.030 vs .040

[Jacob hoke]

So I need some input I was considering having my block bored over to .40 and half filled my power goal is 800hp and $7k however I'm definitely a penny pincher (thus how I saved 7 grand) my question is should I go to a .030 Ross coated piston for $800 or save the cash and have it bores .040 and do HD1400 pistons but loose the extra bore thickness and save a little

 

[Kapok6]

Fk Ross imo. Had wrist pin break on cyl 4 after making 600ish for 2yrs. Friend had same thing happen on his Ross motor as well. Also, Ross requires huge ptw clearance. .006"+ iirc. That's not a big deal for some, but I personally will never use Ross pistons again. Call wiseco and see what the cost would be for a a set of .030" over.

 

[Joshua Callahan]

Quote taken from colt here. This confirms everything I've ever read about 4g63 blocks. I would go with.030 or .020if you have the choice mainly because if you ever need to fix something, you'll have some meat left.

040" (actually .039", 1mm) is the maximum overbore according to Mitsubishi for the 4g63 engine block. Going over this may not get you into the water jacket, but it will severely lower your power potential in the long run due to thin cylinder walls.

 

[Jacob hoke]

Fk Ross imo. Had wrist pin break on cyl 4 after making 600ish for 2yrs. Friend had same thing happen on his Ross motor as well. Also, Ross requires huge ptw clearance. .006"+ iirc. That's not a big deal for some, but I personally will never use Ross pistons again. Call wiseco and see what the cost would be for a a set of .030" over.

Ill Will give them a call in the AM no idea they did .030 who knew there was a best of both worlds thanks

Quote taken from colt here. This confirms everything I've ever read about 4g63 blocks. I would go with.030 or .020if you have the choice mainly because if you ever need to fix something, you'll have some meat left.

040" (actually .039", 1mm) is the maximum overbore according to Mitsubishi for the 4g63 engine block. Going over this may not get you into the water jacket, but it will severely lower your power potential in the long run due to thin cylinder walls.

Even if the block is half filled?

 

[jery1234]

Go as less as you can half fill or not . It did happened to me . 86 mm pistons .

 

[Kapok6]

Ill Will give them a call in the AM no idea they did .030 who knew there was a best of both worlds thanks

Any piston mfg should be able to do anything. Cost would be the factor. Hence the suggestion to give them a call and find out what that cost would be.

 

[spyderdrifter]

I went from stock bore to .040 over once and broke one piston ring when installing. Took forever to get a replacement set. And like the others have said, start out smaller just in case you need a bore job later on.

 

[Jacob hoke]

I guess the best way to really go about it would be to buy a standard bore block and get some good quality pistons at standard bore hell I paid $250 for the honing block alone since no one in the area had one for our blocks however I have 2 blocked that are bored .020 already any idea if there's a market for rebuilt engines I know most people aren't looking for stock engines BTW thanks for the replies guys

Go as less as you can half fill or not . It did happened to me . 86 mm pistons .

Any idea how much a stock bore block runs these days I'm in southern Indiana but haven't found a single one

 

[Kapok6]

Depends where you are. I personally doubt I would buy someone else's built block as there is no way for me to verify the quality of the person that built it. I am usually a stock block kind of guy. If I'm buying someone else's "built" block, it better be cheap. That just my opinion though.

 

[jery1234]

Currently i run 85.5 pistons @ 44psi with no problems

 

[90laserRSfwd]

You may want to avoid the Wiseco's according to a wisemen here on tuners. I'm in the same boat as you.. Take a look.

http://www.dsmtuners.com/threads/1-000hp-full-engine-build-discussion.507097/

 

[Joshua Callahan]

Basically , the now meat you CAN keep from the start, let's you have repairs if necessary down the road. Most people do .020 just to clean up the bore.

 

[Jacob hoke]

Basically , the now meat you CAN keep from the start, let's you have repairs if necessary down the road. Most people do .020 just to clean up the bore.

I agree the issue is the 2 blocks I have are already .020 over so if got about 3 options new block, .030 custom pistons more meat, .040 cheaper pistons less meat not sure the route to take cosidering i have yet to find a stock bore block

You may want to avoid the Wiseco's according to a wisemen here on tuners. I'm in the same boat as you.. Take a look.

http://www.dsmtuners.com/threads/1-000hp-full-engine-build-discussion.507097/

Thanks man that was a pretty useful thread changed my build a little

Go as less as you can half fill or not . It did happened to me . 86 mm pistons .

Do you know of any way to pressure test a block before a catastrophic failure like this even accuses or is it just a roll of the dice w