pantera_efi

iTrader: (1)

Hi ALL, I would like add some tech related to Valve Alloy. (Hot/Cold Valve Lash Considerations)

Jake is a metal engineer and could add some "tech" with regards to the difference in expansion distance between an OEM Exhaust Valve Alloy vs a Turbo Inconel Exhaust Valve.

My lash method is a +.003" difference, larger for Inconel.

My "tech" is related to the SuperTech LS Exhaust Valve made from Inconel, my normal valve supplier.
Guide clearance is also greater with an Inconel Valve.

The RB04 tech was found to be true for my case, my Lola333 F-5000 SBC.
My customer was Vick Edelbrock, a Pantera owner, who had me install a HCI upgrade (his products) on his 351-C including his Carter Carb. I was very impressed by the power increase after a short drive. He too came to my shop for a "test" drive finding the car was now hard for him to control safely. That reason was due to his TALL body. He asked me for a solution, I stated that I could "drop" the floor board (driver side) lowering the seat.

He was very happy with the increase in "head room" and asked me "Why are their Iron Heads on your Lola".
My answer was cost of an AL head upgrade.
Vic stated a NEW Edlebrock AL SBC head was just ready for sale AND I would get a great price.
The Valve Lash with the ISKY cam (Iron Head) was .020"/.022" (steel head) with the lash change from Bobby at Edlebrock to his .010"/.012" with the new AL head setting.

I was VERY pleased with the Edlebrock head change I made to my Lola 333cs winning the SCCA SP Division that year. (ASR)

Lance

rednari2

iTrader: (1)

[QUOTE=Pantera EFI;19881982]Hi ALL, the provided "tech" from Rednair2 is not correct about the roller tip rocker arm. The two rockers, if identical, would be compared by the Valve Side Radius diameter with larger being better for HP.
The "lifters" such as a .866/.904 change adds HP, a know fact.
Thus the same engineering applies to Roller Tip Diameter.

I LOVE this thread due to the FACT that I have GREAT PROBLEMS with the HYD "bleed down" over 6000 RPM.

The SAD thing is that many here due not know how simple a Solid upgrade can be done AND at LOW COSTS.

Lance[/QUOTE

Whoa, I did not say anything about roller rocker arms pal. I was discussing mechanical lifter lash.

rednari2

iTrader: (1)

Talked to Cranes again, and they repeated that 22, 20 is the correct lash for their cams. This is a cold setting, so assuming the motor expands about 10 thousandths, the lash when hot would be closer to 12, 10.

I understand what you guys are saying. I believe low lash cams work well. I wondered why Cranes recommended a larger lash, no doubt to accommodate for the expansion difference between the aluminum block and the iron valve train. Anyway, following the manufactures advice is the correct way.

CAMMOTION PERF

We actually account for the lifter wheel diameter when we grind our lobes. We ask our customers their lifter wheel diameter when they order custom cams. By doing so, we can be sure that the valve acceleration rates match our design parameters.

CAMMOTION PERF

That is actually backwards if you have an aluminum block and heads. If you set the lash to .020" cold in a standard deck, aluminum block/heads LS engine, the lash will increase to about .030" when hot.

G Atsma

I'm glad you responded to this, as I too thought as you do, that aluminum would grow more than the valvetrain, thereby INCREASING lash, not decreasing it. I was wondering if I was missing something....

rednari2

iTrader: (1)

Then what you are saying is that Cranes 22, 20 recommendation will expand to about 32, 30. Huh??

G Atsma

Precisely!

CAMMOTION PERF

Typically the lash specs are specified for hot. I can't speak for Crane, but I would speculate that they meant .020"-.022" hot. .030" would be a lot of lash for a modern camshaft in an LS engine.

rednari2

iTrader: (1)

That point is well taken. I thought we were talking about cold lash. If hot that would drop the lash to about 12, 10.

Ok and if so, then that lash would be similar to a low lash while hot.

CAMMOTION PERF

The lash is more when hot. Aluminum expands more when heated than steel. So, the lash won't "drop" when hot in an aluminum engine, it will increase as the engine gets warmer.

rednari2

iTrader: (1)

This question is for cam motion. The bottom line is that your low lash cams are set about 10 thousandths less than Crane specs when both are hot.

I am not doubting that your cams perform well. Too many members here agree that they do. But how is you grind different from Cranes? Is the Cranes set up just noisier but offers similar performance, or is there an advantage to a tighter lash?

It would seem tighter lash allows for quicker valve lift, but Crane states their grinds compensate for that. I am not trying to be a PITA, I am trying to determine the best set up. A thoughtful in depth reply would be appreciated. Thanx, Red.

speedtigger

iTrader: (16)

There is a detailed explanation of all of that in the first post.

A.R. Shale Targa

iTrader: (2)

I suppose I don’t get to pass “GO” or collect $200 either

rednari2

iTrader: (1)

The first post is posting of general info regarding same. The only topic in it which remotely addresses the issue I raised, is near the end and suggests "race" motors are ok a little loose.

I will follow Cranes advice. I was seeking an answer as to whether a tighter lash creates more power, and no one addressed or answered the issue, even the sponsor.

Good day and good bye on this one.

whatsa347

iTrader: (6)

Oh no, please, come back we all really wanna hear what you have to say about everything......

RB04Av

I can't believe a cam mfr would tell you to set the valves cold. That flies in the face of all logic and common sense. That mfr has NO WAY to know whether you are putting the cam into a motor with Fe or Al block or heads; NO WAY to know what temp the whole thing is at when "cold"; and NO WAY to know what the running temp will be. All of which adds up to, if you set the valves "cold", you have close to .015" of UNCERTAINTY in where the lash will be when the motor is ACTUALLY RUNNING NORMALLY. (which would logically seem to be what a lash "spec" is ALL ABOUT... the cam mfr couldn't care less what the lash is when the motor is sitting on the stand, they design it to be part of a motor THAT RUNS) Which would be SEMI CATASTROPHIC in a setup that calls for, say, .012" lash.

Bottom line to me is, either you talked to an idiot on Crane's tech line; or they didn't understand what you asked; or you misunderstood what they told you. NO WAY that's the right thing to do.

pantera_efi

iTrader: (1)

Hi RED, I too AGREE with the report by RBO4. (Crane=Idiots)

I have found MUCH information in this thread about HP increase with "tight lash".
I READ, tight lash WILL add DURATION AND READ too tight will cause the valve not to seat.

BOTH items effect HP.

My Crane=Idiots case is a report of a "new" Crane company/ownership. The reason is that I accepted a P.O. for a SBC Ready-to-Run distributor at great price of $165.00+Shipping, SHIPPED FOUR YEARS AGO

AS OF THIS DAY, they have NOT PAID my invoice OR returned MY GOODS.

HARVEY Crane was my friend and sold me many cams, all worked fine.

Lance

rednari2

iTrader: (1)

[QUOTE=whatsa347;19884473]Oh no, please, come back we all really wanna hear what you have to say about everything......[/QUOTE

Clown.

rednari2

iTrader: (1)

Yes. S&S, the motorcyle guys, bought them a few years ago. But have sold them again recently. I do not known whats going on at Cranes. I have their springs on my car (04 GTO) and many Gen I builds. All of their products were good.

I know there was much confusion during the ownership by the motorcycle guys. In any event, 12, 10 seems to be the magic number. You get there by setting a traditional lash 22, 10 hot, or a low lash at zero cold.

But no one has answered the question: which makes more power or are they more likely the same, given the same motor and cam grind.