Exhaust Gaskets where to buy and can i use automotive grade?

skuzzlebutt · Post by **skuzzlebutt** » Mon May 18, 2009 12:00 am

Was headed out to the islands this weekend and on the way home we started hearing this very loud tinging/wooshing sound. First thing i thought of was an exhaust leak or a bearing on the pump. Tried to listen for it on the water but was very hard. Finally a day later or so i took a peice of hose and used it like a stethoscope and sure enough the tiny petcock on the port side header is completely gone and spring a bit of water and exhaust out. Glad it found it but heres the story. The guy i bought it off of mentioned when i was looking at the boat that he cross threded the petcock screw when he was winterizing it and was having a mechanic fix it. My guess is they half assed it and jbwelded that sucker back in there. We always smelled this odd burning smell when the motor would run. And now that i think about it it did smell like burning epoxy. We no longer smell it now that the exhaust petcock is gone so to speak.

Anyhow we would like to fix it the correct way by drilling and tapping a new screw in there this weekend. I know i could probably do it with out taking the header off but id rather flip it upside down and do it that way outside of the boat.

--- Can i use exhaust gaskets from autozone or are there "marine" grade gaskets like everything else in the boating world? Its a 78 F25 with a 318. Seems like there are only 6 bolts to hold the header on. Was thinking if i can find them cheap at autozone i would take them both off and inspect them and change the plugs while im at it and do a compression check too. I think this motor is either leaking or burning oil...

Stripermann2 · Post by **Stripermann2** » Mon May 18, 2009 7:59 am

Yes, you can. Fel-pro and others will work fine. If you can get a gasket from a performance shop, even better...

guglielmo6160 · Post by **guglielmo6160** » Mon May 18, 2009 8:03 am

sure you can, they do the same thing in an automotive application,
the things you have to watch for while using automotive in marine stuff is the spark possibility and the water contact stuff, and last of course saftey
they say marine stuff is built better, but thats questionable,

skuzzlebutt · Post by **skuzzlebutt** » Mon May 18, 2009 9:33 am

do you recommend putting any gasket sealer on there like ultra copper or anything like that? or is it good to go just with a dry gasket?

wowzer52 · Post by **wowzer52** » Mon May 18, 2009 10:41 am

Dry gasket only. Do not put gasket sealer on exhaust gaskets no matter what kind or brand you use. They are made for the extreme temperatures and easy removal later. happy fixing.

gjrylands · Post by **gjrylands** » Mon May 18, 2009 10:47 am

Use a dry gasket for the exaust ports.

I've found that there is no difference between the marine gasket and auto. I don't remember Fel-pro's # but you need the set that has 6 gaskets in it, one for each port on the engine, not the set of two.

skuzzlebutt · Post by **skuzzlebutt** » Mon May 18, 2009 10:57 am

ok sounds good. I agree. been looking around at gaskets and they sell the one thats a solid peice. i like the 3 individuals better. im not 100% sure but there appears to be gasket particals all over the engine bay. and they look fresh. they are thin paper and feel crapy. I think the "mechanic" that fixed this up real quick for the guy who sold it is a hack. i'm going to pull them off and do it right. i will be making a post here shortly for opinions on oil leaks...

Stripermann2 · Post by **Stripermann2** » Mon May 18, 2009 11:46 am

Use one piece...try holding 3 pieces together while manuvering a manifold in place and you will no longer be going to church!

I take two bolts, cut the heads off and grind a flat screw driver slot in the center. Use these as studs on either end off the cylinder head, this will support the manifold and allow you to keep the gasket in place while starting the other bolts. Then simply back the two studs out and install your bolts back in...

skuzzlebutt · Post by **skuzzlebutt** » Mon May 18, 2009 12:41 pm

while were at it... whats the ft lbs for those head bolts?

kevin babineau · Post by **kevin babineau** » Mon May 18, 2009 12:41 pm

i do what striper does with the bolts..i keep a set in my tool bag along with a little piece of vaccuum line that i attach to the ends of the spark plugs when installing them tune up during makes it so much easier to start the thread ...i also run a tap into the heads to clean out the thread...wirewheel all bolts...i use a 3m red pad whizzer to clean the matting sufaces...i also use a mercruiser sealer called perfect seal on the threads of the bolts....i use the sealer not to seal but as a anti seize...i use perfect seal way too much but thats what i do....

kevin babineau · Post by **kevin babineau** » Mon May 18, 2009 8:51 pm

after thinking about it my 318 has studs with nuts...30 lbs on the nut

skuzzlebutt · Post by **skuzzlebutt** » Mon May 18, 2009 9:18 pm

if i remember correctly mine has one stud on each side towards the bow and the rest are all bolts. is this the norm? or is all studs the norm?

kevin babineau · Post by **kevin babineau** » Mon May 18, 2009 9:25 pm

as far as i know the orginals had rods with nuts course thread into the head and fine thread on the outside...as long as u have the right length bolts it doesnt matter..i cant remember if on 318 but i think one or two of the manifolds bolts goes into the cooling passage o would drains the block to be safe and put a sealer on the threads...i could be wrong but i think so

ready123 · Post by **ready123** » Mon May 18, 2009 9:26 pm

skuzzlebutt wrote:while were at it... whats the ft lbs for those head bolts?

According to the manual it is 95 ft-lbs torque on the head bolts.
Starting at top centre bolt tighten, moving top to bottom then outboard to next bolt one side then the other to 50 ft-lbs all bolts, then redo to 95 ft-lbs.

Looking at heads bolt order is:
7 3 1 5 9
8 4 2 6 10

You can get an electronic manual for the 318 here:
http://www.marineengine.com/manuals/chrysler/index.html

skuzzlebutt · Post by **skuzzlebutt** » Mon May 18, 2009 9:29 pm

im about 99% sure there are only 6 bolts on these manifolds.