Cold lash after 500 miles, yikes!

[BigBlocksOnTop2]

Those are some big differences. I hope some error on your behalf....I've done it to. I would check retainers for a crack, rocker trunions in the correct position. Did the keepers fit tight on the valves? I would relook all this stuff. Very important to be on the base circle of the cam when setting lash.

[Tom Walker]

F-bird88, you had me concerned on your IOEC statement for a while.

[peejay]

Did you check any of the valves using the same method you set them at originally when you found they were loose? Did you check the valves after you re-set them this time using the same method as originally set? That might have provided some answers for you...

No to both, but if I would have checked them the TDC method I assume they would have been a little tighter.

I lost a pound of hair the first time I encountered a cam with eccentric base circles. I was trying to set up the valves at TDC compression because I didn't want to roll the engine over so many times and I kept getting weird readings and I ended up wasting two hours instead of "saving time".

Exhaust opening, intake closing, from now on!

[MadBill]

It would be easy for a cam grinder to say: "Plus or minus a thous. or so base circle runout on the 0.024"-0.030" lash, what's the big deal?" But when you're monitoring closely for wear and an inconsistent lashing procedure lands you unpredictably on a high or low spot, you could get worried for nothing or worse, miss an important early warning.

The several Jones cams I've measured were all less than 0.001" but with some name brands I've seen 0.003".

A related issue I've run into even with my limited experience is eccentric rocker rollers*. After some perplexing measurements, I marked the suspect parts and found that the lash changed as much as +/- 0.002" as I rotated the wheel against the feeler gauge. I suppose when running it would consistently settle into the "most clearance" position, but... *It just occurred to me that an eccentric lifter roller would mimic base circle runout. Does anyone routinely check same and if so, with what result? Guess I should check my new Isky EZ Rolls before I drop them in.

[CamKing]

The most accurate way to set lash, is to set each valve individually. Turn the engine over, until the valve you want to set, is at max lift, then turn the engine over 360 degrees. That would put the lifter on the center of the base circle. Set lash, then go to next lobe.

[Krooser]

Maybe I'm just an old b*stard but doesn't the valve lash decrease when the engine is hot not increase? After all the parts expand when hot... I always set the valves when hot at the maximum clearance I want.

When I was a kid with a 30/30 cam in my 283 my boss told me to set the valves at .018/.020 intake/exhaust instead of .030. I thought I burn the engine down. What I got was a better mannered street engine that didn't beat up my valve train.

[CamKing]

Maybe I'm just an old b*stard but doesn't the valve lash decrease when the engine is hot not increase?

In most cases, no.
The block grows when it gets hot, so now the distance from the cam centerline to the deck has increased. The cylinder head also grows when it gets hot, so now the distance from the deck to the rocker pad has increased. So, when the engine gets hot, the distance from the cam to the rocker increases. The lifter and pushrod also grow when they get hot, but not as much as the block and heads.

[Warp Speed]

We adjust our valves when the exhaust is almost fully open, and when the intake is almost fully shut.
The difference in lash between a tdc base circle type measurement, the way I mentioned, and even differing places on the base circle, is typically caused by how the spring pressure from other cylinders are effecting cam position in block. This is aggravated by higher rocker ratios.
When running, all bets are off! Hahaha

[1972ho]

Camking on a iron block and iron heads doesn’t the lash decrease by about .003 when the block and head heat up.

[Warp Speed]

Camking on a iron block and iron heads doesn’t the lash decrease by about .003 when the block and head heat up.

With aluminum rockers it certainly can, depending on the water to oil temp delta. The greater the delta, the less the block and heads will grow, and the more the valvetrain components will.
That is assuming oil temp being greater than water.
Again, aggravated with increased rocker ratios.

[rustbucket79]

I've never seen more than a few thousands difference between initial set and after a while. An extra .020 or so after 500 miles even consistently on all the valves would worry me. I would make sure nothing is wearing prematurely, or athe the very least recheck after a test drive to prove nothing moved.

[Keith Morganstein]

I've never seen more than a few thousands difference between initial set and after a while. An extra .020 or so after 500 miles even consistently on all the valves would worry me. I would make sure nothing is wearing prematurely, or athe the very least recheck after a test drive to prove nothing moved.

Yes the OP has some warning signs.

[Krooser]

Maybe I'm just an old b*stard but doesn't the valve lash decrease when the engine is hot not increase?

In most cases, no.
The block grows when it gets hot, so now the distance from the cam centerline to the deck has increased. The cylinder head also grows when it gets hot, so now the distance from the deck to the rocker pad has increased. So, when the engine gets hot, the distance from the cam to the rocker increases. The lifter and pushrod also grow when they get hot, but not as much as the block and heads.

Hit the wrong button...I meant the valves get tighter not looser. Been a long week!

[Tuner]

Assuming no deflection from assembled engine spring pressure, if there is base circle runout on the bare cam itself, the entire lobe is off center.

[stealth]

For street driving I would set the lash much tighter....