Motor rebuild questions?

[ib fast]

Does anyone know for sure if going .20 over requires resleeving? Also does .20 over leave you with 9 to 1 compression?

 

[lightning2strikes]

i believe the type of pistons would decide the compression...

 

[blown99]

Boring a cylinder .020" over should not change the compression ratio that much. There is a formula to figure out the compression ratio - (A+B)/A. If I remember correctly A is the area of the cylinder head (combustion chamber area), and B is the area when the piston is at top dead center. It has been a long time since I've done this equation so please don't hold me to it. The cylinders are not sleeved.

 

[DrTriton]

I would not recommend you bore the 5.4L block anything over .010. If it needs more than that (and it shouldn't unless you have really high mileage), throw it in the garbage. These things do not have very thick cylinder walls to begin with plus you aren't dealing with a naturally aspirated application.

 

[BigVito]

I would not recommend you bore the 5.4L block anything over .010. If it needs more than that (and it shouldn't unless you have really high mileage), throw it in the garbage. These things do not have very thick cylinder walls to begin with plus you aren't dealing with a naturally aspirated application.

imgoing to second this thought on this
these engine do indeed have very thin walls and the stroke is long as it is just harden the internals

 

[ib fast]

So your telling me that the cast iron 5.4 block can't be bored .20 over even with sleeving but there are supercharged 4.6 modulars running 10.5 to 1 compression with no problems that are bored more than .20 over. My motor has 30k and is going to be rebuilt with beefed up internals,arp studs and balancing. I am looking to raise the compression ratio a little while retaining the stock heads as there are no aftermarket heads available,at least none that i know of. Sounds like The only way to get more power after rebuilding is nitrous or a bigger displacement blower. I am removing the motor monday and bringing it to an engine builder so if anyone has any ideas,i would like to hear them.

 

[BigVito]

if you do bore it sleeve it. but if you didnt yet ask Jim@JDM hed know better than I

 

[Need4Speed]

For $400 bucks you can by a brand new block. Not much more than decking, boring and align boring an old block.

 

[Guest]

For $400 bucks you can by a brand new block. Not much more than decking, boring and align boring an old block.

You should be able to get a 97-00 block for the $400 but the '01 blocks cost a couple hundred more. Why?