OK...which head is better?
Looks to me like the Rajo has a better intake port setup but otherwise they look very much alike.

The durability of a RAJO is superior to that of a Frontenac or Roof head. Opinions may vary.

Mark,
What is your criteria for durability? I don't hear of any of them breaking.
John

Lol Mark may be slightly biased in his opinion. =)

Until you're WOT, Wide Open Throttle, above 4,000 rpm, compression ratio is what mostly matters. Then breathing is more of a factor. The Fronty R head has 1 7/8 valves, while the Fronty T head has 1 5/8, IIRC.

Mine broke a lifter once. Had it welded back together.

Both heads will make a Model T go faster than you want to drive it. The webbing( valve seats used to crack and break in the 16 valve DO Fronty's, probably the other 16 also. On the overhead cams chain drives broke busting housings. A lot of heads cracked, both 8 & 16 valve. I think most of these problems occurred from racing hard, speculation on my part. I bent two valve in a Rajo C. I think it was a lube issue and my own fault. Today I think most of these heads will run a long time without issue if maintained. Most of us will never push them as hard week after week as they did in the T racing days.

Faster than you want to go is right! Have ya'll seen this video? http://vimeo.com/20247765

Just spinning out could KILL you.

Seth is absolutely right! I do have a bias. When we decided to reproduce an overhead valve cylinder head a lot of thought and consideration went into the process. We inspected several RAJO, Frontenac and Roof cylinder heads to make an informed decision. Our investigation included inspecting several of each that were damaged to the extent they were beyond repair and could be cut up to inspect them internally. Long story short, the RAJO overall wall thicknesses of the castings were more substantial than the Frontenac and the Roof. Also, on two separate Frontenac samples, cracking was evident in the wall area separating the individual exhaust valve ports leading to the combustion chamber. Of the three brands, the RAJO heads we inspected appeared more substantial in overall construction.

Another interesting observation was the rocker arm assembly. Most of the eight valve cylinder head offerings by both Frontenac and Roof have a smaller diameter rocker shaft compared to the RAJO. They also have only one rocker tower bolt per rocker stand as opposed to two bolts per tower as seen on the RAJO Model 31, B, BB and BBR cross flow heads.

Lastly, I have inspected and evaluated many RAJO, Frontenac and Roof cylinder heads. Although many were of the RAJO variety, I have also inspected and evaluated many Frontenac and Roof heads. Overall, the Frontenac and Roof heads had visible repairs to both the cylinder head casting and rocker assemblies. I believe that would speak to the durability of each head. Don’t take my word for it. Do your own investigation just by reviewing past posts on this forum showing images of RAJO, Frontenac and Roof cylinder heads. I think you will find a lot of the Frontenac and Roof heads show signs of obvious repair whereas the RAJO images do not.

Additionally, I would like you to consider this last observation. Over the past forty years, several folks have reproduced one version or another of the RAJO (five including ours). I have yet to hear of a Frontenac or Roof reproduction. Maybe they came to the same conclusion we did.

Again, I am just offering an opinion and opinions do indeed vary. I think both the Frontenac and Roof cylinder heads will give good service; however, I prefer the RAJO and always will.

Bob we need to take this question to the track (or street) Call Walt and set up a race! I will be there cheering you on and watching for cops. Not sure it will prove which head is better tho as I'm not sure you or I would have the guts to run at the same speed Walt's car. He has front wheel brakes (thats cheating!)

It really shouldn't matter what brand head you reproduce. Just because weaknesses were found in the original Fronty's, it wouldn't mean that you would have to repeat them. Especially since the test of time has made the problems known.

Going fast is fun but going 80 in a car with 25 MPH brakes kinda takes the fun out of it!
I put discs on the back of my speedster so now I can lock 'em up at 80 but it still doesn't slow down much.
I don't think I want to race Walt or you either Mike.
Another subject...my Rajo has a weld repair and my Fronty doesn't.
I know this is just one pair of heads.
I'm not hassling Mark Chaffin.

I had heard that Rajo's heads were cast at John Deere's foundry. Is there any truth to that? If so, I'd say that they probably had pretty good facilities for the time.

Actually, Joe Jagersberger worked and raced for CASE. After being seriously injured while racing for CASE, he went into manufacturing the RAJO equipment. There is some indication CASE did allow the RAJO Motor and Manufacturing Company to utilize their foundries to cast their cylinder heads.

Good point Jerry! We did just that with our RAJO. The wall thickness between to exhaust valve ports was increased from an average of .100 thickness to .200. The thickness of the deck was also substantially increased.

Ralph,

I didn't measure the diameter but the valves on my Fronty T head couldn't be more than 1/16 larger or they would be kissing each other and the sides of the combustion chamber.

Of course the head may have been modified at some time too but I didn't notice any obvious signs of that.

I wish you well.

Walt

I own & run a BB on my Racer and I've driven several Fronty's - I don't notice too much "get up & go" difference. I have a full pressure R Fronty in the shop right now (first Fronty head I've separated and had "hands on") and did notice that one of the head bolts/studs goes RIGHT THROUGH the intake port. I find that peculiar !

Walt & others - how do/did you seal that particular fastener from sucking air ????

Steve,

To tell the truth, I don't recall doing anything special just a stud (like the rest) with a nut on top. Maybe I'm dumb or lucky or both.

While you have it apart, could you measure the depth of the combustion chamber and let me know what you find?

Walt

I don't know what all this discussion is about...valves being 1/16 larger than another. By modern standards OHV heads are standard...or almost obsolete. 16 valve heads (4 per cylinder) are the vogue. That is what a Roof 16 is. Whether a T needs all that breathing is subject to question. All of these heads add to the volumetric efficiency of the T engine... whether it needs it(or can use it) or not. I like my Roof 16 because it is interesting..don't know whether it is better/worse than the others.

I use a washer under the nut, Steve. The stud adds needed turbulence....

The modern idea with 4-valve heads is to get the spark in the center of the chamber, to allow higher compression with same fuel. It's even better than dual plugs in a 2 valve head.

The chamber is just under an inch deep in my R head, and it has been planed.

John - No problem from my side. I wouldn't kick any of the vintage OHVs out of my garage. When Dave first mentioned building his repro RAJO I was on his interest list and would have liked one but I found a deal on the Fronty first. I've liked watching the rockers work all those valves on the Roof and they look fun. All of them will help a T accelerate quicker and go faster than it ever should. I don't plan to find the upper limits for speed on my car, it will go faster than I feel safe which is nice to know but I feel no need to test it (well at least as long as I can outrun Mike).

Just here to have fun be it with 20 HP or more as fits the day.

Walt

Walt (I heard that last part!) lol!

The RAJO comes from Racine, WI. There were a number of foundries there including Belle City Foundry where my friends dad worked. RAJO is also across the street from Modine Manufacturing. Also home to Jacobsen, Massey Fergusen, etc.

Also interesting that the Johnson Wax headquarter building built by Frank Lloyd Wright is just down the street.

Frontenac equipment ran in the Indy 500 for many years and placed well. No RAJO ever ran Indy. This is the answer to the original question!

I have had many RAJO heads and have many Fronty's. The RAJO line has more examples of commercial equipment than the Frontenac line. Frontenac equipment is more for race track and was ran harder and longer.

I don't think either one is better today as we don't make money on the race track and are not going to run wide open without proper cooling and destroy castings. The only interest is what head is it--a commercial truck head or a speedster / race head. Not many would know the difference and only see the aluminum cover.

Tim weren't all the Fronty's that ran at Indy DOHC or SOHC heads?

This has become a very interesting thread.
I've learned a lot.
Just measured the combustion chamber depth on my T Fronty.
It's 1 1/4".

Will do, Walt.

I can add that a fronty head is easier to sell. I can also add that the price of original rajo heads has gone down significantly. I am glad I divested of those before the reproduction came out. I really don't understand the price drop, as I would rather have an original iron one than a reproduction in aluminum. This is not a knock on mark's project, as this was quite an undertaking.

Finally , I prefer the look of the fronty, always have. This from a guy who would never test the limits of either one.

John, The Frontenac Model R head was used at Indy in 1922.

When did production of Fronty heads start and end?

Bob,

I think the patent date is 1919 but they really were not manufactured until a few years later and as stated they started running the Indy in 1922 with a single port R head (that finished I think 3rd). The single cam conversion actually didn't come out until 1928 and the twin cam heads were around in 1925. There was one last Fronty for the Model A called a "stagger valve". This was a dual overhead cam but the intake and exhaust ports were on both sides rather than all intake on one side and all exhaust on the other like the dual overhead for the T block. The twin cam Fronty for the T cracked due to uneven heating and steam pockets that would form in the top of the head (but remember a DO head would most likely run flat out during a race). Most DO heads were drilled in the top by the owner and threaded pipe nipples were installed for a water circulating manifold to get some of the heat out of the head.

I agree with Tim it is probably easier to sell a Fronty than a RAJO. It would be interesting to see some flow test on the various heads. I still think for most you could take the lowly RAJO Model 30 and it will give you more speed than you want with a T.
Were there any difference in the Fronty's T, S or R besides the volume of the combustion chambers?

Here is the patent drawing for the 1st Fronty. The patent was granted in 1921 but Chevrolet and C. W. Van Ranst apparently started working on the head in 1919 and 1920.

"Which head is better? " That is a question that needs to be narrowed down. Better for durability, or for more power and winning races?

I have owned a number of Fronty's and Rajo's over the years and can see advantages for each design. I now have a Fronty SR and an original Rajo BBR. The Fronty has always been lighter but weight reduction is one of the keys to winning races.

It would be interesting to run the two in back to back dyno runs on the same engine with a similar intake manifold, the same carburetors and a same length exhaust pipes to see how the horsepower numbers stack up.

You can learn much more about all many of these heads in a series that we are running on The Old Motor called "Model T Ford Speed and Racing Equipment" @ http://theoldmotor.com/?s=%22Model+T+Ford+Speed%22 and @ http://theoldmotor.com/?p=102142

John,

The T and S head have the same size intake port but the R is a little bigger. I was incorrect about the 1922 Indy, the Fronty powered Ford racer placed 5th not 3rd.

Frontenacs are better. They are better because there are fewer ways to mis-pronounce their name than Rajos.

Frontys are usually pronounced:

Front-tea (correct) IMHO or Front-ten-ack (correct) or Frond-tea (incorrect) or Frond-ten-ack (incorrect).

I've never heard one called a Frond-ten-ock, but maybe someone has.

Rajos are a contraction of Racine and Joe, so should be pronounced Ray-joe.

I've heard them called:

Rod-show
Rad-show
Raid-show
Ray-hoe
Raw-how
Raw-joe
Rad-joe

all incorrect.

Tom almost has the best answer except...my last dog I named Rajo but he always said to me "Roof, Roof, Roof". Now I think he was telling me that the best overhead conversion was a Robert M Roof head.

I give up now and am all confused.


Tim Moore

I took a tour at Speedy Bill's museum in Nebraska a couple years ago and asked the docent how you pronounce Rajo.
He said almost exactly the same thing Tom said.
Mike Conrad...are you reading this?

Tim, does your dog say "roof" to rhyme with "proof", or "roof" to rhyme with "hoof"?

I don't know which is correct.

If you go to Wisconsin and ask anyone from Racine how you pronounce it they say "RAY scene". My guess is it is pronounced "RAY JO".

I am reading this! I think if you can't pronounce it right you should go buy a fronty or is that fronny head, now if only I could convince Bill Bender! He and his Dad always thought it was raw-jo. (I think Bill says it this way just to get my reaction tho) lol!

this discussion came up a few years ago, and at that time someone who lives in racine said even the locals say it both ways..raw cine, and ray cine, so, for once we can all be right!

Clayton said: "this discussion came up a few years ago, and at that time someone who lives in racine said even the locals say it both ways..raw cine, and ray cine,"

Since even the locals don't know, that proves Frontys are better!

(Actually, I like them both.)

Frontenac's were built by Louis and Arthur Chevrolet.

We all know the best way to make a Ford go fast is to use Chevrolet parts. ;)

To anybody who speaks Spanish, ray joe is just wrong when spelled Rajo.

probably a lot of spanish in racine today, but i'm not so sure about it in 1920 !

I was just able to take some measurements on my Rajo combustion chamber depths. Here is what I found:

Rajo BB: 1.00" deep
Rajo BBR: .875" deep

Exhaust ports: 1.5" on both
Intake Ports: 1.69" on both

Exhaust Valve diameter: 1.75" on both
Intake Valve diameter: 1.94" on both

I had new valves put into the BB. The BBR is believed to be NOS. I have no way of knowing if either head was shaved.

Can anyone post details on a Fronty R and SR dimensions? It would be fun to put the Rajo and Fronty heads on a flow bench and see how they compare.

Our research indicates the factory chamber depth of the RAJO Model BB was 1.125 (1 1/8") and the BBR .875 (7/8"). Like you said, your Model BB may have been surfaced at some time. Was also a common practice to increase the compression by speed chasers back in the day.

Your intake and exhaust valve diameters are also correct. Although most Model BB heads have an intake port diameter of 1.69, I have seen a few with stock ports at 1.250 (1 1/4"). Not sure why some were made with a smaller diameter intake port.