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After_Thought
Joined: 08 Oct 2019 Posts: 44 Location: Hudson ohio
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Posted: Thu Mar 11, 2021 8:18 am Post subject: Oil pressure while cranking |
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Fresh engine installed. Went to crank it today to look for oil pressure. after about 15-20 seconds nothing. How long should it take? So scared to crank it more. Is there anything signs i should be looking for if something is wrong? |
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Raize
Joined: 18 Sep 2013 Posts: 176 Location: Scotland
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Posted: Thu Mar 11, 2021 8:34 am Post subject: |
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It doesn't build any pressure cranking. Needs to run. Scary stuff.
Been there, done that, still have all my cam lobes. |
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MikeJinCO
Joined: 08 Jun 2010 Posts: 1228 Location: Maysville, Colorado
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Posted: Thu Mar 11, 2021 9:06 am Post subject: |
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If it is a fresh, never started build it is not unusual. The oil pump is a long way from the oil and needs primed. I know of two ways to get the pump primed. One, remove the plug that holds the oil pressure relief spring, it is low on the side(I think passenger) and stuff he hole full with fresh vaseline. It takes more than you think as the pump pretty much has to get filled. Put the spring and plug back in, remove the plugs and crank until you get oil pressure which may well take a bit. If a second person is handy remove the oil fill cap on the valve cover to make sure the cam is getting lubricated while cranking. Two, remove the plug and oil pressure spring, take a wet and dry shop vac and fit it to the hole. You are almost guaranteed an oil bath. Close it up and repeat as before.
I one took my bath, I've gone to the vaseline method it is slower for results, but a bit cleaner. _________________ Mike
'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild) |
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After_Thought
Joined: 08 Oct 2019 Posts: 44 Location: Hudson ohio
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Posted: Thu Mar 11, 2021 11:09 am Post subject: |
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Thank you so much! Ill try the shop vac method tomorrow. Hopefully it all goes well! I feel a lot better about this |
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924RACR
Joined: 29 Jul 2001 Posts: 8803 Location: Royal Oak, MI, USA
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Posted: Thu Mar 11, 2021 11:11 pm Post subject: |
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It can indeed take quite a while to prime - but it will.
Use a battery booster, and crank as needed, but give the starter time to cool between tries. That said, short bursts of cranking won't do it - I often need to run 30s or more, but so be it. _________________ Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype |
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morghen
Joined: 21 Jan 2005 Posts: 8879 Location: Romania
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Posted: Thu Mar 11, 2021 11:19 pm Post subject: |
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I hope you properly oiled up all turning parts before assembly.
I also used some assembly grease to "prime and seal" the oil pump on my cayman when i did the engine rebuild and it still took a few seconds of actually running the engine to draw oil, fill the engine and pressure everything.
Thats why discipline and clean work environment is so important.
Heard of a guy who didnt properly oil up the bearings on an engine and ended up doing damage to the bearings. _________________ https://www.the924.com |
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Mike9311
Joined: 14 Dec 2004 Posts: 1678 Location: Chicago-ish
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Posted: Fri Mar 12, 2021 12:14 am Post subject: |
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+3 on all that advice
On pumps like these I too use vaseline. I take the pump apart and pack it up. Same with the 1980's Buick Grand National pump. Of course in a hot summer a lot of the vaseline turns to liquid but its still there. I also use ATF on the pistons and rings. Probably old school. Any engine assembly lube everywhere else. _________________ 1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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TJC
Joined: 04 Apr 2010 Posts: 828 Location: Central-ish Arizona, USA
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Posted: Fri Mar 12, 2021 1:41 am Post subject: |
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I use a specific procedure on fresh engines whether they be for the street or race use. Obviously a proper application of assembly lubes must be applied to specific areas such as the bearings, cam lobes, cylinder walls, valve stems/guides, etc. and I use different lubricants for different items. The oil pump must be primed/heavily lubricated so that there is sufficient "petroleum" contact on all metal surfaces to create "suction" when the oil pump is turning. This point cannot be stressed enough otherwise the pump will cavitate. I always prefill the oil filters.
Now one of the most important procedures is that I pre-oil the entire lubrication system by using a conventional pump action "bug/weed/garden" sprayer converted with the proper adaptor per the specific application that screws into an oil galley, (most commonly where the oil pressure sender installs into), and pump at least 3-4 quarts of oil into the engine.
This assures that the complete engine lubrication system ready to go at start up. Other points to follow are that the ignition timing must be set properly in it's static position and that the fuel delivery system is primed and ready to go as well.
Good Luck! _________________ '95 BMW 318i/5 ..."Pearl"
'87 Porsche 944 NA... "Liebchen"
'02 Porsche Boxster..."Sunbeam"
'04 BMW X3..."Xander"
Still on the Prowl!
www.ttrs1.com |
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After_Thought
Joined: 08 Oct 2019 Posts: 44 Location: Hudson ohio
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Posted: Fri Mar 12, 2021 11:56 am Post subject: |
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Alright so i ended up packing the relief spring port with a tone of Vaseline and cranked it for a total of about a minute, maybe 1:30. Still nothing. Assembly lube on the cam. I was just looking through oil filler cap to see if cam was getting oiled while family member turned key, didn't see anything. Having this cap off or even the head cover off wouldn't mess with oil pressure would it? (idk of its some weird pressure thing or something).
Wishing cranking the engine was not so scary.
I guess Ill try the shop vac method next? not sure how ill fit it to that hole but Ill give it my best shot. |
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After_Thought
Joined: 08 Oct 2019 Posts: 44 Location: Hudson ohio
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Posted: Fri Mar 12, 2021 11:57 am Post subject: |
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Alright so i ended up packing the relief spring port with a tone of Vaseline and cranked it for a total of about a minute, maybe 1:30. Still nothing. Assembly lube on the cam. I was just looking through oil filler cap to see if cam was getting oiled while family member turned key, didn't see anything. Having this cap off or even the head cover off wouldn't mess with oil pressure would it? (idk of its some weird pressure thing or something).
Wishing cranking the engine was not so scary.
I guess Ill try the shop vac method next? not sure how ill fit it to that hole but Ill give it my best shot.
Maybe I should also try that sprayer that TJC was talking about through the spot where oil pressure sender goes. |
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After_Thought
Joined: 08 Oct 2019 Posts: 44 Location: Hudson ohio
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Posted: Fri Mar 12, 2021 12:04 pm Post subject: |
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Found this at summit racing (live right next to one). I wonder if it would be a good to have. This would help to get oil pressure right?
https://www.summitracing.com/parts/aaf-all10535
(sorry for all the questions, first time doing any of this) |
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MikeJinCO
Joined: 08 Jun 2010 Posts: 1228 Location: Maysville, Colorado
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Posted: Sat Mar 13, 2021 12:04 am Post subject: |
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Sounds sort of normal to me, it can get pretty spooky. I've only rebuilt two motors and the startup was quite stressful both times. You just have to keep working at it, I think last time I had to pack the oil pump twice. You may need to crank it 3 or 4 times as long.
TJ's' solution is the ideal one, but the location of the oil pressure sender makes it difficult to work with, getting a remote filter adapter which is not expensive might work. The remote filter adapter is a 3/4-16 oil filter thread and screws on in place of the oil filter, and has 1/2 NPT pipe threads for supply and return. Pump oil into the return and it prelubes the entire motor, into the supply backfeeds the oil pump..
. _________________ Mike
'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild) |
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Rasta Monsta
Joined: 12 Jul 2006 Posts: 11723 Location: PacNW
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Posted: Sat Mar 13, 2021 12:17 am Post subject: |
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You're Over_Thinking it. It has enough assembly lube to run for a bit, dead cold, without oil pressure...that's what it's for.
Fire it up! _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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Carrera RSR
Joined: 08 Jan 2010 Posts: 2309 Location: Somerset, UK
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Posted: Sat Mar 13, 2021 12:35 am Post subject: |
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Cranked mine for effing ages and no pressure. Thought F it after a lot of head scratching, checks, back filling oil in the pump etc. so just started it. Soon got pressure. Still alive after 7+yrs of abuse. Super stressful though..... _________________ 1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252 |
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TJC
Joined: 04 Apr 2010 Posts: 828 Location: Central-ish Arizona, USA
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Posted: Sat Mar 13, 2021 1:22 am Post subject: |
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If you were building engines for a living the Summit unit would be fine...but I still wouldn't buy it. Any Home Depot, Lowes, Harbor Freight, etc. will have a hand pump weed sprayer that may cost you $10-15 and when you're done with it you can clean it out and use it for other purposes or throw it away...there, done! You can buy various brass fittings and hose clamps to make a suitable adaptor to fit a port in your engine and the sprayer.
Or you can take your chances and just start the sucker up and hope for the best...works for others apparently, may work for you, but it wouldn't be my first choice. Just sayin'...everyone has their own techniques, procedures, beliefs or even reputation to consider if they build/built engines for a living.
Good Luck & Have Fun, because in the end, that's what it's all about! _________________ '95 BMW 318i/5 ..."Pearl"
'87 Porsche 944 NA... "Liebchen"
'02 Porsche Boxster..."Sunbeam"
'04 BMW X3..."Xander"
Still on the Prowl!
www.ttrs1.com |
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