Hello all

For the last few builds I have done, ('69 Dart, '79 Duster, Ruster and '64 Grüne Hölle), I either had a shop build me a head or I sent one to Mike J. for obvious reasons or I bought one second hand that had been done wiyh larger valves, port work etc.

My question here is about valves.. I want to use 1.5" & 1.8" valves, with new guides and cutting / flattening the valve spring pocket and lowering the valve guide height to permit a higher lift cam(s) as needed.

Does it matter if both valves are advertised for their OE Use (Chevy, I believe) that they are exhaust valves?

I.E.:
Original use/designation: Chevy 1.5" Exhaust valve - My Intended use: Slant 6 modified head Exhaust Valve
Original use/designation: Chevy 1.8" Exhaust valve - My Intended use: Slant 6 modified head Intake Valve


Thanks Sages!

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http://www.youtube.com/hyperpack

Nope. Won't matter.

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Official Cookie and Mater Tormentor.

Agreed. Note that Mike J settled on 1.76" valves for even big bore (0.100" or more over) due to valve shrouding. He told me he did substantial testing and the 1.76" he felt were the biggest that were useful. However, if you were to move the valve over, then 1.8 or bigger might be worth it? Or, just go for it and see how it works...

FWIW, I have a never-run head I bought from a guy in CA back in 1996 with stainless 1.84/1.54" Chev valves in it, and I will try to run it on a 0.104" over engine at some point...

Lou

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Home of Slant6-powered fun machines

Thanks, guys.

That's kind of what I thought, but I wanted to check to be sure.

Was not sure if there were some sort of special considerations for one valve over the other.

Greg

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http://www.youtube.com/hyperpack

Okay Next question sages,

Where do you guys go to look / resource to utilize to find a specific valve spring based on seat pressure / instlled height open height and pressure?

I emailed Ken@ OCG about my cam and He gave me recommended pressures for seat and open, but I am having trouble finding the correct spring pressures/rate for my application at the installed height.

Thanks, sages!


Greg

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I am going thru this now.
I downloaded the Isky PDF for all their springs.
Going to call tech for the confirmation.
I have a height micrometer that makes installed height easy.
And a spring scale so I can check and confirm what I have and what I am getting.

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Hyper_pak

Yes I have that stuff.

I am setting up your old head that you sold me, thank you!
So far the valves seem good, I derusted the ports and have to replace a seal or 2. a few got smooshed somehow.

It has Chevy valves, springs, locks, retainers etc. which is not a problem. and I want to make sure it is matched to my cam and setup. so there are no issues.

My valve micrometer works best installed upside down due to the way it works with the retainer. - goofy.

Greg

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I got mine from Mike Jeffrey!

Honestly there is probably a good bit of wiggle room in those numbers. I mean if you need 100#, 120 is not going to kill you. or 250# 275# should be fine. Especially on a street motor. As long as you can keep the lifters on the cam with a given pressure you should be Ok. Just my opinion.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Because of the small valves and lower rpm you can get away with a little less too.

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Official Cookie and Mater Tormentor.

Glad the head is going to work out for you Greg.

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Hyper_pak

Zilla,

Next time you talk to Mike, he tried some funky angles on the grind, he came up with some impressive numbers by changing the angles. But for the boost I was planning to run, it didn't pan out, IIRC.

It's been a while, but I'll bet he remembers what I'm trying to talk about. Naturally aspirated, he found a way to increase flow by using non-standard angles.

See if that stirs up any of his memories on the subject.

CJ

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Part of Tyrde-Browne Racing

I think he used 30 degrees instead of 45 on the intake to improve low lift flows.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

That's it. He did that on my turbo engine head.

Lou

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Home of Slant6-powered fun machines

Thirty degree valve angles work well on "lower" rpm street/torque motors, with low(er) lift cams. I was doing that on my "stocker" type motors back in the '70's. Another thing we did back then was use cams with (for the time) very fast lift rates. We had to run stock duration and lift back then. We got more "area under the curve" with the lift rate. The limit on lift rate was dictated by the stock valve spring pressure. Today I think the lift rate (flat tappet) is more determined by the lifter diameter. I have always wanted to try a "mushroom" lifter/cam in a slant. I think it might be a good compromise instead of a roller cam.
Bush the lifter bores and spot face the under side. Use a mushroom lifter (Ford "Y" block/Volkswagen/etc) reground cam (Oregon cams?) 3/8 pushrods, beehive valve springs, 7mm valves.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

I believe Mr. Ondayko is in possession of 'The Book of Secrets' now. It will all be in there.

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Official Cookie and Mater Tormentor.