New Motor for RF GT40

[Ron Earp]

Well, as some of you folks know I re-thought my philosophy on a GT40 engine and of course some of that was influenced by my favorite topics, transaxles. Since I am committed to trying and Audi box and learning once and for all "does it work or does it not" I was stuck with the gear ratios and needed a motor that can turn RPM. Also, in the last couple of years I've become involved with wheel to wheel racing I have sort of changed my slant on the car from street to track, hence the sell of my build and purchase of a turnkey minus more suited to track work - brakes, cage, etc.

So, to that effect I decided to rebuild and be done with it all in one fell swoop. I speced out a high RPM motor that had all the goodies and bits to handle the 7500-7900 RPM range and not fly to bits. I picked up my motor from my builder this morning, paid a hefty bill, and took off! However, I think the motor is a good one and here are the basic specs:

342 inch SB Ford
AFR 185 heads, custom CNC porting job
Forged crank, now zero balanced
Forged Eagle H beam rods
DDS main support and windage tray with crank scraper
Comp Cam cam Specs:
0.676" lift IN, 0.673" lift EX, duration at 0.020 287IN 295EX
Timing @ 0.050" IN Open 18 BTDC Close BTDC 58
Timing @ 0.050" EX Open 61 BTDC Close BTDC 21
110 Lobe separation
Comp Cam Valve springs and titanium retainers, 600lb open, 260lb seat
Jesel Comp Series Shaft rockers
Jesel Pushrods
Jesel Keyway solid roller lifters
Ferrea Hollow Stem Intake and Exhaust Valves, 2.02/1.60
Total Seal rings
ARP 1/2" head studs, ARP hardware throughout motor
ACL 3/4 grove race main bearings

I am worried that the 48mm webers won't cut it for flow though. I think I'd asked that before and folks indicated that it'd be on the edge at round 7000RPM and choking beyond that.

 

[JOHNBGT40]

I am basicly /ubbthreads/images/graemlins/ooo.gif running the same set up on my Shelby. You will need to change the chokes to 50 mm. you will definatly run lean with 48mm chokes.

 

[Ron Earp]

They won't take 50mm chokes though, correct? I was thinking that was a fairly serious modification to webers, but can't remember, maybe that was 52mm.

R

 

[Ron Earp]

A picture of motor number 2

 

[Ron Earp]

Motor #2 valve train

 

Looks good Ron. Did they dyno it? What was the hp and torque?

 

[Ron Earp]

This particular one has not been dynoed, but the one that Billy built that was just like it two months before (but with less nice valve train) made 538 fwhp at 7400RPM. However, that engine used a Demon carb and I am thinking the Webers will not perform as well as the Demon. Don't know why, I just have a feeling.

So, right now I'm sort of thinking of various options on how to fuel this thing. Getting webers large enough (seems everyone thinking the 48s won't be enough) would be expensive as the 52mm and larger bores are all custom jobs that cost a bunch of cash.

Injection is looking like a reasonable option since it'd be no problem to get large chokes like what Paul and Roy have on their monster. But, as I've said before, I just don't want all the wiring and mess cluttering up the engine bay as well as the associated pumps, returns, selector valve, etc. I'd love the tunability because I really like messing around with injection systems, but not sure if I want one. Seems I like working on other people's injection systems better!

And lastly, a 4bbl would probably work well and offer great drivability and hp. But, they just don't look the part. Hate to say that, it is a silly reason and I know it, but looks are a large part of this car and the 4bbl doesn't complete the package.

So, now what? Someone convince me of what to do!

R

 

[Dan W]

Ron sounds like you already answered your question. Gotta have the stacks, dont want wires , but dont want to machine them up. Looks like your done with the top of the motor. LOL
Dan

 

Blessed Moderator,

It looks delicious!! I am happy to hear that you succumbed to Bling and kept the pierce’s 8 Stacks. I have the same exact set up, also 600+ lift and short duration. Wait till you jump on it, it will be awesome.

I am about to get a job (very sad)!!! /ubbthreads/images/graemlins/frown.gif Once I get my first paycheck, the car will be strapped in for a dyno run.

I am with you on the issue of Webbers Vs demon/holley . But trust me, you open that engine bay and they are gone go wild over those Webbers. /ubbthreads/images/graemlins/cool.gif

Praise be upon your stacks
/ubbthreads/images/graemlins/shocked.gif

 

[Ron Earp]

They might have to be machined, I just haven't looked at the cost. Then, there is the IDA vs. IDF thing, might be best to get the IDAs, although the same size oriffice would flow the same through either I think.

R

 

[Paul Thompson 'Hooligan']

Hi Ron
Great looking motor! - treat it right - go injection.
Yep I'm biased, but you really don't have to have a messy engine bay just cos you go injected. If you batch fire the injectors, the loom comprises just 5 wires for injectors, plus another 5-7 to cover sensors. The loom I made for Daves R42 terminates in circular Multipin plug so an engine removal requires a twist of the wrist to disconnect all injection electrics.

As for plumbing - if done at start, its easier. Fit a balance pipe between the tanks, draw from one, return excess to the other, if tanks have not been made you can even incorporate a swirl pot area at the rear of the tank you draw from, so no pot needed between tank and engine.

Ignition can be as simple (but still mapped) with dizzy, or as complex (8-coils) as you like. We used to fire an MSD 6AL using the ECU output. Worked well right up to 8000rpm limit we used - no worries...

Look upon the injection as a long term investment, you may rebuild the motor a few times, but you can always tweek the ECU to suit changes to spec, or even characteristics depending on what type of event you enter. If you don't want to go down the Kinsler indvidual throttle body route, then look at a billet 4 barrel body. Daves Edelbrock item fitted to his R42 will flow up to 1000cfm, is low profile and is so simple in design is very unlikely to fail.

Do it right - you know you want to! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

Ps - since your Festival of Speed visit I've cured the miss-fire on my Cosworth (new plugs /ubbthreads/images/graemlins/blush.gif) and used it taking Rodger to the Revival each day - first time I booted it in 2nd/3rd - Rodgers response was "bloody hell, this is flippin quick" and I must say the 'GRIN FACTOR' has increased ten-fold. Holds 25-28lbs boost now right the way up to the rev-limit - Happy days!!!! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

I'll also forward this thread to Rodger as his stroked 351 (408)/AFR185 motor runs 48IDAs with I think 42mm or 44mm chokes at present which must surely not flow enough at higher rpm??

 

[Mark Worthington]

Sweet setup, Ron. Are you using a stock block? If so, how comfortable are you that it'll hold together at 7500 rpm? The main support, zero balance and light valvetrain will ease the strain on the block, but still...

 

[Sandy]

Ron -

I have a question on your motor, what compression did you end up with (might have missed it)? Also what was the thoughts on your how you got to your selected camshafts?

The reason I ask is that for the last couple of motors I opted for Lobe Seperation in the 108 degree range on similar motors (331's, 4bbl, and more compression??) vs. 110 Lobe Centerline that you picked.

Maybe a combustion engineer can chime in (Hint).

I am just getting another motor together with one that has 106 Lobe Seperation, and a bit longer duration, but the others that I have used are somewhat similar in duration but with valve timing different.

Both used same heads, pistons, cams were put in as advertised.

Cam 1- .644"I/.643"E 258/270 @.050 CL108 Max power 530hp@7000 750cfm/super victor intake, Doug Herbert J6H, engine had bad leak down in half of the cylinders (one to 12%) due to lame machine shop and rusted cylinder sleeves.

Cam 2- .691"I/.673"E 257/264 @.050 CL108 Max power @7000-7500 (568-570hp) 850cfm/ported super victor intake Comp Cams custom from Total Engine Airflow. Same motor, new pistons .032 over /ubbthreads/images/graemlins/smile.gif

Maybe a simpler way to ask, what are the benifits of going larger center line vs smaller?

BTW on the injection I placed an order a bit ago with your advertiser (Top End/Weber Carbs) and about the only logical reason that I could convince(justify) to my self is that it just looks good on a GT40. I would be very surprised if the carb does not out HP the injection or webers... But it just doesn't look as good. I'll get it going on a carb as a base line in any case.

Sandy

 

[Ron Earp]

Sandy,

It is right at 11.5:1. I really didn't come to select my camshaft, Billy did based on experience with the grind and discussions with Comp. Billy liked the fact this one made great power and idled well. It seemed to work on the other motor, so he went with it. Was some power left on the table? Probably, but it is more than enough.

I might do what you are planning - get a used intake and carb for baseline and getting the car running, then put the webers or injection on.

Paul, you are completely correct on the injection, it'd be a good thing. Robert's tanks are already setup with pultiple ports and a swirl pot built into the right hand tank separate from the fuel tank, it is just on the end. How big are your throttle bodies? And how much hp can you get to the ground with them? How much cash would I need to budget for a complete injection system using a dizzy? I've got the MSD 6AL and dizzy already, good stuff, so I'd like to stick with it.

Mark, the block is not a high dollar one, just a Sportsman block, but I think it'll live. Plently do drag racing with more power, but if it breaks we'll learn something. I prefer to just do it and learn, than bench race it to death. This motor and car will be used on track and used a lot, so we'll find out a lot about the block and transaxle and hopefully put some hearsay to rest on both.

 

[Paul Thompson 'Hooligan']

Hi Ron

Roy's throttle bodies are 2 1/4" or 2 3/8" I think... so about 58-60mm. They were initially installed on a German touring car that ran a 351 Ford so Roy picked them up 'as new' but secondhand.

Not sure what TBs would cost, but fuel rails ($30 each), 8 injectors ($350 ish), sensors ($100), Pressure regulator ($100) and ECU ($1000?). So I guess about $1600+ for all bar the TBs but this is a guess. If you want a Motec, or use top notch injectors expect to pay more.

Over here (UK) its not too cheap unfortunately, but I'm guessing you have a few more options over there.

Re putting it to the ground, well this year has not been a good one for us, problem after problem, including the demise of the Alloy block. We now have the 4-bolt A4 Steel block back in at 5L and incorrectly mapped, Roy managed a 12.7 @ 125 to Rodger Burstons 12.32 also at 125mph.
Rodgers motor is a stroked 351 (408) with AFR 185 heads, 48 IDAs. Personally I found the 347 easier to drive, far more progressive and loads of low down grunt. The A4 motor has far less torque available but then all hell breaks loose when you reach about 5k rpm - Not so good for hill climbs...

 

[Ron Earp]

Paul, good info, I think your A4 motor would be great for road course, which is sort of where I am aiming since we don't have so many hillclimbs over here. I've emailed Robert for info on their TB diameter. Top End says nothing larger than 42mm chokes in IDFs and those are too small I am sure. Therefore, they might be out.

My goal is to have the car running about 60 days after I get it, and the best way initially while sorting the chassis might be to go second hand 4bbl and intake to get things started. There will be far more chassis sorting issues than motor issues to start with so I can get get her running and go with the 8bbl later. If RF has a EFI setup that will handle the motor then I might go that route, but I have that old Italian disease, "myfundsahlow", so I'd have to be careful on price.

I bet Rodgers motor will pull hard though, but I also think his is choked up a bit with those chokes, he might have Roy and yours milk money if he gets that thing breathing well!

That Cossie you have is damn fast - 28lbs is a lot and I bet it makes the power now! We recently cranked a little boost on the Lightning and got it to produce 551 ft/lb on the dyno at 12lbs boost. I'm conservative with it since it is my daily driver, I'd imagine that the Cossie is making a good bit of torque and power as well.

 

[Sandy]

Ron, if you need a loaner SBF 302 Victor Jr. I have one that is not being used that has some port matching that would work good as a get it going thing. If you need it please give me a holler.

Yes the black art of Cam selection, about all I could dig up on the web was that Idle and low end vacuum is better with larger lobe Center Line Spacing, and peak cylinder pressure is reduced a bit, opposite for narrow. Much beyond that I looked around and found many boost/nitrous/later model stuff with wider lobe centers, circle track and drag more narrow. Will have to twist Fran's arm for that info I guess...

Paul, what happened to the Alloy block? I run the SVO in the mustang might be interested to hear about it if it can save an entry in the 'Learn from my mistakes' book.

Sandy

 

[Paul Thompson 'Hooligan']

Hi Sandy

Semi self inflicted wound really.... We installed a Davies Craig water pump, removed the original pump altogether and plumbed the motor such that water would flow into each side of the block and then be removed from the front of each TFS head via fitting covering the front core plugs on each.

Anyway, due to a few goofs on our part, we did'nt get either the flow correct initally, or the system fully bled.
This in turn led to some serious overheating and a first blowup - AMOC Sprint at Goodwood where the Drivers side head gasket failed. Ever since we had problems with more overheating and water leaks and pulling the motor apart, we dicovered the block has cracked in centre, horizontally, either side of the valley - basically where the arp studs bolt into the block - which would also explain why the head bolts would not torque above 95ftlbs...

I'll take a few pics and post when I get a chance..

We have also dicovered that many 'RACERS' apparently do not allow Alloy blocks to get above about 75C as the metal 'softens' if it gets too hot - although I am no metallurgist so perhaps someone more knowledgeable can speak up?

Fitting the TFS heads to the old A4 block was interesting too, as Roy had fitted 1.7:1 Rockers for increased lift on the 347, which now gives even more lift than before on the A4 as it runs a wilder cam....

Still, Longleat this weekend as a season closer and then we can pull everything to bits again - don't you just love em! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

ps - sorry to have gone a bit off thread Ron!

 

[Sandy]

Paul -

That was a costly mistake! I was about as bad, ran the motor about 245F (120C) water temp for the bulk of the weekend, and finally dropped a valve due to bad driving and bad valvetrain. This was about a year ago. Motor back in place and seemingly doing ok, will have to see if it survives yet another abusive weekend. BTW it always runs about 205F (95C) when running on the track on cool days.

In anycase that was a costly addition to the 'book of knowledge'.

Post some photos when you get a chance...

Sandy

 

RON,
Don't agree ,IDA's weber flow 330 cfm on each barrel with 42 mm choke,tested back to back holley vs ida's on 289 and 331 see my posts on dyno result section,weber surpass holley on torque and power
Regards
Bernie