Pan gasket for 360. What one works best?

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mistreta

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Getting ready to change the pan gasket on my 360. All the ones out there are the 4 piece type. The LA block is different han the magnum, there are one piece gaskets for the magnum but none that I can find for the LA motor.
Any suggestions.

Thanks for the help
Tony in Howell
 
Here's what I do:

I buy a Magnum one piece gasket and a standard 4 piece 360 gasket.

After a test fit, I use the rubber ends from the 360 gasket for the ends (timing cover and rear main cap). CAREFULLY cut the magnum one piece ends off (as the long rails are the same on the magnum and LA 360) then seal the LA ends to the magnum rails with a bit of black silicon.

Costs a little more, but my pan gasket doesn't leak.
 
I also used the Magnum 1 piece on my LA 360. I just replaced the front seal below the timing cover with the LA piece and siliconed in the Magnum side rails. The rear seal is the same. No leaks and you can't overtorque the Magnum rail gasket.
 
I'm trying that too. In fact if I could have just found the front seal I wouldn't have needed to buy another gasket set. I usually have tons of this stuff laying around, but since I moved I can't find half of it anymore.
 
HI ,I'm new to this site but I hope someone can help me with my problem. Three years, three rebuilds and still leaks. so frustrated. so lets start from the beginning. started restoring my 74 duster 6 cyl. first bought a 360 out of 75 truck and sent to machine shop, cleaned , checked, bored long story short, replaced everything. car done engine in and started right up everything good. first time driving got a little oil leak around rear of pan. as i got more miles on it and started giving it more gas the worse the oil leak. oil pressure 30-40 ideling up to 80 when i step on it. let me get to the point it could take me all day to tell you the things i have done since the first build. #2 had machine shop recheck out but the crank had a small grove at the seal area but he said he didn't think that would cause a leak. got all together and still the oil leak. won't leak if i drive real easy. the more i get into it the wores it leaks. i can not tell exactly where the leak is, i have even tried dye in the oil. its always all around the back of the pan, there is nothing coming from the top of the engine. I changed the oil pan again and took out the high folume oil pump and put standard back in. still leaks. #3 pull engine again, put in new crank with premium seals, still leaks. please help me. is there a difference in the pans. i started out with a chrome oil pan and went to a dodge dealer and bought a factory pan still leaks. i put on a new PVC also have an exter breather cap. every time i think i have the problem solved. not so . any one else ever had this problem. "HELP"
 
Its either the rear main seal, the pan gasket, or something is leaking from the top of the motor.

The problem is that everything runs back there. Have you used the same kind of rear main seal each time?

Is it coming out the freeze plug behind the cam?

Are you sure nothing is leaking on the top end? One of the heads, or maybe the seal at the back of the intake manifold (are you using silicon or cork there)?

Bad O-ring on the dizzy?
 
How about the rear cam seal, mine leaked on the 340 I had. I pulled out the old soft plug, cleaned out the reciever in the block and replaced it with a new one with some permatex around the edges. It would run down the back of the block and I swear it looked like the rear main seal leaking. I had to pull the trans and flywheel to get at it..PITA
 
Thanks for all the response. I bought a new one piece gasket, for a 360 magnum, and a gasket set for a LA motor. LX guy's sugestion. The motors a stroker 408, with less than a 1000 miles. The leak is in the same area, back of the pan, like Ed Beight's.
I'm taking it in to a local shop Tuesday, the local Mopar smart guy. I'll let you know what happens. How can you tell, can you tell if it's a rear main?, would the oil be inside the trans dust cover if it was a rear main?
 
everthing has been done 3 times. i have less than 150 miles on the motor since the first rebuild. I have replaced the cam twice because a lifter was up in the wrong place on the second rebuild. but the cam seal has been replaced all three times, once by the machine shop. al the plugs on the back of the engine have been checked, everything is new and freshly paintedand can find no sign of a leak on back of engine. crank replaced and new rear seal replaced three times. i have checked the back of the intake around the heads, the valve covers the oil filter and the distributor. like i said everything is new and clean and there is on oil leaking down the engine anywhere. what else could it be? thanks for your replies
 
Has there been any thrust wear?

Given that, I'd say it was either pan gasket or rear main seal. Are you using the correct seal for your engine? One piece or two piece?

What are you using for a pan gasket?
 
i believe it a two piece seal, and I am using a fel-pro pan gasket. using a light just right i can see up thru the back of the engine and i can see no oil around the rear seal area. I should have bougth a crate engine for what i have in this. but i have to much in this to quit now. runs great just leaks oil.
 
ed beight said:
i believe it a two piece seal, and I am using a fel-pro pan gasket. using a light just right i can see up thru the back of the engine and i can see no oil around the rear seal area. I should have bougth a crate engine for what i have in this. but i have to much in this to quit now. runs great just leaks oil.
Click to expand...

Well, then, where is it? How can something be leaking out the back of the pan and not be leaking out of the rear main seal area?
 
I have a 360 with a Kevco pan and the one piece and it leaked like a sieve. Looked like the Exxon Valdez crashed under the engine. Messy. Might try it one more time or just put a 4 piece gasket set on it.
 
After looking at all the issues that could be causing a leak in the pan area, I got under the Duster to see if I could tell where the oil was leaking. The area between the pan and trans, on my 727 has a inspection opening that let you see the teeth on the front of the trans seems to be not where the oil is. When the moter was first done, the leak was being thrown back on my new TTI's, from the torque conveter spining. I put a piece of rubber over the opening, it helped to keep the oil off the headers. Inside the cover is wet from oil. I'm thinking rear main. Any thoughts?
 
I just went through the same thing with my 408. I had used the rear main from the Fel-Pro gasket set and it leaked. Replaced the pan gasket twice, It still leaked. I ended up usng a new and different rear main (P/N 4798216AC) and now no more leak. Could not find any issues with the old seal, it just leaked. I'm also using like said above a Kevco pan with Magnum gasket.
 
So the part # above is a mopar part ? from a dealer. I'm using a stock pan, but a magnum gasket, using the ends from a felpro gasket set. I wonder how the rear main seals, mopar and felpro are different. So in your case the rear main seal was the problem.
Is changing the rear seal a big job?, whats involved?
Maybe thats Ed Beight's problem also
Thanks for the help
 
I got my seal from Hughes but they don't list it anymore. It was not a Mopar seal. Once you get the pan off the majority of the work is done. Easy to pull the oil pump and the rear cap and replace the seal. Follow the link below to a post over on Moparts that shows the two different seals. The orange one is the one that stopped my leak.


http://board.moparts.org/ubbthreads...ds=+Mopar73340&topic=&Search=true#Post6650274
 
Let me understand this, the trans does not need to be pulled? Just remove the pan, mine has a windage tray also and do the other caps need to be loosened?
Thanks again
 
mistreta said:
Let me understand this, the trans does not need to be pulled? Just remove the pan, mine has a windage tray also and do the other caps need to be loosened?
Thanks again
Click to expand...

Correct you do not need to pull the trans. Drop the steering linkage, remove the pan, remove the windage tray, oil pump and #5 rear main bearing cap. You could loosen a few of the others if necessary. You should be able to push the top half of the old seal out and install the new one. Make sure you don't damage the crank while pushing the old seal out.
 
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