BC

We have a willful ignorance cleanup in Isle 2. Isle 2 please.

Lizard928

actually Mark I have to kindly disagree with you on that last statement.

The tensioner CAN change the intake cam timing.

The reason being is that when the tensioner has no oil in it, the chain slackens.
This will allow the intake cam to move alittle (not alot, but enough to bugger your readings), This movement will be caused by the position of cam lobes in relation to the valve lifters and springs.
IMO in order to make your intake cam readings 100% I think you would need to pressurise the tensioner before taking the readings, and maintain pressure in it. Possibly using compressed air.

I also believe that the exhaust camshaft is far more important compaired to the intake camshaft.

However I am considering making a manual cam chain tensioner for the 928 with the ability to move the location of the tensioner pads up and down, thus being able to advance and retard the intake camshaft in the head to be able to find the most optimum settings. (And be able to ensure no overlap with the turbos)

Tom. M

They are talking cam chain tensioner ..not the belt tensioner...

Louie used to go to great lengths to wedge the chain tensioner up so he could get the proper settings doing it the old way via dial indicator....

I think what most here are saying is that there are lots of variable that can affect a dial indicator cam timing setting...you are just good at repeating it..keeping variables the same each time....

mark kibort

if you are careful, you can get the driving movement from TDC forward without a chance of any slack. any slack means that the intake cams go further than the exhaust cam moving forward for the 20 degree movement, or that at TDC, the intake cam moves foward. It cant, its being pressed on by the valve springs. However, as long as you are making sure the tension is kept tight, there is little or no chance of that happening. anyway, as Bill had noted, the tension of my tensioner set up, was very tight. the old holbert cams with old chains were much looser at times, but not during the tensioning procedure back then. You take the tensioner off my car and do the test , you will get the same results. the chain is that tight.

Brendan, why dont you spray some hylomar on your posts.

Mk

mark kibort

Dont forget, cold compression 190psi per side, and hot compression 210psi per side. equal numbers on both sides. I think in most folks book, this is one of the most important and telling tests.

Thats how the car is set up and I would certainly question anyone to adjust what i have done so far, as to try and improve on what has been done. Something tells me, ether the heads with the 85 block is causing some of this inconsistancy when comparing to other that have done the tests, or maybe there are some differences between cams. I dont know. But what i do know, is that by doing the factory method for setting the cams, ive come up with some pretty good numbers. Sure dont know whether those numbers would be as good if i went and changed my exhaust cam timing 6 degrees retard and my passenger side exhaust cam 3 degrees retard.

The dyno will show the rest of the story, as did the first test of compression for the two sides.

mk

Lizard928

Sorry Tom, I realise now that it could be misinterpretted, however I was talking about the Cam chain tensioner in my last post.

AO

How will this prove anything?

You have no baseline for this motor.

Unless you try setting the cams both ways (which I doubt you ever will do becasue of the possibility of eating crow,) you'll never know.

Sorry, but I just would hate to see a 400+ RWHP number and then have you jump up and down as proof-positive that you were right and he was wrong. The dyno will prove nothing except that you have more power than you did before. Duh!

mark kibort

Andrew,

Now I have a baseline that i am keeping written down. We know the porken tool on my car is saying that the exhaust cam is ADVANCED a full 6 degrees on the driver side, while the passenger side is Advanced only 3 degrees. There are two things going on here. I have a 3 degree difference between the cam timing measurement based on the porken tool. I also have a difference of the passenger cam that should be a 1 degree difference retard to be right, but Ive measured (bill measured ) 3 degrees.

Now, I measured, very accurately the factory setting and used my old techniquie found by what i saw on the Holbert car's original cam settings of 2mm per side. So, basically, with no cam chain slack, and repeatable results of over 20 checks my way, and 5 checks with the dial indicator, i see equal compression, which is the REAL INDICATOR!

Now, to appease you and others if they are out there, im willing to advance my driver side by 6 degrees and see what happens. I have a feeling, things would change for the worse. Im just not convinced that the casting V marks, or cams that come from porsche, or the difference in the head, gasket or block, could cause the descrepancy in the Porken measurements. Again, many have seen equal results by using the WSM and the porken tool. Im here to show that there is a difference on my car and its pretty substantial.

The dyno runs will show the footprint of the new engine. then, we can alll speculate on if i retarded the exhaust cam by 9 degrees and the intake by 5 degrees on what that would do to the HP curves. (to reach the original advice of retarding the cam timing by 2/3 degrees to start go give this stroker motor more HP and less peak torque. Think of the other issue here. I dont think that adjusting window is big enough to change the timing 9 degrees to the retard to reach that goal. Think about that one. If you were me, would you use the WSM or this tool that has shown a serious flaw (when thinkng it works on all 32valve motors) in this case.

I could care less about "eating crow". Thats the differnce with me and most on this list when we get into these discussions. I just want the truth! Others have too much pride and make too many negative assumptions. I would be the first posting here to say THANKS to Ken, if I am wrong, and would love to have the performance that changing would bring. BUT, based on what ive seen so far, and using indicators that most have used since this car was made in 1985, I do believe the Holbert stroker engine is set up correctly. Again, the ONLY think I am saying here is that the WSM technique was done correctly. I have new belts and relatively new chains and used good measuring equipment, with a witness that knows how to use the simple gear as well, to make the tests.


Mk

mark kibort

How about this Andrew and Porken. Why dont you guys take your car and adjust their cams to be 6 degrees advanced at the intake and 3 degrees on the exhaust and see how your car runs . do a compression test. If you guys saw equal results using the tool, vs WSM technique, I have a sneaking suspicsion that your compression will not be equal side to side as mine is. compression hot and cold as i have tested, yielded dead nuts equal values. Now that is a pretty telling test.
I would rather be equal, than right!

mk

Mark Anderson

The motor is not new we just changed out the rods.

BC

This is why I don't think the loss is from a "tight motor"

AO

As I said before, I don't have a disparity between the dial method (WSM) and the Porken's tool method. You are the first person that I know of to have different readings between the two methods - the cause of which is, at best, unclear.

Ken has tried to explain possible causes for variation, but you seem to be dead set on either ignoring them or discounting them - citing items like compression tests as proof-positive that you're right. I'm not entirely sure that a compression test is the best indicator of balanced cam timing. I believe it will tell you if you have a large issue, but I'm not sure if it will tell if the cams are off a few degrees. I submit, however, that I'm no expert in this area - just a skeptic.

What's most disturbing to me is that you, despite your good intentions, seem to be unwilling to contemplate the possibility that, perhaps, your methodology for setting the cams was off a few degrees.

Please remember that many people on this list, including yours truly, invested a lot of time and money in this project and want to see you be as successful as possible. Ultimately it is your motor, so you have ultimate authority. However, for me, your cavalier and righteous attitude on this topic, is leaving a bit of a bad aftertaste in my mouth. I don't think it's much to ask for you to keep an open mind to alternatives.

mark kibort

Andrew,

Im very open to suggestion and ideas of why there is a descrepancy between the WSM (and its not a matter or arrogance , its a matter of simple meaurements) and the the Porken tool. Some, (Brendan) had questioned my abiity to use a simple measuring device. Kind of insulting, considering I was even double checking my work with another gauge and qualified engine builder.

Anyway, Im only standing fast on the fact that the WSM technique has shown 2.0 mm of lifter depression, there was no slack in the chain, as the intake lobe at TDC is pressing on the lifter and valve spring. the cam dont move that easily on their own in this position. Then, after i qualify this by measuring compression of both sides, not only cold, but hot which changed dramatically, I beleve based on the different piston material than stock, it kind of proves im in the right ball park at least. NOT, 6 to 3 degrees off the stock setting.

Ive only discounted the variables that i know were not variables. (ie chain slack) I have not discounted the possiblity that the marks could be wrong on that plate, or that the cams could be wrong. Or, that the head gasket, block, heads are unmatched slightly. I dont know the ramifications there, but maybe Ken could calculate what .003 off the head (if it hasnt been shaved before) and some resurfacing on the block, as well as a thicker head gasket, would change his readings. There is also no explanation of my repeatable measurement values, and then the porken tool showing the passenger side cam currently being 3 degrees retarded. These are all very quirky results with using the tool.

Now, I have one factor that no one has mentioned yet. what about the machined 3 point stars that hold the pulleys AND the porken tool. If it is off, so will all the settings. I quickly noticed that both of these stars didnt look the same. It was a quick comparison, left to right, but it seemed they were not the same. could they be different? could mine be reversed? I should have taken some measurements, but i was fighting and focused on some fit issues due to some corrosion on the cam pulley mounts and was getting too tight of a fit.

A very easy check i can verify, would be find a point on the rotation of the crank where you can measure 20 degree movement and get an exhaust lifter depression. Porken or brendan or the other "experts" should be able to find this point and I will glady verify.

What i do know is that ive timed the cams relative to the intake lifter depression If i have sacraficed exhaust cam position, its a trade off im willing to make right now, until we narrow down all the factors that CAN make the porken tool inaccurate.

Again, im keeping an open mind and spent more time trying to figure out why and if there is an issue than anyone. If we had solid lifters, the test i did yesterday might have told us something, however, i guess the lifters bleed out oil if the engine is not running

mk

BTW, Andrew, this is what is upsetting for me. You basically say i could be off a few degrees with my method, but you dont have an issue with the work shop method. Clearly, there is some unwillingness on the tool side of the camp to understand that their could be factors that could render the method, incorrect.

You said:
"As I said before, I don't have a disparity between the dial method (WSM) and the Porken's tool method. "

"What's most disturbing to me is that you, despite your good intentions, seem to be unwilling to contemplate the possibility that, perhaps, your methodology for setting the cams was off a few degrees."

PorKen

Don't get stuck on the initial reading. The belt will have stretched by the time you check again, so the readings will now have some retard. A new belt loses about 2° on the the ¼ after a few hundred miles, the ⅝ ≤1°.

Even your misguided attempts at using the dial indicator, using equal measurements on both sides, will have been fixed somewhat by the belt stretch.

I would guess that the current 32V'r cold readings are ¼ +1°, ⅝ +5°.

If I were you, I would stop speaking as if your isolated, flawed case, is revelant to 32V engines at large, for a tool you do not own, or have used personally.

The 32V'r has shown what it is designed to show. Your 'results' differ.

LT Texan

This has to go down as the biggest thread hyjack in history!!!!