Engine: Camshaft Specs.

[Skybolt]

I'm about to send my cam off for regrinding and I just want to ask questions before I commit to a grind.

First let me lay out the rest of the specs. The car is a 59 Lark 2 door sedan. The engine will be a 259 with 0.100" over pistons, 4bbl carb, 3.73 differential, 3 speed with overdrive. A dual exhaust system, larger valves and stronger springs. Other mods but I'll leave them out for now.

First question is if anyone has real world experience with a performance camshaft with similar setup? What was found to be a good grind for this gearing and working on about 1hp per cubic inch. I'm not looking at setting any speed records or quarter mile times. Just all around fun driving with some hard driving some times.

Second with said cam what were the specs and rpm range with peak hp and torque figures, if known?

Thaksin in advance and if any one has anything else to add jump right in.

[Bud]

I've been very happy with either the Iskenderian E4 or ST5 grinds. I would recommend the E4 grind for your engine as it works really well in the low to mid range rpm band. It has .425 lift with 260 deg duration with a decent idle vacuum. The ST5 cam has a rougher idle and lower vacuum. I have an ST5 cam in my Avanti engine and I think it is a better cam for mid to high rpm use. The Avanti has a 3.73 diff. and a 2800 rpm converter in the transmission so the cam works well with that setup. Plus the Isky factory is in Gardena which makes it easy for me to get over there personally. Bud

[Skybolt]

Thanks Bud, I plan to do a lot of freeway driving sitting at about 2,200 - 2,800 rpm and want to pull away from there. That might also entail changing down to 1:1 gearing as I come out of overdrive. That would put it into the mid 3,000 rpm range. Mostly I think if it was designed to pull on on ramps to merge with traffic at 70 to 80 and be able to not feel like it's out of breath until I'm up over 100 mph I would be happy. Down low I don't mind if it is not a traffic light to traffic light winner. So, if the E4 sounds performs like that then that might be the specs I'm looking for.

[Bud]

The E4 cam works well in the 2 to 4,500 rpm range which is good for a Studebaker engine with an overdrive transmission. Send me a PM and I'll send you all of the cam specs. Bud

[Mike Van Veghten]

Len -

There's only a coupla grinds that are capible of being put onto a stock Stude cam core..

I'd give Phil a call at Fairborn Studebaker. He may be able to get you an R2+ cheaper than you can have it ground. This would be a good cam for your car and existing parts.

There's always Tighe Cams in AS. ...!
There's a grinder in Utah that I had do a cam, they did VERY nice work (!), (I can find their address for you if you want)...but again...the Iski's the Fairborn, and all the rest....are VERY close in numbers, when doing the R2 or R2+ grinds.

Mike

[Skybolt]

Hey Mike,

Do you have the specs of the R2 and R2+ cams?

Len.

[Alan]

Or you can go to Precision Cams in Montabello. He did all of Stones cams. Just about any grind you can dream up.

[PackardV8]

The Studebaker R1/R2/IskyE4 are all the same grind = 260 degrees and .425" valve lift.

The Fairborn R2+/Isky ST5 are the same grind = 268 degrees and .447" valve lift

FWIW, for a good compromise, send your cam to Isky for a regrind to E4 specs. If you're feeling racy, then the ST5. They are inexpensive and you have braggin' rights.

jack vines

[Mike Van Veghten]

Other thAn what's listed above, no I don't.
But as noted, they are still very much Studebaker cams in the lobe specs.
Also, I'm not positive whether the duration is noted at .020" lift or .006", I know it's not at .050" lift as used by most everyone in todays cams. So be carefull in comparing lift durations, you need to know the lift value at which the duration is measured.

Mike

[Skybolt]

Yes Mike, I'll have to check a few more things before I decide. I've been slack lately and just ask question rather than get the specs myself. So, here's another question to prove that. Given stock specs of a standard head with no material shaved off and the cc at the standard R1 specs how close does the valves come to the face of the head, the surface? Given stock rockers etc... Just so I can work from there as to what lift and such as my pistons will be 0.020 closer to them. If I increase the ratio of rocker arms and have more lift, shave the heads etc... Just wondering how far I can go.

Len.

[Mike Van Veghten]

Back when I did a brief mockup of my engine, I found that with heads that had .020" milled off of the stock head thickness dimension, .500" lift would not pose a problem of head to block problems.
Remember, the valves overhang the cylinder bore (stock). Being that you've bored your block .100" over, you'll have no valve to block problems even when using 1.875" dia valves.

As far as valve to piston clearance, unless you zero deck your block, again, you'll have no problems. IF...you've zero decked your block...at lobe lift of .289" (.447" valve lift), adding a 1.6 rocker will increase the lift by "about" .030" to .47 depending on if the geometry is correct..(pushrod length and rocker shaft height is correct). This will still be under .500" lift (about .477" valve lift).
(Note: with much in the way of head and or block decking, cam regrinding...this throws off the correct rocker geometry. How far depends on how well everything adds up - head thickness, gasket thickness, cam base circle location, valve tip location. Rocker stand machining or shims may be required to get it "correct".
One thing I'd recommend you do in ANY case -

1. Go and buy a coupla cheap springs from a hardware store, that are weak and with sorta stock looking dimensions. Since they are weak, the exact stock dimension isn't critical.
Put these light weight springs in one cylinders valve springs and rotate the crank thru a single revolution....to be SURE....you have no problems. It's about a 20 minute job if you have some sorta spring on hand.
All the math in the world is just paper, you should/need to verify with the real parts used. Lotsa variables to add and subtract, easy to miss something..!

Again, I (anyone !) can say you shouldn't have a problem, but...any build like you have...should ALWAYS be checked, maybe even double checked.
Let me know when you get there, I can come by and throw a few pointers your way if you'd like.

Mike

[PackardV8]

Valve-to-piston clearance is mostly a SBC/SBF 23-degree valve thing. The Stude valves are at less than half that angle, so they really don't come close to the pistons. There aren't any known commercially available flat tappet lobe profiles for Studebakers which can cause V/P interference when installed on the marks.

As Mike said, these engines are sixty years old and who knows what has been done to them with milling heads, blocks and whatever, so trust it's not a problem, but verify on your build.

jack vines

[Skybolt]

Thanks guys, this all helps out a lot. I still have homework to do but I'm a little closer to completion.

[Skybolt]

One last question. With the aforementioned cams what are each of them like once the engine sees upward of 5000rpm? If I set the engine to redline at 6000 plus and want to use shift point above 4000 rpm what will each be like. Basically I have a three speed transmission and will wind it out in each gear. The overdrive is just a luxury to use for causing and dropping the rpm down when needed. Given it's not a standard trans with added overdrive but a four speed with top as overdrive I cant engage the same way, just have to use it like a regular 4 speed noting the rear axle is behaving like a 2.something ratio differential.

[PackardV8]

4500 RPM and below you want the R1/E4

4500-6000 is where the R2+/ST5 makes more power. You'll need larger intake valves and some really good intake port work and a set of headers to get the maximum benefit.

jack vines