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Location: MYR S.C.
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engine rebuild problem
putting my 930 engine back together.
had the heads rebuilt and ported. was just curious so I did a leak down on the left side. LOTS of air leaking past the valves!!!
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86 930 94kmiles [_  _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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08-09-2020, 06:39 AM
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New-ish 911SC Targa Owner
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I think valves leak until they pound their way i to the seats. I've read a handful of threads like this and that seemed to be mentioned in most.
What'd the machine shop that performed the work say about it?
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'83 Targa 300k w/ freshened 3.0 with 930/52 case# 6770540 ARP and Raceware hardware - AEM Infinity 506, Triumph T595 ITBs, B&B headers, Dynomax muff, Fidanza FW, Alum PP-203whp |
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08-09-2020, 06:49 AM
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haven't talked to hm. cant until next week
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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08-09-2020, 07:06 AM
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Location: San Carlos, CA US
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I think you have to run it first before any leakdown test is valid.
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Porsche 2005 GT3, 2006 997S with bore-scoring Exotic: Ferrari F360F1 TDF, Ferrari 328 GTS Disposable Car: BMW 530xiT, 2008 Mini Cooper S Two-wheel art: Ducati 907IE, Ducati 851 |
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08-09-2020, 07:22 AM
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+3 above... first drive then if problems occurs , leak down test..
Ivan
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1985 911 with original 501 708 miles...807 421 km "The difference between genius and stupidity is that, genius has its limits". Albert Einstein. |
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08-09-2020, 07:25 AM
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Rebuilt heads.......
Quote:
Ty, A properly rebuilt heads should pass the liquid tests. If you put liquid like water or alcohol over the dome, there should not be any seepage of fluid during the test. If you do, it is not sealing well. This is a basic test before assembly. Tony |
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08-09-2020, 08:07 AM
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Valve assemblies machined to spec do not leak when assembled.
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Karl ~~~ Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s. |
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08-09-2020, 08:18 AM
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There should not be leakage from the combustion chamber to the ports, unless there is something physically holding the valve off the seat. They do not need to be run to seat properly.
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Patrick E. Keefe 78 SC |
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08-09-2020, 09:24 AM
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do we know for sure it is past the valves....? as t77 told me he has the rockers off so above boys are correct no leak -
Ivan T77..can do it again with a video so we can see it -the leak..
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1985 911 with original 501 708 miles...807 421 km "The difference between genius and stupidity is that, genius has its limits". Albert Einstein. |
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08-09-2020, 10:28 AM
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Are you certain the valves are properly adjusted and that you were on the back side of the cam for the cylinder being tested? The valves should not leak on a newly rebuilt head.
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08-09-2020, 10:32 AM
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red..... i just wrote he has no rocker in ..yet;-)
Ivan
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1985 911 with original 501 708 miles...807 421 km "The difference between genius and stupidity is that, genius has its limits". Albert Einstein. |
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08-09-2020, 10:36 AM
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I have tape on the intake ports, its about to blow the tape off.
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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08-09-2020, 11:41 AM
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ok take it of the engine set on the table pour some gas into the each chamber and see where does it leak -is the best you can do now...does not take much time to take it off..It is strange that machine shop would give heads like this??
Ivan
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1985 911 with original 501 708 miles...807 421 km "The difference between genius and stupidity is that, genius has its limits". Albert Einstein. |
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08-09-2020, 12:04 PM
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valve leakage
I always lap the valves in my self and use Prussion Blue then set valve spring height and reassemble.Do it once and do it right.Then you know.Ciao Fred
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08-09-2020, 12:37 PM
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good point Fred ..but some of the peeps do not have the tool to do that ,that is why they trust the machine shops to do the job...
Ivan
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1985 911 with original 501 708 miles...807 421 km "The difference between genius and stupidity is that, genius has its limits". Albert Einstein. |
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08-09-2020, 12:50 PM
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I reputable guy on here did the heads.
I don't want to say who just in case there really is not an issue definitely leaking past intake on 1 and 3. 2 was not as bad. I have just done cam timing, no other rockers installed
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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08-09-2020, 04:14 PM
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ok
just checked again. its late and had shower so didn't want to stat out there and get sweaty 1 is better. le3aking past rings. I was a bit surprised since they were soaked in oil 3 is still bad. lots blowing out intake port. so I put a rocker on and spun it over a few times but it was still bad. checked 4, it was tight as a drum
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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08-09-2020, 04:40 PM
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Customer Service......
Ty,
Unless you got the job for a bargain, just be thankful. Otherwise, contact the rebuilder and give him an opportunity to fix the problem. Everybody makes mistakes, so allow him to address it. The integrity of your chosen rebuilder will be confirmed by how he handles a situation like this one. You made a decision by not naming him at the moment. Keep us posted. Tony |
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08-09-2020, 04:58 PM
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#1 stopped leaking
3 and 6 are leaking.
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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08-10-2020, 11:14 AM
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I guess its back to working on the race car until I get this worked out.
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86 930 94kmiles [_ _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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08-10-2020, 11:15 AM
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Jeanine
1974 Carrera
1979 930
1980 SC Targa
