very sad end to an other wise very happy evening.

[colbystephens]

so i started reassembling my engine this evening. i had finished plastiguaging my mains, installed my cam, set the crank in place and started torquing the main cap bolts down to proper spec. i'm torquing these down with the proper method - in thirds of force, if you will - and i get to the point of putting 110lbs of torque on the inner bolts. first one goes just fine - second one i don't get a click when i expect to from my torque wrench, so i loosen that bolt and start over from 70 lbs. i get up to 110 again and i still don't have the click when i expect it, but i just figured i must be wrong. i was wrong to assume i was wrong. sheared the bolt in two. so i loaded the engine back into my truck and it will be off to the machine shop bright and early tomorrow hoping that they'll remove the broken piece of the bolt for me for free (i just dropped some serious cash there, so i think my chances are pretty decent.) what i'm concerned about is the cost of replacement bolts. we'll see what happens. i guess it's good that it broke b/c had i overtorqued it and then loosened it and then torqued it to proper spec without shearing the bolt, i suppose it wouldn't be perfect b/c of the possible stretch and "twist" the bolt may have suffered when i originally overtorqued it. maybe this is a blessing in disguise so that i don't install faulty parts. who knows. wow - you read my pouting all the way to the end? thanks for listening to me cry.

 

[midnitewarya]

That sucks dude. Once I installed a brand new TBI, and stripped one of the fuel lines while putting it in. I was sooooo mad. It ended up costing $75 because I had to get a new TBI body.

It is a blessing that you found it without moving on to the next bolts. Just thinking of all the probs that could have caused gives me the creeps.

Hope it works out.

Al

 

[ryoken]

where they new or used?

 

[Seventy4Blazer]

have your torque wrench checked as well. mine has been in a drawer for a ew years and is all screwed up... both of them. one i knew was busted, the other should have been fine...
grant

 

[roadnotca]

Colby, try search on 6.2 main cap bolts to see if those bolts are marginal; I think I read somewhere that someone else snapped one off. Where on the bolt did it snap? Also, was it prepped exactly per the book (lube/dry) and which book? That motor with ~20:1 C/R I wouldn't be surprised if those bolts are right out there at warp 9. They may not be reusable.

 

[colbystephens]

well, here's the deal. just got back from the machine shop and sure enough it was my torque wrench. they checked its accuracy - when my wrench showed 89#, theirs was at 110#, thus, with mine at 110#, i can't even imagine how high the torque may have been - 165-170? crazy. they were easily able to remove the piece from the block, so i'll be back at it tomorrow. they recaliberated my wrench, but it still sux - at least it's accurate at 110# now tho. Thus, my recommendation is don't buy Performace Tools Torque Wrenches. Oh well. I think these bolts are reusable, and they were prepped properly - the machinist told me to use 30W oil on the threads. Last night everything went well - i had torqued them all down to what i thought was 110# so that i could plastigauge my oil clearance, and it worked fine. apparently that one bolt was stressed in the process. oh well.

 

[theperfectgarage]

Sorry to here about that little mishap, and yeah don't cheap on torque wrenches, even though your not a pro, when your needin a torque wrench your doing a pro's job.
Don't forget to put oil under the head of the bolt when you lube the threads, friction there too. Best luck.

 

[sweetk30]

#1 rule with the tourqe wrench is park it back at the bottom when done or it will eat up the acurecy over time.

#2 get them checked and calibrated every year for average use.

 

[colbystephens]

well, i always to unwind the wrench after use. while mine was purchased in the last few months, i was able to trade that one for another one at the shop, which the machine shop checked. turns out, the one brand new out of the box was very innaccurate too - it just happens that i bought a piece of crap. bummer.

 

[ProJunkRacing]

that is a very important tool alway check accuracy of that puppy

 

[mudjunkie 82]

for the extra loot ARP main studs are the way to go..........