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Originally Posted by GASoline71
A follow up... I pulled my 30ft 5th wheel over to Eastern WA an back over the weekend. It pulled 2 mountain passes in 90 degree heat and did just fine. I hope the new bolts and gaskets hold up for at least anothe 100,000 miles. 
Funnly thing though... a lot of Chevy/GMC trucks of the same generation in the RV park we were in with 6.0L engines... most of them with exhaust ticks just like I had when started up cold iron. Once the engine would warm up and everything would swell... tick goes away.
Gary |
Every single LT1 car that I've ever owned (esp iron head for some reason) did the same thing. Rear bolt would always stretch or break, and sometimes the next bolt in would too. The symptoms were the same, engine has an exhaust tick when cold, goes away once it heats up and expands. Back 15 years ago when LT1 B-Body cars were all over the place, I can't remember how many posts people had on forums about a valve tick when cold that actually turned out to be an exhaust leak.
If I was lucky to get a LT1 without a broken rear bolt, I would immediately replace the rear bolts with grade 8 and never had a problem. I recommend the same for LS engines.
So this GM problem isn't limited to the LS series. Pre-LS Vortec-era engines were a little better, but not much. Seems to be GM's bane.
Good writeup on the bolt extraction. We've all had to play the same games on some GM head or exhaust manifold. I've even had to do this on a Mopar when dumbarse me overtightened a stud nut...and snap! That one required me to pull the head after just installing it to replace leaky freeze plugs, new head gasket and all the labor, and then had to do it all over again.
Luckily Mopar big block heads are a cinch to pull. The valve train is about as simple as it gets and needs no rocker adjustments.