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Head gaskets doubled up. Jump to page : 1 Now viewing page 1 [50 messages per page] | View previous thread :: View next thread |
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Paul Hettick |
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Elite Veteran Posts: 705 Location: California | Recently purchased a 318 powered plymouth with a freshly rebuilt engine. Massive vacuum leaks at intake. Removed that and found hasket sealer on the metal intake gaskets. Have not pulled the heads but the edges of the head gaskets are visible and it appears there is 2 gaskets for each head. Why the he k would someone do this? Any ideas? | ||
wizard |
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Board Moderator & Exner Expert 10K+ Posts: 13036 Location: Southern Sweden - Sturkö island | Too high compression for standard fuel? Oldsmobile had thinner head gaskets if the J2 (3x2 carburetors) option was mounted by the factory. | ||
LostDeere59 |
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Extreme Veteran Posts: 402 Location: Hilltown, PA | I'd check everything about that engine very, very carefully. Doubling head gaskets was something done with old steel shim gaskets to reduce compression a bit. Modern composit gaskets won't tolerate that kind of application. My concern is if someone did that, how many times did they have the heads off? Another concern - obviously they didn't get the intake properly sealed, so what else did they screw up? I'd would wonder if the doubling was because they removed too much material from the block when decking it, creating a piston/valve clearance issue, or from the cylinder head potentially causing the same issue, or excessive compression. With todays gaskets and machining capabilities there's no GOOD reason for that kind of installation . . . Gregg | ||
Mopar1 |
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Expert Posts: 3027 Location: N.W. Fla. | Paul Hettick - 2021-03-16 8:49 AM To get metal gaskets to seal you spray them with aluminum paint. Lay flat so there's no runs & let dry well before installing.. Removed that and found gasket sealer on the metal intake gaskets. | ||
Powerflite |
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Expert 5K+ Posts: 9580 Location: So. Cal | Most likely, it is to compensate for too much material removed, that now allow the intake to mount. Without them, the intake may be too far off to mount to the heads. If it works, I wouldn't touch it. that's a major can of worms that you would be digging into. | ||
22mafeja |
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Elite Veteran Posts: 632 Location: Finland | Probably there has been too deep corrosion on the heads , therefore machined away too much and now the intake manifold sits too high. I would mark how the intake sits and remove it and machine off what is necessary. And like Nathan suggested leave the double head gasket untouched if it works. | ||
Paul Hettick |
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Elite Veteran Posts: 705 Location: California | I bolted it back together this morn with fellow pro intake gaskets. Runs better but still wont idle smoothly. The carb base gasket only makes contact with the outer circumference of the carb base. Shouldn't the ports be segregated by the gasket? | ||
60 dart |
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Expert 5K+ Posts: 8946 Location: WHEELING,WV.>>>HOME OF WWVA | metal intake gaskets ? | ||
Paul Hettick |
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Elite Veteran Posts: 705 Location: California | Yes metal. Thought I would roll the dice and see how it runs with the new gaskets. It's better but still runs rough through all rpm ranges | ||
wizard |
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Board Moderator & Exner Expert 10K+ Posts: 13036 Location: Southern Sweden - Sturkö island | Does the engine responds to the mixture screw or not? It's not so important that the carburetor gasket seals over the total area, but I would fix it. | ||
Paul Hettick |
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Elite Veteran Posts: 705 Location: California | Yes the air mixture screws when screwed in will kill the engine. Backing them out will smooth out somewhat but still rough | ||
60 dart |
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Expert 5K+ Posts: 8946 Location: WHEELING,WV.>>>HOME OF WWVA | so its an la 318 -----------------------------------------later | ||
Mopar1 |
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Expert Posts: 3027 Location: N.W. Fla. | Powerflite - 2021-03-16 9:20 PM Actually doubling the head gaskets would move the heads up and out, slightly increasing the distance between heads,Most likely, it is to compensate for too much material removed, that now allow the intake to mount. Without them, the intake may be too far off to mount to the heads. If it works, I wouldn't touch it. that's a major can of worms that you would be digging into. | ||
Paul Hettick |
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Elite Veteran Posts: 705 Location: California | Yes it is an early 318. The intake leaks moved from the bolt holes when gasket sealer was used to the top edge, front to back with new metal gaskets and no sealer. Any way to check if the heads have been milled beyond spec without tearing the whole mess apart? | ||
60 dart |
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Expert 5K+ Posts: 8946 Location: WHEELING,WV.>>>HOME OF WWVA | if the heads were shaved i'd doubt the intake would fit at all , unless the intake was shaved also . first in order would be to replace the intake gaskets to fiber gaskets ------------------------------------later | ||
Paul Hettick |
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Elite Veteran Posts: 705 Location: California | Thanks Chuck had the intake surfaced and used fiber gaskets. All good now. | ||
60 dart |
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Expert 5K+ Posts: 8946 Location: WHEELING,WV.>>>HOME OF WWVA | cool! | ||
Stroller |
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Extreme Veteran Posts: 371 | If the head gaskets were doubled it would change the angle of the intake mounting not also to mention raising the height. As the to carb I'd pull the carb and intake back off and grab a file. | ||
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