| Re: [GMCnet] Aluminum Intake and Sucking Oil #2 [message #111291] |
Fri, 07 January 2011 22:41 |
Gary Worobec
Messages: 867
Registered: May 2005
Karma:
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Senior Member |
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George, I see exactly what you are talking about as I have both manifolds side by side on the bench. Looks like the OEM has about 1/2" of "meat" on the bottom of the port while the Rockwell only 1/4" to 5/16". Your solution seems to make sense to glue the gasket to the manifold rather than the head. As far as the block off plates I did not like the gaskets I got from Mondello hence a new set of Paterson gaskets with the integral block off plates are on the way here. I traded Dick for a good distributor core that I had.
Thank you very much for posting the problem. Probably saved my butt as I would have done it the same way you did originally. I will post side by side pictures this weekend of the two manifolds so others can see the issue.
Thanks
Gary and Joanne Worobec
1973 Glacier 23
-----Original Message-----
>From: George Beckman <gbeckman@pggp.com>
>Sent: Jan 7, 2011 8:20 PM
>To: gmclist@temp.gmcnet.org
>Subject: [GMCnet] Aluminum Intake and Sucking Oil #2
>
>
>
>For those who did not read the previous thread after putting a new aluminum intake manifold on my '74, oil consumption was off the charts. Lucky I did not ruin the engine as it used 4+ quarts in the time it usually uses 1/2.
>
>Here is what I found, today, when I pulled the manifold. I would post pictures if our camera was not somewhere near the Rose Parade. (Grrr)
>
>The Rockwell intake "lips" on the bottom of the ports are 1/8 inch thinner than on the cast iron. The gasket bolt holes on the Mr. Gasket 404 are rather large. We had excellent seal on the head, but the gasket was at the edge of the port lip at the bottom of the intake head on the right back. The gasket was against the head and thin air with only a thread of gasket butted up to the two parts. RTV had been squished out a bit there, but had no real chance of sealing. At first, I thought maybe we had the gasket in upside down, but that was not it. Turning it over would have made a huge gap.
>
>I have a Fram gasket for my next effort. I believe I will put the gasket on the intake, this time. There is plenty of meat to seal against on the head side. I will center the gasket... I may even wallow the bolt hole to allow the gasket to "move it up". I will then do what Randy and I did the first time; mark with a Sharpie, but this time I will mark the gasket and the head so I can tell if it slides down... or up. With the gasket on the head, the manifold tends to slide down the gasket as it works its way down. I see no indication that I had a mismatch of surface angles. The intake lips just drifted off the gasket. There was no chance for a seal. Water ports were fine, luckily.
>
>I don't want to get into a 25 post cat fight on the next bit, but tell you what I found after 500 miles and what I plan to do:
>
>The solid 404 gasket in the exhaust port was already partly gone. It was holding well on the lips of the port, but after 500 miles, I can see the exhaust "barking" is intense there. (A smart guy told me about exhaust barking.)
>
>This whole thing started because the gasket blew out at the top of the unblocked crossover, near the capped choke stove. The cast iron original turned out to be cracked, hence the Rockwell. I am lucky it had not blown out into the valley. I will never again put a gasket on without block-off plates even if the Rockwell is blocked in the casting. Just my two cents.
>--
>'74 Eleganza, SE, Howell + EBL
>Best Wishes,
>George
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