Pulling My 32V Head Appart
07-12-2011, 12:55 AM
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Pulling My 32V Head Appart
I'm the type of person that learns best by doing, so I've been pulling apart an old 928 head to learn a bit about the parts / process before I dig into my own on-car heads. So far it hasn't been very complicated, but like most other things, having the right tools and techniques often yield better results 
I've been documenting the process along the way way so I could reference it later if needed. Next step is to mess around with several different cleaners - citrus, Simple Green, SuperClean (my personal favorite, but requires caution on metals I've discovered) - and see which works best in cleaning up the carbon deposits on the old valves in my ultrasonic.
Photos Of My Process
Heads with valve tappets removes. Left valve has had the collet / keeper removed, right is still intact.
http://www.flickr.com/photos/51967142@N00/5911285320/
Once the collet / keeper is removed, the top washer (WSM #32, Porsche: 944 105 467 03 - aka concave washer) and springs were easy to remove, exposing the valve stem and valve stem seal (928 104 601 00) and lower washer (928 105 469 07). Note, no spacer washer was present in the head I pulled apart.
http://www.flickr.com/photos/51967142@N00/5911286890/
Once the valve is removed, the valve stem seal becomes much easier to visualize - sorry...camera focus would not cooperate at any angle.
http://www.flickr.com/photos/51967142@N00/5911287166/
Removing valve stem seal with a set of task specific pliers.
http://www.flickr.com/photos/51967142@N00/5911283830/
Valve guides revealed. I may try and remove one for the heck of it, but I gather it needs a press...the hammer-the-hell-out-of-it approach didn't work so well Hopefully I won't find any issues with my on-car heads since dealing with the guide complicates matters greatly according to the WSM.
http://www.flickr.com/photos/51967142@N00/5911284464/
View of the valve guides from below. Creepy.
http://www.flickr.com/photos/51967142@N00/5911286168/
View of the valve internals in the order they were removed.
http://www.flickr.com/photos/51967142@N00/5911287882/
Another view of the internals. Note the difference in size between the Exhaust and Intake valves.
http://www.flickr.com/photos/51967142@N00/5910731743/
One more view
http://www.flickr.com/photos/51967142@N00/5910732339/
Part by Part
Valve collet / keeper
http://www.flickr.com/photos/51967142@N00/5911289588/
Top Washer
http://www.flickr.com/photos/51967142@N00/5910733485/
External spring
http://www.flickr.com/photos/51967142@N00/5910733967/
Internal spring - The circle shows the size of the outer spring
http://www.flickr.com/photos/51967142@N00/5911291218/
Valve
http://www.flickr.com/photos/51967142@N00/5911291762/
Valve guide seal - this one looks like it has a crack, along with some separation of the rubber at the base.
http://www.flickr.com/photos/51967142@N00/5910735277/
Lower washer
http://www.flickr.com/photos/51967142@N00/5911292602/
Kit I used to pull the valves out. The major deficit here is that the arm is not fixed to the x-bar. If not careful, the handle can slip and the press can damage the tappet walls. Also the cross bar tends to slide a bit which can lead to the assembly collapsing on itself. I may try to get a couple of collars with the hex bolt locks to put on either bar end to minimize movement when I deal with my good heads.
http://www.flickr.com/photos/51967142@N00/5911293484/
How It All Goes Together
Obviously its not this easy to assemble...and parts are out of place in relation to where they would be installed since the valve guide and "assembly seat" are not present.
Valve with lower stepped washer (Note: PET calls for some model years to have an additional spacer of between 0.5mm - 2.0mm, but my head (MY 86 in think) had none.
http://www.flickr.com/photos/51967142@N00/5911294084/
Valve seal added
http://www.flickr.com/photos/51967142@N00/5911294588/
Inner spring
http://www.flickr.com/photos/51967142@N00/5910738243/
Outer spring added
http://www.flickr.com/photos/51967142@N00/5911295454/
Top stepped washer and collets / keepers added
http://www.flickr.com/photos/51967142@N00/5911295898/
Intake and Exhaust assemblies side by side
http://www.flickr.com/photos/51967142@N00/5911296374/
I've been documenting the process along the way way so I could reference it later if needed. Next step is to mess around with several different cleaners - citrus, Simple Green, SuperClean (my personal favorite, but requires caution on metals I've discovered) - and see which works best in cleaning up the carbon deposits on the old valves in my ultrasonic. Photos Of My Process
Heads with valve tappets removes. Left valve has had the collet / keeper removed, right is still intact.
http://www.flickr.com/photos/51967142@N00/5911285320/
Once the collet / keeper is removed, the top washer (WSM #32, Porsche: 944 105 467 03 - aka concave washer) and springs were easy to remove, exposing the valve stem and valve stem seal (928 104 601 00) and lower washer (928 105 469 07). Note, no spacer washer was present in the head I pulled apart.
http://www.flickr.com/photos/51967142@N00/5911286890/
Once the valve is removed, the valve stem seal becomes much easier to visualize - sorry...camera focus would not cooperate at any angle.
http://www.flickr.com/photos/51967142@N00/5911287166/
Removing valve stem seal with a set of task specific pliers.
http://www.flickr.com/photos/51967142@N00/5911283830/
Valve guides revealed. I may try and remove one for the heck of it, but I gather it needs a press...the hammer-the-hell-out-of-it approach didn't work so well
Hopefully I won't find any issues with my on-car heads since dealing with the guide complicates matters greatly according to the WSM. http://www.flickr.com/photos/51967142@N00/5911284464/
View of the valve guides from below. Creepy.
http://www.flickr.com/photos/51967142@N00/5911286168/
View of the valve internals in the order they were removed.
http://www.flickr.com/photos/51967142@N00/5911287882/
Another view of the internals. Note the difference in size between the Exhaust and Intake valves.
http://www.flickr.com/photos/51967142@N00/5910731743/
One more view
http://www.flickr.com/photos/51967142@N00/5910732339/
Part by Part
Valve collet / keeper
http://www.flickr.com/photos/51967142@N00/5911289588/
Top Washer
http://www.flickr.com/photos/51967142@N00/5910733485/
External spring
http://www.flickr.com/photos/51967142@N00/5910733967/
Internal spring - The circle shows the size of the outer spring
http://www.flickr.com/photos/51967142@N00/5911291218/
Valve
http://www.flickr.com/photos/51967142@N00/5911291762/
Valve guide seal - this one looks like it has a crack, along with some separation of the rubber at the base.
http://www.flickr.com/photos/51967142@N00/5910735277/
Lower washer
http://www.flickr.com/photos/51967142@N00/5911292602/
Kit I used to pull the valves out. The major deficit here is that the arm is not fixed to the x-bar. If not careful, the handle can slip and the press can damage the tappet walls. Also the cross bar tends to slide a bit which can lead to the assembly collapsing on itself. I may try to get a couple of collars with the hex bolt locks to put on either bar end to minimize movement when I deal with my good heads.
http://www.flickr.com/photos/51967142@N00/5911293484/
How It All Goes Together
Obviously its not this easy to assemble...and parts are out of place in relation to where they would be installed since the valve guide and "assembly seat" are not present.
Valve with lower stepped washer (Note: PET calls for some model years to have an additional spacer of between 0.5mm - 2.0mm, but my head (MY 86 in think) had none.
http://www.flickr.com/photos/51967142@N00/5911294084/
Valve seal added
http://www.flickr.com/photos/51967142@N00/5911294588/
Inner spring
http://www.flickr.com/photos/51967142@N00/5910738243/
Outer spring added
http://www.flickr.com/photos/51967142@N00/5911295454/
Top stepped washer and collets / keepers added
http://www.flickr.com/photos/51967142@N00/5911295898/
Intake and Exhaust assemblies side by side
http://www.flickr.com/photos/51967142@N00/5911296374/
Last edited by aaddpp; 07-12-2011 at 11:38 AM.
07-12-2011, 03:09 PM
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07-13-2011, 07:31 AM
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Where did you get the tools especially the pliers for the valve seal?
As far as the valve guides we used a pneumatic chisel with a special tip. The tip slipped into the valve guide and then the gun would rattle it out. It worked pretty well on VW heads. Chilling the guides and heating the heads worked well for installation too.
What did you use to measure the play in the guides and how are you going to cut the valve faces? Again with VW heads we had a special cutter for the valve seats and then would lap the freshly ground valves into the seat. of course on VWs the exhaust valves always were replaced and only the intake values were reground.
As far as the valve guides we used a pneumatic chisel with a special tip. The tip slipped into the valve guide and then the gun would rattle it out. It worked pretty well on VW heads. Chilling the guides and heating the heads worked well for installation too.
What did you use to measure the play in the guides and how are you going to cut the valve faces? Again with VW heads we had a special cutter for the valve seats and then would lap the freshly ground valves into the seat. of course on VWs the exhaust valves always were replaced and only the intake values were reground.
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07-13-2011, 01:16 PM
#8
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Dan, I stuck my text in red in your post below...
Where did you get the tools especially the pliers for the valve seal? I order most of my stuff from Amazon for convenience - here's a link to the pliers (http://www.amazon.com/Schley-Narrow-...0571992&sr=8-1). I also ordered the valve compressor from Amazon, but I would not recommend that model...others I have seen appear to allow you to connect the arm to the cross bar making it more stable.
As far as the valve guides we used a pneumatic chisel with a special tip. The tip slipped into the valve guide and then the gun would rattle it out. It worked pretty well on VW heads. Chilling the guides and heating the heads worked well for installation too. Chilling / Heating sounds like a smart idea...seems to provide a benefit elsewhere like bearing races etc. Not sure it would apply here, but in my research into this I found a 911 clip on Youtube where the guy cut the guide down a bit. I think it was to minimize how much it needed to be pushed out.
What did you use to measure the play in the guides and how are you going to cut the valve faces? Again with VW heads we had a special cutter for the valve seats and then would lap the freshly ground valves into the seat. of course on VWs the exhaust valves always were replaced and only the intake values were reground.
I have not measured the play yet. The WSM says to use a new valve and measure play with a dial indicator with the valve protruding 10 or 20 mm (can't recall exactly right now). I gather this process ensures that you are just looking at the wear of the guide, and not the wear of the guide plus the valve stem. I have some new OEM valves (much less costly than Porsche) on order from Roger which I will use to do the measurements.
As for the valve faces, I haven't done enough homework here yet so I'm still researching how to proceed. My main purpose in going down this road with the heads - besides changing what appeared to be the beginnings of a failing head gasket - is to deal with several valve seals that appear to be leaking. I've started looked into lapping, and cutting, but its only been a quick glance at this point so I'm not sure which is / isn't appropriate. Ideally I would like to just change the seals and put it all back together, but I'm not sure if that's the right way to do things either. What I definitely want to try and avoid is machine shop time since the only place I've found so far is $$$$$ pricey.
As far as the valve guides we used a pneumatic chisel with a special tip. The tip slipped into the valve guide and then the gun would rattle it out. It worked pretty well on VW heads. Chilling the guides and heating the heads worked well for installation too. Chilling / Heating sounds like a smart idea...seems to provide a benefit elsewhere like bearing races etc. Not sure it would apply here, but in my research into this I found a 911 clip on Youtube where the guy cut the guide down a bit. I think it was to minimize how much it needed to be pushed out.
What did you use to measure the play in the guides and how are you going to cut the valve faces? Again with VW heads we had a special cutter for the valve seats and then would lap the freshly ground valves into the seat. of course on VWs the exhaust valves always were replaced and only the intake values were reground.
I have not measured the play yet. The WSM says to use a new valve and measure play with a dial indicator with the valve protruding 10 or 20 mm (can't recall exactly right now). I gather this process ensures that you are just looking at the wear of the guide, and not the wear of the guide plus the valve stem. I have some new OEM valves (much less costly than Porsche) on order from Roger which I will use to do the measurements.
As for the valve faces, I haven't done enough homework here yet so I'm still researching how to proceed. My main purpose in going down this road with the heads - besides changing what appeared to be the beginnings of a failing head gasket - is to deal with several valve seals that appear to be leaking. I've started looked into lapping, and cutting, but its only been a quick glance at this point so I'm not sure which is / isn't appropriate. Ideally I would like to just change the seals and put it all back together, but I'm not sure if that's the right way to do things either. What I definitely want to try and avoid is machine shop time since the only place I've found so far is $$$$$ pricey.
07-14-2011, 06:29 AM
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Dave,
Thanks for the reply. I have just lapped in used valves when they are in good shape with good results. The issue is that the valve spins. So it is important to have a very accurate face.
I was quoted some time back rebuilding an 85 32 valve head $300 for labor plus parts. That sounded reasonable to me and the SF Bay Area is not a cheap place to get such things done.
The tool I had for grinding the valve seats was not easy to use. For the valves I used to have a grinder. I would be tempted to let a machine shop cut the valves and seats and replace th guides. It is just easier to do these things when you have the proper tools. After the cut the valves can still be hand lapped. I used to test the valve seal with acohol.
Thanks for the reply. I have just lapped in used valves when they are in good shape with good results. The issue is that the valve spins. So it is important to have a very accurate face.
I was quoted some time back rebuilding an 85 32 valve head $300 for labor plus parts. That sounded reasonable to me and the SF Bay Area is not a cheap place to get such things done.
The tool I had for grinding the valve seats was not easy to use. For the valves I used to have a grinder. I would be tempted to let a machine shop cut the valves and seats and replace th guides. It is just easier to do these things when you have the proper tools. After the cut the valves can still be hand lapped. I used to test the valve seal with acohol.
07-18-2011, 01:34 PM
#11
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Dan, added my reply below in red
Dave,
Thanks for the reply. I have just lapped in used valves when they are in good shape with good results. The issue is that the valve spins. So it is important to have a very accurate face. Dan, thanks for all the info. I spent some time over the weekend messing around with the lapping process....it seems simple enough to do, though I'm sure some proper technique doesn't hurt here. Only issues / questions were (i) you need a smaller sized suction cup for the exhaust valves - large swizzle stick suction cups are too big and exceed the valve diameter, and (ii) wondering about lapping compound grit on our cars...NAPA only had two types of lapping compound - water based and oil based, no mention of grit...and when I looked online you can find lapping compound from #50 - #1200. I would imagine the finest grit possible (within reason) is where you want to end up. Do you recall what you used? Also, when you used alcohol to test, how do you do this? I've seen a thread a while back where the head in inverted (valves facing up) and the concave valve area is filled with a liquid.
I was quoted some time back rebuilding an 85 32 valve head $300 for labor plus parts. That sounded reasonable to me and the SF Bay Area is not a cheap place to get such things done. The shop I found wants $475 for labor plus parts, but the owners are really American muscle car guys, so the 928 head isn't something they see often, if ever. With the WSM, I should be able to take the required measurements etc. and go back to them if I need to get a shop involved. At least I'll be able to discuss with an understanding of the situation.
The one thing I might use the shop for is cleaning the head. As an alternative I've also been looking into a 5 gal bucket of Berryman Chem-Dip. I picked up a small 1 gal dipping can with a basket on Friday, and it did an amazing job of cleaning the carbon off the old valves - soaked for about 30-60 minutes, and then some light scrubbing with a nylon brush. Somewhere, a while back, I saw a post where someone said they dipped / cleaned their entire head in the larger 5 gal can. Would be interested to know if the Berryman solution is kind to the head aluminum...on the valves everything looked OK.
The tool I had for grinding the valve seats was not easy to use. For the valves I used to have a grinder. I would be tempted to let a machine shop cut the valves and seats and replace th guides. It is just easier to do these things when you have the proper tools. Agreed. Way outside the boundaries of my tool-box and skill-set.
Thanks for the reply. I have just lapped in used valves when they are in good shape with good results. The issue is that the valve spins. So it is important to have a very accurate face. Dan, thanks for all the info. I spent some time over the weekend messing around with the lapping process....it seems simple enough to do, though I'm sure some proper technique doesn't hurt here. Only issues / questions were (i) you need a smaller sized suction cup for the exhaust valves - large swizzle stick suction cups are too big and exceed the valve diameter, and (ii) wondering about lapping compound grit on our cars...NAPA only had two types of lapping compound - water based and oil based, no mention of grit...and when I looked online you can find lapping compound from #50 - #1200. I would imagine the finest grit possible (within reason) is where you want to end up. Do you recall what you used? Also, when you used alcohol to test, how do you do this? I've seen a thread a while back where the head in inverted (valves facing up) and the concave valve area is filled with a liquid.
I was quoted some time back rebuilding an 85 32 valve head $300 for labor plus parts. That sounded reasonable to me and the SF Bay Area is not a cheap place to get such things done. The shop I found wants $475 for labor plus parts, but the owners are really American muscle car guys, so the 928 head isn't something they see often, if ever. With the WSM, I should be able to take the required measurements etc. and go back to them if I need to get a shop involved. At least I'll be able to discuss with an understanding of the situation.
The one thing I might use the shop for is cleaning the head. As an alternative I've also been looking into a 5 gal bucket of Berryman Chem-Dip. I picked up a small 1 gal dipping can with a basket on Friday, and it did an amazing job of cleaning the carbon off the old valves - soaked for about 30-60 minutes, and then some light scrubbing with a nylon brush. Somewhere, a while back, I saw a post where someone said they dipped / cleaned their entire head in the larger 5 gal can. Would be interested to know if the Berryman solution is kind to the head aluminum...on the valves everything looked OK.
The tool I had for grinding the valve seats was not easy to use. For the valves I used to have a grinder. I would be tempted to let a machine shop cut the valves and seats and replace th guides. It is just easier to do these things when you have the proper tools. Agreed. Way outside the boundaries of my tool-box and skill-set.
Last edited by aaddpp; 07-18-2011 at 02:17 PM.
07-19-2011, 06:37 AM
#12
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Dave,
It has been a long time since I had the VW shop. I do say the tolerance of the VW motors and tranaxles were much tighter than the US and British cars I had previously worked on. We used two compounds but I cannot remember the grit. I think one was dark grey and a lighter color. Cutting the valves and guides will get you there. It is probably not necessary to lap the valves. We did it because the seat cutter did not do a perfect job. Remember also valves wear in and seat better after some miles.
For testing we used alcohol because it was less volitile than gasoline. Just turn the head upside down and pour in the liquid. If the valves are seated right it will not leak out. Again lapping and testing is probably not needed on a head with properly cut valves and seats.
As far as cleaning I have been using the Purple Zep all purpose cleaner but it will not break up carbon. It disolves grease very well - especially on aluminum. Just do not soak aluminum parts in as it will eat them away after some time. The berrymans is probably the best thing for disolving carbon. I do not think it will hurt the aluminum as it is a solvent and not a acid or base.
As far as shops perhaps we are a little more lucky here. The 928 head is very much like the 944 head and many other german cars, so the shops around here see them frequently.
It has been a long time since I had the VW shop. I do say the tolerance of the VW motors and tranaxles were much tighter than the US and British cars I had previously worked on. We used two compounds but I cannot remember the grit. I think one was dark grey and a lighter color. Cutting the valves and guides will get you there. It is probably not necessary to lap the valves. We did it because the seat cutter did not do a perfect job. Remember also valves wear in and seat better after some miles.
For testing we used alcohol because it was less volitile than gasoline. Just turn the head upside down and pour in the liquid. If the valves are seated right it will not leak out. Again lapping and testing is probably not needed on a head with properly cut valves and seats.
As far as cleaning I have been using the Purple Zep all purpose cleaner but it will not break up carbon. It disolves grease very well - especially on aluminum. Just do not soak aluminum parts in as it will eat them away after some time. The berrymans is probably the best thing for disolving carbon. I do not think it will hurt the aluminum as it is a solvent and not a acid or base.
As far as shops perhaps we are a little more lucky here. The 928 head is very much like the 944 head and many other german cars, so the shops around here see them frequently.
07-19-2011, 12:40 PM
#13
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^^^^^^
Dan, many thanks for the information you've shared on the valves / heads. It's helpful to have a head start knowledge-wise before I deal with my on car heads. Good also that you brought up the 944...I searched the 944 group on RL, and there were a few local machine shops posted that might be a better option if needed. Thanks again, Dave.
Dan, many thanks for the information you've shared on the valves / heads. It's helpful to have a head start knowledge-wise before I deal with my on car heads. Good also that you brought up the 944...I searched the 944 group on RL, and there were a few local machine shops posted that might be a better option if needed. Thanks again, Dave.
07-19-2011, 12:51 PM
#14
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Do you have the tech spec books for the 32V cars?
If not, be sure to look in them because they have some good detail regarding grind angles and other data that is apparently needed for rebuild. AO has links to them in his signature line, so hunt down a post by him for the link.
If not, be sure to look in them because they have some good detail regarding grind angles and other data that is apparently needed for rebuild. AO has links to them in his signature line, so hunt down a post by him for the link.
07-20-2011, 10:08 AM
#15
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Do you have the tech spec books for the 32V cars?
If not, be sure to look in them because they have some good detail regarding grind angles and other data that is apparently needed for rebuild. AO has links to them in his signature line, so hunt down a post by him for the link.
If not, be sure to look in them because they have some good detail regarding grind angles and other data that is apparently needed for rebuild. AO has links to them in his signature line, so hunt down a post by him for the link.
Dave
