Machine the Head? How do I tell

[tunernewb92]

I think I know the answer but I would just rather run it by some of the guys on this forum. The headgasket on my car took a crap. Reading 135, 119, 111, 119. So obviously the headgasket is gone. We think it was a failpro put on by another shop. Anyway, all I do to check the head to make sure that it does or doesn't have to be machined is put a straight edge on all four sides and across the corners to check for warping right?

Thanks,
Brian

 

[1gDSM4g63]

A warped head is most likely not the case. Replace the head gasket with a Cometic or a 4 layer head gasket with ARP studs torqued right.

 

[tunernewb92]

Ok good, we hope to have a surprise to show off for the car in the coming month, one of the first people on the board to do it as well I believe. Anyway, I didn't want to have to tear down the head due to time restraints and costs and that is good news.


ALSO, I read somewhere that you have to use an 8MM Allen Wrench that fits a 1/2'' wrench tough enough to use on an impact to take the head off, I have the 3/8'' 8MM but its just a craftsman...any thoughts on that?

 

[dsm-onster]

They arn't fail-pros. I've been boosting fel-pro gaskets to 30+ psi for years. If they fail it is the installers fault. A MLS or cometic gasket is WAY WAY overkill. Considering your mods. It is over kill for anything under 450whp IMHO. The fel-pro IS an OE Mitsu head gasket. It is just rebadged with the perty blue paint and about $20-30 cheaper.

Arp headstuds are over kill as well. They are good insurance for a 350+whp build. So it depends on your goal. The stock 6-bolt head bolts can be reused at least once or twice (done it several times). They do not stretch. IF, IF they are oe Mitsu head bolts. There are cheapo pepboy specials that are actually torque to yeild out there. So make sure you check the stretch of the head bolt, then reuse. The 6-bolt head bolts are much larger in diameter than the 7-bolt head bolts. They are very nice pieces and what mitsu should have stuck with for the next years of the 4g63. They are a 10mm hex head not 8mm.

I agree. A warped head is definately a long shot. If you do have a straight edge, by all means measure as you described. Clean the surfaces with a razor blade. Clean out the headbolt threads in the block, and get back on the road.

 

[tunernewb92]

Yes they are 10mm hex bolts I apologize, any ideas if the one I have is good or not?

 

[dsm-onster]

If you look real hard, you can see cheap head bolts bulge at the thread end when they have been used. If you have a single REAL OE headbolt you can check the length against it. The cheapos will be significantly longer, visible to the naked eye.

Also the cheapo head bolts will usually have shiny spots where the surface material has separated due to the bolt stretching. An oem bolt will look completely jet black at all surfaces after use (once cleaned up).

 

[tunernewb92]

One more thing, as long as I follow what my manual says about which specific bolts to loosen at a time, will these bolts strip easy, do I need a special 10mm head or will a craftsman do?

 

[dsm-onster]

I use a craftsman hex socket. Worked for years.