specs is a photo the customer supplied we with. Thanks, J.Rob

How is your water supply to the absorber?

My builder had to upgrade his pump and supply line to his Stuska to hold the GP Hydroplane engines he's building. The absorber is supposed to be capable. 15 hp pump with a 3" supply line. Also had to add air supply capacity to the tune of 8000 cfm.

Supercharged 468 on Methanol.

Should be loud...

Kevin

I wonder if you won't see even more power once the dyno is figured out. Seems odd it would essentially peak at 5500 and flatline from there.

Nice progress!

Jesse....... does your dyno have the boost valve?(I think all 902’s have it)

Does it not make any difference?

I haven’t dynoed a high torque/low rpm combo in a long time, but I don’t think the one here would hold 800ft/lbs@3000 without it being open.

Thanks!
That helps quite a bit, with the inevitable comparisons that come to mind.

Looking forward to the next installment

The water supply is way overkill in this case. I have a 20hp 3Ph centrifugal pump that I bypass a lot of water back to the 1550 Gallon reservoir to maintain 45 psi line pressure--I can and have cranked it up to 65psi+. It doesn't work that way with a Superflow anyways. The SF has a suction inlet which uses a little impeller to fill the absorber . You should be able to dunk this thing in a lake and have the absorber work properly. This particular model (871) absorber is rated for 2500 hp/2000lb/ft and so is the load cell. Thanks for the questions though Kevin. J.Rob

Oh yes of course I have the boost valve--I think all 901/902's have it because SF's crappy priming system never works all that well. So you fire and engine and have to run and open the boost valve and then close it. I've only ever had it prime a handful of times with out assistance. Oh and yes I've replaced the mechanical seal now 4 times in it's 11 years of use. The boost valve only seems to make a difference on smaller less powerful engines at least that I can notice. Oh and thinking back to EMC testing days--When the contest RPM was 2500-6500 I would always choose a smallblock and this dyno always struggled with 430+ tq @ 2450-2500 rpm.

Would you mind looking through some of your past tests of large cube combos and sharing your data and thoughts especially about the lower RPM end of the scale. I really think this unit should be capable of performing a pull from 3800-6000 rpm without any issue. I could be wrong though. I do remember being very impressed my first time at EMC (2009) with how easily the DTS could pull down our 471 TR to 2300-2400--and remember thinking "Our brandnew 902 couldn't do that I don't think" Thanks for the help guys. Maybe I should change the thread title to SF-902 Dyno Saga--since the engine has been flawless and the dyno has not. LOL J.Rob

The dyno here is a 1997 vintage 901.
When it was ordered then, the boost valve was an option.
The dyno shop I worked at in the early 90’s had a 1986 sf-901...... and that one didn’t have the boost valve.

The prime solenoid has a very small pathway through it, and gets clogged somewhat easily.

I don’t think it acted up on this one until it was about 12 years old.
I took it apart, cleaned it out..... and it worked fine for several more years.
I’ve done it once or twice more since then, and it needs to be done again.

Opening the boost valve on this dyno makes a very noticeable difference on how low you can pull the big tq/low rpm combos.

I almost never need to use it for the typical stuff I build.

I’ll see what we have for sheets with high tq/low-ish rpm.

The only thing I have handy is a mild 505 from a few years ago..... which was 592tq@3200....... and I didn’t use the boost for that motor.



I know we’d be able to do that here with that motor........ and likely without the boost.

As it turns out I do have a run here from a 572 wedge street motor with EZ 295’s on it, and about 10* more cam than your Hemi build........ from 3800-6100.
This run is with an ootb 337 intake and a Mighty Demon 850 carb, and my dyno headers.
Those are 2 - 2 1/8 x 4, so they’re not helping the numbers down near the bottom.
By 3800, the absorber is pretty happy...... so this is no problem at all.


The real high tq/lower rpm stuff would be something for a boat with a roots blower on it....... and I dont have any of those sheets here.
But I’ll see if I can dig something up.

One last thing....... and forgive the dumb question....... but I’m going to ask it anyway.......

You have adjusted the capacity valve...... right?

Well...... not necessarily.
The HP line is just math......... the TQ line is measured........ and the TQ curve is already dropping pretty steadily.
The only way the “dyno” could really be the cause of that is if the load isn’t being transmitted into the load cell correctly(which I suppose is possible).

That’s not to say the curve couldn’t be improved with “tuning” though.

Just seems odd to me it would have a nearly perfect flat HP "curve" over a 600rpm range (and possibly more if pulled higher)

Thanks for the help Dwayne that's awesome. That 57I2 of yours looks like Ron's.

Yes I had the capacity valve backed out all the way. Good news though toward all apart started over found the servo was indexed incorrectly and made a couple other changes. Dyno is working awesome now. Thanks for all the help. J.Rob

Glad you got it figured out.

Power numbers seem good....... with a vastly improved curve compared to the “before” combo.

The fuel flow dropping off at the top end seems a little odd though.
(Fuel cell running low?)
It was using a way more fuel on the first sheet you posted.

Let’s give this a try......

Very nice! ^ That is more of what I was expecting to see, a curve rather than a plateau.

Yes actually my 2.5gallon cell was very low on that last test and fuel pressure dropped to 3 psi. I topped it up but will not be running it again until Friday when the customer comes by to witness and load it up. Good eye. I have the wideband results on that test at the shop but it may not line up to what the fuel turbines recorded. Thanks again for your assistance. J.Rob

Did you perform any mods to the intake or did you leave it as shown in this pic ?

I’m speaking about the area under the carbs.

A carbide burr and sanding roll never went near it. Just bolted a 1/2" spacer under each carb for clearance. I wasn't really after ultimate power with this--It's just a street car 1970 Challenger --I'd like to keep this customer around awhile longer. J.Rob

Did manage a video earlier today. 572 Hemi/Dyno

Nice work Jesse,

Big improvement in the right direction. The power curve looks almost identical to mine ; peak tq @ 4500 & peak hp @ 6000. I'm sure the customer will be very happy. Sounds nice on the dyno ! Will you be running it again on Friday (Dec 11) ?



Ron

Yes running it tomorrow, the one and only dyno session the customer has been to was when this engine ran so poorly. This is the example in the graph and that was after a full day of chasing problems and the tune--It started out much much worse. It was safe to say he was disappointed. Hoping to make a much better impression tomorrow. Take care, Ron, J.Rob

K

Not criticizing the manifold, just trying understand why a similar manifold on a motor I did last year was fat.

I keep leaning this thing out and it kept making more power but I ran out of runway and had to take the motor off the dyno.

My BSFC looks terrible to me. No runner bungs for EGT, just one in each collector.

Well we did notice the dual widebands were nearly identical bank to bank under all conditions BUT WOT. Under WOT the Driver's bank was a full point richer than the Passenger side. I think its just a quirk of the dual plane design and I too have run out of time to explore it further. We had to richen this up a little and it seemed to make a touch more power everywhere but mainly to keep it a little safer for the end user. My carb guy is great and set these 600's up ahead of time so secondary fuel adjustments were easy. J.Rob

Very nice! It should be a blast to drive.

Here are the last few pulls. Went from 32 to 30 degrees, went from short to long clusters, raised the oil pressure from 50’s to 80’s (same pull that I went from 32 to 30 - shame on me for two changes for same pull). Notice the BSFC - fat no? EGT ran from 790-992, highest it got was 1029.

Thread derailment!!

In reference to Transmans post about the carb tuning and bsfc.
It’s not a good idea........ since its not directly indicative of whether or not the carb is rich or lean.

Example....... imagine the motor on the dyno, steady state run at 5000rpm, making 500hp, using exactly 250lbs/hr.
So, the bsfc is .500.
Let’s say there is a wideband reading in the pipes and it’s showing 12.5:1.

Now............we attach a big hyd pump to the front of the crankshaft.
One that uses up 100hp@5000rpm.
So, with the pump attached to the front of the motor(eating up 100hp), the dyno only registers 400hp on the load cell.

The motor is still actually making 500hp, using the same amount of fuel and air it did before, and is still the same a/f ratio....... but since the dyno only registers the power as 400hp(because there is a 100hp parasitic draw on the front of the motor)the bsfc is now .625.
But...... the motor is not running any richer.

Bsfc is an efficiency reading...... the result of measured power vs fuel consumed.
Nowhere is the ratio of air to fuel referenced to arrive at a bsfc number.

Sure.......”generally” high bsfc numbers track with rich a/f ratios, but they don’t always.

I have tested a number of motors through the years that really didn’t like lean mixtures.
You’d richen them up....... a/f ratio reading would confirm....... motor would make a big move in inscreased power....... bsfc would go down.

What high bsfc numbers are really telling you is....... you’re not making good power for the amount of fuel you’re using.

Most of the stuff I test doesn’t make the best power when they’re getting into the danger zone for being lean.
That being said, I usually tune for best power, while making sure there is some safety margin built in by erring to the richer side.
And then the bsfc numbers just end up where ever they are.
If the motor makes pretty good use of the fuel those numbers will be decent........ and if it uses a lot of fuel but doesn’t make great power...... the numbers won’t look that good.

Thanks Dwayne, since it was my first dyno session in my life and I have looked at many here I had to ask the question.

As I stated earlier, it kept making more and more power as I leaned it out but ran out of time.
Back in the day we did all of this at the track, no one had dynos.

I always start fat worrying about the starving child/children then start leaning out.

Are there fuel flow and hp numbers to go along with those bsfc numbers?

And no a/f ratio measuring during that session?

By looking at how much higher the bsfc numbers are at the end of the pull, I’d say you were probably running the motor at a high enough to see the hp curve start heading down.
Even if the a/f fuel curve is pretty flat at the top end of the pull, if you’re running the motor high enough to see the HP start falling off...... the bsfc numbers will start to go up.
The rpm is going up, and as long as the valvetrain isn’t doing anything odd, the air flow should still be increasing with rpm.
More air flow pulls more fuel in with it.
So, you have air flow and fuel flow increasing..... at the same time the HP is decreasing........ and the result is the bsfc/bsac numbers are getting worse.
You’re using more air and less fuel...... and making less power with it.
Even if the a/f ratio was perfectly flat....... the bsfc/bsac numbers would still be going up.

|Whipped up some fuel lines for the customer so he doesn't have to run flexible braided stuff-he didn't want that. J.Rob

Those lines look awesome!

Yes, very nice

Thanks, they look better in the picture though. J.Rob

Forming lines like that is a "acquired" skill, not easy to be taught in a class room

Motor was making more HP but stopped the pull at 6500. It didn’t stop climbing from 4K to 6500. BSFC climbed slowly as well. Pulled the stick when it made 612 HP. I’ll send you some info by PM - don’t want to derail again.

Thanks Cab I think-lol.

Today was definately one for the Win column. Customer came in, I hit the button for the electric chokes, pumped the throttle twice and hit the switch. Engine fired and settled into a nice fast idle of about 1800 rpm. Let it run while I monitored dyno water , coolant and oil temps, jazzed the throttle twice and the idle came off the fast idle setting and proceeded to warm up at 1080-1100+rpm. Made a couple of short pulls from 3800-5000 to put some more temp in the oil and made a couple more from 3800-6000 without shutting it off. Best pull of the morning came in @ 734HP @ 6000rpm. We were all curious to see what would happen with the little air cleaners on because the first time around they were worth 40hp without them. It was a pretty nice outcome actually. Oh and as a bonus I think I sold his old crossram and carbs for him. J.Rob

Well done...congrats

Just ran a 520 inch BB Ford on the dyno the other day. This is a street motor for a pickup truck. Low compression, small cam type of motor. It made 450 hp and used 300 lbs/hr at WOT. Worst BSFC I've ever seen on the dyno. Engine ran nice and smooth. Sounded great, had a ton of vacuum at idle. Owner will be happy with all the torque but I don't think he will be happy with his gas bill!

Quick video of the air cleaner pull. J.Rob

572 Hemi Air Cleaner Pull

Just out of curiosity, how would that type build respond to a good single plane intake? Either a big single or 2 - 4's.

Did the motor like or hate those air cleaners?
I've seen both results depending on the air cleaners used

subscribed

Not sure but it was 734HP without and 718HP with the air cleaners. J.Rob

On another thread I read that a single would be worth 30-40HP which seems reasonable. J.Rob

16 HP loss with the littles one
I saw a 20 HP increase on a 470 C.I. 440 motor with a tunnel ram with 2 750 CFM Jet prep Holley double pumpers going from no air cleaner to running two 9 inch tall velocity stacks with 10 x3 inch air cleaners mounted on the top of the stacks
The dyno operator said no way it would make more power with air cleaners on before that pull but the engine owner would not race it with them so we went ahead and tested them anyways and found out the dyno operator was wrong

if such a thing were available, would a 12 [or 14] by xx long by 3 or 4" tall single element [think inline hemi factory style element] hurt or hinder, compared to two 10x3" air filters ?
would there be too much turbulent air between the carb throats for an engine that big using such a filter element ?

I've stack two stock type Fram 6 pack air cleaners elements on one of my dyno testing session, two was better than one but both lost HP compare to no elements on that motor, that was on my old pump gas 511 C.I. 400 stroker motor with the Eddy low deck six pack set up on it
Running the air cleaner base made more power than not running it also