Help me with a new FI engine setup
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Help me with a new FI engine setup
Well, I just got word back from the guy looking at my engine that I blew up this summer. He says I should probably replace all the pistons, they are showing some good wear. I probably have 10-20k on this engine.
The problem is that I had some Ross custom pistons in this engine and I don't really want to wait around for them to make another set and I've had to replace some of these before. I'm not totally sold on the quality of the parts. So I'm looking at my options. I'm looking at the best combination of performance, time, and cost.
I currently had a 383 with 6" rods, custom pistons, stock ported heads. I need to keep the compression around 9:1.
1.) Get more custom pistons.
Cost: ~$900
2.) Reduce the CI to a 355 and get SRP pistons. CR 9:1 Pistons: $575 Crank: $625
Cost: ~$1200
3.) Get SRP Pistons and Get bigger heads
Cost: ? Depends on heads
I don't really want to get a new intake manifold because of all of the rear mount distributor stuff I've done to it. Are there any after market LT1 heads that use the Stock LT1 manifold?
The problem is that I had some Ross custom pistons in this engine and I don't really want to wait around for them to make another set and I've had to replace some of these before. I'm not totally sold on the quality of the parts. So I'm looking at my options. I'm looking at the best combination of performance, time, and cost.
I currently had a 383 with 6" rods, custom pistons, stock ported heads. I need to keep the compression around 9:1.
1.) Get more custom pistons.
Cost: ~$900
2.) Reduce the CI to a 355 and get SRP pistons. CR 9:1 Pistons: $575 Crank: $625
Cost: ~$1200
3.) Get SRP Pistons and Get bigger heads
Cost: ? Depends on heads
I don't really want to get a new intake manifold because of all of the rear mount distributor stuff I've done to it. Are there any after market LT1 heads that use the Stock LT1 manifold?
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Well, I just got word back from the guy looking at my engine that I blew up this summer. He says I should probably replace all the pistons, they are showing some good wear. I probably have 10-20k on this engine.
The problem is that I had some Ross custom pistons in this engine and I don't really want to wait around for them to make another set and I've had to replace some of these before. I'm not totally sold on the quality of the parts. So I'm looking at my options. I'm looking at the best combination of performance, time, and cost.
I currently had a 383 with 6" rods, custom pistons, stock ported heads. I need to keep the compression around 9:1.
1.) Get more custom pistons.
Cost: ~$900
2.) Reduce the CI to a 355 and get SRP pistons. CR 9:1 Pistons: $575 Crank: $625
Cost: ~$1200
3.) Get SRP Pistons and Get bigger heads
Cost: ? Depends on heads
I don't really want to get a new intake manifold because of all of the rear mount distributor stuff I've done to it. Are there any after market LT1 heads that use the Stock LT1 manifold?
The problem is that I had some Ross custom pistons in this engine and I don't really want to wait around for them to make another set and I've had to replace some of these before. I'm not totally sold on the quality of the parts. So I'm looking at my options. I'm looking at the best combination of performance, time, and cost.
I currently had a 383 with 6" rods, custom pistons, stock ported heads. I need to keep the compression around 9:1.
1.) Get more custom pistons.
Cost: ~$900
2.) Reduce the CI to a 355 and get SRP pistons. CR 9:1 Pistons: $575 Crank: $625
Cost: ~$1200
3.) Get SRP Pistons and Get bigger heads
Cost: ? Depends on heads
I don't really want to get a new intake manifold because of all of the rear mount distributor stuff I've done to it. Are there any after market LT1 heads that use the Stock LT1 manifold?
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Good call, Diamond has a good looking piston in their catalog, 11426, that should be a great replacement. It has a -31cc dish and should be just under 9:1 compression. I just need to find a place that sells them at a good price.
Drifting
Joined: Nov 2003
Posts: 1,637
Likes: 2
From: Honeoye Ny
Mine have some abnormal skirt wear as well. Im thinking it'a a combo of stratospheric revs for a 383 and not enough wall clearence for the amount of power Im makin.
Do you recall what your piston to wall clearance was and what alloy? (im guessing 2xxx series) perhaps that may have played a role in the skirt wear?
Wiseco's currently around 3-4 weeks for a custom set, I have your exact same motor. But like you said, with rings it's at least $90 a hole
Do you recall what your piston to wall clearance was and what alloy? (im guessing 2xxx series) perhaps that may have played a role in the skirt wear?
Wiseco's currently around 3-4 weeks for a custom set, I have your exact same motor. But like you said, with rings it's at least $90 a hole
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Mine have some abnormal skirt wear as well. Im thinking it'a a combo of stratospheric revs for a 383 and not enough wall clearence for the amount of power Im makin.
Do you recall what your piston to wall clearance was and what alloy? (im guessing 2xxx series) perhaps that may have played a role in the skirt wear?
Wiseco's currently around 3-4 weeks for a custom set, I have your exact same motor. But like you said, with rings it's at least $90 a hole
Do you recall what your piston to wall clearance was and what alloy? (im guessing 2xxx series) perhaps that may have played a role in the skirt wear?
Wiseco's currently around 3-4 weeks for a custom set, I have your exact same motor. But like you said, with rings it's at least $90 a hole
If I do switch to different pistons would I have to rebalance the internals? Could I get away without it if the old pistons way close to the same amount as the new ones?
Drifting
Joined: Nov 2003
Posts: 1,637
Likes: 2
From: Honeoye Ny
brian if they are with in a gram or two you are fine to not rebalance. Anything over that will jiggle a little.
Mine are a -37cc dish to give 8.86-1 compression with my heads and gasket combo. It's so octane tolerant I probably should have increased the compression some. But I can run 87.
Mine are a -37cc dish to give 8.86-1 compression with my heads and gasket combo. It's so octane tolerant I probably should have increased the compression some. But I can run 87.
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Well, I had my current pistons weighed and they are 438.9 grams. The diamond pisonts are only 417 grams. So if I go with those it looks like I'll have to rebalance every thing.
I have a friend that is a materials engineer and she is going to look at the fractured pistons for me and help me figure out what went wrong. But I'm guessing I need to go with a different manufacturer if I've wasted a few of these pistons already.
When talking in pistons what is a C.D.? The pistons in the diamond catalog have that listed and it is a 1.125 but I have no idea what it is.
Does anybody see anything that might be not standard or get me into trouble with these?
Bore_Stroke Rod__ C.D. Weight Pin____ __ CC’s 64cc 70cc 76cc Ring Set Part #
4.030 3.750 6.000 1.125 417 .927 x 2.950 -31.0cc 8.4 2.0 7.7 09024030 11426*
Ratios fi gured for 0” deck@9.000”
*Includes oil-ring support rails.
I have a friend that is a materials engineer and she is going to look at the fractured pistons for me and help me figure out what went wrong. But I'm guessing I need to go with a different manufacturer if I've wasted a few of these pistons already.
When talking in pistons what is a C.D.? The pistons in the diamond catalog have that listed and it is a 1.125 but I have no idea what it is.
Does anybody see anything that might be not standard or get me into trouble with these?
Bore_Stroke Rod__ C.D. Weight Pin____ __ CC’s 64cc 70cc 76cc Ring Set Part #
4.030 3.750 6.000 1.125 417 .927 x 2.950 -31.0cc 8.4 2.0 7.7 09024030 11426*
Ratios fi gured for 0” deck@9.000”
*Includes oil-ring support rails.
Last edited by mn_vette; Jan 2, 2008 at 09:40 AM.
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Melting Slicks
Joined: Jun 1999
Posts: 2,872
Likes: 3
From: Wilmington NC
are you losing ringlands on the pistons? breaking pieces of piston around the edge? if this is the case it is usually detonation.
my custom ross pistons were designed based on my 355 with stock stroke crank and I had them put as much meat above top ring and towards the center of the piston as they could fit to add some strength and help take a bit more of a beating while tuning or unforeseen blips of detonation from bad gas or big weather sing changes.
this is on of the main reasons i like doing the 355 rather then the 383 or even 396.. the stroke of the crank pushes the wrist pin too high reduscing the compression height and leaving little room for strength in the top ring land to pistons crown distance.
the othe rbenefit as far as geometry is as Rick stated above.. the 355 is going to pose less side loading from rod angle with a smaller crank throw... so run a few extra revs lengthen the torque curve and you will scarecly mis the extra cubes and you ill love the long hard pull of the smaller higher revving 355 in the mid to high end rpm range.
just my 2 cents.
Chris
my custom ross pistons were designed based on my 355 with stock stroke crank and I had them put as much meat above top ring and towards the center of the piston as they could fit to add some strength and help take a bit more of a beating while tuning or unforeseen blips of detonation from bad gas or big weather sing changes.
this is on of the main reasons i like doing the 355 rather then the 383 or even 396.. the stroke of the crank pushes the wrist pin too high reduscing the compression height and leaving little room for strength in the top ring land to pistons crown distance.
the othe rbenefit as far as geometry is as Rick stated above.. the 355 is going to pose less side loading from rod angle with a smaller crank throw... so run a few extra revs lengthen the torque curve and you will scarecly mis the extra cubes and you ill love the long hard pull of the smaller higher revving 355 in the mid to high end rpm range.
just my 2 cents.
Chris
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
I thought I would give you guys an update. My engine guy got back to me again and said that I can probably reuse the 6 pistons that are left over in my engine. I should probably end up replacing them, but I guess I'll save the $1,000 for coated pistons and replace them next time the engine goes south. That seems to happen ever couple of years 
I'm also replacing my 224/218 cam with a 224/227 cam with the same lift. I'm hoping that this will help open up the top end without killing my MPG. And yes that is a big concern to me, I drive this car alot when its running.
I'm also replacing my 224/218 cam with a 224/227 cam with the same lift. I'm hoping that this will help open up the top end without killing my MPG. And yes that is a big concern to me, I drive this car alot when its running.
Drifting
Joined: Nov 2003
Posts: 1,637
Likes: 2
From: Honeoye Ny
Hmm I dunno about the increase in exhasut side duration. Have you increased the flow in the hot side? Bigger A/R,downpipe turbine etc.
If not it may not help your situation.
If I remember right you have TFS heads dont you? they should have an adequate intake to ex ratio for a staright pattern cam.
Btu again without hard data on the old setup it's pure speculation.
If not it may not help your situation.
If I remember right you have TFS heads dont you? they should have an adequate intake to ex ratio for a staright pattern cam.
Btu again without hard data on the old setup it's pure speculation.
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Hmm I dunno about the increase in exhasut side duration. Have you increased the flow in the hot side? Bigger A/R,downpipe turbine etc.
If not it may not help your situation.
If I remember right you have TFS heads dont you? they should have an adequate intake to ex ratio for a staright pattern cam.
Btu again without hard data on the old setup it's pure speculation.
If not it may not help your situation.
If I remember right you have TFS heads dont you? they should have an adequate intake to ex ratio for a staright pattern cam.
Btu again without hard data on the old setup it's pure speculation.
I'm running stock ported heads. Not alot of work done on the exhaust side though. I don't recall off the top of my head what the flow numbers are. Not spectacular, but not horible.
I was thinking that this cam should not be much different from the 224/224 which is an extra 6 degrees of exhaust from what I'm running now.
