Cold Valve Lash Question

[tubbedamx]

I have a question about setting cold valve lash and I think I’m overthinking it.

Working on an 408, iron block, iron heads, solid roller with iron crane adjustable rockers.

Cam card calls for .008 hot. I’ve been reading lash increases with heat and an all iron motor will increase .002-.003. I have it in my head the lash will tighten up with heat.

I guess my question is set the cold lash .006 a good start.

Thanks

 

[Murray]

So, you want to start at .006 and tighten that up when it warms up?

 

[Newbomb Turk]

I would set them at .008 COLD and then get it hot.

Then check the hot lash and see what it gains. Then you’ll know how tight to set them cold.

Normally I say .002-.004 tighter when cold but those lobes call for .008 hot.

.002 tighter is a 25% reduction in lash and .004 tighter is a 50% reduction in lash. That a bunch.

If the card said hot lash of .020 and you went .002 tight that’s only a 10% reduction in lash and .004 is only 20%.

Running the numbers I suppose setting the lash at .002 tighter cold isn’t THAT much tighter as a percentage.

I’d still set them at .008 cold and get some heat in it and measure it hot. You’ll know how tight to go.

 

[tubbedamx]

So, you want to start at .006 and tighten that up when it warms up?

I would like the lash to open up to .008 as the engine comes up to operating temperature

 

[tubbedamx]

I would set them at .008 COLD and then get it hot.

Then check the hot lash and see what it gains. Then you’ll know how tight to set them cold.

Normally I say .002-.004 tighter when cold but those lobes call for .008 hot.

.002 tighter is a 25% reduction in lash and .004 tighter is a 50% reduction in lash. That a bunch.

If the card said hot lash of .020 and you went .002 tight that’s only a 10% reduction in lash and .004 is only 20%.

Running the numbers I suppose setting the lash at .002 tighter cold isn’t THAT much tighter as a percentage.

I’d still set them at .008 cold and get some heat in it and measure it hot. You’ll know how tight to go.

Thank you, that’s what I’ll do.

 

[Newbomb Turk]

One more thought. I see you’re in Boise.

If you drive the car when it’s cold (I’ve driven my car when it was in the single digits) you can get the lash to close up and when cold. Then you can get some dead cylinders when you start it up again.

My car stays in the garage. Several years ago we went to my sister in laws for Christmas. It was 12 degrees when we left the house at noon. By the time we headed home at 6 pm it something crazy cold. Like 4 degrees.

When I started it up after sitting outside in the cold I had 3 or 4 cylinders that were missing because the lash closed up enough it was holding some valves open.

Once it got some heat in it they started hitting again but it’s something to be aware of.

I’ve also had customers with solid roller lifters on hydraulic roller lobes that cold lash at .004 and they had the same issue.

As long as you know it then you understand it.

Just something to keep in the back of your mind.

 

[tubbedamx]

Single digits, that’s dedication-haha. Thanks that’s a good point, I’ll definitely keep that in the back of my mind. Fortunately, it lives in a heated garage.

 

[CRUZE 418]

Lash grows with heat. That really seems tight. On Engine Masters, HP went up with more valve lash to a point. If it was mine, I would feel better in the low to mid teens when hot.

 

[mbaird]

Wow ! I didn’t notice how low your lash was when I saw your cam card at your house. That will be a great / quiet running engine . Jones designs great cams.
Just remember to rotate the engine clockwise when you set the lash ! Lol. ( see post about setting my brothers lash on his Firebird)

 

[Dana67Dart]

I was always under the understanding that lash gets smaller when hot. Why a tick goes away when the engine heats up on solid lifter engines

Meaning if you had 0.008 cold it would become 0.006 ( just numbers for example,) hot

So if you set lash cold you go bigger than the hot lash spec

Like 0.010 cold and it becomes 0.008 hot




The push rod grows in length when hot. I guess the head and block does too so maybe the combo could cause the lash to open?????

 

[CRUZE 418]

Noise? That sound is what I always liked about solid lifters, and a quiet exhaust system.

 

[Icetech]

I have a question about setting cold valve lash and I think I’m overthinking it.

Working on an 408, iron block, iron heads, solid roller with iron crane adjustable rockers.

Cam card calls for .008 hot. I’ve been reading lash increases with heat and an all iron motor will increase .002-.003. I have it in my head the lash will tighten up with heat.

I guess my question is set the cold lash .006 a good start.

Thanks

View attachment 1716394632

View attachment 1716394633

Just curious, how are you liking that cam? a customer of mine was in earlier this week that races some massive cube ford and was praising jones non stop. Said he used to run 800# over the nose and with his jones cam went down to like 590# and the motor is much happier, and just as fast

 

[tubbedamx]

Just curious, how are you liking that cam? a customer of mine was in earlier this week that races some massive cube ford and was praising jones non stop. Said he used to run 800# over the nose and with his jones cam went down to like 590# and the motor is much happier, and just as fast

i think its pretty good, the seat of your pants dyno says the car pulls pretty hard. Mike has an excellent reputation. This cam is pretty small, the car is primarily a cruiser.

He’s extremely easy to work with both online and over the phone. I’m also using his pressure fed solid rollers.

 

[Icetech]

i think its pretty good, the seat of your pants dyno says the car pulls pretty hard. Mike has an excellent reputation. This cam is pretty small, the car is primarily a cruiser.

He’s extremely easy to work with both online and over the phone. I’m also using his pressure fed solid rollers.

Nice... that's pretty much the exact cam i want.. for the way i drive and being a street car it's more than enough... i would need springs/cam/lifters... eck.. adding up fast he doesn't have prices listed.. i expect the lifters were in the $800 range? if you don't mind..

 

[tubbedamx]

Nice... that's pretty much the exact cam i want.. for the way i drive and being a street car it's more than enough... i would need springs/cam/lifters... eck.. adding up fast he doesn't have prices listed.. i expect the lifters were in the $800 range? if you don't mind..

I don’t recall the exact price but I think they were around there. I just looked at his site it’s call for prices.
XLR-8 Roller Lifters | Jones Cams

 

[SSG_Karg]

I’m amazed at how little lash that cam calls for. For comparison, my 422 is a very similar combo. Iron block, iron heads, iron rockers, and a Howards .600” lift solid roller. Howards wants hot lash at .022” and I cold lash it at .017-018”. I called Jones before purchasing a cam but I thought the grind he recommended was low on lift, at around .585” if I recall correctly.

 

[mbaird]

I’m amazed at how little lash that cam calls for. For comparison, my 422 is a very similar combo. Iron block, iron heads, iron rockers, and a Howards .600” lift solid roller. Howards wants hot lash at .022” and I cold lash it at .017-018”. I called Jones before purchasing a cam but I thought the grind he recommended was low on lift, at around .585” if I recall correctly.

View attachment 1716395081

Very close to my cam and same lash recommendations

 

[Bewy]

The Jones cam is probably a hyd lobe being used with sol lifters. Comp Cams has both flat tappet & roller lobes that can be used with hyd or sol lifters.

 

[Icetech]

The Jones cam is probably a hyd lobe being used with sol lifters. Comp Cams has both flat tappet & roller lobes that can be used with hyd or sol lifters.

 

[Bewy]

IR lobes are nothing new...or exclusive to Mike Jones. Crane & Cam Dynamics had then decades ago...as probably did others. Don Hubbard writes about them in his 1998 camshaft book.

 

[Icetech]

IR lobes are nothing new...or exclusive to Mike Jones. Crane & Cam Dynamics had then decades ago...as probably did others. Don Hubbard writes about them in his 1998 camshaft book.

I figured... just was putting that in case that's why he uses such a tight lash

 

[Woody500]

IR lobes are nothing new...or exclusive to Mike Jones. Crane & Cam Dynamics had then decades ago...as probably did others. Don Hubbard writes about them in his 1998 camshaft book.

The Novis' Bud Winfield deserves some credit for modernizing cam lobe designs. Novis first ran before WWll, IIRC.
Meyer-Drake, later with George Bignottis' help(Geo was Louis Meyers son-in-law)made advancments, & no doubt others forgotten now.

 

[Woody500]

Also, the tighter the lash , the more important the adjustment method. I've heard no mention of the 'Valve Overlap' adjustment or how it is more accurate.
I won't describe it here because it's so ez to look this one up.
I hope there's a lot of people to chime in, maybe Engine Masters touched on it??