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post #1 of (permalink) Old 04-29-2000, 09:33 PM
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header gasket leak, 401 crank in a 304

I have two questions. First, I have CJ7 with a 401 and i have tried header-gaskets and stock exhaust gaskets, but i still have a exhaust leak on the #1 cylinder. The next step I plan is to weld around the surface of the header to give a wider lip around the port?? The brand of headers that I am using is Blackjack. Has anyone had a similar problem??

Second, I have another CJ7 with a 304. Today I found some metal in the oil pan, I think it is the remains of a bearing. At this point I have checked the rods- seem to be OK. My next step is to look at the main bearings, if my crank is damaged could I use a crank from a 401, I have a spare???

Thanks to all

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post #2 of (permalink) Old 04-29-2000, 09:59 PM
 
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Re: header gasket leak, 401 crank in a 304

Im pretty sure a 401 crank willnot fit into a stock 304 block

Ill trade you a perfect condition std size 304 crank for that 401 crank!

Ill even throw in some $$$

OzarkJeep
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post #3 of (permalink) Old 04-29-2000, 10:55 PM
 
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Re: header gasket leak, 401 crank in a 304

Take a fine flat file and check the header gasket surface to see if it is flat first...
sounds like it might be warped, or have a high or low spot...
Blackjack isn't the best brand of headers around, and I have had mega problems with them in the past doing just what you describe...
-------------------------------------

304 and 360 share the same crankshaft. They are the same part number, and the same specs.

The 401 crankshaft WILL NOT FIT!

Make the trade.

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post #4 of (permalink) Old 05-04-2000, 01:59 AM
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Re: header gasket leak, 401 crank in a 304

The headers usually leak around the dog-leg in the port. Stare and compare the remains of the old gasket to the header. Sometimes welding around the outside of the tube and reshaping the inside to better match the head will do the trick. Factory manifolds will not cost you much in performance and will seal much better.
The 401 crank will fit into the block, but you will need 401 rods, 401 rod bearings and custom pistons. The main journal size is the same but the rod journals are larger on the 401. The rods and crank are much stronger, as they are forged.
If you don't find bad mains or rods in the 304, pull the cam and check the timing components, cam and cam bearings for wear.
Hope this helps, good luck!

post #5 of (permalink) Old 05-04-2000, 08:06 AM
 
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Re: header gasket leak, 401 crank in a 304

He is correct about AMC cam bearings...
I've never seen anything like it...
I don't know if it's bad oiling, bad bearing material, or some screwed up machining practice, but there is no such thing as a 'slightly used' cam bearing in an AMC V-8...
Even if they have been in a very short period of time they will look like they have 500K on them...

Check you #7 & #8 rod bearings very close...
These are the ones that get practically no oil.

Good luck.

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post #6 of (permalink) Old 05-04-2000, 12:03 PM
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Re: header gasket leak, 401 crank in a 304

Copper silicone works great around both sides of your header gaskets. We've even used it without gaskets on race cars. You can always have a mechanic hook up an air planer to your head. It slowly goes over the surface where your headers bolt to the head smoothing out the head without taking your motor out of the vehicle. Doesn't cost that much either. It will help guarantee you don't have warping. Also, we have cut between each collector on the header. This originally was to help us line up the bolts better--turns out it helps the headers turn and bend where they need to and not bind against each other.

John
89YJ-350V8,etc.
post #7 of (permalink) Old 05-04-2000, 01:23 PM
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Re: header gasket leak, 401 crank in a 304

[img]/wwwthreads_images/icons/tongue.gif[/img] When I first laid eyes on that peculiar dog-leg port on the AMC V8, I thought: "Hmmmm.... this is a place for studs!" So we made studs for each and every one of the holes, and we used TWO nuts...an oversize next to the manifolds, and a standard nut on the outside. PLUS we used some special washers that just fit in back. Overkill? Maybe? But it sure looks and holds good.[img]/wwwthreads_images/icons/smile.gif[/img] You can do stuff like that when you have all this cheap moonguy[img]/wwwthreads_images/icons/wink.gif[/img]labor around the shop[img]/wwwthreads_images/icons/laugh.gif[/img]

CJDave
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post #8 of (permalink) Old 05-04-2000, 02:00 PM
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Re: header gasket leak, 401 crank in a 304

yes.. have used studs before.. and they have worked great.. and i also double nutted them..

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