Question for The Serious Racer. Valve Lash

[Canyon707]

I have no cam card and cannot locate the cam through comp cam without the serial number. So here we go with a lash question. Suggested valve lash???? I was told it should be aroune .026 .027 I am looking for similar builds to try and compare to this motor. Here are the specs on my motor. 511 400 factory block Main girdle ARP main studs Eagle 4.25" stroker crank Eagle Rods Ross Pistons Clearances are .0025-.0030/.0030 Clevite bearings and Total Seal rings
All balanced of course Muscle Motors ext oil pump
Compression ratio is a bit over 12-1 Comp Roller .730/.730 lift 284/288 @ .050
Comp lifters
KB Gear Drive
Indy 440-1 heads with full CNC port flow [email protected]
T&D rockers
Pac Springs, retainers, locks and caps
New 2.25/1.88 Manley Valves
ARP Head studs
Trick Flow pushrods
Fel Pro Head gasket
Indy 440-3 Intake, Dominator flange

thanks Mopar Chris..

 

[dvw]

Always better to start tight. Loose beats up the valve train. Set it cold, check a few hot, recheck those same valves cold. Now you know how much change you'll get hot. Set it cold. My roller with -1 Indy heads likes .014" intake, .015" exhaust cold. 285/292 Comp roller, .470" lobe lift, 1.7 rockers bring it to .799" lift. Experiment from there.
Doug

 

[vintage chromoly]

Crower solid flat tappet.
.017 cold.

 

[Mike Gaines]

As we discussed, I checked the Comp Cams website and ALL of the "drag race" roller cams from mildest to wildest showed Valve Lash either 26 and 28 OR 28 and 30...so I would guess you couldn't go wrong with 27 and 29 (hot) to start out and go from there.

 

[dvw]

As we discussed, I checked the Comp Cams website and ALL of the "drag race" roller cams from mildest to wildest showed Valve Lash either 26 and 28 OR 28 and 30...so I would guess you couldn't go wrong with 27 and 29 (hot) to start out and go from there.

My cam is a Comp. RX 1718 int lobe, XCX 1862 exh lobe. Recommended lash is .020" hot. I run it at about .019" hot. Lash also changes with rocker arm ratio. What if your recommended lash is designed for 1.5 rockers and you switch to 1.7? Take your lash and divide by designed ratio, then multiply by the new ratio you are using. In this case .020/1.5=.0133 x 1.7=.0226. Again tight lash won't hurt anything mechanically. has 400 passes, no wear.
Doug

 

[Tempest 455]

I used to run a cam similar to that and ran .012"/.015" cold with Al heads.

 

[Canyon707]

I may have forgot to mention my rockers are 1.6 T&D rockers

 

[HEMI-ITIS]

Aluminum,Makes a difference,,,

 

[Canyon707]

Aluminum,Makes a difference,,,

Indy's are aluminim so I have to make the compensation for them.

 

[HEMI-ITIS]

I'll know next year how aluminum heads grow,up till now the steel heads only were 3 thou difference hot to cold.That only way for you to know is lash 'em hot and check 'em cold.

 

[dvw]

My -1 Indys run .005" looser hot.
Doug

 

[HEMI-ITIS]

My -1 Indys run .005" looser hot.
Doug

Do you have an aluminum block?

 

[Mike Gaines]

My -1 Indys run .005" looser hot.
Doug

My Indy's run .004" looser hot...so pretty close to yours.



I have since replaced that Indy Dual plane Intake and 850 Demon with an Edelbrock Single Plane intake and 1050 Dominator.

 

[Canyon707]

I was told by comp that .006 was the number. It was very close on my Elbrock heads .016 and .018 hot I set them .010 and .012 then checked them hot and pretty much right on. I had a starting point with that motor. This one I don't.

 

[malex]

I bought a soild roller from Comp, later had a custom roller made by them, silimar to your specs. On both camshafts the cam cards indicated .020 hot for both intake & exhaust. On the dyno with the custom roller the cam liked .016 intake and .020 exhaust.

 

[not so famous bob]

I was told by comp that .006 was the number. It was very close on my Elbrock heads .016 and .018 hot I set them .010 and .012 then checked them hot and pretty much right on. I had a starting point with that motor. This one I don't.

.016-.018 on my solid roller also. I set them .011-.012 cold, straight across. raised port aluminum victor knock offs. am going to tighten them down to .010 next time, one side is a little noisier than the other.

 

[66Satellite47]

My old Lunati solid roller .690 [email protected] used .027 lash (hot I think). General Kinetics Mushroom lifter (radical, power about equal to all my rollers) was .025 hot. I used both of these on iron head motors. My newer flat tappet with EDE heads .016 Int .018 Ex hot lash recommended. Gained about .004 cold to hot, so if was setting cold I'd be at .012 - .013.

 

[Budnicks]

Crane roller {tad bit smaller for a street engine},
Super Gold 1.6:1 rockers on ported Eddy RPMs
0.016"/in & 0.018"/ex cold, 0.021"/0.023" hot,
I like mine a bit on the tighter side,
I've never had any issues

I also use lash caps religiously too
always make custom length Smith Brothers pushrods too
I make sure the rockers are located/centered properly
I've never had a failure "yet", {knock on wood}

I've been doing it pretty much the same way for 40 years now
almost 0.030" is lose,
even on my old P/S or T/S engines/mountain Motors
I "rarely/almost never" ran them that lose,
even with almost 1" gross valve lift

good luck

 

[Coffee&Cars]

I guess they are all different. If you install the cam and use the right tools you could probably get some specs on it. Then talk to Comp about it. I have a Comp solid roller and the lash on the intake is .024, Ex .026, 273 degrees at .050, 306 total, .625 lift for comparison.

 

[Canyon707]

Crane roller {tad bit smaller for a street engine},
Super Gold 1.6:1 rockers on ported Eddy RPMs
0.016"/in & 0.018"/ex cold, 0.021"/0.023" hot,
I like mine a bit on the tighter side,
I've never had any issues

I also use lash caps religiously too
always make custom length Smith Brothers pushrods too
I make sure the rockers are located/centered properly
I've never had a failure "yet", {knock on wood}

I've been doing it pretty much the same way for 40 years now
almost 0.030" is lose,
even on my old P/S or T/S engines/mountain Motors
I "rarely/almost never" ran them that lose,
even with almost 1" gross valve lift

good luck

Well I spoke with a mopar engine builder and he said set them cold .022 and .024. It really makes me want to tear this down and pull the cam and find out for sure but, most of all these numbers are safe. Just would be nice to know. I am going to check what there current settings are tomorrow.