De-tuning my 2001 ilmor supercat 517
 

Hello all.
Figured I'd start a thread documenting my engine build for my 24-7 pantera project.

I bought a "mothballed" supercat engine from ilmor last winter. It's a 517 CI NA engine. 4.530 bore with a 4" stroke. The engine came with all top shelf stuff. Kryptonite crank, carillo rods, carr rod bolts, cp pistons, APBA brodix "spec" intake and 2plus heads, jesel belt drive and rocker arms, etc...... A really good starting point.

So far:
Heads have been hand ported (spec heads were run "as cast" per the supercat rules)
We kept the inconel exhaust valves but replaced the 2.300 titanium intake valves with stainless. I'll post some flow data later.

Intake has been hand blended and modified to accept my 4150 carb. We milled an inch off the top and re-drilled and tapped for the 4150.

The engine went to the machinist yesterday.

It has bronze lifter bushings and a 55mm cam. The cam is massive and useless to me. Bob will be the cam guy.

I want to try to save the pistons and have the dome milled down to kill some compression. The machinist has a fixture for measuring the volume of the domes and a fixture to hold a piston for machining. He says that as long as we have .225 thickness left after milling them we will be ok (NA engine).

So, the plan is to get the compression down to 9.5:1, call bob with the flow numbers and desired usage data and get a valvetrain on order.

Any thoughts?

10:1 , 93 octane, and go big !

Just got off the phone with the machinist. He's CC'ing the heads and piston tonight and getting a baseline.
I need around 120CC to be at 9.5 with a 4.530 bore and a 4" stroke.

Couple pics:
http://i205.photobucket.com/albums/b...ps05d0905b.jpg
http://i205.photobucket.com/albums/b...psf0d7e8e5.jpg
http://i205.photobucket.com/albums/b...psc7f22493.jpg

After measuring everything and doing some math, the engine is at 13.1.
Looks like we can mill .100 off the 13:1 pistons as the tops are .325 thick as they sit.

Most likely, I won't be able to gain enough combustion chamber volume by milling the pistons I have even with a thick head gasket. That said, it looks like I will be buying some new slugs.

On a side note, the exhaust is lightning headers with dry to the outlet pipes.

Just throwing this out there...you could run E85 and leave it. Depends on what type of boating you do. My brother is running it in his jet boat and loves it. Also, if your heads are aluminum (didnt read it here) you could get away with what SB said (10:1).

Why did you change the titanium valves and mill the intake?

Titanium valves are great for 8000 rpm racing engines that get the valvetrain replaced at set intervals.
I'm building a 6000 rpm engine that I don't want to take apart twice per season. The stainless are more durable and will last for a long time.

The intake was milled an inch (cast in carb spacer) to gain hatch clearance and to be retooled to accept the 4150 carb.

No E-85 for many reasons for me.

We will call bob with the cylinder head data and talk about compression ratio, max rpm and a valvetrain.

A .140 head gasket would knock off about 1 point of compression.

Well, I just talked to the machinist.
The bore is 4.540 and the stroke looks like 3.910. He's going to call baker and see if they have any records on the crank as they were the shop that serviced the crank and he found a "job" number on the crankshaft.

he talked to cometic and they do not recommend a thick head gasket in a marine application due to the loss of quench and the increased potential for detonation.

Also, talked to a friend at wiseco about a piston and they can provide a -14cc dome piston with the larger wrist pin and coated skirts. I believe it's a newer product they call "quick 16" series.

Leaning toward having new pistons made.probably a better final product and cheaper in the end.

I talked to cometic about using a .140 gasket I was worried about the strength of the gasket with a large bore because there isn't much between the cylinders. They said no problem the thicker the gasket the stronger. Then the tech guy started on me about the added quench area... My question to him was what kind of experience do you have in building large bore motors. His reply "none but I know it's not a good idea in a small block". I said yeah a small block not a big block with more than a 4.5" bore it's a different ball game. If it's an issue in a marine engine call Mercury and ask them why some of there motors are .100 in the hole. Ask GM why they have 502's .050 in the hole. Call Gene Fulton Sonny Leonard or someone that knows what they are talking about and ask them if it's ok to leave the piston .200 in the hole. Some people just have no buisness giving advice on what they have no clue about. What I have learned is calling most most manufacturers tech lines is a total waist of time and I'm better off consulting with my 2 year old.

I hear you on the tech hotlines.
That said, even with the .140 head gasket, I'm still at 12:1. Doesn't look like I can mill enough off the dome to get where I need to be. For the price of new pistons, I don't think it's worth messing with.

Baker says that brodix recommends a 4.540 bore to optimise the combustion chamber. The guy rembered quite a bit about the supercat program. He remembered the stroke being slightly less than 4".

Thanks for the replies. I appreciate all the ideas.

look into race tek pistons.they will make whatever you want.they are not cheep but you get what you pay for.

Thanks mike. I appreciate the help.

Update on this madness:

I ended up Calling carillo/cp and talked to a super guy in the piston division. He was able to pull up the original supercat job and had all the particulars available. He said they did the job for Pfaff racing. Must have been sterling for the east coast and Pfaff for the west coast. Anyhow, he had a "shelf" piston in their sportsman "bullet" line in 4.560 and with a compression height of 1.275. Great value as they come with the file fit rings and available with a .200 wall pin. With a 9.780 deck, a 124cc combustion chamber, a .050 gasket, the 3.920 stroke crank and the 6.535 long rod we came out at 9.9:1 compression. We can make the final adjustments after any decking the block and milling the heads with a thinner or thicker head gasket.

I'll say that mike at CP was extremely helpful and knowledgeable and treated a one and done guy like me as a valued customer.

Also, my buddy that will be assembling this creation emailed the cam information sheet to bob and we got a 55mm cam spec'd out. He has the quote but it was something in the neighborhood of 246/254 and 700ish lift on a 111LSA.

The block is at victory engines for a .060 overbore and he will be resizing the Carillo rods and balancing the whole deal when the new pistons arrive.

Just thought I'd update this thread in the off chance anyone is interested and following.

Love good threads like this , please keep the info coming!
Subscribed.

Sounds like a great build. Like picking up an sb2 from North Carolina and tweaking it to street drive in a camaro

The cam you spec'd sounds pretty mean, what was the ballpark lift/duration on the race engine? 13:1just sounds cool saying it....

imo,this will be a good running build that will have no problem running 93 oct fuel.i do believe going with a piston change was the only way to do it right.the cyl heads are not the best but i would have used them as you did.i think you will be pleasantly suprised with the dyno results and i hope you will keep us posted.

Cool thread!

Pull just a little timing out of it and 93 should be no problem.

Chris

thats the best route to go.

what kind of hp/tq are you looking for or want?

Isn't the answer to that always - as much as possible.

Thanks for the interest and replies guys.
Here's the cam doctor results from the supercat cam:

http://i205.photobucket.com/albums/b...pswrzgaoow.jpg

Just a tad too big. :party-smiley-004:

How many rom are you going to spin this thing?

6000 rpm max. 3500 to 4000 cruise.

That cam doctor is from the supercat cam, not the cam from bob.

well now we know what cam to run for 7500rpm.

very true but w/ a max of 10-1,,just asking.

In my case, I'm not going for maximum hp and torque. This is going into a 24 foot pleasure boat with a bravo drive. We think it will wind up at about 700 HP and 650 fT lbs of torque.

what did these motors make originally?

800 HP and around 800 Ft lbs. Of torque from the research I've done. Spinning 7500 to 7800 RPM.

thank you
700hp is gonna be a tall order for a 517ci engine at 6000rpm.

a 4.560 bore with a 3.910 stroke would be 510.84 cu in.i thought i read that the bore was going to be 4.560 and the stroke was 3.910.with 10 to 1 compression ratio spinning a max of 6000 rpm it should be a good running engine but 700 hp might be a little high.my guess is around 650.650 in the 24 ft boat with a bravo drive should be a rocket ship and a blast to drive.

The crank measured 3.920 and the bore will be 4.560 so that should be a 512.

When I started the thread I thought I had a 4 inch crank with a 4.530 bore. It ended up being a 3.920 crank and a 4.540 bore to make a class legal 509.

The dyno will tell the tale as far as where we end up power wise.
As mike said. In a 24-7 hull, it should prove to be plenty fun.

Thanks for the interest guys.
I'll keep updating as we go.

Have a great Christmas all,
Rob

S-30/Mike,
All good observations regarding the specific output of this engine. In the initial conversations concerning the transformation of this engine package, the target of 700 hp was based upon a semi-compression engine turning in the neighborhood of 6600 RPM. After a number of exchanges, all the practical aspects were assessed, and the project moved towards a more performance orientated recreational engine rather than a competition package.

With the move to 9.5:1 compression ratio and max wide open throttle target of 6000 RPM, the number 650 to 670 is much more realistic in this application. The subsequent reduction in duration (we have changed the cam specs four time so far) will build better acceleration in the midsection and yet still carry RPM beyond peak. The 55 mm core with its decreased deflection and reduced pressure angle will make for a very stable valve train.

My experience in racing a 510 engine making north of 700 hp is; they are a blast to race, but not a recreational engine you want to live with on a daily basis. The service life of your parts go down and your maintenance cycle goes up, not to mention the lack of maneuverability in tight spaces gets real old real quick. This is a well thought out project and will certainly make its marks for both performance and durability.


Merry Christmas and Happy Hanukkah. We wish you all a healthy, happy, and prosperous new year.

Bob

bob,no doubt that this build will reach the intended hp goal,i really like the idea of the 55 mm cam.650 in a 24-7 should be a rocket.merry christmas,happy holidays to all.

Thanks bob.
We will be ordering the cam and associated hardware shortly.
I appreciate your patience and help on this as we want to get this right.

Have a great Christmas all.

I doubt that's how much torque they made, just based on hp and rpm.

So anything new with your project? Did you ever get the flow numbers for your heads?

Ordered the Pistons last week. Went with CP bullet Pistons. One of the cool things about them is you can order them with .150, .180 or .200 walled pins. I went with the .200 wall pins.

My friend is dropping off the block, crank, pistons and rods at victory engines sometime later this week. We will be resizing the rods, boring the block to 4.560, sizing everything up to order bearings and we're having the bronze lifter bored bored and honed for larger .903 lifters. Oddly enough, they were .842 lifters.

Going to order the cam, lifters, springs and hardware from bob shortly. Going with morel needle bearing lifters and the isky tool room springs that bob recommended.

Also, got the barnes dry sump pump all cleaned up and ready to re-assemble. Had to switch the location of one of the mounting plates to align the pulleys.