RAJO head questions

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PetefromTexas
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RAJO head questions

Post by PetefromTexas » Tue Dec 10, 2019 8:15 pm

Hey all, I have an opportunity to buy a RAJO head. After talking with a few people, we believe it is a model B or a C35 head. It missing the intake, exhaust etc. The rocker and valve assemblies are all there though. I can fabricate most everything but I’m most curious about pushrods. Are they available? Are they hard to find?


Here are a couple of pics. Waiting on more.
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Henry K. Lee
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Re: RAJO head questions

Post by Henry K. Lee » Tue Dec 10, 2019 9:45 pm

Pete,

A lot of times it is easier to make your own from YB Ford blocks or early Chevy 216 with a removable ball cup. You then can get drill rod material and cut to fit to your own required length.


Hope this Helps,

Hank

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AndyClary
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Re: RAJO head questions

Post by AndyClary » Wed Dec 11, 2019 12:00 am

Mark Chaffin makes cups that screw into an adjustable lifter, then you can use a standard style pushrod you just need to determine the length.

Andy


Dan McEachern
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Re: RAJO head questions

Post by Dan McEachern » Wed Dec 11, 2019 1:49 am

Just FYI, those are Ford 6 cylinder rockers- not original Rajo. They will need some work to get the geometry at the valve stem end to be even close to correct. Also, that's definitely not a B head.

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Henry K. Lee
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Re: RAJO head questions

Post by Henry K. Lee » Wed Dec 11, 2019 5:33 am

Good catch Dan, I was wonder that myself.

Hank


Kevin Pharis
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Re: RAJO head questions

Post by Kevin Pharis » Wed Dec 11, 2019 11:34 pm

I’m certainly not the RAJO expert... but looks like a C-35 to me. Take a good look at the deck thickness of this, or any, overhead. They have a tendency to have an excessive amount of material removed to increase compression. This one appears to be a bit thin under the plugs, and the short flange too. Maybe someone can post the nominal head height for you to compare


wayne sheldon
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Re: RAJO head questions

Post by wayne sheldon » Thu Dec 12, 2019 3:52 am

More over-head valve heads for model Ts have been ruined by people milling them way too much in order to increase the compression, than almost anything other than being sent for scrap when they were cheap. The really sad thing is, easily half of them never got put onto an engine after they were milled. Many years ago, I knew several people that collected the dern things, and milled every one they ever bought. I met one fellow that had about twenty of the things on the shelf in his garage. He proudly proclaimed how he had milled every one of them! I think in the years I (more or less) knew him, he may have run two of the heads he owned.

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RajoRacer
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Re: RAJO head questions

Post by RajoRacer » Thu Dec 12, 2019 10:51 am

Let us remember that "milling" & "surfacing" are normally two different operations - I wouldn't install any cylinder head without having it "kissed" on a Blanchard grinder.

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Susanne
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Re: RAJO head questions

Post by Susanne » Thu Dec 12, 2019 1:38 pm

Exactly. They did a demo in shop class this year on a head milling machine (using a modern, junked, cracked head) to show just how easy it is to overmill a head in to a water jacket. I also remember someone selling a stock T head that had been milled into the water jacket... :shock:

Remember, these parts were good off the shelf. If you feel the need to pu the CR, there's plenty of room to run domed pistons rather than carve away irreplacable metal. Just saying.

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Henry K. Lee
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Re: RAJO head questions

Post by Henry K. Lee » Thu Dec 12, 2019 2:16 pm

Well put folks on the over milling, Seen way to many destroyed to over the years.

Hank

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rnkugel
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Re: RAJO head questions

Post by rnkugel » Thu Dec 12, 2019 3:20 pm

My C-35 head has a lot more "meat" between the plug holes and bottom. Just saying.
1915 Touring
1926 RAJO Speedster


Kevin Pharis
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Re: RAJO head questions

Post by Kevin Pharis » Thu Dec 12, 2019 10:04 pm

Kevin Pharis wrote:
Wed Dec 11, 2019 11:34 pm
Maybe someone can post the nominal head height for you to compare
Anybody???

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AndyClary
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Re: RAJO head questions

Post by AndyClary » Thu Dec 12, 2019 11:47 pm

I have a model 30 (AKA commercial) Rajo head. Single intake four exhaust ports. The thickness of the head at a head bolt boss is 4.660 inches. There is about a quarter inch between the surface to where the spark plug bump begins. I measured my Mark Chaffin Rajo and the head thickness is 4.690. Looking at the original post I would think it has been milled, maybe as much as .200" .

Andy


Tracer
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Re: RAJO head questions

Post by Tracer » Fri Dec 13, 2019 1:19 am

I have several Rajos and I’m pretty sure that’s a model 30 or the commercial head


Jsteele
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Re: RAJO head questions

Post by Jsteele » Fri Dec 13, 2019 10:07 pm

It is definitely a "C". No bump out on drivers side and oblong or rounded rectangle center port. As mentioned before the rockers are not correct, but that is not uncommon.

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