Exhaust manifold gasket starting point

[mutt and jeff]

Without starting WWIII, I just, at this point in time, need a starting point. I am hearing an exhaust leak and my son sees black soot at the manifold to block area on my 66 A1. After reading a lot of foum posts about gaskets, copper, grease, silicone, etc., I need someone to start me out in the right direction. I have no history with the MUTT salad that I believe to be a A1, but with A2 windshield and A2 emissions gas tank and who knows what else.

So, here are two pics of my engine. Is it the early version that requires no gasket and do I proceed to loosen or remove the manifold and grease or silicone it up and re torque to the correct specs and sequence?
Is it an early A1 engine, but install a gasket anyway?
Is it an A3 engine and requires gasket or gaskets?

I can download the manual, but need to know what I am looking for. Thank you in advance.

engine 1.JPG

engine 3.JPG

[mutt and jeff]

I guess I can pull the valve cover and read the head number and use that to determine if it is early or A2. Early is silicone red perma gasket and later numbers are A2 and require gaskets? Am I on the right track with that?
Late afternoon showers here in GA so probably wait till I pull it in the shop tomorrow to pull the valve cover. Probably need that gasket, clean it up and repaint it as well. The do the manifold while paint is drying.
Solved my little exhaust leaks along the pipes and then could really hear the under the hood puffing. Don't want to mess with timing or carb until I get the exhaust issue solved.

Fun, fun, fun.

[Mr. Recovery]

No need to pull the valve cover! as far as the head goes the only difference is the exhaust mounting bolt bosses are heaver/thicker, only need to pull the intake and exhaust manifolds.

dan-2beers.jpg

[mutt and jeff]

Presume if there are no old gaskets, don't need new gaskets? Either scrape off old silicone or wipe off old grease and that will tell me what was on it to begin with?

[Mr. Recovery]

Presume if there are no old gaskets, don't need new gaskets? Either scrape off old silicone or wipe off old grease and that will tell me what was on it to begin with?

Yes, I have only used the gaskets 1 time only because I didn't have a replacement, the old one had been over tighten and crushed around the openings.

this is a later head with the bigger bolt hole bosses.

20200721_153744 151 heavy head.jpg

dan-2beers.jpg

[rickf]

On the early heads the exhaust manifold was a snug fit in the bore of the head so they used graphite grease as a sealer. Think the goo that is used in CV joints Molybdenum sulfide grease. I never used that since the high temp silicone was not around in the 60's and that is what I use. The later heads you will know if you lay the exhaust manifold in the recess and it rocks back and forth and you can see a gap on either side of the manifold then you will need gaskets. You have to pay very close attention to the tightening specs since they are both different from gasket to no gasket and they are also a lot less than you would think. A lot of people just crank them down and crush the manifold. You are probably going to find the infamous stainless steel bolts in the manifolds and they are always a problem to get out. The threads gall on the way in because they were put in dry or tightened too much and if that happens they are going to break. IF it doesn't want to come out you can try some light oil but if it is a stainless bolt do NOT use Kroil or PB Blaster because you need lubrication, not penetrant. Odds are that it is gets stuck it is going to break. Use grade 5 bolts when you put it back together.

[m3a1]

Don't know if this will be of any help but go here for details on my experience with doing a manifold (without gasket) for the first time. I followed the instructions that came with the kit and found it to be a very straightforward job. Follow the torque specs to the letter. They are exceptionally light. I also made some decisions to NOT use the stainless steel fasteners, which are also detailed there.

viewtopic.php?f=13&t=12204&start=150

Remember, if you're getting into this project, now would be a good time to deal with any issues you may have, or think you may soon have, with the expansion plug in the block below the mounting flange. It cannot be dealt with without removing the manifold. The area behind this particular expansion plug is almost the lowest point in the cooling jacket and a lot of debris does collect there.

Also remember that your manifold tube may be out of shape (from over tightening by the last guy) or otherwise damaged.

Cheers,
TJ

[mutt and jeff]

OK, without incurring the wrath of the mechanics and purists, I am going to ask a Bubba type question...be gentle. Keeping in mind that I have not determined the level of restoration of the A1, I am still researching what it needs or will need. It starts and runs OK, but not great, so I am trying to determine what this engine will need. I am 80 percent leaning towards a engine removal, and some minor reworking like pan gasket, checking expansion plugs, manifolds, head gasket, etc.

So I want to do compression tests and piddle with the carb and timing to see how bad some things are. But, this exhaust leak has me thinking that I need to get it resolved before I test the other aspects.

So, if I can address the exhaust manifold situation more permanently down the road, is it possible to just loosen the manifold bolts (fingers crossed) and apply the silicone gasket material and tighten to torque specs? Then I can test my other issues and leave it with the intention of having to do a proper job at my convenience.

Is there a way to "plug" the manifold leak temporarily to do my other evaluations?

I'll clenth my teeth and listen . . .

[rickf]

When you loosen the exhaust manifold you are also loosening the intake manifold as they are put on together. So retigtening it may or may not seal the intake from leaks. Most likely it will not if it is the original gasket.
.

[mutt and jeff]

I've pulled the MUTT into a bay and will start disassembly first thing in the morning. Evaluate gasket condition and all the bolts I break getting everything off and then go from there. Wish me luck.

[rickf]

Good luck. If you need to drill any of those bolts be sure to use a NEW drill bit and run it fairly slow. Stainless steel is a bitch to machine.

[m3a1]

I'm going to talk plainly.

1. Any efforts on that engine will be greatly compounded by having it still in the vehicle, especially in the worst case scenario as described by Rick.
2. Is this a problem that is so bad that it must be addressed immediately? Your comments suggest you have other, more pressing jobs.
3. If this goes sideways, are you prepared to have your vehicle red-lined until it can be sorted out?
D. Is there a better time and circumstance in which to do this job? Choosing your battles is important. Choosing when to fight them is equally as important.
5. Check which bolts are stainless steel with a magnet BEFORE wrenching. That will tell you where you need to use extra care.

Cheers,
TJ

[mutt and jeff]

Uh, Oh, not going well. I'm working my way to the manifolds, and I stop along the way to clean, sandblast, prime and paint the oil bath air filter, then the valve cover and it just takes me time to find all the correct wrenches. I removed the market light and fender black out light as they will need attention and the fender top will need attention and it get's them out of my way for the manifold work.

Anyway, I felt a loose bolt at the front of the manifold and was hoping that just a loose bolt was my issues, but learned that the bolt is loose because the cast lug that it bolts into on the head is broken in half right through the tapped hole. I'll keep removing manifolds and parts tomorrow and get a photo, but I don't know if that lug is cast and a difficult weld or if I have some options with a backing plate and nut and bolt in that area, or if I'm looking at a new head.
I've got a short block engine coming from my parts stash that has a head on it, but I don't know if it is A1 or A2 until I get it in the shop.

But now I know why the exhaust leak in the first place. Probably wasn't helping intake either.

Fun, fun, fun.

[rickf]

That bolt would not have affected the intake but you still need to address it. As far as the head any head will work on any engine, it does not have to be an A1 head. That piece that broke is the boss that will be substantially bigger on the desired heavy duty head, so look at that on the engine you are getting. I have welded that boss up solid and redrilled that hole and threaded it with success, it is not structural so not too much to worry about but you are not going to do it on the vehicle. Depending on how much of the tab broke off you may be able to back it up with a tapped piece of steel plate.
But at the rate you are going with finding all these other tings to do in the process of getting there this could take a while.

[mutt and jeff]

Just long enough for me to forget how everything goes back together.
But, I pick my battles. Good thing to know I can weld up that boss if I need to and that it is not life threatening. Good news is that other bolts appear newer and are not SS, so I'm hopeful that no other bolts will be hurt in the process. Valve cover had no gasket on it just 1/4" of silicone gooped all around the perimeter. Have gasket and gromets in stock, so after painting, this should leave a much cleaner engine compartment.