Small exhaust leak

[RLDSL]

I noticed remnants of a small exhaust leak on #7 while poking around the engine on the stand today. A bit of oily residue around the manifold /head and down onto the exposed part of the head gasket. A quick check with the torque wrench found the last bolt loose, so it looks like that's where all the residue came from.
Question for the masses is, with only 5000 miles on that exhaust gasket, do I risk just torquing that thing down, or should I pop a fresh exhaust gasket in there?
and 2, does it look like any of that oil residue might have been coming from elsewhere like the head gasket itself?

Thanks----Robert

 

[icanfixall]

That oil seems to be from some other place.. As for just retorquing the gasket, sure. It may work and really you aren't out anything if it does. Did you use new exhaust manifold bolts? If not that may be why the bolts loosened up on you. They have an interferance thread so they wont back out. If the gasket doesn't hold then I feel you need to replace it and the bolts. I bought mine from Ford Parts Online (Bob Utter Ford in Sherman Texas).

 

[RLDSL]

I bought this engine already assembled with just a handful of miles on it ( it still had assembly lube in the lifter valley so I figure he was straight with me on it ), but it's a safe bet that they didn't use new exhaust manifold bolts

 

[RLDSL]

Let me back up here a minute, do the manifold to block have an interference thread as well? I know the studs do, but I didn't think the ones into the block did. those looked like a standard thread when I had them off my other engine.

 

[icanfixall]

What manifold to block are you refering to??? Also what studs do you think have an interfrerance fit. The only bolts or studs for that matter that have an interferance fit are the exhaust manifold bolts. The head studs "float" in the block. The block has 1 5/8th inch of threads and my RAP studs have 1 1/4inch of threads top and bottom.

 

[RLDSL]

The loose bolt was exhaust manifold to head. I thought those were standard bolts, not interference fit. The studs I was referring to are the ones on the ends of the exhaust manifolds where the up pipe/ crossover pipes hook up that have the interference fit, I thought, that's what you were talking about.

 

[2manydsls]

An exhaust leak will usually appear as black soot, same as inside of tailpipe. If it is oily, it came from somewhere else unless engine has big problem.
Ross

 

[RLDSL]

Sheesh, I just remembered where that oil came from... It dripped out of the end of the refrigerant line when I was moving it out of the way
Man I'm paranoid after the freeze plug coming loose.
After all of the other weeps and seeps I've found on the thing, I think I'm just going to pop the heads off while it's on the stand and give it all new gaskets. At least if I put it together , I know it won't leak and I'll quit worrying about it. Right now I'm at the point where it lost one freeze plug, and another leaking, the water pump was seeping around the gasket and a couple of bolts and the oil pan was leaking like a sieve. I'm just not feeling good about their assembly and it's going to bug me until I go in there and see for myself. This is what I get for letting wife.gov talk me into buying an engine already built instead of rebuilding it myself to save me some strain

 

[icanfixall]

Good idea but don't use an oil pan gasket. I use Permatex Ultra Copper Plus. Never have had a leak in all the years of using it. Chevy big blocks don't have valve cover gaskets from the factory either. Just clean the surfaces with something like acyatone or brake cleaner in a spray can. It works great. Don't get the acyatone on you or breath it. It gets caught up in you kidneys and wont flush out. It just stays there.... Not good either.

 

[RLDSL]

I'm not a fan of silicone in any form. I've just never had good luck with it. If I go gasketless, I'll go with the anaerobics, they seem to like me more . but for this project, I just got three tubes of racing formula Hylomar gasket dressing in the other day found a little cheaper source here . A film of that on each side and there won't be any leaks period. Going to use it on the freeze plugs as well.

I picked up a quart of acetone last night to start cleaning things up. I learned my lesson on that stuff the hard way working with fiberglass a bunch of years ago. I've got the high dollar respirator now that's some nasty stuff over time. It always used to get me when wife.gov would break out the fingernail polish remover in the house without firing up the vent fan I finally drilled it into her head what that stuff can do to kids so finally she takes it outside.

Acetone actually is produced naturally in the body in very small amounts, in folks who go nutso on the low carb diets, their bodies produce massive amounts of the stuff ( carbohydrates are required to burn fat, so in the absence of them, the body produces keytone bodies i.e. acetone to burn fat , which as you mention, plays heck on kidneys) so if anyone has kids going into med school, tell them to specialize in kidney problems, because all these people on Atkins diets are going to have kidney problems in 20 years.
At one time I thought I wanted to be a dietitian and went to college for that, but I ran out of money the 5th year.

 

[Diesel JD]

Robert you must be a smart guy. That's no easy major. To show how redneck I am about these things, I used standard Grade 8 bolts on my exhaust manifolds when I did the heads in the engine. As best as I can tell they haven't backed out yet, though sometimes it sounds like I might have an exhaust leak here or there. I'd do whatever makes you comfortable on the gasket. I'm not impressed with them, but at least they aren't too expensive. I'd just hate to see you have to try to replace those gaskets in the truck, they are no fun there. Should be easy on the stand.

 

[icanfixall]

Ok.. Heres what I did to make my exhaust manifold logs to seal up. First I bought new "exhaust manifold bolts" From Ford parts online. Then because I had the machine shop to work in I used a Blanchard grinder and surfaced the manifolds flat. I know everyone doesn't have this kind of options but it sure was worth it. The manifolds get hot and cold and over time warp and leaks will happen. Thats why they are made out of cast iron. They get so many heat and cooling cycles. Stainless works too but it does work harden after some time too. It sure would be neat to make up a custom exhaust manifold out of stainless 90 degree ells wouldn't it....

 

[RLDSL]

It sure would be neat to make up a custom exhaust manifold out of stainless 90 degree ells wouldn't it....

.....I'm Thinking.......I bet I could sleep in the thing for a few weeks......it'd be worth it... right???
I was able to pass the shiny polished aluminum radiator off as a necessity, but I don't know if I could get away with stainless exhaust manifolds

 

[oldmisterbill]

Several interesting things
1. I had no idea the exaustmanifold to head bolts had an interference fit,but it makes sense. I have always used high quality (from a well known manifacturer)grade 8 bolts.I have heard of taking a real sharp chisel and putting a line or 2 down the bolt ,using a hammer/with a light blow on the chisel,then lightly dressing it with a 3 cornered jewlers file,(I have to admit i have done it a couple times too) to make a bolt that won't loosen up ,yet do no damage to the female threads.

2. I often use ACE hardware furnace cement very sparingly as a seleant on my exhaust manifold gaskets-has worked well many times.Remeber not to be sloppy oif u have a turbo.But as Gary says milling the surface is best (us po fok don't have all this fancy stuff)

3. i have used stainless studs for pipe to manifold connections(even have used stainless bolts for head to manifold)but never use stainless nuts to stainless bolts or visa versa-they will gall and lock up tight with the heat.Use steel.I dislike brass nuts on ex studs as they gall up too.
4. Gary I have to agree to dissagree about silicone on oil pans.It too must be used sparringly.I had a reman done at a shop in Waterville ME.The first one crapped out on the way home(a 6.9 in my old 84)he bought a 7.3 and resleeved it(we found out a couple years later he bored it .030 over)never gave a problem with the over bore.When I got home from Maine with it I looked it over-the installation was lousy-loose wires tranny lines hanging(not clipped so they wouldn't rub-sharp bends on the starter wires(at the terminals) because they just tightened them without watching how they wound up. And most important there was major silicone hanging (should I say dripping) from the oil pan.I had noticed a fluctuating of oil pressure on the drive home (185 miles)-I pulled the engine and reinstalled it,removing the oil pan to check it,playing on a hunch.A big snot of sislcone was up in the oil pu screen.I had a pic of it because I sent it to the rebuilder,but lost it in a computor crash.After that oil pressure was constant. If used properly silicone is good,but too many amatures missuse it.

5. When I have a vacum or exhaust leak(especially a small one) I use a stethascope with a long tube attached to it instead of the little diaphram,it will pin point the smallest leak to the exact spot.

Robert- a quick question -I like to use ether for cleaning because it dries nice and clean-what are the harmful effects of ether.I used to use a lot of laquer thinner but I know it isn't safe healthwise.


My 2 bits Mr Bill

 

[Dirtleg]

It sure would be neat to make up a custom exhaust manifold out of stainless 90 degree ells wouldn't it....

I can tell that in some ways you and I are very much on the same page. I was thinkings twins with T3's on the ends. I am so waiting to have my own shop again so that I can do these kinds of projects. Here is a picture of some of my work.

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I would definitely rather be building with stainless. Just love tig welding.