Valve Lash Issues.

[Munciettype]

I jist got the long block back together after many years and little cash and noticed a problem. As I rotate the assembly I have a lot of rocker arm movement when the cam is at the base of the lobe. I don't remember an valve lash before the rebuild. I didn't put a feeler gage under the rocker but lets say at one point they don't touch.

Anybody know what the height of the valve is supposed to be and how to check it.

I have been around for a while reading and until now not had much to add but really appreciate the great topics and support everyone gives in this community on this board and the others.

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[kidglok]

Do you have adjustable rockers?


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[Munciettype]

No stock.

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[TurboTdr3.8]

I just got the long block back together after many years and little cash and noticed a problem

What kind of rebuild did you do , that might help in explaining what went wrong with your adj of the valves , did you have the block squared and your heads cut and valve job ? You may need different length push rods ?

 

[earlbrown]

something's not right. I don't have a head book here at the house, so I don't remember the exact tip height..

That being said, valve tips get taller as the face and seats wear. Nothing will make them lower with use. Either a machine shop got crazy tipping the hell out of your valves, your pushrods are too short, your head gaskets are waaaaaay thicker than stock (doubt it), base circle of the cam is much much smaller than stock (doubt it), or the lifters are partially collapsed. (quite possible, are the comp lifters?)

 

[earlbrown]

What kind of rebuild did you do , that might help in explaining what went wrong with your adj of the valves , did you have the block squared and your heads cut and valve job ? You may need different length push rods ?

Decking the block/shaving the heads would tighten 'lash' and/or increase lifter preload. To add slack to the valve train the rocker shaft would have to move away from the camshaft.

 

[Munciettype]

Stock rebuild with and a new ESP Grind Cam I bought a while back. New valves and .010 bore stock pistons 40lb injectors and new TE44 turbo.

I was told I didn't need new push rods with the cam and lifter setup. But the big question is the valves the guy that did the heads isn't around anymore and I can't remember what they are its been 6-7 years ago.

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[bison]

something's not right. I don't have a head book here at the house, so I don't remember the exact tip height..

That being said, valve tips get taller as the face and seats wear. Nothing will make them lower with use.

I've seen them get lowered in use in high rpm/cylinder pressure engines. Aka tulip.

 

[Chuck Leeper]

something's not right. I don't have a head book here at the house, so I don't remember the exact tip height..

That being said, valve tips get taller as the face and seats wear. Nothing will make them lower with use. Either a machine shop got crazy tipping the hell out of your valves, your pushrods are too short, your head gaskets are waaaaaay thicker than stock (doubt it), base circle of the cam is much much smaller than stock (doubt it), or the lifters are partially collapsed. (quite possible, are the comp lifters?)

 

[Munciettype]

Stock lifter not Comp.

I feel like an idiot I did have the block squared up and heads cleaned that may be it. Can you get push rods for these things in varying lengths? And I guess if I can get a feeler gage under it and check the differences I add ??? amount to the stock rod length to order them?

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[Munciettype]

Looks like I need to gage the rocker to valve clearance and add about .030 for lifter preload.

Does that sound correct?

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[TurboTdr3.8]

http://www.fullthrottlespeed.com/itemdesc.asp+ic+761TC7888+eq++Tp+ , get one of these and you can find the right one

 

[Munciettype]

Nice thanks I forgot about those. Does the .030" preload sound rite?

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[TurboTdr3.8]

Does the .030" preload sound rite?

that should work

 

[Mike Licht]

you could use more preload with the stock lifter if you want it quiet

 

[Munciettype]

Thanks Mike. .040"-.050" maybe?

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[Mike Licht]

.050 is good stock is a bit more than that

 

[earlbrown]

Stock lifter not Comp.

I feel like an idiot I did have the block squared up and heads cleaned that may be it. Can you get push rods for these things in varying lengths? And I guess if I can get a feeler gage under it and check the differences I add ??? amount to the stock rod length to order them?

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No, you can't use a feeler gauge as pushrod length and valve lash aren't directly proportional. Decking your block and shaving the heads should have increased your lifter preload not loosened it so much you end up with lash.

Are the brand new lifters or are they shorter because the convex surface has been wiped away? What is your deck height now? Are you using 109 block pushrods with a 'tall deck' older style or 4.1 block?

The only way to accurately measure for pushrod length is with an adjustable pushrod checker. Install it, take out all the slack and add what ever preload you want.

 

[whitehot1]

Stock rebuild with and a new ESP Grind Cam I bought a while back. New valves and .010 bore stock pistons 40lb injectors and new TE44 turbo.

I was told I didn't need new push rods with the cam and lifter setup. But the big question is the valves the guy that did the heads isn't around anymore and I can't remember what they are its been 6-7 years ago.

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Did you get new lifters with the new cam? if not that could be part of the problem along with the pushrods.

 

[Munciettype]

New lifters with the new cam and stock block.

You are correct I didn't think about the geom. of the rocker arm. Sorry I am at work and thinking on the fly.

I am still worried about the valve length. Better to short then to long but if they are to short I may have excessive spring pressure. I need to check that as well. I guess I get to buy some new toys.

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