Thread:

No timing marks?

Originally Posted by rampgirlll

Do it in firing order. But we have the 7-4 swap. One of my chronies came to my rescue because the guy was getting mean. I'm not much on getting into pissing matches. Gigglin & drinkin is more my style.

Originally Posted by Moneypit

As usual guys and girls, if you ask 6 people, you'll likely get 6 different answers to a variety of assembly/tuning questions... I happen to prefer the firing order TDC method to set valves, :

Ray, I only read 1 way to adjust lash, not 6. There were different "order" but the SAME METHOD. EO-IC. RG said follow the firing order. What she didn't say was follow the fiiring order at TDC, and adjust the valves for that cylinder. Following the firing order is not the same as the TDC method.
You have posted that method more time than I care to remember. You are the ONLY person I know if that even considers that method on a perofomance camshaft.

You can't use that method on stock Z/28 chevy let alone a 310^o cam ground on 106^o
It DOES NOT WORK on all cams. Do you recommend 3/4 reach plugs for ALL chevys? It could possibly cause any less damage


You adjust the valves on a 1969 Z/28 just once, and you learn to stop using a method that only worked on flatheads, and should have been abandoned with the invention of the rocker arm.

LINK; Valve lash 30-30 Duntov

Originally Posted by gn7

Ray, I only read 1 way to adjust lash, not 6. There were different "order" but the SAME METHOD. EO-IC. RG said follow the firing order. What she didn't say was follow the fiiring order at TDC, and adjust the valves for that cylinder. Following the firing order is not the same as the TDC method.
You have posted that method more time than I care to remember. You are the ONLY person I know if that even considers that method on a perofomance camshaft.

You can't use that method on stock Z/28 chevy let alone a 310^o cam ground on 106^o
It DOES NOT WORK on all cams. Do you recommend 3/4 reach plugs for ALL chevys? It could possibly cause any less damage


You adjust the valves on a 1969 Z/28 just once, and you learn to stop using a method that only worked on flatheads, and should have been abandoned with the invention of the rocker arm.

LINK; Valve lash 30-30 Duntov

I dont use that method but have checked my way(exh open-set intake, intake closing-set exh) against the other way(each cylinder at tdc firing stroke, set #1 then 90* set#8, and so on through the firing order) and its always the same, atleast with my cams.
Are you trying to say that a 69' Z-28 engine has either valve even remotely close to being open at tdc-firing stroke? I would say that the lifter would be on the base circle on both lobes. The intake has closed then the piston travels up the cylinder on the compression stroke, the intake wont open again till after the exhaust stroke so a long ways from having the intake opening at TDC/firing stroke, the exhaust wont open till XX degrees before BDC on the power stroke so quite a ways from that valve event as well.

Originally Posted by Hass828

I dont use that method but have checked my way(exh open-set intake, intake closing-set exh) against the other way(each cylinder at tdc firing stroke, set #1 then 90* set#8, and so on through the firing order) and its always the same, atleast with my cams.
Are you trying to say that a 69' Z-28 engine has either valve even remotely close to being open at tdc-firing stroke? I would say that the lifter would be on the base circle on both lobes. The intake has closed then the piston travels up the cylinder on the compression stroke, the intake wont open again till after the exhaust stroke so a long ways from having the intake opening at TDC/firing stroke, the exhaust wont open till XX degrees before BDC on the power stroke so quite a ways from that valve event as well.

Whimpey short ass duration turbo cams with wide LSAs don't count.
Yes that what I am saying. Thats what the guy that wrote that page is saying. Its what anybody that has ever lashed the valves on a 30-30 Duntov will tell you.

Its not that they are open. Its that the lifter is on the clearance ramp. Loooooooog gradual ramp. Very very gentle on the valve train as well. So if the lifter has risen even .001, and you multiply that time 1.70, your lash is going to be .0034 looser when the lifter is on the base. Doesn't sound like much. But add that to the .030 it should be, and its gets a little noisey. And thats if the lifter is only .002 high at TDC. Add in any error if your not using a degree wheel and guessing at a 90^o rotation from #1 TDC each time, and it gets even worse. You don't need a degree wheel or damper to do the EO-IC method perfectly. Even if you follow the firing order and adjust 2 valves each 90⁰ rotation. Because you still looking to see if the Ex is opening, or the intake closing. You simply eliminating one rotation of the crank.
With most modern cams, specially rollers, its not nearly as bad. Specially as the LSA gets wider. But a 310^o 106 lsa flat tappet could get you in a ton of trouble.



Bottom line, even though it works on a short duration, wide lsa turbo cam, doesn't mean it will on a higher lift, loooong duration, narrow lsa cam. Its SAFER to do it right, and get use to doing it right. Same exact amount of time to do it. One rotation of the crank, foillowing the firing order. 2 valves per 90^o. Your simply adjusting different valves.

Originally Posted by gn7

Whimpey short ass duration turbo cams with wide LSAs don't count.
Yes that what I am saying. Thats what the guy that wrote that page is saying. Its what anybody that has ever lashed the valves on a 30-30 Duntov will tell you.

Its not that they are open. Its that the lifter is on the clearance ramp. Loooooooog gradual ramp. Very very gentle on the valve train as well. So if the lifter has risen even .001, and you multiply that time 1.70, your lash is going to be .0034 looser when the lifter is on the base. Doesn't sound like much. But add that to the .030 it should be, and its gets a little noisey. And thats if the lifter is only .002 high at TDC. Add in any error if your not using a degree wheel and guessing at a 90^o rotation from #1 TDC each time, and it gets even worse. You don't need a degree wheel or damper to do the EO-IC method perfectly. Even if you follow the firing order and adjust 2 valves each 90⁰ rotation. Because you still looking to see if the Ex is opening, or the intake closing. You simply eliminating one rotation of the crank.
With most modern cams, specially rollers, its not nearly as bad. Specially as the LSA gets wider. But a 310^o 106 lsa flat tappet could get you in a ton of trouble.



Bottom line, even though it works on a short duration, wide lsa turbo cam, doesn't mean it will on a higher lift, loooong duration, narrow lsa cam. Its SAFER to do it right, and get use to doing it right. Same exact amount of time to do it. One rotation of the crank, foillowing the firing order. 2 valves per 90^o. Your simply adjusting different valves.

Not arguing with you, just saying that sounds crazy that the exh lobe would be already taking up clearance at tdc of the firing stroke. Thanks for the info I never knew that one. I'll stick to the EO-IC method I've been using then. I dont mind turning the engine over a few times.

I thought TDC was obvious but we do have marks to follow. Turn it over 90 for each hole.

Originally Posted by gn7

Ray, I only read 1 way to adjust lash, not 6. There were different "order" but the SAME METHOD. EO-IC. RG said follow the firing order. What she didn't say was follow the fiiring order at TDC, and adjust the valves for that cylinder. Following the firing order is not the same as the TDC method.
You have posted that method more time than I care to remember. You are the ONLY person I know if that even considers that method on a perofomance camshaft.

You can't use that method on stock Z/28 chevy let alone a 310^o cam ground on 106^o
It DOES NOT WORK on all cams. Do you recommend 3/4 reach plugs for ALL chevys? It could possibly cause any less damage


You adjust the valves on a 1969 Z/28 just once, and you learn to stop using a method that only worked on flatheads, and should have been abandoned with the invention of the rocker arm.

LINK; Valve lash 30-30 Duntov

Bob, you can site your way as the only way if you choose, but I have seen major issues when people try it that are not as familiar with it as you and some other highly experienced people... I will say however, that the PS89 has been the ONLY PS boat over the years that has never had a valvetrain failure... It's really hard to argue with success if success is the overall goal.... Have you forgotten the tried and true method of adjusting several various cylinders at different intervals? Some intake, some exhaust, and rotate 180* and do several others? ....There is always more than one way to skin a cat.... I won't argue that my way is any better, or worse, only that it works just as well in 99.9% of applications....
Ray