Assuming similar types, or not assuming similar types. Which do you prefer and why? Which is more common?
I would prefer the one I find at a flea market for $100.00. LOL
I've never run any OHV on a T but this Fronty racing head. I have put 50-100K miles on it since 1997, when it came on the Speedster. It has given trouble only twice. First time, maybe ten years ago, a rocker arm broke in half. I had Shirley weld it together, and it's still good. An intake valve started leaking about six years ago, and I had it surfaced.
Just recently it was time for a ring job, so I took the opportunity to have my head examined. One valve was leaking, and the valve guides were all baggy as bloomers. Took it to John Hollins, Orange County MTC member and engine shop owner. He inspected it, replaced the guides, and ground the valves, found the seats good, and now it's ready to go.
Humble Howard runs a Rajo, and thinks I'm about the only one running a Fronty. That's not quite right. He says Frontys are notorious for cracking. Mine has an inconsequential crack along the top edge, and a hidden water leak into #4 exhaust. I fix that with Aluma-Seal.
My R head is advertised at 100 psi compression (instead of CR), the S head is 80 psi and the T head is 65, as I remember. The R and S heads have 1 7/8" valves, which almost kiss. When Chevrolet needed exhaust valves for their Big Block motors, they chose Frontenac valves, by the Chevrolet brothers. Yup, my valves are stainless.
It's said you can't raise the compression on a Frontenac head much by shaving it, and mine has been shaved. You have to use higher popup pistons to really raise the CR. The lifters are 3:2, so a stock T .240 cam gives you .350 lift. The other .010 is lash.
I haven't seen pix of OHV chambers on here, so I took a few:
Yes, those are rotator cups. They were T cheap, so why not?
I guess they didn't realize the exhaust valve doesn't need to be as big as the intake valve.
The $50 pic is of the head gasket I've had around for years. Used to be I'd lose the gasket between 3 and 4 every couple of years. Then I wised up a little and replaced the head bolts with studs. No more leaking head gaskets.
I'm surprised no one really has a favorite. Apparently there is no parochialism with overheads like with kevlar vs. wood, coil vs. dist. etc?
I did a laurel roof head for a guy in Belgium and that engine had more power than the rajo and frontenac, I am not talking the dual over head cam motor though those are unbelievable power and a price with them, I have only seen one complete dual over head fronty, What eye candy it was!!!!!!
I think there's more discussion within the different models of the same make, than good/bad between makes.
Reasons for OHV:
Higher compression, which gives more power at all rpm.
Better breathing for more power at high rpm.
Dual spark for more complete burning and more power.
Reasons for Overhead Cam:
More power at higher RPM.
Did I miss anything?
I sure like my Fronty but mine is the mild "T" version. To bump the compression, I use the high done pistons. Oh, and an A crank so 1/4" longer stroke. There is quite a variation between the various versions of the Rajo and the Fronty and I don't see either brand as significantly better. There are strong and mild versions of both running around here and I picked mine because it came available, was complete and a good price. If a good Rajo or an S or R Fronty had showed up at a good price I would have been happy with any of them.
Yeah Ralph,.....looks cool!
I have both sitting on my shelf...still undecided on which to use
Ed, that is me, I'm leaning toward the Fronty.
I kinda like my Roof Liberty Eight.
Hey, What about the new one available from Chaffin?
I've never read why he chose to repro a RAJO, and that one in particular.