Engine coming out for Head Gaskets and WYAIT's - UPDATE: Heads back on!
#76
Drifting
Interesting, should be nice to get it going and see how everything is working. After I had my engine out and did a lot to it, it ran better than ever, revved like crazy.
Worf has become too much of a staid yankee, no color in there. I really like my yellow plug wires, not cheap, they actually came to me thru DEVEK, kind of a collectors item. Jorg I believe had blue vacumn hose lines in one of his engines and they not only looked good but made it much easier to follow what was going on.
Now we need you and Brad to take these euro's out with a gopro camera and get some footage in some scenic area up there. Have you guy's done your exhaust?
Worf has become too much of a staid yankee, no color in there. I really like my yellow plug wires, not cheap, they actually came to me thru DEVEK, kind of a collectors item. Jorg I believe had blue vacumn hose lines in one of his engines and they not only looked good but made it much easier to follow what was going on.
Now we need you and Brad to take these euro's out with a gopro camera and get some footage in some scenic area up there. Have you guy's done your exhaust?
#77
Rennlist Member
Thread Starter
Interesting, should be nice to get it going and see how everything is working. After I had my engine out and did a lot to it, it ran better than ever, revved like crazy.
Worf has become too much of a staid yankee, no color in there. I really like my yellow plug wires, not cheap, they actually came to me thru DEVEK, kind of a collectors item. Jorg I believe had blue vacumn hose lines in one of his engines and they not only looked good but made it much easier to follow what was going on.
Now we need you and Brad to take these euro's out with a gopro camera and get some footage in some scenic area up there. Have you guy's done your exhaust?
Worf has become too much of a staid yankee, no color in there. I really like my yellow plug wires, not cheap, they actually came to me thru DEVEK, kind of a collectors item. Jorg I believe had blue vacumn hose lines in one of his engines and they not only looked good but made it much easier to follow what was going on.
Now we need you and Brad to take these euro's out with a gopro camera and get some footage in some scenic area up there. Have you guy's done your exhaust?
#78
Drifting
Mine had the original exhaust when I first got it, but if you really want a euro to scream at redline you need to open it up. The open exhaust and RRFPR's are what makes mine so fast, the sound is amazing too.
Either way, should be fun!
Either way, should be fun!
#79
Rennlist Member
I'd love to open up my exhaust a bit but I must say I love the all stock look. I've begun to suscribe to the 'if it ain't broke don't fix it' maxim. Brian, you up for a rat race?
#80
Rennlist Member
#81
Rennlist Member
Thread Starter
It Runs!!...But....
Pulled the fuel pump relay, cranked engine, got oil pressure, then jumpered fuel pump to pressurize the fuel system and check for leaks. All systems go. Reinstalled the fuel pump relay and it fired up almost immediately, idled nicely, no funny noises. Then, Dave noticed the oil drip. Passenger side cam tower was leaking oil toward the rear at the head mating area. Shut it down, confirmed all bolts were tight, and then came to the conclusion that the cam tower had to come off. I was confident that I had installed the gasket correctly, and torqued all of the bolts to spec. I used Greg Brown’s improved 16v cam tower gaskets, and was pretty sure I had not torn it when torquing the bolts.
We spent the next few hours clearing the way to allow removal of the cam tower, and once off, the gasket was perfect, mating surfaces clean and free of scratches – no apparent reason for a leak. And, yes, the gasket was on correctly with the hole aligned with the oil feed from the head. Some pondering time later, we concluded that the most likely culprit was improper torque. Dave suggested checking each bolt hole in the head to make sure there was no obstruction preventing complete seating of the bolts.
We found that all holes in the head allowed the bolts to bottom out completely with 3 threads showing (cam tower removed), except for one – right in the vicinity of the leak. That one tightened with quite a bit more thread showing. It appears that something in the hole buggered the threads. Flushing and cleaning out with a q-tip did not remedy the situation. The overall depth measurement matches the others, as measured with a probe. The thought is that the resistance once turned in to the buggered thread gave a spec torque reading, without appropriate clamping of the cam tower to the head. It was close enough to look fully seated.
So, the plan is to chase those threads, check for proper bottoming of the bolt, and then reinstall the cam tower with a new GB gasket. We will fill the cam tower with oil through the upper bolt plug holes and see if any oil leaks out before buttoning everything up.
It was a great feeling to hear it fire up nicely, and then a big letdown to have to start taking things apart again. But, like Dave said, it could have been worse, considering the scope of this project.
We spent the next few hours clearing the way to allow removal of the cam tower, and once off, the gasket was perfect, mating surfaces clean and free of scratches – no apparent reason for a leak. And, yes, the gasket was on correctly with the hole aligned with the oil feed from the head. Some pondering time later, we concluded that the most likely culprit was improper torque. Dave suggested checking each bolt hole in the head to make sure there was no obstruction preventing complete seating of the bolts.
We found that all holes in the head allowed the bolts to bottom out completely with 3 threads showing (cam tower removed), except for one – right in the vicinity of the leak. That one tightened with quite a bit more thread showing. It appears that something in the hole buggered the threads. Flushing and cleaning out with a q-tip did not remedy the situation. The overall depth measurement matches the others, as measured with a probe. The thought is that the resistance once turned in to the buggered thread gave a spec torque reading, without appropriate clamping of the cam tower to the head. It was close enough to look fully seated.
So, the plan is to chase those threads, check for proper bottoming of the bolt, and then reinstall the cam tower with a new GB gasket. We will fill the cam tower with oil through the upper bolt plug holes and see if any oil leaks out before buttoning everything up.
It was a great feeling to hear it fire up nicely, and then a big letdown to have to start taking things apart again. But, like Dave said, it could have been worse, considering the scope of this project.
Last edited by BRB-83-911SC; 05-06-2012 at 11:18 PM.
#82
Captain Obvious
Super User
Super User
Nice that it wasn't anything catastrophic, sucks that you had to tear it all down.
I think the gasket will be fine if you reuse it. Also, if there is enough threads in that hole, putting a thick enough washer will make the bolt clamp properly and remove the need to touch the threads. Last thing you need is something to go wrong when re-cutting the threads.
I think the gasket will be fine if you reuse it. Also, if there is enough threads in that hole, putting a thick enough washer will make the bolt clamp properly and remove the need to touch the threads. Last thing you need is something to go wrong when re-cutting the threads.
#83
Three Wheelin'
Nice going man. I hope to be in your position by this Fall (engine back in and running well). We should turn this thread into the "Pulled my motor" club for all questions/tips relating to "pull the motor" jobs.
Regarding your valve cover leak, that sucks, but it's a small thing considering the adventure of pulling the motor and (like an old house) discovering things that weren't done properly, or things that you didn't anticipate would need much time to R&R. I'm being pretty thorough on my 928 as the motor is out now, i took apart the starter which i never thought i'd need to do but it needed repainting and the proper way to do it was to pull the casing apart to spray paint each piece, which leads to cleaning the whole starter (WYIT) etc. I'm sure you know this feeling.
Regarding your valve cover leak, that sucks, but it's a small thing considering the adventure of pulling the motor and (like an old house) discovering things that weren't done properly, or things that you didn't anticipate would need much time to R&R. I'm being pretty thorough on my 928 as the motor is out now, i took apart the starter which i never thought i'd need to do but it needed repainting and the proper way to do it was to pull the casing apart to spray paint each piece, which leads to cleaning the whole starter (WYIT) etc. I'm sure you know this feeling.
#84
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Brian and I have become quite adept at removing the cam tower in the car. We've got it down to under two hours. I'll spare the details.
This morning we marked the exterior of the cam tower at exactly the point from which pressurized oil was leaking. When we removed the cam tower and examined it very closely we found this:
That's a oddly-circular depression at exactly the point we marked. It's about 0.001" deep. You can just feel it with your fingers but it isn't as deep as a piece of paper is thick.
There's a matching impression on the head surfaces at the corresponding point.
After lunch, memory and inspiration struck. This...
... is an OE cam tower gasket. Notice the "chad?" (Note, that Brian used Greg Brown's gaskets, NOT the OE gaskets. Greg's gaskets arrive "chadless.")
Funny that the chad from the OE gasket is pretty-much exactly the size as the depressions on the cam tower and head mating surfaces.
Are you thinking what we're thinking?
Oh, one more thing: the OE gasket is 0.002" thick.
This morning we marked the exterior of the cam tower at exactly the point from which pressurized oil was leaking. When we removed the cam tower and examined it very closely we found this:
That's a oddly-circular depression at exactly the point we marked. It's about 0.001" deep. You can just feel it with your fingers but it isn't as deep as a piece of paper is thick.
There's a matching impression on the head surfaces at the corresponding point.
After lunch, memory and inspiration struck. This...
... is an OE cam tower gasket. Notice the "chad?" (Note, that Brian used Greg Brown's gaskets, NOT the OE gaskets. Greg's gaskets arrive "chadless.")
Funny that the chad from the OE gasket is pretty-much exactly the size as the depressions on the cam tower and head mating surfaces.
Are you thinking what we're thinking?
Oh, one more thing: the OE gasket is 0.002" thick.
#85
Three Wheelin'
#86
Rennlist Member
Thread Starter
#87
Rennlist Member
Sorry, I don't get it.
#89
Rennlist Member
2 things:
1. deck the face of the cam tower?
2. dimple the area around the high pressure oil passage?
On mine, the gasket squeezed out and broke (tore) in that area.
Greg's gaskets and installation dry with very clean surfaces did the trick for me - finally.
But I wonder if dimpling the cam tower around those high pressure passages would be wise?
Dan
1. deck the face of the cam tower?
2. dimple the area around the high pressure oil passage?
On mine, the gasket squeezed out and broke (tore) in that area.
Greg's gaskets and installation dry with very clean surfaces did the trick for me - finally.
But I wonder if dimpling the cam tower around those high pressure passages would be wise?
Dan
#90
Rennlist Member
Thread Starter
So, here are the Cliff's notes:
So, the solution is to install that chad back in place with a new gasket, right? ....just kidding.
- Engine fully assembled on the stand, used Greg Brown cam tower gaskets, installed dry, cam towers properly torqued.
- Install engine, start and check for leaks. Passenger side tower leaking.
- Curse
- Go for coffee
- Pull cam tower with engine in car. Gasket looks good, no *obvious* reason for leak.
- Clean bolt threads (some were gunked up a bit, thinking false torque reading)
- Reinstall cam tower with a new Greg Brown gasket, dry.
- Start it up, and same leak.
- Curse loudly
- Go to lunch
- Mark exact location of the leak.
- Pull cam tower again, and look very closely at the exact location of the leak, and discover that ever so slight depression.
- Brainstorm possible causes, and see no signs of fresh damage, scratches, etc. and conclude that the depression has been there a while. What could cause that? Must have been some sort of foreign object between mating surfaces causing deformation of the aluminum once torqued.
- Look more closely at the head in that same location (razor blade on end with a light behind) and notice a similar depression directly opposite the one on the head. Just enough to see light, but not enough to slip a piece of paper through. So, what could it be?
- We recall seeing a bolt hole with the punched "chad" remaining attached to the gasket on one of the cam tower gaskets in the VR kit (didn't use the OE gaskets in the kit), so we pull it out and compare the chad to the indentation. It couldn't have been a closer match. So, the hypothesis is that at some point in the past (probably at the factory, since there is no evidence this engine has been apart before), the original cam tower gasket had a hanging chad that went unnoticed, and when the bolt was pushed through, it punched the chad aside and it remained trapped between the head, the gasket and the cam tower until we tore it down.
So, the solution is to install that chad back in place with a new gasket, right? ....just kidding.