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Coolant near BB head locating pin? #2784840
06/13/20 07:31 AM
06/13/20 07:31 AM
Joined: Jan 2003
Posts: 949
Indiana
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68_661charger Offline OP
super stock
68_661charger  Offline OP
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Indiana
Ive been getting a small coolant bubble near the exterior head locating pin on the number 1 cylinder on a stockish 383. I have re gasketed twice with steel shim gaskets. First time with spray sealer which was a noticeable leak. Second time with no sealer and better results with only a tiny coolant bubble. Never enough to even drip. I get the bubble on startup cold or warm, radiator cap on or off no change. I have never over heated it. Stock machined decks and heads So my question is, How close is this locator pin to coolant?

Attached picture shows area of leak but Im not sure if leak is head side or block side.
Im willing to mag and machine just looking for direction on why the leak is in this spot.
Thanks guys.

20200517_200017_HDR~2.jpg20200517_201257_HDR~2.jpg
Re: Coolant near BB head locating pin? [Re: 68_661charger] #2784843
06/13/20 07:43 AM
06/13/20 07:43 AM
Joined: Oct 2004
Posts: 3,097
back in Georgia
dthemi Offline
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Just guessing here, but it looks like the surfaces are too course for a steel gasket. I know they all say to use nothing on the gaskets, but even with a near mirror finish, I use RVT around all water passages, block side, and head side. Not a ton, just thinly wiped with my finger around them all. Some of those lines I see on the picture, look like they would channel water to the outside of the block.

Another very outside chance is check the depth of your dowel pin hole in the head against the height of it in the block to make sure it's not resting on the dowel. Set the bare head on the block and make sure it doesn't hold the head up.

Re: Coolant near BB head locating pin? [Re: dthemi] #2784850
06/13/20 08:17 AM
06/13/20 08:17 AM
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Posts: 949
Indiana
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68_661charger Offline OP
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I did double check dowel pin length and its good. I do see what you are saying with the cut of the deck...

Re: Coolant near BB head locating pin? [Re: 68_661charger] #2784856
06/13/20 09:28 AM
06/13/20 09:28 AM
Joined: May 2005
Posts: 1,944
Apollo, PA.
B1MAXX Offline
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Deck surfaces can be really marginal in terms of flatness/ finish. I think that's why all the stock replacement head gaskets are not steel shim. I would think that a normal replacement gasket would seal right up.

Re: Coolant near BB head locating pin? [Re: B1MAXX] #2784865
06/13/20 10:08 AM
06/13/20 10:08 AM
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Indiana
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68_661charger Offline OP
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You are probably right on using a better gasket but I hate to lose the compression points. I do like the sound of trying rtv around the cooling ports....

Re: Coolant near BB head locating pin? [Re: 68_661charger] #2784867
06/13/20 10:10 AM
06/13/20 10:10 AM
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Milwaukee WI
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TRENDZ Offline
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Milwaukee WI
I would suggest a composite gasket.
Sealer may work with the steel shim, but you’re probably getting tired of pulling the head.


"use it 'till it breaks, replace as needed"
Re: Coolant near BB head locating pin? [Re: TRENDZ] #2784869
06/13/20 10:16 AM
06/13/20 10:16 AM
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Indiana
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68_661charger Offline OP
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Id do it once again if the rtv trick might work. CR is measured low so it would be great to keep the shim gasket.

Last edited by 68_661charger; 06/13/20 10:18 AM.
Re: Coolant near BB head locating pin? [Re: 68_661charger] #2784909
06/13/20 11:26 AM
06/13/20 11:26 AM
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So. Burlington, Vt.
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fast68plymouth Offline
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So. Burlington, Vt.
To answer your question........ the small hole to the right of the dowel pin hole in your first pic is a coolant hole.

If the leak is as minor as you say, I can’t imagine that a dose of stop leak wouldn’t solve it.

As for the composition gasket......... mill the heads .020 and use a Fel-Pro 8519 gasket, and you won’t lose any compression...... as well as have a flatter head with a better surface finish(if done on good equipment).


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Coolant near BB head locating pin? [Re: fast68plymouth] #2785394
06/14/20 02:17 PM
06/14/20 02:17 PM
Joined: Jan 2003
Posts: 949
Indiana
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68_661charger Offline OP
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Thanks for all the advice. Im going to disassemble it and mill the heads and use a composite gasket.
Do the dowel pins go all the way into the water jacket on the block?

Re: Coolant near BB head locating pin? [Re: 68_661charger] #2785623
06/15/20 10:17 AM
06/15/20 10:17 AM
Joined: May 2005
Posts: 1,944
Apollo, PA.
B1MAXX Offline
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Not any of the ones I have seen.

Re: Coolant near BB head locating pin? [Re: 68_661charger] #2785721
06/15/20 01:42 PM
06/15/20 01:42 PM
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Bend,OR USA
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Cab_Burge Offline
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Bend,OR USA
Originally Posted by 68_661charger

Do the dowel pins go all the way into the water jacket on the block?
Not on any early (pre 1990) Mopar V8 blocks I've seen or heard of twocents


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)






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