Projects 3 port Olds on a T motor - Poor Mans Rajo

The other day Idug out my spare bare T block to check out the route to what is known as a “poor man’s Rajo”. The 1921 Oldsmobile 43-A 3 port (exhaust) head is a straight bolt on for the 1920’s Chevy OHV motors, but with a 3/4"-1" thick adapter plate and a bit of machine work can be mounted on to a Ford T block to give , what was, a poor mans OHV conversion for the 4 pot Ford flattie.
It has been done a few times in recent years, was done a lot back in the 20’s and 30’s and so Olds heads have become a bit rare and a bit more expensive than they used to be. I have been doing a lot of research and even found a fella via the MTFCA who has a kit of parts to do the job that he would be prepared to sell me.. that’s great but I can’t afford the best part of $2000 +shipping +import taxes into Scotland nor the headache of explaining why I spent that much on some bits of ally plate and a bag of nuts n bolts to my other half!
So.. this morning I sat the Olds head on the T lump.. lined up the pushrod holes with the T valve guides and surprisingly they are very close to a good fit .. I’m going to nip into town and buy a lump of 1” ply to make up a template to see what is involved. I did download a lot of pics during my research so have an idea of what’s involved, but will need to do some accurate measuring to work out how it goes together. If anyone on here has done the job, or even better has an adapter plate that I can get some dimensions from Id love to hear from you

 

Very cool, awesome project

 

More

 

You may want to search the forum. one interesting post as follows:

https://www.jalopyjournal.com/forum...y-ohv-heads-on-ford-b-blocks-good-bad.177893/

 

Ok then!
Ive been doing a fair bit of searching for info, and asked a few questions on the MTFCA forum and a fella came back with some mods he'd done to an Olds head and set it up for a T block, he sold it on before running it but he did share the pics.
My head has had two rough holes punched in the top into the water jacket as you can see in the pics so, I'll have to either patch them or, more likely cover them with a plate that will double up as a mount for higher ratio 1.5:1 rocker arms and shaft to get more lift out of the stock T cam. This fella covered the whole top surface of the head after milling everything flush, I'll most likely mill the existing stools off and in between each pair then have two smaller plates to cover the holes and mount the new stools on.

 

Just a comment on the 1.5 rocker arms with the T cam. My experiment was with a 16hp OHV Tecumseh [Tecumseh took their FH 12hp engine and converted OHV head with 1:1 rocker arms keeping the FH 12hp cam; 33% more Hp with larger carb.] that I used in Garden Tractor pulling. In theory you gain lift [with tiny bit of duration gain] but the valve opening rate is so fast [re: Violent] you will loose some low end and make the most power little before and little after the stock flathead torque peak. I ended up changing the rocker ratio down to 1.25 and that ended up being a happy medium, about 20hp and did well as long as I geared to keep the rpm above 2500, max around 4k..

 

Looking Good! Black Bob. Though it would look better setting on that chevy block!!!!! The push rod fit is much better than I expected. I had heard from T people that you have to bend the push rods some. I wonder if that is sideways to get the valves into the combustion chamber? Be Safe, Have Fun!!!!!

 

I'm not going to make any changes to the Olds head that won't be transferrable to the Chevy lump. The Chevy motor, once built is going in the same T, it just needs a lot more work to get it together and I want to try the Olds head out on the T lump. I'm looking at modifying the T valves to create longer lifters (effectively a 2 part pushrod set up) that will help line everything up

 

Had an early start today and snatched an hour of quiet time to measure up the Olds gasket and get the sizes into a cad drawing, I can use this and a similar one done from a T gasket and some accurate measuring of the block and the Olds head to create a 3d drawing of the adapter plate.. sitting by the stove with a brew type job.. bonus! I was also looking at the Olds head lined up by eye on top of the T block its clear that there will need to be a bit of modification to the push rods or to the valve guides, which are just holes drilled through the T block casting with no insert. To give the push rods enough room to tilt and follow the rocker arm as well as help deal with the 1/8” difference on each pair of bores front and rear, either the valve guide holes would beed drilled right out to around 3/8” (which im reluctant to do to a healthy block) or stock T valves could have the heads machined down and stems shortened to create lifters that would sit down in the port and lift shortened or custom made short push rods.

 

LOL, Those are the pics of the adapter I owned. A friend of mine bought everything from me so i could recoupe the money on my Fronty Head

Good luck with the project. I researched that whole deal alot, but when a "proper" head became available, it was an easy decision as to which one I would use. There are some pitfalls in that whole deal of the conversion---although I am not sure if the Old's head fixes any of that Vs. the Chevy head I had.

 

HaHa, yes i think I saved them off your post on the MTFCA pages .. useful reference. I looked at putting the '28 Chevy head on the T but the Olds one needs the rockers changed which will help centre the valves over the bore

 

Just by looking at the intake/exhaust runners (versus the intake "caverns" on the '28 head), third exhaust, etc. the Olds head should be a much better performer than the '28 Chevy head... however, there are unconfirmed reports that the '28 head flows better. Herb mentioned that to me years ago, but said that it was just info he had been told (and neither one of us could really imagine that it was true), but I haven't gotten to a point to test both out.

Really looking forward to watching your progress, Bob!

 

Fascinating project. I have no experience at all with t engines, and have never even seen the Olds head you are using. Could you post a picture or two of the combustion chamber side of the head? I'll be following...

 

Thanks

 

A lot of deep thinking!!!!!! Does your Olds head have those two water holes added in the back to match the gasket?

 

Dave, there is in combustion chamber on either an Olds or Chevy head from this period, they are flat, the piston does not rise to the top of the bore in the Chevy or Olds motors and that creates the combustion chamber. that's why a plate is needed to create one on the T lump due to the popped up piston crowns

 

LOL yes, sometimes I'm prone to over thinking !! I like to think it all trough, then draw it, then transfer to plywood then fire up the grinder, mill and the lathe. No they haven't been drilled, I read somewhere that that area is prone to leaking and some people have bypassed it with external plumbing

 

To raise compression, some of the racers of the day simply bolted 1/4 inch pucks to the top of their pistons- there is roughly an inch of squish at the top of the stroke (and somewhere around 5:1 compression) on the early Chevrolet engines, so this would improve compression a good bit.

Bob, Herb (ebtm3 on the HAMB) honed his deck and head , then used copper rings around the piston bores on his block so that he didn't have leak issues. This process is popular with the JDM crowd (have seen it done on a number of OT Honda K24 blocks) and the tooling has become much less expensive!

Using the adapter for the T/Olds conversion will create some limitations on power gains, but overhead valves will still be a vast improvement!

 

Deep thinking is not bad! I do the same as you, think through, draw, use some kind of wood to check. (you can burn wood to keep worm.......and get rid of the evidence of a mistake!!!
I was asking about the holes, because of the two Olds head that I have, both have been highly modified and raced. Neither one has the holes, but both have had problems with #4 exhaust valve and have been hard seated. (that valve only)

 

I've riden in a '26-'27 T with a stock Chevy head conversion. The gentleman lived in a very hilly section (think like a mini San Fransisco) of Connecticut. He never used low gear other than to get going from a stop. The hill power was very impressive and GPS 45-50 mph was impressive for what was a bunch of used parts. I forgot what carb he had on it, but it was obviously too small by the way you could richen it and pull the choke on slightly and it would pick up even faster.

@Mac the Yankee , here is some compression for ya , but custom for the Fronty Head.
.

 

Just as a note of interest, Ak Miller and his brothers ran a Chev roadster, I think a '31, with an Olds head. The first time out, Zeke was supposed to be the pilot, but as Ak put it, "Zeke got a case of the wobbly knees", so he drove. Ak was 14 at the time.

 

I'm with you on the pre machining process... I'd be really interested in hearing/seeing what has been done to them, if you would be ok sharing? I plan to cut new valve seats to suit bigger, possibly SBC valves depending on what fits without issue, my head is bare and also needs repairs to the top (that can be covered with a plate that will support new rocker supports) so I'm all for building in good mods where I can

 

Chad, that's a sharp looking T lump!

 

So very much like the 348/409 but without the angled block deck. Neat! And diesels.

I imagine that you could get some serious compression simply by changing the thickness of the plate. Or like a diesel, get some squish area with pistons made with a recess for valve clearance and the combustion chamber.

Very interesting

 

Back when I was messing with Model T's, it seems like I read about guys adapting the complete Chevy engine to the T oil pan. Does this sound right?

 

I'll see what I can put together.

 

No pics... but I have heard this done before. Both back in the day... and fairly recently. The Chebby is only bout 160”... but with an A or B crank installed can be 180” or so. And the head bolts right on...

 

One has to wonder who was the first person to sit looking at those parts thinking to himself, I wonder if I can get that head onto that block? And probably pulled it off without a full machine shop. It boggles the mind!

 

Most impressive, Sir!

 

Ive got a complete and a less complete '28 Chevy motor and a spare T oilpan and trans that I have been messing about with to do this, I just fancied seeing how much fitting the Olds head to the T would take and what sort of performance increase i'd get. .. I guess the first guys to do it had a much bigger scrap yard to play with and had less worries about rarity to hold them back