anderson3754

Basically a why question on hydraulic flat and roller cams

When I adjust valves using the procedure in a Chevy Manual it just never works out. I always end having a problem and have to do them over, using EOIC method.

When I have used the Chevy Method the intake manifold has always been on, not allowing me to see and verify the lobe position. Is it me, just doing it wrong. Or is this way of doing it flawed.




Bring#1 TDC compression stroke
Adjust Exhaust valves 1-3-4-8
Adjust Intake valves 1-2-5-7

Rotate engine 360* so that #6 is now at TDC compression stroke;
Adjust Exhaust valves 2-5-6-7
Adjust Intake valves 3-4-6-8

Thanks

resdoggie

Are you doing it this way? Ensure both ends of the pushrods are properly seated. Begin tightening the nut. As soon as you feel the slightest resistance to rotation of the pushrod, stop. Now turn the nut down another 1/2 to 3/4 turn.

anderson3754

Yes that part I understand. My problem is with this technique. For the past 5-6 years I have been using the EOIC or opposing cylinder method with out any problems. Last weekend tried the way in the Chevy Manual again, and after startup we ended up doing them over, using EOIC, it turned out just fine again. The intake was on, so again I can't see the cam to discern if the technique is flawed or if it is me just doing it wrong.

Regards

chvet73

I'm sure some people would disagree but for the last 45 years I have adjusted my hydraulic lifter Chevrolet engines by ear with the engine running and never had an issue.

anderson3754

Yup me to, I have done it that way many times. I'm just trying to figure out why the above technique from the Chevy Manual just doesn't seem to ever work out for me.

Regards

garygnu

the EOIC is just fine .or put timing tape on your balancer ,and set the valves as you rotate the crank a quarter turn for each cylinder .or cut the top off a use distributor cap and the rotor and watch the lifters as you rotate it a quarter turn at a time ,and set the valve for that corresponding cylinder .

7T1vette

Did you bother to pump up the lifters in a can of oil before you installed them? I don't know how they'd feel without being 'primed', as I've always done it. I also use the "shake" method (instead of the "spin" method) as it is easier to identify the zero lash point.

Tom454

That's exactly why he's having a problem. The back-pressure from the lifter is indeterminate... sometimes it's soft... sometimes it's hard. So the point at which the turning pushrod exibits resistance might be when the lifter plunger is just right, or when it's all wrong. The "shake" method determines the correct zero lash on lossey goosey lifters AND on mighty tighty lifters. (I used to give demo's of this in my shop)

diehrd

[QUOTE

When I adjust valves using the procedure in a Chevy Manual it just never works out. I always end having a problem and have to do them over, using EOIC method.





Bring#1 TDC compression stroke
Adjust Exhaust valves 1-3-4-8
Adjust Intake valves 1-2-5-7

Rotate engine 360* so that #6 is now at TDC compression stroke;
Adjust Exhaust valves 2-5-6-7
Adjust Intake valves 3-4-6-8

Thanks[/QUOTE]


Well rotating it 360 degrees puts you right back where you started

anderson3754

I'm not having a problem setting the preload correctly, and the lifters do not have to be pumped up to set the proper preload.
I'm fully aware of the shake method and the twirl technique to find zero prior to setting 1/8, 1/4, 1/2, 1/3, 2/3 preload what ever happens to be chosen.

My question is reference to a specific technique which is in a GM Chevy manual that specifically states:

Bring engine to #1 TDC on the compression stroke and adjust the following valves.
EX 1 3 4 8 INT 1 2 5 7

Rotate engine 360* so #6 is now at TDC on comp stroke and adjust the
following valves
EX 2 5 6 7 Int 3 4 6 8

This technique has something to do with the base circle and the clearance ramps, it may be acceptable on a stock profile cam like on a 327 350 396 etc. I'm thinking it specifically applies to the exhaust valves being on the clearance ramp just enough so the valve is not even starting to open, but still enough to skew the preload, that you will not be able to use this method with modern cams that have a longer/faster
ramp then than a standard historical stock Chevy hydraulic or solid lifter cam.

With a friend were gonna do a rocker arm swap this weekend on a 454 and were going to yank the intake off and visually look as to what is happening. We have both used this method over the years with unsuccessful results, Always resorting back to EOIC or each cylinder rolled around the firing order and adjusting each cylinder on TDC compression stroke.

With no disrespect intended, no one as taken the time to actually read the question and comprehend it, the assumption was made that I do not know how to set preload.

I've been a Lurker for a long time, I like this forum and would like to
interreact. I'm extremely knowledgeable and enjoy helping. I make no claim to being an expert or a engine builder, hence the opening statement. "that my question was a "why question".

I'll figure it out this weekend and that is a guaranteed fact, because myself and my friend we both want to know. When we do this rocker arm swap were going to yank the intake off and discern were the problem is, with this technique.

Respectfully

diehrd

Try it this way ..
http://www.centuryperformance.com/va...procedure.html

anderson3754

Thankyou for trying to help me. I use that way from time to time it's called Opposing Valves technique.

I want to know why that version in the Chevy Manual does not work out and creates problems.

Regards

anderson3754

Well rotating it 360 degrees puts you right back where you started[/QUOTE]

No...... it's a 4 cycle engine..... 720 * would bring you back to #1 at TDC compression stroke.

360* simply brings you to #6 TDC compression stroke.

lars

You can e-mail me for my paper on how to do it correctly - it's the method used during factory assembly and by every racer in the pits running hydraulic cams.

Lars
V8FastCars@msn.com...

Duane4238

Anderson,
I've never had any luck with that method, either. I do use it, though, to get things close enough to get the engine running. Then I adjust each valve while running. Has always been the easy way for me.
Duane

anderson3754

E-mail sent
Regards

anderson3754

Hey Hi. I think that method is flawed ,having something to do with the lifter being slightly on an exhaust ramp when setting the preload. I'm trying to visualize this in my head I don't think it affects the intake valves. I'm going to have to see an engine with the intake off to be sure where the problem is. Anyways it is nice to know someone else has had problems using that technique.

Regards

Tom454

anderson3754

Tom454
Goodmorning, yes the plunger has to be at the top of the lifter, and care must be taken not to compress it when setting the preload.

No apology is necessary, it's just a misunderstanding. I probably should have stated my question differently to avoid confusion.

Regards
Mark J Anderson