Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > Porsche 924/944/968 Technical Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
rudidelange's Avatar
 
Join Date: Jun 2004
Location: south Africa
Posts: 209
how I got oil pressure - quickly after a rebuilt!

What initially started as a weekend project to fix 2 minor oil leaks landed up in an engine rebuilt. In retrospect I believe it was not necessary.

After 6 months the dreaded day came to obtain oil pressure and then to start the engine.
Plugs out, DME relay removed, coil wire disconnected, and approx 150 ml of oil squirted into the tube of the oil filter housing, cranking but no oil pressure. I cranked approximately 10 x and the longest cranking time was about 20 seconds. I was scared of cranking longer as I assembled the engine lightly with engine oil.
The next day I pulled the oil pressure sender, and the oil pressure relieve valve they were dry and there as no oil in those passages. I then use tight fitting flexible tubes and filled those passages with oil and also filled the tube inside the oil filter housing with 500ml of oil until it OVERFLOWED as well as the recesses in the oil filter housing. I replaced the oil pressure relieve valve, the sender unit and oil filter. On the first crank of 15 seconds, I got 1 bar of oil pressure. Stopped and cranked again and got 4.5 bar pressure after 7 seconds.
Replaced all the other goodies and the car started after approx 5 seconds. The car ran like a dream for the first 7 kilos and then disaster struck A valve broke in two at 2000 rpm and at approx 40 km / hour. More about this later, I am busy repairing this little mishap.

__________________
1983 944 RHD Original. Uses all my spare cash!
1947 Morris Sold
1972 Benz Sold
1975 Benz Sold
1976 Benz Sold
1977 Benz Sold
Old 07-20-2006, 10:02 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
SoCal Driver's Avatar
 
Join Date: Feb 2002
Location: Costa Mesa
Posts: 8,587
Garage
Exhaust valve?
__________________
Hugh - So Cal 83 944 Driver Person
NOT a 'real' Porsche -- Its Better!!!!
When was the last time you changed your timing and balance belts and/or cam chain and tensioner?
New Users please add your car's year and model to your signature line!
Never break more than you fix!
Old 07-20-2006, 10:05 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
rudidelange's Avatar
 
Join Date: Jun 2004
Location: south Africa
Posts: 209
No, inlet valve. It broke just below the keepers inside the upper spring retainer.
The valve damage the piston somewhat - not serious and some damage to the cylinder wall, also not serious. I think the damage to the cylinder wall was caused by a loose piece of aluminium that came from the crown of the piston. The guide was not damaged. The valve was stuck in an open position in the guide and the upper broken pice with the retainer and keepers was in one pice and fell out the top of the head when I opened it. I cannot seen any damage on the cam.
It was a new valve, new valve springs, new seat and new guide. I consulted with some engineers, looked at the broken edged through a microscope and our conclusion was that a microscopic / hairline crack in the valve could have started it all. It had typical "shock wave" progressive cracks in the break area. The clearances betwween the valves and guide were according to spec, the installed spring height as well as the hight of the valves were all within Porsche's specification. I double checked and measured each 2x. The only item that I did not check was the pressure / strength of each new inner and outer spring. I will do that this weekend. What I have noticed is that the new outer springs are shorter than the old outer springs.
I also discussed the broken valve with engine rebuilders and wholesale parts suppliers. It seems that such a breakage is not common, especially in engines with hydraulic lifters. It can occur where the geometry of the rocker arms are not correct and a lateral force is applied on the valve. It can alos happen if a mechanic would hit a valve on the top with a hammer after installation. This is apparently an old practice to ensure that the keepers and retainer is properly seated. This was not done as I assembled the head myself.
I will post some pics next week of the damahe and valve.
__________________
1983 944 RHD Original. Uses all my spare cash!
1947 Morris Sold
1972 Benz Sold
1975 Benz Sold
1976 Benz Sold
1977 Benz Sold
Old 07-20-2006, 11:11 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Apr 2003
Location: Durban,South Africa
Posts: 327
Garage
Bad luck Rudi, hope you come right soon. Do not know any guys in our club who do their own 944 wrenching here, so I unfortunately do not have access to guys with practical experience on these cars (except the ones you pay big bucks). That is where pelican forum and guys like Socal are so helpful. Did you ever do anything about your gearbox?
Old 07-21-2006, 02:00 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
rudidelange's Avatar
 
Join Date: Jun 2004
Location: south Africa
Posts: 209
No, I will most probably drive until the whine becomes bad and then look into it
__________________
1983 944 RHD Original. Uses all my spare cash!
1947 Morris Sold
1972 Benz Sold
1975 Benz Sold
1976 Benz Sold
1977 Benz Sold
Old 07-21-2006, 03:11 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
Razorback1980's Avatar
 
Join Date: Nov 2005
Location: Houston, Texas
Posts: 2,944
Garage
Send a message via AIM to Razorback1980
With an overhead cam, is there any way to get the geometry off? I guess if the valve guide isn't installed correctly. You may want to check that.
__________________
Tom

1990 944S2 Cabriolet
2002 Chevy Silverado 2500HD
2003 Maroon Ford F350 dually
Old 07-21-2006, 06:04 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered User
 
Join Date: Nov 2004
Location: Alberta, Canada
Posts: 2,696
I'd think if a valve guide went in crooked that'd upset the geometry. If the valve guide's hole was egged at all this could happen. Sometimes the metal just plain fails, as uncommon as that is...

Bad luck, Rudi.

__________________
'84 944 - new-to-me DD!
'83 944 - looks like ass, runs like horse - in primer.
'82 931 - roadster project - forever incomplete.
'80 924 - spouse's yellowjacket.
Some wrecks and a 924 racer.
Old 07-21-2006, 11:17 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 03:43 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2020 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.