Mopar Small block 590 Valve Lash

[joes68340s]

Anyone running tighter valve lash on the Mopar 590 solid cam. How tight can you set this cam with Iron heads.

 

[roccodart440]

What's the lash on that again? .028int // .032ex

Definitly .002.

If I recall correctly though, IQ52 said I could go .004 with mine but I have aluminum heads.

 

[PRH]

With regards to the cam and lifters, you can tighten the lash as much as you want, until you’re at about zero.
However, when you get too far up the clearance ramp, the power will drop right off.

You can keep tightening it until it slows down.

On the other hand, if it slows down when you tighten it at all, I wouldn’t try running the lash on that cam any looser than .035”.

Tightening the lash does not always equal more power.

 

[roccodart440]

The reason I tried going tighter was primarily to reduce valve train noise. I also thought .032 was a bit excessive and might have added wear to the valves or rocker arms.

 

[PRH]

More lash is usually a little harder on parts....... but in a drag car it shouldn’t be a big deal.

I would only run the lash as much as .004” looser than the specified lash.
But if tighter was better, I’d run them as tight as whatever worked best.

 

[DusterW2]

Anyone running tighter valve lash on the Mopar 590 solid cam. How tight can you set this cam with Iron heads.

I ran 0.025/0.025 with iron heads. Definitely a little quieter. Cannot comment if any performance gain or loss.

 

[roccodart440]

More lash is usually a little harder on parts....... but in a drag car it shouldn’t be a big deal.

I would only run the lash as much as .004” looser than the specified lash.
But if tighter was better, I’d run them as tight as whatever worked best.

This was a street car that saw occasional drag strip use. I went .024 // .028. Never ran it looser and it was dyno'd at that spec as well.

 

[33IMP]

Ran a .590 iron head big block at .025, cause that was the thickest single feeler gauge I had.
Intake and exhaust. Never set them to factory spec, so I don't know if it was faster or not. No problems at .025, ever.

 

[MOPAROFFICIAL]

With regards to the cam and lifters, you can tighten the lash as much as you want, until you’re at about zero.
However, when you get too far up the clearance ramp, the power will drop right off.

You can keep tightening it until it slows down.

On the other hand, if it slows down when you tighten it at all, I wouldn’t try running the lash on that cam any looser than .035”.

Tightening the lash does not always equal more power.

If it makes more power with more than .028/.032...I'd advance the cam or change cams to one size smaller.

 

[Bewy]

A 0.028" lash cam can be quieter than a 0.018" lash cam. Depends on the lash ramps of the lobes.

Going looser, 0.004" would be the max for valvetrain safety. You can go a LOT tighter without hurting the valve train, but idle will be rougher & less idle vacuum.
Quoted lash numbers are always engine running [ hot ].

 

[7e5hangten360]

i never tried the .590 cam . but i ran the .557 mopar cam in a 340 , which uses the same lash setting as the .590. i also thought it was too noisy so i compared the lash of the .557 to similar cams from comp and crane, on paper . i ended-up lashing the .557 purple at .022/.022 and the car did perform its best at that lash setting (un-corrected for weather conditions) . again, it wasnt for better e.t. as much as running quieter on the street.