Topic: New engine noise

[83MT]

I just got my rebuilt engine reconnected and running. Right at first, exhaust was coming out of the exhaust manifold, but after about 5 minutes of running, I couldn't see any more come out, and haven't seen it since. Could it just be that it took a bit for the gasket to seat or something? Or could it still be leaking, there's just not a bunch of crap burning out of there and so I can't see it? Anyways, it sounds a bit like a helicopter driving down the road. Not at idle, only when I've got my foot on the gas. Would it just need the valves adjusted this soon? I know without seeing the truck it's hard to narrow this down too much, but are there some things on a brand newly rebuilt engine that should be making so much noise? I figured after running for a bit it would need a valve adjustment, but I didn't expect it to be this loud right off the bat. Anyways, any advice on what to look for on a engine that's on it's first few miles after a rebuild would be great!

[joey0712]

SOUNDS LIKE AN EXHAUST LEAK TO ME

[83MT [OP]]

Yeah, ok. I wonder why, right off the bat, new gasket, it's leaking? I even re-torqued it, and that didn't help. Could it be that I need my manifold resurfaced?

[RN37DD]

i had some strange noise like that.. the hose was off the smog pump connection at the check valve. also make sure your manifold bolts/studs are not bottoming out.  if they are, manifold well not seal even if the bolts/nuts are tight,

[83MT [OP]]

How would I know if they're bottoming out? And why would they if my manifold is as thick as it ever was? Also, not sure where the smog pump or check valve is...sorry, still learning.

[79coyotefrg]

i had some strange noise like that.. the hose was off the smog pump connection at the check valve. also make sure your manifold bolts/studs are not bottoming out.  if they are, manifold well not seal even if the bolts/nuts are tight,

[83MT [OP]]

Well, the one manifold bolt-hole that was hiding from me has no bolt in it. It's the one on the bottom, closest to the firewall. I've now realized it doesn't have a bolt because the previous owner stripped it. Is there a way, without buying expensive equipment, to fix that, or am I either buying expensive equipment or taking it to the shop?

[RN37DD]

well it all depends... how lucky do you feel? I've removed some broken bolts real easy and some were impossible. remove the manifold and see what you've got. if there's enough there you might be able to use a good vise grip and remove it. solvent and a little heat well help. if it's broke off flat then your going to need to drill it and use an easy out. if you don't feel good about it, have someone who's done it get it out. some well even weld a nut on the stud and remove it that way.

[83MT [OP]]

No, the bolt's not broken. The original stud is missing, and someone used helicoil and a bolt. The hole is still stripped out, though. When I backed the bolt back out, the coil came out with it...I talked to a couple mechanics and the parts guy at the dealership, and I've heard to maybe try a 1mm bigger stud/bolt, or even thread in the stud with a bunch of JB Weld, let it set, then see if I can torque a nut onto that. That's what I'm trying for now. If that doesn't work, I'll tap it. Thanks!

[Plekto]

Well you have two options then.

Take it all apart and re-thread it or take it apart and re-thread it.  (JB Weld will turn to ash with the temps involved - BT, DT - bolt kicked itself out 48 hours later)

[83MT [OP]]

Ah, man. Ok thanks. So it's looking like a tap then? What about trying an 11mm bolt? The stock stud is 10mm. Worth a try, or waste of time?

[RN37DD]

 depends on how much metal was removed. my favorite repair for that would be useing keyserts. they're used  for aircraft as well, so they have to work. i've found that helicoils are mostly good for a one shot repair, one that you never plan to remove again.

[joey0712]

Just tap it out. Then u dont have to worry about it later and it will seal up tight

[83MT [OP]]

Yup, a co-worker brought in a tap set for me. I'll try the 10mm first to see if I can get stock size to work. If not, I'll go up one size. Seems like I could do this with the manifold on.....no? Or would it just make it easier with it off? Thanks a lot everyone.

[83MT [OP]]

depends on how much metal was removed. my favorite repair for that would be useing keyserts. they're used  for aircraft as well, so they have to work. i've found that helicoils are mostly good for a one shot repair, one that you never plan to remove again.

Yeah, and that helicoil would have worked fine, too, if the PO had put the original stud back in, but they decided to fill that stripped hole with a bolt, so it had to come out. I hate dealing with other people's screw-ups!

[83MT [OP]]

Well.....figuring I'd just clear the hole out a bit by running a bolt in and back out of it...I figured I'd run a slightly longer bolt, just to see. Got it torqued down to 33ft/lbs. Good?