Once you have found TDC on #1 all you have to do to find the rest is start turning the engine 90* at a time. Each successive 90* from #1 is the TDC for the next cylinder in the firing order. 18436572


Warning...that is only true for 90* V-8's like SBC's and BBC's.

 

If your balancer doesn't have a bunch of marks, add a piece of timing tape. Every 90* you'll be at TDC on two cyls, one will be on it's compression stroke like stated above.

 

When I assemble an engine, I take the balancer and mark it 3 other places, 90 degrees from TDC, 180, and 270. When the mark comes up when you turn the engine with a breaker bar, then you know you're close to TDC on the next cylinder so you can adjust the valves.

 

Hydraulic cam??? Why find TDC just to adjust rockers?

Loosen all rockers. Tighten all rockers "finger tight". Turn crankshaft EXACTLY one turn. SOME rockers will be loose again. Tighten only the loose ones "finger tight".

Tighten all rockers your choice of preload. Factory spec is 1 full turn of the rocker nut. Most guys use 1/2 turn. Lock the adjustment if required. Put the valve covers on.

Have a beer. You're done.

 

Wow is it really that easy? I have a Hyd roller same thing? I need to readjust mine here soon im at about 500 miles......Does it matter where you start? You have to find TDC first on #1 right?

My old small block I had a pair of stock valve covers with the center cut out just enough to see the rockers. I did it with the motor running hardly any oil would spill. But that was many moons ago.

 

But that's not the "Old McDonald" method...you know, EIEIO....

 

This isn't entirely accurate, as both rockers will be loose NEAR TDC on compression stroke (but maybe not on the exhaust stroke)...

IMO, use a piston stop of some sort... Rotate the engine one direction (BY HAND) until in contacts the piston-stop, make a mark (lined up with the pointer, etc). THEN, rotate the engine the opposite way until the piston again contacts the stop, make another mark...

TDC should be about equal-distance between these two marks...

I also like to them make a "witness mark" on the pulley, lined up with the TDC mark, because even if the outer ring slips (on OEM balancer), the pulley and inner balancer should not deviate from the crank (unless the crank/shear key is gone)...

 

Ok, got it guys, thanks.
Schurkey, I had that beer!:beers:

 

I changed a set of rocker arms on a 454 this morning... went from big full rollers to just the roller tipped Comps.. (I know, but it's what the customer wanted because the stock valve covers wouldn't fit over the rollers..)

I used the TDC+90x8 method... and ya know what, the engine fired right up with no problems, and no lifter ticking.. so you wipes that insist the EIEIO method is the only way to do it (cough cough dave ray cough) you're full of doo doo. :yes:

 

I used the TDC+90x8 method.

I use same method on hyd cams, works perfect.
Have managed to reach over 600hp on the dyno with that method and hyd rollers.

Marcus

 

My only question left is how much pre-load? I was thinking 1/2 turn. I believe like I said earlier I only did a 1/4 turn last time.

 

What brand and part nr lifter? I would at least start with 3/4 turn of preload since you have alu heads.

Marcus

 

Its the GMPP lifter that came with the zz502.

 

300.

 

You'd be fine with the two-turn method.

The GM Specification on my New CHEVROLET 350 Crate motor with factory Hydraulic Cam is 1/8 turn past zero lash...!
I might be coaxed to go a 1/4 turn, but I'm thinkin' a full turn (or even a half turn) would be a little tight... No?

If GM is now using restricted-travel lifters, you certainly need to follow their preload advice.

 

Hey Mike this has been a good thread though I don't know if your original question was directly answered. With both the intake and exhaust rockers loose you know that the lifters are both on the base circles of the cam. This is not the same as TDC, that is a more precise measurement. I have seen lash adjustment methods that point out that you can adjust both intake and exhaust valves simultaneously (saving time and only having to turn to engine over once) but it sounds like it might be more challenging to do than it seems. Need a really sharp eye and calibrated arm. I think it would be an easy assembly method where, with the intake manifold off, you could visually inspect the positions of the lifter tops. I get a bit confused watching rockers- they all look the same unless I use marking chalk. The EOIC gives you more margin for error turning the crank around and still get your adjustments done in order. There are only a few degrees available that both valves are on base circle, where just one you have a lot more degrees to work with.

 

The GM Specification on my New CHEVROLET 350 Crate motor with factory Hydraulic Cam is 1/8 turn past zero lash...! I have the manual. Here it is copied & pasted from the manual:

Oil Filter: ...................................................... AC Delco part # PF454 or PF1218
Valve Lash: .................................................. 1/8 turn down from zero lash
Fuel: ............................................................. Regular unleaded - 87 (R+M/2)


I might be coaxed to go a 1/4 turn, but I'm thinkin' a full turn (or even a half turn) would be a little tight... No?

 

The machine shop across the street from me even told me that with bigger cams they don't even use the two turn method anymore. Said it was fine for stock cams. They do it either TDC and 90, or eoic. Guys been in business 30+ years building race motors so he must know something..