[jcruse64]

Looks like I'm going to tackle the exhaust leak on my '73 truck. It's coming from the driver's side, and sounds like the gasket needs replacing. No idea if the gaskets are factory, or if the PO put these on years ago.

I've gone through the archives first, and it sounds like factory didn't always send these out the door WITH gaskets, but sometimes did? My first question is, should I put new gaskets back on this motor, or take the manifolds to a machine shop and have them true these up, and then re-install w/o gaskets?

Next question is, if I need to go with gaskets, should I still have a machine shop true these manifolds up first?

Next question is, if gaskets SHOULD be used, what type/brand gasket would be best? I see on RockAuto a set from Felpro, and a set from Mahle (graphite), along with a much cheaper set (composite?) from Mahle. Any recommendations here?

Finally, the hardware. I started on getting them loosened from the engine today. I let the engine run for a while to get warm, then cool down a little bit, and then started working the bolts and nuts loose. Some loosened up on this first try. Those that didn't, I hit with PB Blaster, let the truck get warm again and then cool a bit, and worked on again, and was able to get them loosened and started out. So, I think I can get these all safely out.

Would it be best to replace all this hardware with new stuff?

From reading here, it appears that on SB's the 2 outer studs on each manifold go into the water jacket, so when replacing them back, sealant MUST be used to stop water. What sealer is best, and do I put it all over the threaded end that threads into the block, or just the tip of the studs?

Is it a good idea to use the anti-seize stuff on all other threads, to prevent rusting together in the future?

What is torque spec on these; 30 ft/lbs?

Any other good tips on servicing this part of the engine? Looks like it has the heat-riser setup on the pass side; anything there to watch for?

Thanks,

Joe

 

[dodge82273]

felpro fine , check your manifolds for flat / straight / clean ( not rusted thin where gasket goes ) , or get them trued IF you can , no harm done there ...  sealant is like deodorant , every one has their preference , I'd use locktite "gasketmaker "  trick with these is to use the cone washers that oem installed , run motor and retighten them while hot , grade 5 bolts that do not run out of thread before getting tight , grade 5 ( or better )  nuts(4) ( note all holes in heads are coarse thread while the end studs are oem fine thread on the nut side ) IF the end studs stay in head and weren't leaking water , or rotted in half , threads good where nuts sit , leave 'em there .... ain't broke , don't fix it ..

flapper in 1 side is to "force" exhaust thru intake crossover , heating intake quicker on cold start up . The crossover is often completely clogged however , and the flapper's bi-metalic spring is often shot , some folks remove the flapper leaving the shaft to "seal" the holes , in any case be sure it is NOT stuck , restricting flow .
check for tight a few times over a period of time / use ....  I always use gaskets .

 

[DODGEBOYS]

l would NOT have them machined = you will either hafta bend or cut and reweld the exhaust

 

[jcruse64]

That might not a big deal, because this truck needs new exhaust run anyway. Mufflers rusting and going to get replaced when some other work is finished.

Found a hardware kit for the manifolds:

http://www.rtspecialties.net/proddetail.asp?prod=1000028B

 

[dodge82273]

looks correct , other than the washers , which you want , the rest is alot of money IMO , but I'm cheap , out of touch with the price of simple stuff . Like I said if the studs don't come out and are reuseable I don't mess with them .

 

[Broncowilly]

OP, when you go back together with it, use anti-seize on the threads.

 

[KurtfromLaQuinta]

OP, when you go back together with it, use anti-seize on the threads.

I agree with anti- seize.
It's really hard to beat Permatex Ultra Copper High Temp Silicone for any exhaust seal.

 

[jcruse64]

It's really hard to beat Permatex Ultra Copper High Temp Silicone for any exhaust seal.

In lieu of manifold gaskets? or WITH gaskets?

10-4 on the anti-seize.

Thanks!

 

[Elwenil]

With gaskets.  The silicone does a good job of filling in the low spots so the gasket can seal better.


Bit of trivia here, but the vast majority of Mopar engines never had exhaust manifold gaskets.  They were just machined flat to match the head and bolted on.  The factory parts manuals rarely ever list a gasket.  The only ones I can think of off the top of my head that do are late '70s big blocks.

 

[jcruse64]

Thanks El, will add to shopping list.

See, I thought I'd read that about no gaskets from factory in a few of the threads I searched on, both here and on Moparts. Probably no way to know if the gaskets that are on this engine are factory or not.

 

[Elwenil]

Unless it's an engine from the muscle car era, I'd guess they were not there from the factory.  For what it's worth, I don't think I have never seen a listing for exhaust manifold gaskets for a LA 360.

 

[jcruse64]

I need to pull out the FSM for this truck and see if it says anything about them. The engine is  '73. At any point, the manifolds need to come off and be inspected for a crack, or other bad news.

 

[crazzywolfie]

i have pulled the exhaust manifolds off my 81 a few times and always put them back on without a gasket and had no leaks. i do got exhaust gaskets for if they ever start leaking but hopefully that never happens.