Oil Check Valves????
08-17-2002 | 09:55 PM
#1
Thread Starter
Burning Brakes
Joined: May 2002
Posts: 1,208
Likes: 2
From: Las Vegas, Nevada
Oil Check Valves????
OK, I'm stumped?????
I went in today and changed out my cam covers. I had them powdercoated in a hammertone finish in gloss black. They turned out really good and the rest of the intake looks amazing. I decided that while I was there, I would remove and clean the oil check valves in the heads. Maybe I'm dense but I couldn't find them????
I had a writeup on it and the manual but I'll be damned if I could see them. There appeared to be two round silver inset discs in the general location of where I was supposed to find them but the heads were blank? No hole for the M6 x 40 bolt that I picked up and no 3mm set screw on the side of the head to release anything. Maybe I just missed it but I'm disappointed. I finally had to go ahead and put the covers on without cleaning them so "tartersauce"
The next thing is those bloody cam cover washers. My cam covers must be slightly warped in the center because those two bolts won't completely tighten. I had the thick washers there but they are still loose even with the shoulder bolts tightened.
So any thoughts on either the check valve or the washers for the cam covers would be really appreciated.
BTW - Applied Powdercoat in Oxnard, California did my intake and cam covers and they look fabulous. Vic is the man. He turned my stuff around in three days and he was already busy. I am going to post pics of my stuff when its finished and full contact info. for Vic. He and his brother race a 944 so he's one of us. He is very reasonably priced and trustworthy. He has done a bunch of Porsche parts now including Chris's red S2/S4 hybrid. He sears by the hammertone finish for our cars because of the rotten castings. The hammertone covers up many of the imperfections. He even had one of his guys sand down high spots on my cam covers to get them even better. Two thumbs up for Vic.
<img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />
I went in today and changed out my cam covers. I had them powdercoated in a hammertone finish in gloss black. They turned out really good and the rest of the intake looks amazing. I decided that while I was there, I would remove and clean the oil check valves in the heads. Maybe I'm dense but I couldn't find them????
I had a writeup on it and the manual but I'll be damned if I could see them. There appeared to be two round silver inset discs in the general location of where I was supposed to find them but the heads were blank? No hole for the M6 x 40 bolt that I picked up and no 3mm set screw on the side of the head to release anything. Maybe I just missed it but I'm disappointed. I finally had to go ahead and put the covers on without cleaning them so "tartersauce"
The next thing is those bloody cam cover washers. My cam covers must be slightly warped in the center because those two bolts won't completely tighten. I had the thick washers there but they are still loose even with the shoulder bolts tightened.
So any thoughts on either the check valve or the washers for the cam covers would be really appreciated.
BTW - Applied Powdercoat in Oxnard, California did my intake and cam covers and they look fabulous. Vic is the man. He turned my stuff around in three days and he was already busy. I am going to post pics of my stuff when its finished and full contact info. for Vic. He and his brother race a 944 so he's one of us. He is very reasonably priced and trustworthy. He has done a bunch of Porsche parts now including Chris's red S2/S4 hybrid. He sears by the hammertone finish for our cars because of the rotten castings. The hammertone covers up many of the imperfections. He even had one of his guys sand down high spots on my cam covers to get them even better. Two thumbs up for Vic.
<img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />
08-18-2002 | 12:54 PM
#2
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Honeslty, im not sure if all model years had the oil check valves? Anyone? My 87 does. I have a page on my website about them. The smell set screw is the biggest PITA to get to. Once it was loosened the rest was easy. BTW, get your self a magnetic pick up tool...and dont dop the parts when the come out.
as for the cam cover bolts. Line them up. They are different lengths if i recall. Its been a while. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
as for the cam cover bolts. Line them up. They are different lengths if i recall. Its been a while. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
08-18-2002 | 01:49 PM
#3
Thread Starter
Burning Brakes
Joined: May 2002
Posts: 1,208
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From: Las Vegas, Nevada
Hi Tony,
Thanx for responding.
The cam cover bolts come in two lengths, a sort and a long. There really isn't anyway to mix them up.
The play left in my bolts is like less then 1/2 a mm. My friend Chris did his covers as well and he didn't have any play in his bolts at all after he tightened them up.
You may be right about the check valves. There appears to be something where the check valves might live but there is nothing to remove? It just looks like a small round silver disc? There isn't a threaded hole in the top and I felt around the head in that area and couldn't find a set screw of any kind.
Has anyone with an '85 / '86 specifically, done the oil check valves?
I still have a quick chatter at startup and its driving me nuts?
Thanx for the continued help
Thanx for responding.
The cam cover bolts come in two lengths, a sort and a long. There really isn't anyway to mix them up.
The play left in my bolts is like less then 1/2 a mm. My friend Chris did his covers as well and he didn't have any play in his bolts at all after he tightened them up.
You may be right about the check valves. There appears to be something where the check valves might live but there is nothing to remove? It just looks like a small round silver disc? There isn't a threaded hole in the top and I felt around the head in that area and couldn't find a set screw of any kind.
Has anyone with an '85 / '86 specifically, done the oil check valves?
I still have a quick chatter at startup and its driving me nuts?
Thanx for the continued help
08-18-2002 | 01:57 PM
#4
Burning Brakes
Joined: Jul 2001
Posts: 1,051
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Hi Bernie:
I tried to reuse the original spacer material on my 86 US model cam cover washers. See below. You may need to add a washer and potentially sealant to each bolt.
The check valves are fluid carrying bolts at the tensioner area. you will see the oil tube attached under the bolt head. The 87 uses a completely different ball and spring. I do not know if Euro is different.
Good Luck,
Gotta' Run,
Will check the post later,
Cam Cover Removal Service:
Thoroughly clean the engine first, without removing any factory stickers.
If you remove the cam covers on a 1986 model, these are recommended replacement parts per head:
Rubber Intake sleeves
Rubber Vacuum Elbows
Intake Sleeve Hose Clamps
Rubber Intake Hoses – Most of them are formed.
2 O-Rings at air flow meter
Breather hoses (on one side)
Check valve for chain tensioner
Crush washers for tensioner
Thermostat
Thermostat O-ring
Fuel Injector O-rings
Cam Cover Gasket Set – May include the following:
Camshaft seals
Camshaft cover bolt seals
Cam Cover gaskets
Cam Cover seals for plugs (on one side)
Cam Cover plugs - possibly
Breather hoses (on one side)
Spark plug hole sealing rings
Warning: My washers, beneath the cover bolt heads, had a cushion of rubbery looking substance stuck beneath them about 1/16th inch thick. Upon investigation, none of the big 3 could find a part # or reference to this part/substance. Other 928 owners told me that a spacer is required for my model to prevent leakage at the cover gasket. Therefore, if your washers have spacers stuck to them, leave the spacers alone.
Note: The Allen Head bolts may be very stubborn. Have a good 3/8 inch socket type of Allen wrench on hand.
If removing cams, for the chain tensioner service add:
Chain
Tensioner – only if deeply grooved (in my opinion)
Loctite 574
I tried to reuse the original spacer material on my 86 US model cam cover washers. See below. You may need to add a washer and potentially sealant to each bolt.
The check valves are fluid carrying bolts at the tensioner area. you will see the oil tube attached under the bolt head. The 87 uses a completely different ball and spring. I do not know if Euro is different.
Good Luck,
Gotta' Run,
Will check the post later,
Cam Cover Removal Service:
Thoroughly clean the engine first, without removing any factory stickers.
If you remove the cam covers on a 1986 model, these are recommended replacement parts per head:
Rubber Intake sleeves
Rubber Vacuum Elbows
Intake Sleeve Hose Clamps
Rubber Intake Hoses – Most of them are formed.
2 O-Rings at air flow meter
Breather hoses (on one side)
Check valve for chain tensioner
Crush washers for tensioner
Thermostat
Thermostat O-ring
Fuel Injector O-rings
Cam Cover Gasket Set – May include the following:
Camshaft seals
Camshaft cover bolt seals
Cam Cover gaskets
Cam Cover seals for plugs (on one side)
Cam Cover plugs - possibly
Breather hoses (on one side)
Spark plug hole sealing rings
Warning: My washers, beneath the cover bolt heads, had a cushion of rubbery looking substance stuck beneath them about 1/16th inch thick. Upon investigation, none of the big 3 could find a part # or reference to this part/substance. Other 928 owners told me that a spacer is required for my model to prevent leakage at the cover gasket. Therefore, if your washers have spacers stuck to them, leave the spacers alone.
Note: The Allen Head bolts may be very stubborn. Have a good 3/8 inch socket type of Allen wrench on hand.
If removing cams, for the chain tensioner service add:
Chain
Tensioner – only if deeply grooved (in my opinion)
Loctite 574
08-18-2002 | 03:07 PM
#5
Thread Starter
Burning Brakes
Joined: May 2002
Posts: 1,208
Likes: 2
From: Las Vegas, Nevada
Thanx Thom,
The only bolts on my 85 that look to have a rubber gasket material under the washers was the the bolts at either end of the cover. This rubber was completely shot and I know where to find replacements. All other bolts had washers with no rubber on them. The bolts that were in areas of oil all have new o-rings now but the ones in none oil areas do not have a seat for o-rings so none were put there.
The 2 bolts in question are the 2 center bolts on the driverside cover. They are both oiled areas so I replaced the o-rings. They use the long shoulder bolts and thick washers which I used. The problem is even with the shoulder bolt bottomed, thick washer and o-ring in place, the 2 bolts didn't compress the cover in that area. Oddly enough, the same 2 bolts on the passenger side cover did compress with exactly the same config. (1 bolt on the passenger side cover does go through a mounting bracket but this bracket is almost exactly the same thickness as a washer so I didn't use washers on that).
The check valves are a different story. All evidence of check valve location I have found points to them being at one side of the head or the other. So your saying that the check valve is placed next to the chain tensioner? Could you be more specific on the location?
It appears that I'm going to have to take the covers off again to fix these washer/gasket assemblies so I may as well go after those check valves again.
I hope the new gasket sets that I just installed are not affected by another removal of the covers. I didn't use any extra sealant on any of the gaskets so I would assume that they should just pop off and go on again.
Remember that I am a 928S, not an S4 so I am not sure of exactly how all of this matches up with the S4. They did change the covers and the cover bolts on the S4. S4 covers won't work on my S and the bolts were all switched to hex socket cap screws on the S4 with a completely different gasket / washer arrangement.
Still checking!!!!
The only bolts on my 85 that look to have a rubber gasket material under the washers was the the bolts at either end of the cover. This rubber was completely shot and I know where to find replacements. All other bolts had washers with no rubber on them. The bolts that were in areas of oil all have new o-rings now but the ones in none oil areas do not have a seat for o-rings so none were put there.
The 2 bolts in question are the 2 center bolts on the driverside cover. They are both oiled areas so I replaced the o-rings. They use the long shoulder bolts and thick washers which I used. The problem is even with the shoulder bolt bottomed, thick washer and o-ring in place, the 2 bolts didn't compress the cover in that area. Oddly enough, the same 2 bolts on the passenger side cover did compress with exactly the same config. (1 bolt on the passenger side cover does go through a mounting bracket but this bracket is almost exactly the same thickness as a washer so I didn't use washers on that).
The check valves are a different story. All evidence of check valve location I have found points to them being at one side of the head or the other. So your saying that the check valve is placed next to the chain tensioner? Could you be more specific on the location?
It appears that I'm going to have to take the covers off again to fix these washer/gasket assemblies so I may as well go after those check valves again.
I hope the new gasket sets that I just installed are not affected by another removal of the covers. I didn't use any extra sealant on any of the gaskets so I would assume that they should just pop off and go on again.
Remember that I am a 928S, not an S4 so I am not sure of exactly how all of this matches up with the S4. They did change the covers and the cover bolts on the S4. S4 covers won't work on my S and the bolts were all switched to hex socket cap screws on the S4 with a completely different gasket / washer arrangement.
Still checking!!!!
08-18-2002 | 06:08 PM
#6
Burning Brakes
Joined: Jul 2001
Posts: 1,051
Likes: 0
Hi Bernie,
See this link to the 928 Int’l site jpeg. (You can do an item search there too, to see what various parts look like there.) The check valve is the thing that looks like a bolt. The pictured spring goes in the middle of the tensioner.
<a href="http://www.mailordercentral.com/928intl/images/92810502808.JPG" target="_blank">http://www.mailordercentral.com/928intl/images/92810502808.JPG</a>
If you did not take extremely careful note of bolt placement upon removal, it is still possible that you have the bolts in the wrong holes. (A good way to keep track of positions is to punch bolts into a piece of cardboard in a pattern that reflects their original installation placements.) At this point, you can remove the cover without damaging the seal. Then screw bolts down into holes to see how high they protrude after they bottom-out. If placement position is not the problem, you are back to placing spacers – like washers – under the bolt heads. Use the OEM washers next to the cover to properly compress the sealing o-rings. Did you replace the Spark plug hole sealing rings? See my parts list for other needed items.
By the way, I think it was Jay Wellwood that had the same spacer material on the back of his washers. I could never find that stuff. Can you tell me about your source and product?
The 1985-86 engines are identical for automatic transmission equipped cars. See the 928 Specialist site for engine specs. 1987 S4 engines are really different. See:
<a href="http://www.928gt.com/928specs/928specs.htm#Specs" target="_blank">http://www.928gt.com/928specs/928specs.htm#Specs</a>
Good Luck,
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
See this link to the 928 Int’l site jpeg. (You can do an item search there too, to see what various parts look like there.) The check valve is the thing that looks like a bolt. The pictured spring goes in the middle of the tensioner.
<a href="http://www.mailordercentral.com/928intl/images/92810502808.JPG" target="_blank">http://www.mailordercentral.com/928intl/images/92810502808.JPG</a>
If you did not take extremely careful note of bolt placement upon removal, it is still possible that you have the bolts in the wrong holes. (A good way to keep track of positions is to punch bolts into a piece of cardboard in a pattern that reflects their original installation placements.) At this point, you can remove the cover without damaging the seal. Then screw bolts down into holes to see how high they protrude after they bottom-out. If placement position is not the problem, you are back to placing spacers – like washers – under the bolt heads. Use the OEM washers next to the cover to properly compress the sealing o-rings. Did you replace the Spark plug hole sealing rings? See my parts list for other needed items.
By the way, I think it was Jay Wellwood that had the same spacer material on the back of his washers. I could never find that stuff. Can you tell me about your source and product?
The 1985-86 engines are identical for automatic transmission equipped cars. See the 928 Specialist site for engine specs. 1987 S4 engines are really different. See:
<a href="http://www.928gt.com/928specs/928specs.htm#Specs" target="_blank">http://www.928gt.com/928specs/928specs.htm#Specs</a>
Good Luck,
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
08-18-2002 | 06:21 PM
#7
Thread Starter
Burning Brakes
Joined: May 2002
Posts: 1,208
Likes: 2
From: Las Vegas, Nevada
Thanx Thom,
The oil check valve is part of the chain tensioner assembly? I guess all of the info I've collected on this are not accurate for 85-86?
Those posts show the check valves being in the front lower portions of the head. I guess I will be going back in.
All eveidence on bolt sizes show only two lengths. One long and one really short. It would be impossible to mix those up. DO you think there are bolts with minute length differnces - on the order of half a millimeter?
I will post the replacement washers once I have picked them up. They are basically a thin flatwasher with a rubber gasket underneath bonde to the washer. Not sure if this is a direct replacement but it will definately do the trick. I think I may have sourced them in metric as well.
Thanx for the continued help Thom. I still need you to absolutely, positively confirm that the check valves are part of the tensioner assembly. I don't want to pull all of this down again for no reason.
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
The oil check valve is part of the chain tensioner assembly? I guess all of the info I've collected on this are not accurate for 85-86?
Those posts show the check valves being in the front lower portions of the head. I guess I will be going back in.
All eveidence on bolt sizes show only two lengths. One long and one really short. It would be impossible to mix those up. DO you think there are bolts with minute length differnces - on the order of half a millimeter?
I will post the replacement washers once I have picked them up. They are basically a thin flatwasher with a rubber gasket underneath bonde to the washer. Not sure if this is a direct replacement but it will definately do the trick. I think I may have sourced them in metric as well.
Thanx for the continued help Thom. I still need you to absolutely, positively confirm that the check valves are part of the tensioner assembly. I don't want to pull all of this down again for no reason.
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
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08-18-2002 | 07:16 PM
#8
Burning Brakes
Joined: Jul 2001
Posts: 1,051
Likes: 0
Hi Bernie,
If you have a US model 1985 automatic, and you saw the picture, you saw the check valve. I replaced both of mine. Some people think it is not necessary to replace check valves. I did not want to take chances. If you are hearing a strange noise, it is not necessarily the check valve.
The bolt is 10x20mm, and uses a 14mm socket. See the picture I made for this occasion. <a href="http://us.f1.yahoofs.com/users/a5080a5d/bc/My+Photos/Oil+Check+Valve.jpg?bc0a6h9A4NtQbIHL" target="_blank">http://us.f1.yahoofs.com/users/a5080a5d/bc/My+Photos/Oil+Check+Valve.jpg?bc0a6h9A4NtQ bIHL</a>
Let me know if you can view the picture on my Yahoo site.
Watch the aluminum crush washers. Plug up all holes nearby with paper towels before you disconnect the oil carrying tube. There are crush washers on each end. Always replace a crush washer after it has been disturbed.
I have no more opinions about your bolts.
HTH,
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
If you have a US model 1985 automatic, and you saw the picture, you saw the check valve. I replaced both of mine. Some people think it is not necessary to replace check valves. I did not want to take chances. If you are hearing a strange noise, it is not necessarily the check valve.
The bolt is 10x20mm, and uses a 14mm socket. See the picture I made for this occasion. <a href="http://us.f1.yahoofs.com/users/a5080a5d/bc/My+Photos/Oil+Check+Valve.jpg?bc0a6h9A4NtQbIHL" target="_blank">http://us.f1.yahoofs.com/users/a5080a5d/bc/My+Photos/Oil+Check+Valve.jpg?bc0a6h9A4NtQ bIHL</a>
Let me know if you can view the picture on my Yahoo site.
Watch the aluminum crush washers. Plug up all holes nearby with paper towels before you disconnect the oil carrying tube. There are crush washers on each end. Always replace a crush washer after it has been disturbed.
I have no more opinions about your bolts.
HTH,
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
08-18-2002 | 09:42 PM
#9
Thread Starter
Burning Brakes
Joined: May 2002
Posts: 1,208
Likes: 2
From: Las Vegas, Nevada
Hi Again Thom,
Yes, your input on this has been great!!
I guess a writeup for check valves on the '85-'86 models is in order. The ones I found are very misleading.
I just wanted to clean the assembly but it sounds like you changed yours out entirely? I have read that all they need is a cleanup to stop the quick chatter that happens right after startup. Once again, these are different from what I read soooo?
Do I need to clean 'em or replace 'em? I guess I also need to order in replacment crush rings for this fix?
BTW - The washers I was thinking of are called "Bonded Sealing Washers"
There not tough to find but I am searching for the proper metric equivalent to the old ones. You won't get any leaks through the bolts where these go - none oiled area, but the cam cover gasket may not compress properly and cause leaking around the cover if you don't compensate for the lost rubber part of the washer.
I will post a part number and location once I have them
Thanx Again Thom......
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
Yes, your input on this has been great!!
I guess a writeup for check valves on the '85-'86 models is in order. The ones I found are very misleading.
I just wanted to clean the assembly but it sounds like you changed yours out entirely? I have read that all they need is a cleanup to stop the quick chatter that happens right after startup. Once again, these are different from what I read soooo?
Do I need to clean 'em or replace 'em? I guess I also need to order in replacment crush rings for this fix?
BTW - The washers I was thinking of are called "Bonded Sealing Washers"
There not tough to find but I am searching for the proper metric equivalent to the old ones. You won't get any leaks through the bolts where these go - none oiled area, but the cam cover gasket may not compress properly and cause leaking around the cover if you don't compensate for the lost rubber part of the washer.
I will post a part number and location once I have them
Thanx Again Thom......
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
08-22-2002 | 06:56 PM
#10
Thread Starter
Burning Brakes
Joined: May 2002
Posts: 1,208
Likes: 2
From: Las Vegas, Nevada
Hi Thom,
Sorry to bring this back up again but I'm sure its VERY useful info for 85-86 owners.
I have not found any info about these check valves in the manual.
I can get replacements from 928Inter for about 20.00 a piece. Cheap enough
I guess I need for crush washers to go with that?
The question is - Do they have to be replaced or could they be cleaned like all the others? And, what is the removal procedure. Do they just come out no problem or does anything else need to be done (removal of the cams as an example LOL)
If you could give me just a little more detail, I would appreciate it.
Haven't opened it up yet so I want all ducks in a row this time.
BTW - I did get my hands on those bonded sealing washers for the non-oiled areas of the cam covers. I got them through Fastenal. I will post a pic and part number once I'm sure they do the trick.
Thom, thanx in advance
Sorry to bring this back up again but I'm sure its VERY useful info for 85-86 owners.
I have not found any info about these check valves in the manual.
I can get replacements from 928Inter for about 20.00 a piece. Cheap enough
I guess I need for crush washers to go with that?
The question is - Do they have to be replaced or could they be cleaned like all the others? And, what is the removal procedure. Do they just come out no problem or does anything else need to be done (removal of the cams as an example LOL)
If you could give me just a little more detail, I would appreciate it.
Haven't opened it up yet so I want all ducks in a row this time.
BTW - I did get my hands on those bonded sealing washers for the non-oiled areas of the cam covers. I got them through Fastenal. I will post a pic and part number once I'm sure they do the trick.
Thom, thanx in advance
08-23-2002 | 03:04 PM
#11
Burning Brakes
Joined: Jul 2001
Posts: 1,051
Likes: 0
Hi Bernie,
If I recall correctly, you do not need to remove anything other than the cam covers. Plug holes with paper towels first. No special tools are required. If your check valves are making noise, replace them. 17 years of wear… hmm. No way would I want to pull the intake and covers again. If they fail, you may need to rebuild the heads, and engine… hmm.
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
If I recall correctly, you do not need to remove anything other than the cam covers. Plug holes with paper towels first. No special tools are required. If your check valves are making noise, replace them. 17 years of wear… hmm. No way would I want to pull the intake and covers again. If they fail, you may need to rebuild the heads, and engine… hmm.
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
08-23-2002 | 03:49 PM
#12
Thread Starter
Burning Brakes
Joined: May 2002
Posts: 1,208
Likes: 2
From: Las Vegas, Nevada
Thanx Thom,
That's enough for me.....
Phonin' my pals at 928Inter.
Cheers (a big one)
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
That's enough for me.....
Phonin' my pals at 928Inter.
Cheers (a big one)
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />