Setting Valve lash

[Mart]

What's the best way to find TDC on #1, and does anybody have a good procedure for setting valve lash.

The Haynes manual says to turn the crank 90 degrees for every valve, but the shop manual say to get #1 at TDC and you can adjust 8 valves at a time.

If I am reading it right??????

Help, any suggestions

Mart

 

[Mart]

Anybody

 

[Mart]

OK, one quick question for anybody who has done this, one you have taken the lash out, and made the extra 1/2 turn should you be able to twist the pushrod??


Mart

 

[SG4206]

OK ; this is a simple way - with the left bank valve cover pulled , spin the engine until the intake valve closes on # 1 cyl., then bump the engine until the timing mark is on 0. This is top dead center #1.
On a solid lifter motor ,now lash to spec; rotate 90 degrees and do #8 .rotate 90-do #4 and so on down the firing order.
A hyd.cam motor can be done the same ,but you need to spin the push rod and tighten the rocker nut at the same time. When the push rod stops spinning, turn the nut 1/8 turn tighter. This will be enough pre - load .
The process is very critical ; be sure you want to tackle this .

 

[Mart]

Oh yeah, I'm sure.

Right now the pushrods feel like my 6yr olds teeth (loose and ready to fall out )

Thanks
Mart

 

[RonJ]

Put the first half of the firing order over the second half of the firing order.

1-8-4-3​

6-5-7-2​

When #6 is on overlap (both intake and exhaust are slightly open at the same time), #1 is TDC and can be adjusted. A slight rotation of the crank to put #5 on overlap, then adjust #8 etc., etc, etc.

It sounds complicated, but it's not!!

Hope this helps ..... Ron ......

 

[rrubel]

If you do a search on replacing rocker arms, you'll find a great post in answer to my questions about a year ago. It explains in detail which ones to do when; IIRC you cannot just do intake and exhaust on the same cylinder at the same time.
[RICHR]

 

[RonJ]

If you do a search on replacing rocker arms, you'll find a great post in answer to my questions about a year ago. It explains in detail which ones to do when; IIRC you cannot just do intake and exhaust on the same cylinder at the same time.
[RICHR]

If a given cylinder is TDC between compression and power strokes, why can't both valves be adjusted?

They will never be closed more ..... .

Ron ...

 

[jim coulter]

The easiest way if you dont want to try and watch the balancer constantly is to get on one cylinder, doesn't matter which(I like to do 1, then 3, then 5, then 7 and then switch to the passenger side) you turn the engine over till the intake starts to open - adjust the exhaust. continue to turn the engine over till the exhaust opens and starts to close, when the exhaust gets about 1/2 closed-adjust the intake. when through move to next cylinder. Adjust the rockers by turning the pushrod between your fingers while adjust the nut to tighten, when all play is gone(you can barely roll pushrod between fingers) its time to tighten last bit. If your using stock 1.5 ratio rocker arms tighten the nut 3/4 turn, if your using 1.6 ratio rocker arms onlytighten 1/2 turn. If your turning the engine by hand it will turn easier if you remove all the spark plugs.

 

[SG4206]

Ron-
You are correct; both rocker arms do get adjusted at the same time when at TDC.
Mr. rrubel is incorrect in his last statement. Jims method works good ; but leaves more room for more error.
If you do not want to go down the firing order to adjust the rockers ;or try Jims method ; With a hyd. cam ,you can start the engine and adjust the rockers while running. Back off the nut until the rocker clicks ; then tighten 1/4 turn.
There is always more than one way to skin a cat ; I've been building chevy engines for 40 years, and always suggest the basic correct method. Forget the shade tree short cuts to do a job, and stick to the proper proceedure. Only you can sort out the good and bad info. Do your homework ; you can get 100 different answers from a 100 people.

Most importantly - have fun and enjoy your hobby.

 

[Mart]

OK, so here is what I finally did,

1. Set TDC on #1
2. Mark Balancer every 90 degrees
3. Adjust lash on #1 until I just feel it drag then tighten approx 1/8 more (more than that just felt too tight).
4. Rotate 90 degrees set lash on #8
5. Just follow the firing order for the rest.

I found this to be the simplest method and did not take that long.

As far as tightening them the extra 1/2 to 3/4 turn, that seems really tight, I could not even move them when I did that

 

[rrubel]

Dunno. I'm relying on my (admittedly poor) memory. I do know that GM recommends a different procedure, where you only need to move the crank/cam once (set for #1, do a bunch, set for #6, do a bunch). It's in the shop manual.
[RICHR]

 

[Mart]

Rich is absolutly right, that is the procedure in the manual, I have it.

But if you look at the valves, I'm not sure if all of the specified valves are closed.

After searching aroud I found more articles mentioning a different way and not one that did it the way GM did.

Who the He-- knows, I'm done and that's what counts, I just hope this thread helps someone else out and does'nt send them to the loony bin:J trying to sort all this out.

Mart