NEW 360 LA CRATE TEARDOWN

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My front main bearing bore was +.003 too big. inbound pistons were above deck. Worst one +.009 and outbound pistons were in the hole, both banks. Not the rods or pistons, I checked them. Must be the block deck or crank.
 
ch1ll said:
My front main bearing bore was +.003 too big. inbound pistons were above deck. Worst one +.009 and outbound pistons were in the hole, both banks. Not the rods or pistons, I checked them. Must be the block deck or crank.
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Wow! Must have been a hangover day !
Im guessing the block but since you mention it I thought it was strange that the crank wasnt turned .010 mains and rods.
All standard on this one.
Could be crank too.
 
QUINN FORBES said:
Wow! Must have been a hangover day !
Im guessing the block but since you mention it I thought it was strange that the crank wasnt turned .010 mains and rods.
All standard on this one.
Could be crank too.
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I’m thinking it’s the deck block but who knows. Project has stalled. Anyway I got a roller 360 block(I believe) and I’m continuing on with that.
 
QUINN FORBES said:
Wow! Must have been a hangover day !
Im guessing the block but since you mention it I thought it was strange that the crank wasnt turned .010 mains and rods.
All standard on this one.
Could be crank too.
Click to expand...
My crank, mains and rods have been ground either.02 or.03 under by mopar performance. It was freshly decked as well. If I had to guess, it is the deck. Maybe got too hot while being decked and it is not flat although the finish is good. Then again it may be the crank.
 
Mr. Sinister said:
That is a different engine than what we were prepping and yes we were doing MAGNUM crate motors.
If I added confusion, that it is not my intention to.
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As someone who was there, you provided interesting & accurate details. I was just trying to make sure everyone knew what it applied to and where fell into the Mopar crate motor timeline. Thanks!
 
Locomotion said:
Is the difference 1.660" H116CP vs 1.675" KB107

I thought I heard that KB Pistons was a supplier at one point. Mopar always shopped around.
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Yes, I have the 1.660” pistons.
Not sure of the kb 107 but maybe if the other “factory” used kb107 then the compression would be up around 10:1 instead of my 9:1.
I suspect when these engines were built by someone other than Cummins they used kb107 pistons with 10:1 compression and maybe more off the deck too.
None of which I am sure…yet.
 
We covered this in your previous thread. There were two part numbers. You have P4876908 which should have a 1.63" compression height. I have the part number P4876907 which should have a 1.58" compression height. You CANNOT go by current H116 part numbers because Chrysler did some weird **** and ordered semi custom parts for their desired result. Mine actually has valve reliefs that will NOT clear a 2.02 intake valve. That was on purpose because it was intended as an LA replacement short block, which usually had 1.88 intake valves.

Also, the valve reliefs in mine were not normal. They were cut with some sort of ball or egg shaped cutter, so there was not even a flat angle to match the valve angle like you usually see. I bought a cutter to enlarge and flatten that to a normal relief. I will see if I can find the pictures of those reliefs or get a new picture this weekend. The exhaust valve reliefs still look like the intakes used to look. They were the same for both valves.

This short block Quinn has does use better conventional style pistons, same Sealed Power brand as mine, and this is a good foundation to build something on.

Sorry for the long rambling message. Just trying to be clear.
 
QUINN FORBES said:
Confusion indeed!
I have two different mopar catalogues with the same P4876908 part number.
the only difference being pin height.
Crate engine catalog states this block is 10:1 comp with cast heads (587 or 596)
The 2005 mp catalogue says 9.1:1 with the same heads.
The only difference being pin height.
My calculations tell me Im in the 9’s for compression due to the pistons at top being in the hole a c hair.
About .024 in the hole.
Maybe the Cummins built here in Canader had lower compression?
View attachment 1716064221

View attachment 1716064222
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I get about 8.9 to 1 compression with your piston and bore dimensions, a Fel Pro 4.18 bore and .048 compressed thickness head gasket, and a guess of 72cc for 596 casting head.

If you do nothing but change to a Cometic head gasket with a 4.06 bore and .027 compressed thickness you are around 9.37 to 1 compression.

Then of course as the chamber gets smaller the numbers go up a little from there. Make sure you measure your chamber volume to get better numbers.
 
Yes I remember Bob,
Do you know where your block was built?
It is hard sometimes to determine what Ma Mopar did at times with all the mixin and mismatching but its always worth the deciphering in the long run.
 
Bobzilla said:
I get about 8.9 to 1 compression with your piston and bore dimensions, a Fel Pro 4.18 bore and .048 compressed thickness head gasket, and a guess of 72cc for 596 casting head.

If you do nothing but change to a Cometic head gasket with a 4.06 bore and .027 compressed thickness you are around 9.37 to 1 compression.

Then of course as the chamber gets smaller the numbers go up a little from there. Make sure you measure your chamber volume to get better numbers.
Click to expand...
Thats about what I get using an online compression calculator.
Thankyou Bob!
Bobzilla said:
The sticker on mine shows remanufactured in USA. The picture of the sticker is in post 13 of the other thread, linked below.
360 crank knurling?
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also thankyou for helping me find my own post! Hahaha, Im still figuring out stuff on this forum as I am a newbie.
I should have been on here years ago but no excuse.
Was curious about different assembly plants and different pistons but not knowing wont stop me from going forward.
 
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