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Mon Feb 21, 2011 9:01 pm

Ok.. So I've read here on the board about bigger cams needing to be adjusted differently then the old traditional TDC method for stock engines. It was referred to as lobe per lobe adjusting.

I've done some searching and saw it mentioned in several threads, but no real good explanation on how to do it?

I've got a 2276 with a CB 2288 (FK8 equiv), when I adjusted the valves to loose zero the "normal" way, at other spots off TDC during the revolution each valve clearance opens up some.

Can someone walk me through this procedure?

Reference:
http://www.thesamba.com/vw/forum/viewtopic.php?t=402970&start=0

http://www.thesamba.com/vw/forum/viewtopic.php?t=378705&highlight=lobe+lobe+adjustment

http://www.thesamba.com/vw/forum/viewtopic.php?t=96703&highlight=lobe+lobe+adjustment

Mon Feb 21, 2011 9:04 pm

Not sure what you mean by different?

I have a FK-8 and set the valve lash to a "loose zero" because I have chromoly pushrods. I use the degree pulley to set the engine at TDC and BDC.

Mon Feb 21, 2011 9:12 pm

What he is getting at is that with some cam profiles the lifter is not sitting on the base circle at TDC or BDC, I can't describe the best way to do it but the way I've done mine is to turn the crank till the opposite valve is at its highest lift, then adjust the opposite valve, that way the lifter is on the lowest point. It takes me some more time as I adjust each valve individually but I know the loose zero is set at the base circle not on a part of the ramp.

Mon Feb 21, 2011 9:15 pm

Glenn wrote: Not sure what you mean by different?

I have a FK-8 and set the valve lash to a "loose zero" because I have chromoly pushrods. I use the degree pulley to set the engine at TDC and BDC.

Not trying to discuss loose zero versus some specified clearance... Thats been covered to death. I'm running loose zero on my Manton Chromolly PR's

What I'm looking for is discussing the difference of adjusting both valves with the cylinder at its respective TDC, versus adjusting one valve at a time by finding the heel of the lobe.

I just don't have a good understanding on how to find the heel and adjust them one by one.

Mon Feb 21, 2011 9:18 pm

66brm wrote: What he is getting at is that with some cam profiles the lifter is not sitting on the base circle at TDC or BDC, I can't describe the best way to do it but the way I've done mine is to turn the crank till the opposite valve is at its highest lift, then adjust the opposite valve, that way the lifter is on the lowest point. It takes me some more time as I adjust each valve individually but I know the loose zero is set at the base circle not on a part of the ramp.

That's a good idea! Didn't think of that...

keep'em coming folks.. Just trying to figure out what the best way to go about this is. Want to make sure to keep my new valve train happy.

Mon Feb 21, 2011 11:25 pm

66's method is perfect. The V-8 way that I learned years ago couldn't use 66's method since the lobes aren't shared but also works perfect without having to run back and forth 18 times to look at the other side. Here it is....

Do one cylinder at a time.....
To adjust a cylinder's intake valve, rotate the engine CW until the exhaust valve is open about .100. Now set the intake lash. Rotate again thru the intake valve opening cycle until the intake is closing but still open by about .100. Now set the exhaust lash. Repeat procedure for the other three cylinders. Done.

If this is the initial setting on a freshly assembled engine I would run thru it twice. If it is just checking for regular maintenance you can just run thru it once.

RC

Tue Feb 22, 2011 6:51 am

I think the OP is talking about using cams that are advanced or retarded. The TDC BDC method would not be exact but it is close enough. Dont over think the simple things

Tue Feb 22, 2011 7:08 am

Dougy Dee wrote: I think the OP is talking about using cams that are advanced or retarded. The TDC BDC method would not be exact but it is close enough. Dont over think the simple things It isn't over thinking. Many hi-po cams only have a 100* of cam base circle area or less and can easily be on the ramp at TDC or BDC. Hope McTuckey chimes in on this, He knows the score......

RC

Tue Feb 22, 2011 8:06 am

Dougy Dee wrote: I think the OP is talking about using cams that are advanced or retarded. The TDC BDC method would not be exact but it is close enough. Dont over think the simple things

Thanks for the input, but that was not what I was talking about.

Several folks have said it, with larger cams with more overlap, at TDC the lifters can end up being on part of the ramp. So to adjust big cams properly, you need to adjust each valve when it is not on a ramp (i.e. at the heel of the lobe).

I was just wondering if anyone had any helpful advice/procedure that they use to adjust valves this way.

I think 66brm hit it on the head... If I rotate the engine until one of my valves is at full lift, the shared lobe valve on the opposite side of the engine should be on the backside of the lobe.

Tue Feb 22, 2011 8:20 am

66brm's way is the way I'd do it. If you're working on #1 and #3 exhaust lobe, find full lift of #1 then adjust lash on #3 side (sitting at base of lobe). Now spin crank 1 turn (1 crank turn = 1/2 cam turn) to bring the base of lobe to #1 side and adjust lash for #1. Slap on a dial indicator if you want accuracy finding full lift.

Tue Feb 22, 2011 8:33 am

do it the way RC said to do it and the system will be loaded each time.otherwize you may have the oposing valve pushing back with no countering force.remember camshaft do flex,and the bearings do have clearance.if you want the valves ajusted the same then they need to be preloaded the same or close to it.you will be surprized on how much better it sounds and runs. no more power knock that 90% have.if you dont know what that is forget it. and when and if the power knock starts to show up you know it is time for an ajustment.good luck

Tue Feb 22, 2011 9:50 am

Am I all stupid if I just say, turn the engine around adjusting one valve at a time, and just adjust it when it is most loose...
That way you know you are at the lowest place...

Tue Feb 22, 2011 2:51 pm

dalland wrote: Am I all stupid if I just say, turn the engine around adjusting one valve at a time, and just adjust it when it is most loose...
That way you know you are at the lowest place...

No not stupid, I was just looking for a more concrete/analytical way to find the lowest point of the lobe

I've got two really good recommendations from this thread. Thanks everyone for the input!

Tue Feb 22, 2011 4:26 pm

I do it hte way RC does it, just using TDC doesn't always mean the valve is off lobe especially when you get cams with durations like 312*

brad

Tue Feb 22, 2011 5:49 pm

Isn't the reason for adjusting valves at TDC of the compression stroke to make sure the valves are closed then?

Tue Feb 22, 2011 8:47 pm

66brm wrote: What he is getting at is that with some cam profiles the lifter is not sitting on the base circle at TDC or BDC, I can't describe the best way to do it but the way I've done mine is to turn the crank till the opposite valve is at its highest lift, then adjust the opposite valve, that way the lifter is on the lowest point. It takes me some more time as I adjust each valve individually but I know the loose zero is set at the base circle not on a part of the ramp. Do mine the same way as well always have.After i have felt i have adjusted it to right lash i spin motor and check to see if the adjustment is correct.(looking to see if the lash gets looser).

Takes more time for sure though

Wed Feb 23, 2011 4:17 am

74 Thing wrote: Isn't the reason for adjusting valves at TDC of the compression stroke to make sure the valves are closed then?

X2

Wed Feb 23, 2011 6:41 am

74 Thing wrote: Isn't the reason for adjusting valves at TDC of the compression stroke to make sure the valves are closed then?

That will be correct w/ stock cams. But if you had installed aftermarket, do you know for a fact what the phasing on the cam if you had dialed it or degreed it??

Just because you put he piston up top does not mean the lobes are phased correctly and closed valves. Depends how you installed the cam... straight up? or advanced..or retarded. All three will affect the cam lobe phasing.

To VEEDUB, find the lowest point on the lobe or heel by observing the valve when it starts to lift backwards and forward. Note the degree reading on the pulley... you can see the halfway points.

Or.. the way I do it, turn the crank until you see the start of the lift on the valve (valve opening).....back off to what you think is halfway...adjust the valve lash/lockdown....then keep backing off until the valve starts to lift again (valve opening). Now...do the turning again and this time just feel for the valve lash...measure w/ a feeler if you like.

Best to have it done w/ 2 people so you can say "go forward" or "back" while you feel for the valve lash. You can do it by yourself but it is a bit tedious. If you do it by yourself, just move the crankshaft a little at a time and check.

FK8 is nothing. Try adjusting an FK89 or 98. For these type of cams I use only the Pauter roller rockers (aluminum ones). No swipers like the Berg...but I do use swiper rockers on smaller ones like FK8 or less.

Enjoy.

Wed Feb 23, 2011 10:58 am

Thanks for the input!

Mon May 09, 2011 11:02 am

If you adjust the valves using RC's method above or adjusting the valve if the opposing valve is at full lift so you know you are at the bottom of the base circle, if you go back to TDC on the compression stroke should both of the valves be closed?