bypass-21

So this question pertains to my 1973 nova with a 6 banger, but I have asked so many questions about my 84 trans am and have recived suggestions and answers that were either spot on or better. The question is that in May I cleaned and lapped the valved on the nova due to a bad vacuum leak. As I was getting ready to put it all back together a friend said i needed to resurface it by sanding the head and block. I let him do it since he sounded like he knew what he was doing, put the head on tightened the bolts in the right order, put them at 90lbs, put water on the radiator and were good, now its August and the head gasket I put on blew (air bubbles from gasket), so I wanted to know what I could have done to cause it

Thanks again guys

FtrSpeedy

Too tight, too loose, bad gasket, the sanding process.

sofakingdom

iTrader: (1)

If that's really 90 ft/lbs, there's your problem right there.

Ever seen what happens to valve covers and their gaskets when you over-tighten them?

Well, that's what just happened to your ...... head. (sound odd somehow to use that word in the singular)

I'd suggest popping it off, having it PROFESSIONALLY resurfaced, and re-installing it with a more appropriate torque in the neighborhood of 60 - 65 ft-lbs. If you're lucky, it didn't permanently distort the block enough as well, to prevent any future successful use.

paulo57509

After you get the head off (again), clean the deck surface on the block and check it for flatness before you bolt the head back on.

bypass-21

a few days ago i took it off and sent it to a trustworthy machine shot by my place. they said that they are going to check the head for vacuum and offered (if it fails) to mill it for perfect vacuum, on another note, how would i check the block for flatness? i know its a stupid question but i want to know what if there is anything special i have to do. i hope engine is OK, i'm a little worried

thanks guys, more info is appreciated

crazyjc15

what you need is a precision straight edge. i looks like, in fact it is, just a piece of steel about 2" wide, 1/4" thick, and about 2-3 ft long. only thing that seperates it from the scrap pile is the fact that it is precision milled to be perfectly flat along the sides. stand it up along your deck, and use a feeler gauge to see if there any gaps, shouldn't be more than a few thousandths of an inch gap, measure this with the straight edge in several different orientations to make sure the deck is smooth in all directions.

bypass-21

I went down to my friend who owns the mill shop, he has been looking at my head since i took it off, from what he said is a long time ago (when under the original owner who i bought it from) it must have over heated and he must have kept driving. beacuse he showed me that trick, did it and confirmed its warped i'm glad i did not over torque it since the torque is supposed to be 95ft/lbs. he assured me it could be fixed and the block is fine, but its gonna run me about 300 bucks.

last thing i need to know is weather to buy new head bolts or get use the same ones that came with the car.

thanks again guys! your all awsome!

FtrSpeedy

If you have the spare change to get new bolts thats what i would do. But i dont believe is a must unless you have high compression engine.

bypass-21

okay then, i might as well get new ones to be on the safe side, so does anyone know how much they usually run?