De-tuning my 2001 ilmor supercat 517
11-21-2014, 07:40 PM
#1
Gold Member
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?
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?
11-21-2014, 07:44 PM
#2
Registered
iTrader: (1)
10:1 , 93 octane, and go big !
11-22-2014, 06:52 AM
#5
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.
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.
11-22-2014, 09:46 AM
#6
Registered
iTrader: (1)
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?
Why did you change the titanium valves and mill the intake?
11-22-2014, 11:02 AM
#7
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.
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.
11-25-2014, 07:45 AM
#9
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.
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.
11-25-2014, 08:26 AM
#10
Registered
iTrader: (2)
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.
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.
