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ideola
Joined: 01 Oct 2004
Posts: 15550
Location: Spring Lake MI
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 Posted: Sat Apr 04, 2009 9:35 am Post subject: A tale of two valve stem seals |
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In the category of "no wonder she was burning oil"...
Check out the #2 and #3 intake valve stem seals I pulled out of the 941 today (a "good" seal on the far left for comparison):
One of the coily things went loose in the head, and managed to get sandwiched between the #1 exhaust lobe and tappet. Shots of the damage:
Replaced all the valve stem seals today, restarted, and very little to no oil smoke. Finally!
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erstwhile owner of just about every 924 variant ever made
Last edited by ideola on Thu Mar 22, 2012 1:44 pm; edited 1 time in total |
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Chrenan
Joined: 15 Jan 2003
Posts: 3903
Location: Canada
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| Posted: Sat Apr 04, 2009 11:59 am Post subject: |
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I pulled a bunch of material out of the oil filter pickup on the engine that came out of my car. Look familiar?
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1987 951 - M193 Version for Japan |
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11733
Location: PacNW
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| Posted: Sat Apr 04, 2009 1:11 pm Post subject: |
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I bet Shaggy is going to be spitting out a fistful of that stuff, especially after 18 years of storage.
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Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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Rich H
Joined: 10 Jun 2007
Posts: 2665
Location: Preston, Lancs, UK
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| Posted: Sat Apr 04, 2009 6:09 pm Post subject: |
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Ooops!
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1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec |
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RC
Joined: 25 Mar 2007
Posts: 2637
Location: Australia
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| Posted: Sat Apr 04, 2009 6:41 pm Post subject: |
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OMG what a lot of crap!
So that was just from old age and deterioration in both cases? |
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Scorpio
Joined: 05 Jul 2007
Posts: 1957
Location: Brisbane, Australia
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| Posted: Sat Apr 04, 2009 7:34 pm Post subject: |
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theres enough metal there to make a daewoo!
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1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT
Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!! |
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stevekat
Joined: 19 Jan 2008
Posts: 719
Location: Los Angeles, CA
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| Posted: Sat Apr 04, 2009 7:52 pm Post subject: |
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| Were you able to replace the valve seals with the head on the car? |
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924guy
Joined: 29 Dec 2003
Posts: 2088
Location: Port St. Lucie, FL
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| Posted: Sat Apr 04, 2009 8:42 pm Post subject: |
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| Scorpio wrote: | | theres enough metal there to make a daewoo! |
dawoos have actual metal????? 
I expect to find the same story when i get around to cracking open the 931 engine on the floor of my garage.. 
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Eric
78 924
82 931 SE "smokey"
99' VehiCross
Y2K Honda Insight
http://www.cardomain.com/id/924Guy
Performance by Pasha |
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924RACR
Joined: 29 Jul 2001
Posts: 9075
Location: Royal Oak, MI, USA
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| Posted: Sat Apr 04, 2009 9:31 pm Post subject: |
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| stevekat wrote: | | Were you able to replace the valve seals with the head on the car? |
Yeah - I lent Dan my valve spring compressor and valve stem seal pliers. We'd met for lunch a few weeks ago, and I pointed out how much the car was smoking (after following him)...
Probably will run a little better now too, without fouling up the plugs so bad! 
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype |
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ideola
Joined: 01 Oct 2004
Posts: 15550
Location: Spring Lake MI
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| Posted: Sat Apr 04, 2009 10:38 pm Post subject: |
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Yep, thanks to Vaughan, I was able to replace them with the head in situ.
The car has smoked from day one. Ray Wolf, the PO, disclosed a "smoking turbo" when I bought the car, but I'm betting a good bit (if not all) of the smoking was due to these two valve stem seals. The #2 and #3 plugs were both badly oil fouled, as you would expect. #1 and #4 were both a bit lean when I first pulled them out, but I got that corrected with a little mixture adjustment.
Chrenan, thankfully mine weren't as badly destroyed as what your picture indicates, but you can see one of the coily things in your photo, that's what got loose in mine and destroyed the one lifter. I've replaced it, but I did put the original cam back in because the replacement cam I had must be a regrind or something because I can't get the adjusters to work properly with it. I'll be pulling the cam cover every 1K miles or so to monitor the damaged lobe and whether it shows any damage on the lifter. If it does, I have another cam with matched lifters I may end up swapping in.
I won't be able to tell the total effect for a bit...we've started repairing the crash damage from when the car was stolen back in 2006. But the initial indications on startup yesterday were very promising, as it appear to burn much less oil on startup than what I'm accustomed to seeing.
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erstwhile owner of just about every 924 variant ever made |
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Joes924Racer
Joined: 03 Nov 2002
Posts: 11964
Location: Oregon, Denver Colorado native!
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| Posted: Sat Apr 04, 2009 10:52 pm Post subject: |
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Wow.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo. |
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Martijnus
Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands
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| Posted: Sat Apr 04, 2009 10:58 pm Post subject: |
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I still don't get why they teared....
I've never seen this happen... the only way I know stem seals can rip to shreds is when the spring dish hits them or when they aren't put in properly.
What brand/quality were those seals? or is that unknown?
The spring seal part shouldn't come loose by itself. Even when the seals are really old.
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"Rule: Turbo's make torque, and torque makes fun." (C. Bell)
924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment |
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Chrenan
Joined: 15 Jan 2003
Posts: 3903
Location: Canada
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| Posted: Sat Apr 04, 2009 11:12 pm Post subject: |
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Yeah, the old engine certainly smoked a fair bit, and constantly fouled the plugs. My guess is the last few previous owners could have cared less. Sometimes its worth the effort to do a total rebuild just to be sure you are starting with a clean slate.
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1987 951 - M193 Version for Japan |
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RC
Joined: 25 Mar 2007
Posts: 2637
Location: Australia
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| Posted: Sun Apr 05, 2009 1:08 am Post subject: |
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| Martijnus wrote: | I still don't get why they teared....
I've never seen this happen... the only way I know stem seals can rip to shreds is when the spring dish hits them or when they aren't put in properly.
What brand/quality were those seals? or is that unknown?
The spring seal part shouldn't come loose by itself. Even when the seals are really old. |
]
Was thinking the same thing myself. Never seen seals disintegrated like that except for mechanical interference. Certainly not from old age, even on older original Japanese and Euro engines with OE positive sprung lip seals.
Particularly knowing these heads have 5mm shorter valve guides on the inlets and being supplied longer ones from an aftermarket but OE supplier. Think Scorpio or Bumblebee was too. Wonder who else? Also the circlip does not come with the guides and it is required to get the depth correct, without special tools or measuring. Many shops wouldn`t bother and just drive them down.
Curious about these heads, if the guides have been previously replaced, or the seals incorrectly fitted. They are quite hard to fit down past the internal ridge on the seal and into the groove on the guide. With the part #s (and therefore length) being mixed up in 2 supplier`s catalogs that I`ve seen it is likely an industry wide problem.
Was the damaged seals on only the intakes?
The cam and lifter wear can not be attributed to the seal spring. Picture is typical of wear to these components on our flat tappet engines. It is direct metal to metal galling caused primarily by insufficient lubricant quality or quantity. IMHO another example of the accelerated wear directly attributable to the lack of ZDDP in modern oils. |
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ideola
Joined: 01 Oct 2004
Posts: 15550
Location: Spring Lake MI
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| Posted: Sun Apr 05, 2009 3:45 am Post subject: |
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| Martijnus wrote: | | What brand/quality were those seals? or is that unknown? |
They appeared identical to the replacements from the Victor Reinz kit I used.
| RC wrote: | | Curious about these heads, if the guides have been previously replaced, or the seals incorrectly fitted. They are quite hard to fit down past the internal ridge on the seal and into the groove on the guide. With the part #s (and therefore length) being mixed up in 2 supplier`s catalogs that I`ve seen it is likely an industry wide problem. |
I don't have much history on the mechanicals of this car. It is not a stock series I, however. Has series 1 ignition, but the block, intake, TB, turbo, and exhaust are all series 2. Not sure about the head or pistons. My guess is that the last time the head was serviced before I acquired the car the valve stem seals were not properly installed.
| RC wrote: | | Was the damaged seals on only the intakes? |
Yes, it was only the #2 and #3 intake seals. The rest of the seals all looked fine, and there was no fouling on the #1 or #4 plugs as with the #2 & #3 plugs.
| RC wrote: | | The cam and lifter wear can not be attributed to the seal spring. Picture is typical of wear to these components on our flat tappet engines. It is direct metal to metal galling caused primarily by insufficient lubricant quality or quantity. IMHO another example of the accelerated wear directly attributable to the lack of ZDDP in modern oils. |
This was my thought as well when I first saw the tappet damage last year, so I replaced the cam oiler tube and the elbow just to be safe. However, I am now of the opinion that the damage was done by the valve stem seal spring. The piece of spring was completely flattened out, and I found it directly adjacent to the #1 exhaust lobe and lifter, right where the damage was. None of the other cam lobes or tappets have any damage whatsoever, in fact, they look flawless. I would expect for a lubrication problem to exhibit more uniform and general wear across the entire cam / lifter train. But I could be wrong, it could just be coincidence.
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erstwhile owner of just about every 924 variant ever made |
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