Hello, I'm about to go into the garage and attempt to set the valve clearance on a B20-B.
My query is : how to set the piston at TDC for cyl. #4 ? I can figure out cyl #1 by using timing marks ( 0 deg. with both rockers up would be tdc #1, i assume). Is tdc for #4 180 degrees further?

Thanks for the help! I've been a 700 series guy for a while, and have forgotton about the finer points of "öld school" mechanics.

On a 4 cylinder engine #1 and #4 are at TDC at the same time but.....
Doesn't have to be at TDC. Just has to be fully closed. If the adjacent
valve is wide open it usually will be. I normally adjust the ones that have
clearance, mark them with chalk as I adjust them, turn it 180°, do it again,
and keep on till they are all marked. Then I go back and check to make sure
none have more than the right clearance (in case one was not quite all the
way closed when I adjusted it before). I sorta integrate the setting and
rechecking along the way. I realize that is not the most efficient in terms
of engine motion but it seems to be in terms of my time. I set mine to 0.020".
Some guys like less but I have burned B30 exhaust valves with less in the desert.
--
George Downs Bartlesville, Heart of the USA!

Thanks Walrus....I set them and went for a drive. There is still a little tickety boo under there, but the engine has slightly more pickup, sees to run just fine..

These pushrodders are a little noisy on a good day, are they not?

I'm tempted to put a 100 miles on it, then recheck them. It was fun!


Cheers, Josh

Yes, they do make a little valve noise. Better a little noise than having
them not close all the way. Probably a good idea to check again later.
--
George Downs Bartlesville, Heart of the USA!

They are or can be noisy, nothin' to worry about unless it gets noisier in a short period of time. That's usually an indication of a bad timing gear-sounds a lot like clackety valves.

The quick and dirty:
Note where number one spark plug wire is and remove cap. Find 0 degrees on the crank pulley...you're distributor rotor should now be pointing at (where) number 1 or number 4 (spark plug wire was).

At #1 TDC, adjust valves # 1, 2, 3, and 5.
Turn the crank 360 degrees.
At #4 TDC, adjust valves # 4, 6, 7, and 8.

There is a very precise method in the Tech Archive at www.vclassics.com

Best,
Shayne.

I had to graph that out, Shayne. I was skeptical but the symmetry of the cam makes it work. I will use that method from now on!

On the graph the "rule of nines" works very well too.

--
Mike!

I heard that's how they got them out of the service center at the dealerships as quick as possible, but I could be wrong. I guess that's why I call it the quick and dirty method. Heh.
Shayne.

Gee this goes way back...

20 yrs ago i had '68 145. i don't remember where I got the degree figures, but I marked the crankshaft pulley with marks for intake and exhaust just opening. I only had to turn the engine to line up the mark with arrow on the block, then finger tight the screw to bring the tappet to zero clearance on the valve. Quick check afterwards to verify there was still some clearance at TDC. It was quick to adjust and gave the smoothest, quietest engine with solid lifters I ever had.

Cheers

'89 245, 405,000 km

I didn't see my favorite method for setting valves, so I'll add it to the list.

- Roll engine until rocker arms for #4 cyl "rock" (exhaust valve closing and intake valve opening). This puts #4 at (or very near) TDC on the intake stroke, so #1 is also at TDC with both valves fully closed and ready to adjust.

- Roll engine until rocker arms for #2 rock, adjust valves on #3.

- Roll engine until rocker arms for #1 rock, adjust valves on #4.

- Roll engine until rocker arms for #3 rock, adjust valves on #2.

This method does not require you to look for timing marks, pull the dist cap, or anything else... you're simply using the relationship of the cylinders to each other, to determine absolutely when a pair of valves are closed. This is essentially 4 half-turns of the crankshaft start to finish, and is pretty much idiot proof. I should know. :-)
--
1971 142E ITB racer, 1973 1800ES, 2002 S60 T5