Exhaust Manifold bolts

[jhenegh]

Any issue with using normal grade 8 bolts in the exhaust manifold? I've read somewhere the bolts are interference threaded. My old ones came off with a 1/2" socket rather than 9/16" because they were so rusted... so I need new ones. Didn't break any though !

Thanks

 

[BDCarrillo]

Grade 8 is overkill. Grade 5 would be just fine. I'd recommend lockwashers to keep them from backing out from heat cycles and vibration.

 

[jhenegh]

Blue loctite is rated to 300F. If the cylinder head, where these bolt into, reaches 300F, don't I have bigger issues?

 

[BDCarrillo]

Keep in mind they are in direct contact with the exhaust manifold, and heat travels through metal well. Loctite on exhaust hardware is a fairly fruitless endeavor.

 

[riotwarrior]

Keep in mind they are in direct contact with the exhaust manifold, and heat travels through metal well. Loctite on exhaust hardware is a fairly fruitless endeavor.

True...be that.

Stage 8 locking hardware or perhaps safety wire em...

ARP may have WaVe lock bolts for the application, I'm not sure.

Have you tried to purchase NEW at Ford or IHI?

 

[icanfixall]

The exhaust manifold are a interveriance thread. Ford or International will have them. Anything works for a while but why risk a leak. Do it once. do it right and not need to redo it.

 

[jhenegh]

I'll check and report back

 

[The Warden]

The exhaust manifold are a interveriance thread. Ford or International will have them. Anything works for a while but why risk a leak. Do it once. do it right and not need to redo it.

What he said. Early 6.9l's didn't use the interference thread bolts like later 6.9l's and all 7.3l's use; they had standard thread bolts with pieces of metal that went between two bolts and had tabs to lock the bolts in place. I made the mistake of putting the early stle bolts back on when I did my heads, and the tabs didn't lock properly...and I've had an intermittent exhast leak ever since. The problem is, at this point, I would need to remove both exhaust manifolds and replace the gaskets (after cleaning up the surfaces), which entails removing all of the pre-turbo exhaust system components (a serious PITA with an ATS 088, especially with getting the up-pipe to reseal) to get things happy...I'm living with the leak for now, but I would strongly recommend going to Ford or IH and seeing if you can source the proper interference bolts. I wish I had!!

 

[jhenegh]

$3.52 each at dealer. F4TZ9S425B is the number on my receipt. 14 coming my way. We'll see if they're right.

 

[riotwarrior]

$3.52 each at dealer. F4TZ9S425B is the number on my receipt. 14 coming my way. We'll see if they're right.

I'm thinking for that amount a Drill press and some bits would to a long way to saftey wiring the bolts in place myself...works on aircraft!

 

[jhenegh]

Time is money right now unfortunately. Snow plow truck with an engine on an engine stand isn't a great money maker.