Question for anyone who knows... I have just finished more or less rebuilding this engine.. went to put head back on w/ new gasket and have had nothing but hell trying to torque it down. Upon searching for a tap to clear the bolt holes we made an interesting discovery that the bolts we took out were 12.9 and check out at 12mm, and the bolts that come with the felpro kit for the head are 11.9, have yet to confirm for sure the bolt diameter. Thread size on both is 1.5. I need to confirm what the correct bolt/thread diameter is for the 2.5L 4Cyl Engine in an 86. It has been suspected by a couple auto shops I checked with that if the bolt size is 11mm stock, then the block has been modified to accept 12mm or someone owning it previously decided that 12mm bolts were going on .. regardless of threadtype. In either case, I need to confirm that stock thread diameter, and if in fact it has been modified find out where i can get a set of 12mm bolts. Am takeing one of the 11.9 bolts into a hardware store to comfirm its diameter.

Kevin

It's got to either be an 11 or a 12 mm bolt. A 12 won't fit and an 11 will be sloppy. How hard is that to tell? Of course they usually stretch as they're being torqued down so they will be narrower in the middle of the used ones. Good luck!

Phil

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87 FIERO GT 2.8 5spd
0-60 in 6.8 seconds!

Doh! Yeah, still not sure about bolt size, but found a very interesting article about what the #'s on the top of the bolts mean.

http://www.norbar.com/pdf_files/TorqueValueGuide.pdf
http://www.qldcorvetteclub.com.au/tech.htm

Thus far this is all turning out to be very interesting ... just really annoyed at having my car down for something so ultimatly simple. I'm hoping to have this resolved by the weekends. As soon as I can verify its a 12mm i'm picking up a tap and clearing those holes. Just unsure about the torque specs. So far as I can tell my head is an 85 head, and my block appears to be the same... though my car is 86.. heh. So, technicaly i'm a mix i guess... thus would I be able to choose between the absolute 85 torque spec of 92ftlbs or the angle torqueing ... which i'm very skeptical of. I'm far more comfortable with having an absolute destination torque value. Either way, I just want it done. This project was fun... but i'm at my wits end. anyone with any ideas as to what i'm looking at here for bolt size, or has insight into which route to go and the pros and cons of each method. *chuckles* if I turn my dad lose w/ the sucker he'll be out there w/ a torque wrench and just slapping 100lbs on in in intervals of 25 like he's done to his aries and the omnie we had a long time ago.. heh. I'm not to sure I want to have him do that but i have to give him credit.. he's never had any problems in the past having done it. Anywho.. just looking for some insight from anyone who can help.

Kevin

Update! Have just finished cleaning out the bolt holes thoroughly and replaced the bolt in question that was giving me so much trouble and torqued it directly to 92lbs. Everything appears to be holding pressure and am doing a test start tonight... with any luck this will be it. Compression is reading out at 145,155,120,150. The 120 is anticipated due to scoring on #3. All compression is holding with no leakdown what so ever.