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Hemi rebuild

Paul_G

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Starting the rebuild of of a Gen II Hemi. Are there any books that cover this in detail? Any tips and advice is welcome.
 
I just use a factory FSM.
I agree. Also depends on how big and bad you are going with it. Mine may have gotten away from me abit.... Might be a little overkill.

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Aluminum heads? Roller cam? Stock oiling system? etc? FSM will be sort of a guide but you'll probably want to ask lots of questions on here.
First thing you will want to do is very carefully disassemble it and I would check all clearances, end plays etc. I would even write down every fastener torque value as you go and take a ton of photos. Don't throw away any old parts either, you may want to go back to them for reference before ordering new ones.
 
I have this book, I think you should buy it and read it a few times before turning any bolts. It goes into great detail. I forget how old it is, probably 10 years but it's relatively current, a lot of the old books aren't relative anymore.

Amazon product ASIN 1613250746
 
Aluminum heads? Roller cam? Stock oiling system? etc? FSM will be sort of a guide but you'll probably want to ask lots of questions on here.
First thing you will want to do is very carefully disassemble it and I would check all clearances, end plays etc. I would even write down every fastener torque value as you go and take a ton of photos. Don't throw away any old parts either, you may want to go back to them for reference before ordering new ones.
Indy Cylinder Head 426-1 CNC 285 heads. Solid roller lifters, although I found a plunger for a hydraulic lifter in the oil pan today. Cam has a bad lobe on it. F1 Procharger at 10 PSI of boost.

Disassembled the engine today. Got some info from the rotating assembly. Eagle 7.1" H beam rods. Crank has these numbers on it, 4.500x2.200 BBC, 839, 59. Could it be a 4.5" stroke? No numbers on the pistons, but the top of the wrist pin is in to the oil ring.

#2 piston had a portion of the ring land broken. That cylinder wall is pretty scratched up. The rest of the pistons had some light up and down scratches in them, and some had a lot of detonation, like little weld spatter craters.

Rod bearings looked good, crank bearings not so much. they have light scratches in them.

The engine goes to the machine shop on Friday. See what they think of it.

Tried to measure a piston diameter. I come up with 4.26". Measured the top of a bore at 4.28". When it was still assembled there was a lot of distance between the piston and cylinder wall. I could not measure it, but I could see the top ring sitting in there.

I am trying to measure the stroke of the crank. I am thinking to put the crank and a piston back in, put the piston at bdc and meaure the distance to the deck, then put the piston at tdc and measure to the deck, (the domes rise above the deck). Add the numbers and that should the stroke. Will it work?

Tomorrow I plan to clean up the heads and see if there is anything going on with them.
 
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Yup: That should be a 4.5 stroke crankshaft, common with the Chevy rod journals and 7.1 rods. Sounds like you'll need to bore it, it's at .030 now. Your method for measuring stroke sounds good to me.
You'll see when you get the book that it will go into great detail as to what bearings you have and what to run etc. it's a lot more complicated choosing the right parts with what's available. I used to just order trimetal fully grooved main bearings but there are tons of choices now depending on the crank journals and usage.
Hemis are a pain to figure true compression ratio on. You should mock it up and do a down fill volume on it. You'll have to look the procedure up but basically you have to figure how many CC the cylinder holds with the piston down a certain amount in the bore (so the piston dome is below the deck height) also the CC of the head chambers of course as well as head gasket thickness. It would be nice to know what your current compression ratio was before ordering new pistons. If it's been detonating you're going to have to look into it.
Sorry I can't be more help but hopefully this will help a bit. That book will help you a lot.
 
Should be straight forward for a rebuild. Hemi’s should have solid cams. Even with big stroke cranks they want to turn some RPM. Bottom end clearances should be in-line with any performance big block. When swapping cams you need to check just about everything including making sure the valves have clearance with each other. Spend lots of time looking at the valve train. I always mock them up incase I need to change, grind, etc.
 
Running that procharger system will require some planning. As I recall you had fuel starvation issues. Most likely that did the damage. Running boost or power adders one has to be safe and not run to lean or to rich. The boost or adders just increase the type of burn. Might try calling some known Hemi rebuilders such as Barton, Indy, Banning and see what they can offer.
 
Thought some pictures might be helpful. Closer look shows three pistons with broken ring lands, and one of them has bent oil rings. Furthest right in the one pick has detonation craters. I had three cylinders down on compression, you guessed it, the same three with broken ring lands.
The rod bearings are not bad, but the mains are not good, see in the pic below. Metal has obviously gone through this engine.
Have one head on the bench cleaning it up. The head is not to bad. Put a straight edge across the surface and it looks good. I will do an alcohol test to see if the valves are sealing.

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Are there support rails under the bottom oil ring. I believe they are recommended when the pin hole is into the ring land.
 
I have been looking around for a piston that will lower the compression. Not finding anything. Using summits compression calculator what they have will be close to 11:1. OK for N/A, but I would like to keep the blower and be safe.

What are ways to get the compression down to 9:1 or lower? Mill a few thousands off the dome?
 
I have been looking around for a piston that will lower the compression. Not finding anything. Using summits compression calculator what they have will be close to 11:1. OK for N/A, but I would like to keep the blower and be safe.

What are ways to get the compression down to 9:1 or lower? Mill a few thousands off the dome?
Custom pistons. Call Diamond or Ross and see what they say.
 
I have been looking around for a piston that will lower the compression. Not finding anything. Using summits compression calculator what they have will be close to 11:1. OK for N/A, but I would like to keep the blower and be safe.

What are ways to get the compression down to 9:1 or lower? Mill a few thousands off the dome?
You are looking at shelf pistons, you will need to expand your horizons and call piston manufacturers directly. They may, indeed, have a shelf flat top that Summit doesn't carry. Doubtful, but worth asking. A little tip, when you call, tell them your goal for comp and hp and listen to what they recommend. Use their expertise.
 
Did some measuring yesterday. This build does not fall in to any of the common cubic inch categories, not 528, 540 or 572. In between 540 and 572. Which is ok with me. I dont want to take the block to max size piston bore of 4.50" just for a cubic inch number and leave no room for clean up in the future. I am happy to take away just enough bore to clean them up and be round again.

The stroke is 4.5" as the crank is marked, and as I measured it.
The top of cylinder bore right now is 4.28", which is .030" over.
The Eagle rods are 7.1" as per Eagle spec.

I talked with Kenny at Indy Cylinder Head. The crank and rods in this engine are not the brands they use, so they did not build it. He did say the next bore size is 4.31" or .060 over. If I want to take it under 9:1 compression it will have to be a custom made to order piston.
 
What block do you have?
 
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