Valve lash compensation

-
boilermaker said:
View attachment 1715206381
Here is t trivia question. What am I doing in this picture? First person to answer wins a new Kcar
Click to expand...

I just changed cams, to a more fuel inj. friendly cam. Solid street roller, the other cam was w/in .006 of what is was supposed to be, measured at the retainer, this cam is .026 short on lift , measured the same way , so I know that its the cam cause all the rest of the parts in the valve train are the same . I think compcams just threw it out there on the machine work !! Really dis appointed in them !!

Oh, it was custom ground supposedly-------
 
Using the air cleaner lid to see the dial indicator to measure valve lift at the retainer.
 
yellow rose said:
I'd send the pictures to Mike at B3 and let him look at them. IMO, you can correct it a bit but you aren't far off. I'd rather have the pattern narrow and off center than make it centered and wide. Wide is bad.
Click to expand...
It is not bad at all IMHO. Yes, being off center a bit is not problem at all.
 
famous bob said:
I just changed cams, to a more fuel inj. friendly cam. Solid street roller, the other cam was w/in .006 of what is was supposed to be, measured at the retainer, this cam is .026 short on lift , measured the same way , so I know that its the cam cause all the rest of the parts in the valve train are the same . I think compcams just threw it out there on the machine work !! Really dis appointed in them !!

Oh, it was custom ground supposedly-------
Click to expand...
I would measure lobe lift at the lifter. If it is not what you ordered send it back.
 
Oh, the choices!!!!!! I however will have to decline, I was the “proud” owner of a 2.2 charger from that period and just recently finish my last therapy session and am finally free!!!!
 
famous bob said:
.616 , wound up w/ .591 , at the retainer .
Click to expand...
I had a .573 lift cam after lash of .019 end up at .530

When you get a pattern that's off to the exhaust real far chances are you're losing a lot of lift. If it's to the intake side, like never is, you gain or make up for in a incomplete weird way being the geometry issue still lingering
 
Last edited:
MOPAROFFICIAL said:
I had a .573 lift cam after lash of .019 end up at .530

When you get a pattern that's off to the exhaust real far chances are you're losing a lot of lift. If it's to the intake side, like never is, you gain or make up for in a incomplete weird way being the geometry issue still lingering
Click to expand...
pattern is very well centered on both intake and exhaust, and not very wide.
 
famous bob said:
.616 , wound up w/ .591 , at the retainer .
Click to expand...
You're doing quite well there.... most of that amount of lift loss can be attributed to the pushrod's angle to the lifter axis, for your amount of lift. I am kinda surprised the lift loss is not more once the rocker to pushrod angles, and the rockers sweep, are taken into account.

The cam mfr's numbers for valve lift just simply take the lifter lift and multiply by 1.5 or 1.6, and totally ignore the geometry effects.

Percent of lost lift due to 58 degree lifter angle?
 
nm9stheham said:
You're doing quite well there.... most of that amount of lift loss can be attributed to the pushrod's angle to the lifter axis, for your amount of lift. I am kinda surprised the lift loss is not more once the rocker to pushrod angles, and the rockers sweep, are taken into account.

The cam mfr's numbers for valve lift just simply take the lifter lift and multiply by 1.5 or 1.6, and totally ignore the geometry effects.

Percent of lost lift due to 58 degree lifter angle?
Click to expand...
I think Bob's running a big block , there's no pushrod angularity issues like a sb.
 
The width of the stripe indicates geometry, where it is on the valve tip does not
do not fool with a narrow stripe trying to get the stripe centered, get the stripe narrow
if then you are nearly off the side of the stem you have to backspace the shafts
I've run a lot of 2"+ springs with longer valves- which makes the geometry more of a challange
Mopar Official
in another thread there was talk of preferring low pushrod seats over high in q Big Block- I've found tall lifters harder to clearance the pushrods
 
Wyrmrider said:
The width of the stripe indicates geometry, where it is on the valve tip does not
do not fool with a narrow stripe trying to get the stripe centered, get the stripe narrow
if then you are nearly off the side of the stem you have to backspace the shafts
I've run a lot of 2"+ springs with longer valves- which makes the geometry more of a challange
Mopar Official in another thread there was talk of preferring low pushrod seats over high in q Big Block- I've found tall lifters harder to clearance the pushrods
Click to expand...

I had a bad time trying to get pushrod clearance . Took about 5 tries. W/ raised port heads, and 1/6 rockers there seems to be a little angle issue . Not going to worry about it, it was fine before the cam change, and this cam should be even easier on things, ( 6 degrees less duration and about .010-.012 lift smaller). As I posted before , I have a very thin rub stripe that is centered up and down and sideways. Side ways took a bunch of fiddeling with.
Do u guys use all spring shims and spacers, or a combination of springs and spacers ? I used all shims and spacers, seems the springs would help the set up a bunch to me. My pushrod measurement came out at 9.400, ordered them from hughs back then, also have a new set of compcams 9.400 in the box, they are about .006 bigger outside diameter than the hugs tho.
 
yellow rose said:
No. The rocker doesn't know or car what it's made out of.

Secondly, I have never seen lash get tight when an engine heats up. So the idea of setting the lash loose cold with cast iron heads and block is wrong. I set my CI stuff .002-.004 tight cold. And then check them hot to see how much they close up.

Third, there is no way if lash that cam at .026 cold. Not for all the tea in China. If it were me, I'd start at .018 cold and then check it warm. I wouldn't go any looser than .020 hot and maybe, and it's a damn skinny maybe .022 hot on the exhaust. There is no reason to run the lash that loose.

Double check your rockers also - a friend in CA ordered some from same company u mentioned and what he ordered wasnt what he recieved his engine was a RB .
Click to expand...
 
You must log in or register to reply here.
-

Back
Top