3.4L M96-01 Valve Job Specs Needed
06-25-2011, 06:31 PM
#1
Three Wheelin'
Thread Starter
3.4L M96-01 Valve Job Specs Needed
Hello,
A couple questions for the pros...
1.) What is the preferred method to clean valves once removed? Brass wire wheel OK, followed by a polishing wheel? Obviously a gentle treatment.
2.) Does anyone have the specs for 3 angle valve job? Or is lapping without cutting recommended to recondition. I understand the valve seat heights should be 1.69-1.70".
3.) What is the recommended method to safely clean the heads? For example just plain ol' de-greaser and a gentle brush. I've read bead blasting and hot tanking = not good, but I've also read those can be safely done at a shop that has the right experience and tools.
Thanks.
A couple questions for the pros...
1.) What is the preferred method to clean valves once removed? Brass wire wheel OK, followed by a polishing wheel? Obviously a gentle treatment.
2.) Does anyone have the specs for 3 angle valve job? Or is lapping without cutting recommended to recondition. I understand the valve seat heights should be 1.69-1.70".
3.) What is the recommended method to safely clean the heads? For example just plain ol' de-greaser and a gentle brush. I've read bead blasting and hot tanking = not good, but I've also read those can be safely done at a shop that has the right experience and tools.
Thanks.
Last edited by logray; 06-26-2011 at 01:06 PM.
06-25-2011, 10:17 PM
#2
Three Wheelin'
Thread Starter
And courtesy Macster, from a 987 forum in this post about a 9PA:
"...964 valve clearances are 0.0011 inches to 0.0022 inches with a wear limit of 0.0059 inches..."
"...I mentioned the 964 valve clearance numbers and they both said those numbers are very close to the valve clearances for the new engines, in fact most Porsche engines. There's no magic involved..."
But that still leaves open the 3 (or 5) way angles and depths, no where to be found. Surely someone has done this. Or perhaps they haven't, and the valves are just lapped by feel without any 3 or 5 way stuff.
Thanks again in advance for any info on this topic.
"...964 valve clearances are 0.0011 inches to 0.0022 inches with a wear limit of 0.0059 inches..."
"...I mentioned the 964 valve clearance numbers and they both said those numbers are very close to the valve clearances for the new engines, in fact most Porsche engines. There's no magic involved..."
But that still leaves open the 3 (or 5) way angles and depths, no where to be found. Surely someone has done this. Or perhaps they haven't, and the valves are just lapped by feel without any 3 or 5 way stuff.
Thanks again in advance for any info on this topic.
Last edited by logray; 06-26-2011 at 04:37 PM.
06-26-2011, 04:36 PM
#3
Three Wheelin'
Thread Starter
The head gaskets arrived and they appear to be painted black. It seems like some of the paint on the old gaskets was peeling off.
"
"
Last edited by logray; 07-06-2011 at 03:07 PM.
06-30-2011, 08:27 PM
#4
Three Wheelin'
Thread Starter
Here are the angles they used for the valve job:
30 - 60 - 45
Ex guides were between .0015 and .0025 (except for the 5 that they replaced, one of which had an astonishing amount of play and is most certainly the source of the tick in #2)
In guides were between .0012 and .002
Stem heights were 1.695" to 1.702"
They also said anyone would be crazy to run guides that are nearing .0059" wear and wouldn't let one out of the shop.
The part number they used to replace the bad guides was: 996 104 115 60
The heads were cleaned and gently bead blasted. New seals, vacuum tested, valves cleaned and 3 way cut, 5 guides replaced. Lightly sanded mating surfaces among other work.
30 - 60 - 45
Ex guides were between .0015 and .0025 (except for the 5 that they replaced, one of which had an astonishing amount of play and is most certainly the source of the tick in #2)
In guides were between .0012 and .002
Stem heights were 1.695" to 1.702"
They also said anyone would be crazy to run guides that are nearing .0059" wear and wouldn't let one out of the shop.
The part number they used to replace the bad guides was: 996 104 115 60
The heads were cleaned and gently bead blasted. New seals, vacuum tested, valves cleaned and 3 way cut, 5 guides replaced. Lightly sanded mating surfaces among other work.
06-30-2011, 09:11 PM
#5
Race Director
Looks like you've found a shop that knows what it is doing.
That 0.0059" wear limit is just that: a limit; not a target or an upper value that is acceptable.
I agree if one found an engine with a valve stem/guide wear of 0.0059" he'd not be doing his job if he didn't strongly urge the owner to have the clearances addressed. I wouldn't think he'd have to try too hard. The ticking noise would probably have driven the customer in to see about doing something about the noise before the wear approached that much.
Generally one wants to clean the valves in such a way to avoid scratching them or changing the surface texture. I used carb cleaner letting the valves soak in the stuff.
For aluminum heads I had those sent out and cleaned. They can't be hot tanked -- it will dissolve the head -- but there are alum. safe cleaning processes which can involve chemicals or some kind of air driven media. Walnut shells and other organic material can be used. Glass or metal blasting can loosen up the surfaces treated and these can shed bits of alum. over time. Also there's a heck of a cleaning task to remove all grit.
For the angles used for the valves/seats had I been required to come up an answer I would have suggested putting a valve under a magnifying viewer to the point one could view the existing angles and a reasonable guess could be made. Or buy a new valve and look at it under the viewer.
Or if you select a shop that has done this work before those values are probably burned into the brain of the automotiove machinist.
Alot of that black soft stuff one finds in his oil and oil filter comes from pieces of that sealant coming loose over time. Of course you're holding a piece that covers a water passage. Since many do not drain their coolant or pay attention to its contents like they do oil any of this stuff in the coolant goes unnoticed.
Have to say, though that if I am seeing things right that's alot of excess sealant. I wonder if that engine was apart sometime in the past?
Sincerely,
Macster.
That 0.0059" wear limit is just that: a limit; not a target or an upper value that is acceptable.
I agree if one found an engine with a valve stem/guide wear of 0.0059" he'd not be doing his job if he didn't strongly urge the owner to have the clearances addressed. I wouldn't think he'd have to try too hard. The ticking noise would probably have driven the customer in to see about doing something about the noise before the wear approached that much.
Generally one wants to clean the valves in such a way to avoid scratching them or changing the surface texture. I used carb cleaner letting the valves soak in the stuff.
For aluminum heads I had those sent out and cleaned. They can't be hot tanked -- it will dissolve the head -- but there are alum. safe cleaning processes which can involve chemicals or some kind of air driven media. Walnut shells and other organic material can be used. Glass or metal blasting can loosen up the surfaces treated and these can shed bits of alum. over time. Also there's a heck of a cleaning task to remove all grit.
For the angles used for the valves/seats had I been required to come up an answer I would have suggested putting a valve under a magnifying viewer to the point one could view the existing angles and a reasonable guess could be made. Or buy a new valve and look at it under the viewer.
Or if you select a shop that has done this work before those values are probably burned into the brain of the automotiove machinist.
Alot of that black soft stuff one finds in his oil and oil filter comes from pieces of that sealant coming loose over time. Of course you're holding a piece that covers a water passage. Since many do not drain their coolant or pay attention to its contents like they do oil any of this stuff in the coolant goes unnoticed.
Have to say, though that if I am seeing things right that's alot of excess sealant. I wonder if that engine was apart sometime in the past?
Sincerely,
Macster.
06-30-2011, 10:12 PM
#7
Three Wheelin'
Thread Starter
One of the old grey haired bearded crazy looking old men at the shop has seen a lot of Porsches, mostly air cooled. They also see a lot of BMWs which say are similar.
I voiced my concern about glass beading and they looked at me like I was nuts. They said as long as you keep the PSI low and keep your distance its never a problem.
When I started talking about specs they started to rattle off every angle for just about every valve out there. My eyes crossed. Apparently it is completely dependent on what the existing valve angle they measure and the computer/machine is set accordingly. They also had a valve sitting on their desk that was about 1 foot tall.
I am starting to believe it has, even though the PO said it had never had major work. I saw the evidence of the strange gasket material on the 1-3 head gasket but absent from the 4-6 gasket. I wonder if it is some sort of glue that was holding the two sides of the metal gasket together? Also RTV was used to seal the intake riser on 4-6, in addition to the gasket. Seemed odd.
I am starting to believe it has, even though the PO said it had never had major work. I saw the evidence of the strange gasket material on the 1-3 head gasket but absent from the 4-6 gasket. I wonder if it is some sort of glue that was holding the two sides of the metal gasket together? Also RTV was used to seal the intake riser on 4-6, in addition to the gasket. Seemed odd.
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06-30-2011, 10:23 PM
#8
Three Wheelin'
Thread Starter
AND
There was a knock/tick on cold startup that was slowly getting worse. Enough so that I was uncomfortable driving the car without worrying about it. It would seem to go away once warm, however using the screwdriver stethoscope trick I found that it was still there in #2, even after warmed (just not audible without the stethoscope). It was faint enough to where I couldn't tell if it was the intake or exhaust side, as I could hear it from both top and bottom. I thought it might be lifters... but knew that it could also be worn guides.
However once I tore the cam covers off I found out that the lifters were in great shape (to the best of my knowledge, I am not an expert). They will still be replaced.
This prompted me to go further and commit to the valve job and new head gaskets and new head bolts. Much to my delight, once I pulled the heads I discovered that the bores and piston heads were in tremendous shape.
07-01-2011, 01:40 PM
#10
Three Wheelin'
Thread Starter
Sure thing. The block is sitting on my tool chest.
Unfortunately now I have to play the waiting game for the head gaskets. The morons screwed up the shipping, they are only 130 miles away from me and they picked Fedex Saver instead of Fedex Home.
Sheesh.
Unfortunately now I have to play the waiting game for the head gaskets. The morons screwed up the shipping, they are only 130 miles away from me and they picked Fedex Saver instead of Fedex Home.
Sheesh.
