Landseer

87 is interchangeable with 88 and 89.

(Except where GT and Clubsport are concerned. They are interchangeble only with each other. FWIW).

The ones Doc had originally referenced above were 85/6, but I think he just read the cryptic WSM chart a little sideways.
I was afraid you were chasing them, scratching your head. Those are totally different than 87,8,9.


The spec books. In the CD set.

Andrew hosts them now, I'll post his link.

https://docs.google.com/fileview?id=...ZGFjZjI3&hl=en

Landseer

Also, somewhere up top you mentioned parallel.

The stroke of the measuring dial gauge needs to be parallel with valve travel, right? Not parallel with cylinder bore.

Again, just following along here.

aaddpp

Thanks for the link to the file. I remember that I had seen this in the past, but at the time I hadn't gotten quite this deep so I had nothing to relate it to - makes more sense now! As for the numbers, I know what I am looking for going forward, so I'll see if it all fits together - I expect it will, but a little confirmation wont hurt.

Also, I think you are correct on the alignment...its in parallel with the movement of the valve. I did a screen grab of the youtube 928 engine video #3 which has a decent illustration showing alignment relative to valve and cylinder. Holding an angle measure up to my screen shows about a 15-16 degree difference compared to the plane of the spark plug channel.

Thanks,
Dave

docmirror

Hmmm, gonna be interesting to find out what cams are in that car. The first set of numbers I published way back were for code 28.43, or 28.41 which is a S4 with 5 speed. However, if he has suffix numbers on the end of the cam (.09, .60, etc) that could be ROW cams.

See last column in pic below. If he has ROW cams, they are different lobe profiles. Higher power, and could explain the delta in the plunge measurement.
<edit: sorry about capturing the email balloon. )

Landseer

Let's start from the top. Cam PNs: Left bank 928.105.292.04, 928.105.294.02, right bank 928.105.291.04, 928.105.293.04. This is for 87 model year, US build. Or, it could be 928.105.272.00, 274.00, and 271.00, 273.00. The later numbers are for the 88, but I'm betting that's what you have.




.43 and .44., as well as .45 and .46 engines are all from 85/86 MY. Those bolded above in your original post are from that engine according to WSM and Spec Book.

.41 and .42 are the universal "worldwide" engine starting in 87, carrying into 88 and 89. (worldwide, not ROW)

Correct me if wrong, of course, but based on the documentation, the patient should have cams as follows:
Cam PNs: Left bank 928.105.292.09, 928.105.294.08, right bank 928.105.291.09, 928.105.293.09 . This is for 87 model year, US build. Or, it could be 928.105.272.00, 274.00, and 271.00, 273.00 (If somebody replaced some/all with equivalent 1988/89 cams (non-CS, non-GT)).

Make sense? Not trying to be a smartass in any way, just trying to figure it out 'cause I need to dive into one soon myself.

docmirror

According to Porsche, 28.41 is S4 ROW/US. That would be 1987 5 speed cams. Which is what this car is. Don't care about the .43 or .44 engines. So, the PNs I supplied originally is suited for this car. I call the ROW cams, because they are different PN for the later 88-91 cams. It's darn confusing that's for sure.

While the later cams are interchangable I don't know if the profile is different or not. What we're trying to resolve is a cam lobe profile difference using the plunge vs the 32Vr tool. The WSM specifies using the plunge method, and one reason for that is because the cams may have a different profile in relation to the keyway index on the end of the cam that fits the flange. That flange is the reference for the 32Vr tool, and it may be(not sure, but we have prelim indications) that the keyway is registered differently on the early 87 cams, vs the later 88-91 cams.

Landseer

Agreed!

But check your post. You called-out 85/86 cams.

aaddpp

If I am reading the spec sheet above correctly, the "Identification Code on the Rear Cam Face" is what the numbers I posted correspond to. I won't say with 100% confidence until I have a chance to look at them again, but I don't see anyway the first two column numbers ending in .04 or .02 are the ones in my car - the "4" at least is an unmistakable number whatever the orientation.

So...I am pretty sure there was a "6" or "9" in there, probably leaving the worldwide column as the only option. Again I will go back and confirm. I will even try and grab a piece of clay or something like it to see if I can get an impression. Taking the rear cam-bridge off is also an option to help access the numbers, but that's something I would like to avoid.

Anyway...in the meantime I have printed the TechSpecs document and will bring myself up to speed.

If we are talking worldwide cams...is this something people have done / could have ordered? I was told something to the effect that the first owner (of three including me) was not short on cash, and could probably have had whatever he wanted if money could buy it.


Dave

Landseer

What we are all saying is that Porsche had a bunch of different 928 platforms and needed to consolidate. It took them a few years.

Starting in 1987, they finally got to one engine, regardless of market (only sub variations for 5 speed vs auto, but that didn't affect cams is my understanding)

aaddpp

One more question I'll toss in here...On the tech sheet it had figures for when the exhaust should open and close in degrees away from TDC and BDC (bottom dead center???). To measure this, do you need a special tool or can you use the ballancer marked accordingly. I would guess for a down and dirty measurement you could take the ballancer circumference in milimeters and divide by 360 to get mm / degrees and then measure...

Dave

76FJ55

To get your cam part numbers try taking a digital photo of them using the mirror then you can just flip the photo electronically to eliminate nag confusion with the mirror image.

Landseer

Check with Blown 87 about the application of a large diameter degree wheel on top of balancer. He commented something about a degree wheel recently.

You are researching pretty deeply.
It will be interesting to see if you have the right cams. Am wondering if you have a measurement issue or a very worn cam lobe wrong cam or something else.
Do you really have an issue?


Good idea with photo.

aaddpp

That's what I was thinking to do, but I forgot the CF card for my good camera at work. Only issue here I found was with lighting, you need to get the light at an angle that will cast the right shadow on the stamp in order to be able to read the numbers. Reversing a photo is definitely something I will give a shot to thought....

Not sure...really this is at the edge of my automotive knowledge. It just seemed like the degree measurements would provide an additional check if the timing is squared away. BTW, now that you mention the degree wheel, I think I remember a photo a while back...I think it was made by Moroso.

Dave

docmirror

Yup, I read from the far left column, it should have been the far right column. Oops. 28.41, so discount the first set of cams in my prev post and go by the image provided.

aaddpp

Finally had some time around the car this evening and was able to pull the numbers off the back of the cam shafts using a mirror, an incandescent bulb (yes is made a difference) and a piece of clay to make impressions. Here are the numbers I pulled:

Driver Top: 292 09
Driver Bottom: 294 08

Pax Top: 291 09
Pax Bottom: 293 09

Based on the data sheet posted by docmirror, I looked at the engine code just below the water bridge, and the number seems to correspond with the cam shaft #'s... mine was M 28/41 and data sheet shows M28.41

Everything seems to match up with the worldwide category. What does this mean exactly? The owners book shows a purchase and quite a bit of service at a dealership in the Midwest. For what its worth, I have an early 87 with a flip up wing.

Will look at the books tomorrow to see what next steps are, but figured I would post in the mean time.

Thanks,
Dave