 How is oil pressure relief handled?, in my '76 GC without the valve??? |
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| jk76.914 |
 Oct 5 2006, 02:21 PM
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#1
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Senior Member  Group: Members Posts: 809 Joined: 12-April 05 From: Massachusetts Member No.: 3,925 Region Association: North East States  |
I have a '76 2.0 with GC case. There is no oil pressure relief valve in the case. The one between the pushrod tubes at cylinder 1. Just a deep hole, as cast.
So how exactly did VW handle oil pressure relief in this case? The engine ran just fine, and extremely reliably for 98000 miles, which is when I tore it down to rebuild it. Jim |
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| Brad Roberts |
Oct 5 2006, 03:29 PM
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914 Freak! Group: Members Posts: 19,148 Joined: 23-December 02 Member No.: 8 Region Association: None |
I beleive they left them out because of the hydraulic lifters needing more oil than the solid lifter engines. They changed the casting for the Buses with hyd lifters.
They probably figured out they didnt need it. Most of the race engine builders I know prefer that case. One less thing to fail. The worst that can happen: more oil in the heads under sustained high RPM driving. B |
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| Dave_Darling |
Oct 6 2006, 04:37 PM
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#3
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914 Idiot Group: Members Posts: 15,196 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California 
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The way it works is that the valve at the front end of the motor does the work. Instead of having one valve at the "end" of the system that opens up when pressure gets too high, and another one at the "beginning" of the system that does approximately the same thing, they just went with the one at the beginning. That's the one that is covered by that plug with the large slot in the end...
--DD |
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| jk76.914 |
Oct 6 2006, 11:22 PM
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#4
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Senior Member Group: Members Posts: 809 Joined: 12-April 05 From: Massachusetts Member No.: 3,925 Region Association: North East States |
Thanks for the replies. What I couldn't figure was that since VW went to the the so-called dual relief cases in '69 or '70 to solve some problem, isn't my case open to having whatever that original problem was again?
Also, looked it up in my parts book, the relief valve near the oil cooler parts are exactly the same numbers as in the earlier engines that also have the relief valve at the other end. So all they did was take the pressure relief valve out. No mods (apparently) to the other relief valve to compensate. I know that the hydraulic cam cases don' t have the pressure relief valve either, but my case is a '76, and the hydros hit in '78 (IIRC), so I'm not so sure VW got that big a jump on the planned switchover to hydraulics. Maybe, though. Oh well. Seems to work fine, so I'll worry about other things instead. Thanks again, Jim |
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