Well I think the exhaust manifold threads are ****&d. Previous owner had headers or similar(removed when traded in) and this was obvious in how nice the exhaust components were. I didn't care or make much of it.

Well, they must have used aftermarket header bolts that were shorter and didn't have a proper shoulder on them. I replaced with new, comparable 10.9 hardware from Lowes and should have just gotten OEM.

All the middle bolts were loose when I went to pull the blown gasket.

When I got the OEM bolts yesterday, it was obvious I was lucky it lasted even a hundred miles before. Most of the bolts seemed to tighten nicely save for one in the middle that was a little iffy. I used two gaskets and crossed my fingers.

After running it down the street for about 10 minutes(with no exhaust leak!) I pulled back in the shop and decided to check the bolts hot. Turning in without much pressure, all three bolts in the middle just spun. SMH.

So I probably have 30 miles before it eats those gaskets. It was making 4psi right past 1000RPM and light throttle so I at least got a taste of the improvement over before but I'm pretty disgusted knowing that it's coming right back.

So options are:

1) pull it all off, helicoil the holes in the truck
2) above and take the head off
3) get another set of heads to facilitate a swap more quickly
4) #3 but with ported heads
5) There's a guy on Craigslist with a complete 6.2 DI engine out of a low-mile truck for sale.

Guess I'm going to take the night and drink about it.

 

Or tap the holes for a larger bolt and go with it. If it fails, go with other options you listed.

 

That's not a bad idea. I feel like the problem then would be the holes in the gaskets. GM makes them tight. I had to grind a couple of the bolt tips to a point(the part that was already non-threaded on the tip) as any slight misalignment results in no-go. But I could drill those out too, I suppose.

Currently I'm just pissed and embarrassed that I let all this crash over $3 worth of hardware. Not my first rodeo and surely not the silliest situation I've created but right now my time is very very tight around two jobs.

 

I vote for the helicoil repair method.

 

damn. Id say get them fixed right. If you really want to buy that other seat of heads, have a machine shop check them out and might as well replace the springs and seals.

either way = time and $$$$$$ sucks to hear man

I used arp exhaust studs when i built my motor. not sure if they are any better or worse but they were like $130 bucks LOL

 

Just a minor set back. Don't let it bother you. If you have the funds put a good set of performance heads on it. Might as well slide a cam in while your at it

 

I dont think it will be that hard to helicoil them on the truck.

 

I know. Just a really full work schedule this week and no time to even touch it so I'm in pouty, stomp my feet mode. I'll be over it by the weekend!

 

Well the 6.2 is on the way. But still going to try to get out of work at a decent time today and tear it all back off for helicoils. Will certainly make it a lot easier to sell said 5.3. Or knowing me, keep and build later.

It occurs to me that GM may not have offered 6.2(L86)/6L80 as an option. Seems like the L86s all got the 8L90? Anyone around here with knowledge of that stuff? I have a lead on a 8L/tcase combo but may not be worth it(or even compatible?)

 

L86 not coming with the 6 spd transmission is no problem. Your engine control module and transmission control module are 2 separate pieces and your L83 controller will run the 6.2L no problem. All you need to do to start is copy & paste all the 6.2L parameters.

As far as the exhaust manifold threads either helicoil or timesert will both serve you well