Once again... Another Valve geometry question

rdubb17 · Sep 24, 2007

So I was reading last night on a car-cares website about measuring pushrod length. According to there statements, they said that measuring for stamped steel pedistal rockers isn't as important as measuring for roller rockers as the contact area for the stamped steel is much greater than the roller point for the roller rockers. I kind of have to agree with the statement. Can anyone back this claim up? I lost the webpage, because I was reading it last night.

BlownFiveLiter · Sep 24, 2007

I think that could go either way. The roller tip on a roller rocker is precision ground, and needs a good wear pattern in order to have a healthy valvetrain. The stock stamped rockers, well... there's nothing precision about them. Not even the 1.6 ratio they're supposed to have. They tend to be all over the place. I'd still measure though, you don't want to put abnormal stress or side loading on the valves and prematurely wear out valve guides.

Killercanary · Sep 24, 2007

StangGT1995 said:
I think that could go either way. The roller tip on a roller rocker is precision ground, and needs a good wear pattern in order to have a healthy valvetrain. The stock stamped rockers, well... there's nothing precision about them. Not even the 1.6 ratio they're supposed to have. They tend to be all over the place. I'd still measure though, you don't want to put abnormal stress or side loading on the valves and prematurely wear out valve guides.

I agree!

final5-0 · Sep 24, 2007

While the OEM rockers might be more forgiving

IMHO ... the most important thing to focus on is ..........
the basic way things work here :Word:

Consider this

No matter what rocker is used

What if the heads have been cut
What if the block deck has been cut
or even
What if both have been cut

You could go on and on

What if the pr's are too long
What if the pr's are too short

So I kinda agree
but
It things are out of whack

It is quite possible for the steel rocker to slide all the way to the extreme
end of the valve tip and that is just not acceptable

Just be sure and check it for peace of mind like others have said

Grady

rdubb17 · Sep 24, 2007

Thanks guys, Will do. I will check with stock pushrods tonight. Do I have to use a solid lifter for this test?

Killercanary · Sep 24, 2007

rdubb17 said:
Thanks guys, Will do. I will check with stock pushrods tonight. Do I have to use a solid lifter for this test?

You need to either do that or use checker springs. I use checker springs so that the lifter doesn't end up altering my values if its off a little. Summit sells the checker springs, last time I checked they were around $10 for a set of 2. Simply remove your valve spring and install the checker spring. The checker spring has just enough pressure to keep the valve closed, but not enough to force the oil out of the lifter like the stock springs do.

rdubb17 · Sep 24, 2007

http://store.summitracing.com/partdetail.asp?autofilter=1&part=PRO-66793&N=700+115&autoview=sku

those will work fine? I've heard most people convert a hydralic lifter to a solid.

I have a feeling that if I color the tip of the rocker with this spring pressure, I won't be able to see the wear pattern. Correct me if I'm wrong.

blksn955.o · Sep 24, 2007

I got a stock roller lifter made solid from Tmoss to check mine(cannot thank enough for the help he gave when I was going threw this ).

On the valve tip I used a very light coat of grease. You just need to be really carefull setting the rocker down on the valve and make sure it sits very still while you tighten it. I kinda played around with the grease and diff. shims to get the hang of it. I put alot of shim in first and then took them out so I could see the diff. in travel in the grease easier.

Its a good idea to get an adj. PR checker too. Do a search on the subject and look my some topics started by me I remember posting the steps I did in the order I did them in good detail.

rdubb17 · Sep 24, 2007

Will do guys. Thanks for the help. I got to thinking on the way home tonight that checking the PTV with a hydralic roller will effect the clearance. Out of everything I've been reading about PTV clearance, I've never heard of switching to a solid roller to measure it. Am I just being too OCD?

blksn955.o · Sep 24, 2007

Thats prob. due to people assuming your going to run the ligh check spring. The light spring will not compress the hyd. roller lifter but keeps the valve in place. Plus you gen. will not have to remove the lower intake to put in a solid or made solid lifter.

rdubb17 · Sep 24, 2007

No no. Using the REGULAR spring checking for PTV clearance. This would compress the lifter giving "false" ptv clearance measurements.

blksn955.o · Sep 24, 2007

I thought you were talking about why you had not heard about using a "solid" lifter.

There is alot to checking PTV...the toll. allowed by the play-doh/whatever, the compression thickness of the HG, the cam timing, dur./lift, rocker arm ratio, valve size, piston travel (+/- in the hole).

rdubb17 · Sep 24, 2007

Oh my misunderstanding. Utilizing the lighter springs will enable me to check both PTV as well as valve train geometry correctly.

Killercanary · Sep 24, 2007

rdubb17 said:
Oh my misunderstanding. Utilizing the lighter springs will enable me to check both PTV as well as valve train geometry correctly.

Correct! I too used grease to check mine as the marker trick didn't work for me.

5spd GT · Sep 25, 2007

As you decided, it is good to check

There are a few factors that can make one engine/pushrod different than another:

- The base circle of the camshaft
- Height and location of the lifters
- Offset or centered pushrod cups
- Location of the pushrod cups or adjuster screws in the rocker arms
- Geometry of the rocker arms and rocker arm ratio
- Installed height of the valves
- Milled cylinder heads
- Milled engine block

Check piston to valve clearance with a solid lifter. If putting in new lifters, use an old lifter and weld the plunger to the lifter wall with a couple spot welds. It works for just checking piston to valve clearance. For an engine spinning in the 6,000 RPM, .080" on the intake valve and .100" on the exhaust valve (heat expands the valve) will suffice.

final5-0 · Sep 25, 2007

Getting your V T setup correctly is important

If it ain't correct you could damage valve guides, valves, rockers,
springs, have excess noise and other bad kinds of things

It is common that a lot of peeps don't look into this and get lucky
but
If you hang in these forums very long
you will see some pay a price for lack of attention to details

I'd encourage anyone who wants to learn about this important issue
to look at some of the big cam companies web sites.

They got very good tech articles with informative pics which clearly
show how it all comes together :Word:

Grady

rdubb17 · Sep 27, 2007

http://www.compperformancegroupstor...re_Code=CC&Product_Code=4758-2&Category_Code=

I unsuccessfully tried this last night. I put the valve springs on and it seemed as if they were way too long. They had way too much spring pressure, are these cut to length springs? When I turned the crank over, as soon as the lifter came up, it sunk in just like it would do if I had the high pressure springs. I also was talking to the speedshop guy and he was unable to find a solid lifter for these purposes. Can someone point me in the right direction as I'm wasting an incredible amount of time trying to get this right!

Thanks!

EDIT* - How do I know what the optimal setting is for degreeing the cam? I say this because I want to accurately check my PTV clearance and degreeing the cam will effect the readings.

rdubb17 · Sep 27, 2007

Bump anyhelp?

Killercanary · Sep 27, 2007

Those are the correct springs, they are NOT cut to length, and there is no reason that they should have had enough pressure to collapse the lifter. If you have an oil pump priming tool, prime the lifters first and then try it. there may be no oil left in the lifter allowing it to collapse easily, but it still shouldn't be able to do that with minimal amount of force exerted by the checker springs. If you don't have a priming tool, try removing the lifter if you can and soak it in engine oil for an hour or so, or try squirting oil in the oil hole on the side of the lifter.

rdubb17 · Sep 27, 2007

Awesome man, I will try that tonight - the lifters have been out for an unknown amount of time so I'm sure there isn't anything in them. Thanks for the response!

Once again... Another Valve geometry question

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