External oil pumps/roller cams/bronze gears

[Jamo]

Morris

I always took a good supply of basterma, string cheese and lavash...works wonders.

It took a bit of time for the now famous (infamous?) Jamo signature Model mods...four trips for ass fittings...and things like the arruminum hood scoop, sanded body/stripes, etc. First time on those items for customer cars, but it was worth it given the final product. Tough waiting though, I know.

Best of luck.

[PatBuckley]

[Morris]

Jamo

Good idea.... maybe I should take some Chicago Pizza and Omaha steaks..... and lots of Beer.....

Now that you say that ..... that's how we built the GT1 Corvette..... 3 guy's moved in the house and we did it.... and feeding them was a real task....

And we only worked until midnight ..... everynight the last week...


Pat

What does that little face mean....

Morris

[SFfiredog]

Jamo r Jelly,

The valve springs are next. Unless you are a mechanic and like changing distributor gears and valve springs every 5k to 10k miles or so, you might want to consider a mechanical flat tappet cam.
It will cost you less money than an external oil pump or dry sump and with the right cam profile we should be able to keep the power loss to around 20 horsepower.
Adjust the valves once a year and forget it.
--Mike

[PatBuckley]

Morris -

It was intended for someone else (ricklake) and to me it means "whacko".

[Sizzler]

Virtually all street hydraulic- and mechanical-roller cams now come from the major cam companies with iron gears pressed onto the end of the camshaft to allow the use of stock-type iron distributor gears instead of the softer and less durable silicon-bronze gears.

Who provided the cam and/or bronze gears?

[Jamo]

Hey Mike

I'm seriously thinking about that...flat tappets be sounding verry verry good to me. If I was racing all the time, the 20 or so horses and the other characteristics of the roller cam/lifters would make some sense. Worrying about that damn gear and keeping the valves in adjustment are not fun giving the long drives we take.

I was sitting over at Boghosian's today looking at Dick Smith's motor...flat tappets seemed to do ok for him.


Sizzler...yup, the production motor type cams do have that...maybe in a year the mfgs will move to them for this racing stuff. BTW, who are you quoting?

[RICK LAKE]

Pat Buckley THANKS PAT How is your shrink? Rick Lake

[Jamo]

Gentlemen...pretty please?

[PatBuckley]

Don't need one Rick - you looking for a recommendation?

[Jamo]

Great...thanks...am I gonna have to close my own thread?

[Turk]

.

[RICK LAKE]

Pat Buckley Hey Pat, Have a nice July 4 holiday Catch you after it Rick Lake

[PatBuckley]

I hope yours is everything you want it to be, Rick.....

[Ron61]

Jamo,

My 69 T.C. came with a flat tappet cam in it and I have never had a distributor gear problem or any other problem except the spun bearing. My engine builder told me to stay away from roller cams for mostly street driving and said with the roller rockers I would only lose about 10 - 20 horse over the roller cam. After he did the figures and then ran it on the dyno, I actually lost just 14 horsepower. And as Mike said, adjust them once a year and spend the rest of the time enjoying it. You aren't going to miss 10 - 20 horse out of that 600 + anyway.

Ron

[Jamo]

Boghosian and I are sitting on it over the weekend. He's going to give me the pros and the cons Tuesday. Obviously, I would retain the roller rockers. Joe's checking out some grinds to chose from, and whether anybody has a bis nasty roller can that'll take a steel gear, which he doubts. We're also checking out prices of wet external pump setups.

[PatBuckley]

Roller cams - all else being equal, if they only gained 14 -20 HP I doubt they would ever sell another one.

[Jamo]

From what I understand, it's not just the hp gain.

Less chance (zero) of flattening the cam over time, ability to maintain high revs (maybe higher revs to begin with), more precise tuning/valve action with bigger cams, etc.

Then again, steel distributor gear vs. bronze, less catastrophic cam damage if a pushrod bends, primary use on the street/long drives and no desire to be screwing with the motor more than I have to.

I'm going to assume 30 hp loss and still see if it makes sense after considering everything. Will I miss 30 hp? He!!, I didn't miss not using the secondaries for the past year (another story).

I keep thinking about Smith's motor being a flat tappet. Joe's in the midst of building a Shelby block based monster for a Mark IIB GT40 for the European historic series (they get serious over there...first race is a 6 hour enduro ), and he's going to use a flat tappet setup for durability's sake per the customer's request.

Sounds like a new topic.

[RICK LAKE]

Jamo Roller cams like Pat said will make more HP than a flat tappet. Joe is very fond of the H&M 610 cam, Great tork and good HP. With this many cubes this motor is big enought to rotate the world. Dick better have spare tires I have called and e-mailed H&M and get no reply from them. If the valve ramps are not servere the roller will work better. You need to limit the rpm level. Running 700 pound valve spring is what is hardest on the motor and cam wear. I am surprised that Joe is not going with a roller bearing cam motor. Nascar uses this. Dick is going from a 431 motor to 496, this cam is going to be 10-15% larger, for the best power. I'm going hydro roller cam crane 587-607. I am going with light valve springs, the motor is not going to see over 6200 rpm. A roller lifter causes less friction than any other lifter but a Schubeck. Price on Schubeck is 2-3 times more, but the wieght is 1/4 of a steel lifter. You should look into a custom cam for the motor to get what you want. Great Tork, flat band from 2500 rpm to 6000, and HP from 3250 to 6250 rpm with a shift point at 6500 rpm, Msd chip the same 6500 rpm. This should be all the motor your cobra will take and still be drivable. More is not allways better. Rick Lake

[SFfiredog]

Originally posted by PatBuckley


Roller cams - all else being equal, if they only gained 14 -20 HP I doubt they would ever sell another one.

Pat,

Here is my insight on the roller cam issue. In my first post, I stated to Jamo that I could spec a flat tappet cam that would only lose around 20 horsepower compared to the roller cam that is in HIS motor presently.
I would need to see Jamo's cam card.
The flat tappet I would pick might have more duration and less lift and possibly a different lobe center than the roller in his motor now.
It is true that a solid roller cam, in most applications, can be worth 30 to 50 horsepower over a flat tappet cam if the roller cam is ground to take maximum advantage of the roller lifters. What I mean by this is the radical ramp profiles that can used by a roller that literally slams the valves opened and closed. I have seen roller cam lobes that have over 275 deg duration @ .050" lift
but less than 300 deg duration advertised @.015" lifer rise.
Those lobes allow maximum cylinder filling and produce huge cylinder pressure #s which make big horsepower.
A flat tappet could never do this and live.
At the same time, lobes like that will kill all but the best valve springs ($500 to $600) in no time and even those will die in short order on the street.
The valve seats take a beating as do all the other valve-train related parts.
I love solid roller cams but for these purposes they are not the greatest choice for a street car that has to idle and run at low speeds for extended periods of time.
Roller cams and lifters rely heavily on "splash" oil feeding. In a racing engine the RPMs are usually run high enough to keep everything plenty lubed.
On the street, when idling or crawling around town, this doesn't happen.
The same thing happens to roller valve springs that rely on lots of oil to help cool them.
Racers usually have spray bars in the valve covers to direct oil on the valve springs to keep them cool.
To me, the biggest issue is the "what if" factor.
If the roller lifter breaks a roller wheel bearing, which, unfortunately happens all too often, it can do serious damage to most of the engine components.
Break a valve spring and you can destroy the entire engine.
(just ask some of the Ford roller cam 514 crate motor customers)
This is not to say that flat tappet cams don't break valve springs,
it is just much less likely.
About the worst that can happen with a flat tappet cam is to have the cam go flat.
When this happens, it goes on over a period of time and is hopefully caught during valve adjustment.
The metal contamination is not good but the particles are small enough to usually not cause catastrophic failure, unlike tiny chunks of roller needle bearings that can jam oil pumps.
Then, add in the distributor gear issue that started this post.
One day, some cam company will make a roller cam with a cast gear for a Ford but for now, we just have to envy the Chevy guys.
For the last few years I have been experimenting with the flat Schubeck composite lifters with great success.
I believe this combination is the best of both worlds, the reliability of a flat tappet with cam lobes approaching those of a roller cam.
This combination is what I suggest for those customers that can afford it.
I could talk for days on this subject but for now I'm done.
--HTH,
--Mike