How does my pushrod length look?

[jimrstang]

Hey all,

Here are the marks made on the valvestem from my rockers. I used an adjustable length pushrod.........but it will not go any shorter. It looks to me like the Pushrod length could be a little shorter, but just wanted some opinions.
thanks

Jim

 

[5spd GT]

Looks pretty good to me, and you are right, it could be a little bit shorter towards the intake side.

What combination of parts are you using?

Heads, rockers, camshaft, headgasket, rebuilt bottomend?

 

[jimrstang]

thanks,

Im going to try and use one that is about .100 shorter...and see how that looks.

The motor is a 351 windsor roller block, 9.5:1 keith black pistons, stage 1 trickflow cam, edelbrock victor jr heads, harland sharp 1.6 roller rockers, edelbrock rpm air gap intake.

 

[jerryD]

are you using a solid lifter when checking for length? other wise if you are using a stock hydro lifter, it is getting plunged down and throwing off your measurements.

 

[Wallzy]

Jerry is right, don't make that mistake it won't work out well for you in the end.

 

[jimrstang]

actually I was using the hyd. roller lifters. I am adjusting to zero lash, then 1/2 turn on the rocker nut, and turning the motor over, to get the markings.

If I tried that with a solid lifter, wouldn't the length be wrong when I go back to my hyd. lifters?

thanks
Jim

 

[Wallzy]

There is very good chance that your Hydraulic Lifters will collapse as you check it’s wear patch on the top of the valve. When the motor runs and the lifters get oil pressure, they do not collapse under normal operating conditions. So if you set up your valve train to a collapsed lifter now, when it runs it will seem as though your push rod is too long and cause problems.

 

[jimrstang]

thanks alot....I will pick up a solid lifter to check again. Are the solid lifters the same length as a roller lifter?

 

[mike93lx]

i have heard of people welding a hydraulic lifter so you can be sure to get the right length. hopefully someone will chime in on that.

 

[jerryD]

i just took and old stock lifter and tack welded it around the plunger. somewhere there are articles how to take apart the lifter and mess with the plunger.

 

[MrXCESSIVESPEED]

BTW, Harland Sharp rockers typically require a shorter pushrod than other brands due to the design.

 

[jimrstang]

I have also read that they can be checked just by rotating the cam to where it is on the base circle for a particular valve, install the pushrod and rocker.....then just roll the roller tip on the rocker to get the wear pattern on the valve stem.

I have tried this, and the wear pattern is still in the middle of the valve stem....am I safe to assume that I have the correct pushrod length just from this method?

 

[302RollinHard]

NO.
Read, ponder, ask questions.
You have to get this right or you will have a crappy running engine, and or damage stuff IE cam, lifters, possibly the whole engine.
Valve train setup is very important. You have to have the right valve springs intalled at the right height with the correct length pushrods to minimize risk of fubarring the engine.
http://www.compcams.com/information/Products/Pushrods/

 

[jimrstang]

yea....you guys are right...the plunger is getting pushed down when im rotating the engine by hand, and therefore giving me inaccurate measurements.
I am going to take apart a lifter and fill it with washers so it will act like a solid lifter.

I also realized that when I checked my piston to valve clearance with clay...that the plunger was probably doing the same thing, which makes sense, because after checking it....... the clay was barely touched by the valve.

So, now i need to take the head back off.....and do that again also.

 

[302RollinHard]

Very good thinking. Let us know if you have any more questions.

 

[88-378]

Hey all,

Here are the marks made on the valvestem from my rockers. I used an adjustable length pushrod.........but it will not go any shorter. It looks to me like the Pushrod length could be a little shorter, but just wanted some opinions.
thanks

Jim

Can someome actually point to where i should be looking? Trying to learn.

 

[302RollinHard]

http://i241.photobucket.com/albums/ff280/bcriser/Valvestemmarks.jpg
Look at the marks. Marks are supposed to be fairly narrow and centered on the tip of the valve. It is better IMHO to have the marks more narrow than perfectly centered. (given the choice I would have the mark slightly off center and narrow than wider and in the middle.) Too wide a mark indicates improper geometry and will lead to accelerated valve seal wear. Marks way off center also indicate improper valve stem geometry.
I this picture the marking on the left valve stem is about as wide as I would want a valve stem mark for what it is worth.

 

[NKau]

If you have an extra lifter, you can actually take it apart, flip the plunger over, and put it back together. It will now act as a solid lifter.