Comp Cams Valve Lash

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Comp Cams Valve Lash

Post  Ol Yaller 73 on May 27th 2018, 8:03 am

Got a question. I have an iron head 460, running a Comp Cams 294B-8 solid flat tappet cam. Stainless valves. Roller Lifters.
The lash recommendations are.030 intake and exhaust. This seems a little big. Anyone running this? What would you set them at?
Thanks!

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Re: Comp Cams Valve Lash

Post  dfree383 on May 27th 2018, 9:02 am

I don’t like them that loose, I’d try .020-.022
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Re: Comp Cams Valve Lash

Post  BOSS 429 on May 27th 2018, 9:50 am

dfree383 wrote:I don’t like them that loose, I’d try .020-.022


x2
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Re: Comp Cams Valve Lash

Post  rmcomprandy on May 27th 2018, 11:08 am

Ol Yaller 73 wrote:Got a question. I have an iron head 460, running a Comp Cams 294B-8 solid flat tappet cam. Stainless valves. Roller Lifters.
The lash recommendations are.030 intake and exhaust. This seems a little big. Anyone running this? What would you set them at?
Thanks!

That cam is designed with a .0175" lash ramp on the lobe so, .030" is the maximum HOT valve lash which should be run when using a 1.73/1 rocker arm.

I would set them wherever it runs the best between .012" and .030"; intake and exhaust do not need to be the same.

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Re: Comp Cams Valve Lash

Post  valvemotion on May 31st 2018, 9:23 am

rmcomprandy wrote:
Ol Yaller 73 wrote:Got a question. I have an iron head 460, running a Comp Cams 294B-8 solid flat tappet cam. Stainless valves. Roller Lifters.
The lash recommendations are.030 intake and exhaust. This seems a little big. Anyone running this? What would you set them at?
Thanks!

That cam is designed with a .0175" lash ramp on the lobe so, .030" is the maximum HOT valve lash which should be run when using a 1.73/1 rocker arm.

I would set them wherever it runs the best between .012" and .030"; intake and exhaust do not need to be the same.

I agree 100%

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Re: Comp Cams Valve Lash

Post  BBFTorino on May 31st 2018, 12:18 pm

I've run mine at .012 and .014 intake/exhaust (hot) because the loose lash tents to beat the crap out of the pushrod ends!!

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Re: Comp Cams Valve Lash

Post  rmcomprandy on May 31st 2018, 6:09 pm

BBFTorino wrote:I've run mine at .012 and .014 intake/exhaust (hot) because the loose lash tents to beat the crap out of the pushrod ends!!

If you stay on the intended lash ramp of that lobe profile, the contact velocity of a flat tappet cam will remain the same 99% of the time. It just takes less duration from there to get going faster up the ramp, sooner.

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Re: Comp Cams Valve Lash

Post  DaveMcLain on May 31st 2018, 9:14 pm

rmcomprandy wrote:
BBFTorino wrote:I've run mine at .012 and .014 intake/exhaust (hot) because the loose lash tents to beat the crap out of the pushrod ends!!

If you stay on the intended lash ramp of that lobe profile, the contact velocity of a flat tappet cam will remain the same 99% of the time.  It just takes less duration from there to get going faster up the ramp, sooner.

That's right most solid lifter cams have a constant velocity ramp for that very reason. On some old factory cams this area can be pretty long which should make the lash setting very forgiving in that some valves could be quite a bit looser and not make any more noticeable noise than one set significantly tighter. With this type of cam setting the valves tighter really doesn't do anything except add some duration.

Where most people screw up is with what to do with the lash when changing the rocker ratio. Since the lash setting happens at the valve it should be increased as the rocker ratio is increased to keep the contact points on the ramps (duration) the same.


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Re: Comp Cams Valve Lash

Post  Albert Clark on June 1st 2018, 5:46 am

Ol Yaller 73 wrote:Got a question. I have an iron head 460, running a Comp Cams 294B-8 solid flat tappet cam. Stainless valves. Roller Lifters.
The lash recommendations are.030 intake and exhaust. This seems a little big. Anyone running this? What would you set them at?
Thanks!


The question is why are you running a solid lifter camshaft with Roller lifters?

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Re: Comp Cams Valve Lash

Post  dfree383 on June 1st 2018, 6:15 am

Albert Clark wrote:
Ol Yaller 73 wrote:Got a question. I have an iron head 460, running a Comp Cams 294B-8 solid flat tappet cam. Stainless valves. Roller Lifters.
The lash recommendations are.030 intake and exhaust. This seems a little big. Anyone running this? What would you set them at?
Thanks!


The question is why are you running a solid lifter camshaft with Roller lifters?

Albert is the only guy with a keen sense for the odious
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Re: Comp Cams Valve Lash

Post  rmcomprandy on June 1st 2018, 9:18 am

Albert Clark wrote:
Ol Yaller 73 wrote:Got a question. I have an iron head 460, running a Comp Cams 294B-8 solid flat tappet cam. Stainless valves. Roller Lifters.
The lash recommendations are.030 intake and exhaust. This seems a little big. Anyone running this? What would you set them at?
Thanks!


The question is why are you running a solid lifter camshaft with Roller lifters?

YES ... that fact went un-noticed.
That sure should not be done ... ever.

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Re: Comp Cams Valve Lash

Post  pmrphil on June 1st 2018, 1:17 pm

I just figured he said "lifters" when he meant "rockers". He had just stated he had a solid flat tappet cam.
Maybe he can come back on here and clarify - oops or BIG OOPS. Smile

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Re: Comp Cams Valve Lash

Post  Lem Evans on June 1st 2018, 2:24 pm

294B-8 is a flat tappet grind number.

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Re: Comp Cams Valve Lash

Post  BBFTorino on June 3rd 2018, 2:25 am

How about running roller pushrods with your solid rockers and plastic lifters?? Very Happy

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Re: Comp Cams Valve Lash

Post  Albert Clark on June 3rd 2018, 5:54 am

BBFTorino wrote:How about running roller pushrods with your solid rockers and plastic lifters?? Very Happy


Let me ask you something? You just come on here to flap your lips and or to hear yourself don't you?

some of the things you spout off make as much sence as going to a proctologist to have your teeth worked on

Yours Truly Albert

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Re: Comp Cams Valve Lash

Post  Dave De on June 3rd 2018, 10:54 am

Albert Clark wrote:
BBFTorino wrote:How about running roller pushrods with your solid rockers and plastic lifters?? Very Happy


Let me ask you something?  You just come on here to flap your lips and or to hear yourself don't you?

some of the things you spout off make as much sence as going to a proctologist to have your teeth worked on

Yours Truly Albert

OUCH
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Re: Comp Cams Valve Lash

Post  supervel45 on June 3rd 2018, 4:06 pm

Albert Clark wrote:
Ol Yaller 73 wrote:Got a question. I have an iron head 460, running a Comp Cams 294B-8 solid flat tappet cam. Stainless valves. Roller Lifters.
The lash recommendations are.030 intake and exhaust. This seems a little big. Anyone running this? What would you set them at?
Thanks!


The question is why are you running a solid lifter camshaft with Roller lifters?

Good catch. I have the same cam and I even did not snap to the roller lifters and had to do a double take. Cool

Guess it will take a bunch of the lope out with roller lifters, LoL.

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Re: Comp Cams Valve Lash

Post  DaveMcLain on June 4th 2018, 5:59 pm

rmcomprandy wrote:
Albert Clark wrote:
Ol Yaller 73 wrote:Got a question. I have an iron head 460, running a Comp Cams 294B-8 solid flat tappet cam. Stainless valves. Roller Lifters.
The lash recommendations are.030 intake and exhaust. This seems a little big. Anyone running this? What would you set them at?
Thanks!


The question is why are you running a solid lifter camshaft with Roller lifters?

YES ... that fact went un-noticed.
That sure should not be done ... ever.

Good catch on the lifters... I've seen that done a few times and one that I can think of was on a Chrysler 2.5 overhead cam engine that came in with a noisy valvetrain. They were known to break a cam once in a while out near the middle. This must have happened to this engine one time or another and somebody changed the cam but used the one for the non roller followers! The rollers wore a groove close to 1/8th inch in the lobes and put a bunch of crap into the engine but after swapping on the right cam it ran once again.

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.030 Lash and Lifters

Post  Ol Yaller 73 on June 7th 2018, 6:40 am

OOPS, I meant roller ROCKERS, not roller LIFTERS. Thanks to all the sharp eyes out there! I stand corrected.

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