In search of parts associated with converting a 1928 Chevrolet cylinder head to bolt to a Model T block. I already have my own head, but I'm in need of the adapter plate, water outlet/thermostat housing, and pushrods.
Philip : i built my own adapter plate ...I digitized the T cylinder ,valve and bolt pattern and the same on the Chev. head ...I have not tested my new revision with the smaller chamber in the adapter plate ,but the old design worked well...I used 216 Chev. pushrods that I shortened and I cut a concave radius in the T tappets to position the bottom end of the pushrod ...I will try to add photos this evening ...always an optimist...gene French 970-581-2808
I'm assembling one right now too. I'm caught up on trying to find the front water outlet. I may have to make one, because they don't seem easy to be find.
Gary Wallace is the best source going for this era of Chevy part:
Most of this stuff is out there, you just have to dig to find it. If he doesn't have it, he can usually point you in the right direction. Your best bet is to call and leave a message if he doesn't pick up.
Gene any chance you share your drawings
I will be building these for sale when i get some of my other projects finished ( including building a house)...I won't be sharing my drawings... several months ago there was an adapter plate on ebay with drawings , from what I could see by zooming in it looked like a lot of fractional dimensions and dimensioning from another dimension ...the plate sold high for what I could see ...BUT , someone has a drawing for that particular plate ... maybe someone on this forum ...not me but thanks for the inquiry ... always an optimist...gene french
I do have very precise drawings for the adapter plates and depending on cost may be able to provide some shortly.
These drawings are not the Jern plates but an other machine shop that for some reason made the drawings and plates back in the 70's.
I have a couple 3 port Oldsmobile heads and plan on installing them on T blocks, therefore my reason to try and make some adapter plates.
Once the cnc program is finished I will have a finished price.
Gene sound like your pretty busy.
BBC I be interested in one if they ever come on the market
Back in the early 90s I had a Jern thunderbolt
Kept blowing head gaskets so I sold it
I will try to add photos of my original design and new "small chamber" ( probably too small chamber )cylinder head adapter and the push rod that I used and will use with the new plate ...the push rod is built from a too long 216 cubic inch Chev. 6 cyl. push rod ...there is a photo of the T tappet that I cut a radius into for a tappet ...I did this in my small lathe with a 1/4" carbide ball mill ...I plunged .150" deep then offset .015" to make a .265" diameter concave radius for the pushrod seat ...hope the photos show some of this ...also I still need to cut a arc segment clearance for the spark plugs on the new chamber and radius the transition between the valves and cylinder areas and cut the outside profile ...all is done on a cnc mill and is repeatable ...I will probably hand cut the radii in the chamber area ...then probably end up re-cutting the chambers to reduce the cyl. pressures ...always an optimist...gene french
also , I did not forget the holes for the pushrods or water passages in the new small chamber adapter plate ...I have not done that yet ...always an optimist...gene french
I just picked up two Chevy heads last night. They are available, and I can take pics. Thanks
I have noticed on my head that the fins on the outside of the chevy head are in difficult places. I might need to groove one a little bit to get the push rods to clear.
OK, now I'm curious. I have a head sitting on top of a T block. Not all the rockers line up with the T valve guides---they spread further out towards the ends. Is there mods made to the block to run a one piece pushrod? The way I was looking at it was to run two piece push rods.
I also was going to make a plate out of steel to keep similar metals/expansion rates, Gene, is yours aluminum? What gaskets would you use? I was hoping to use the commonly available Rajo style gasket on the T block and the stock Chevy gasket up top.
Your reduced chamber plate is very interesting indeed.
both plates are 6061 T6 aluminum ...I used home made paper gaskets on my original big chamber adapter plate( 20mm thick plate) ...the material was .015 thick and I soaked gasket stock in oil before installation ... probably compressed to about .012 or possibly a little less ...did NOT blow or leak BUT the block was flat , the plate flat and the Chev. head flat ...my big chambers had slightly over 60 lb. pressure at cranking speed ( cheap gage )... I am planning on using "O-rings" with the smaller chamber plate( 1" thick plate)...regarding rocker arm alignment ...I bent 2 of the rockers to align ...( only needs a slight bend )...you will use a waterpump with this application ...always an optimist...gene french
I think that the push rods that you could buy from Jern were 2 piece. The bottom rod fit in the old valve guide hole with a ball socket that the upper piece could be placed in and off set to line up with the rocker. Looking at the ones that have passed thru my hands, you are correct that not all the rocker arms do line up. I was thinking along the lines of Gene, just bend the rockers to line up.
I have all so a full set of drawings for the plate but I am not at liberty to share. They do not include the water inlet piece. Some of the dimensions go down to 4 and 5 places behind the decimal point. I wittled a water outlet out of a block of aluminum.
The first plate I had was steel and not finished, was just too much needed work for my skill level at the time with no drawings or plans to help show what was needed. The 2ed one, the hole for the pistons was really not done correctly in what I had learned, the Ford pop up area should have been off set from the Chevrolet valve area so both the stock Chevrolet and Ford over head gasket could have been used. Because of the small water passages between the Ford block and Chevrolet head, I plan on adding at least one more water passage pipe between the Ford inlet behind an Atlas water pump and back of the Chevrolet head.
Side note; check the valve action before you go to far. Some of the plates may work great with the smaller 27 and earlier heads but may not work without some fitting with the larger 28 valves.
That was my understanding of how Jern's pushrods were also and would be very easy to duplicate. In the high performance world there are a handful of pushrod suppliers that will make anything you want for not alot of money. Ball and cup end pushrods are quite common in that arena. My last set of v-8 big block Chevy pushrods were $160/set for custom length .080" chromoly 3/8" rods
It would be nice if someone would rejuvenate the "poor mans Rajo" setup and bring them to market again. I do understand there is a ton of time and effort as well as machine work involved. Hoping that CNC can bring down the price of these compared to Jerns setup and use more commonly available gaskets vs. special ones. Those were the two issues I had with Jerns setup---price and special gaskets.
With Jern's passing it's a bugger for guys with his plate re; gaskets between the head and plate (both the T and A applications). Yes you can get them made by places like Olson's Gaskets but are longer an off the shelf item. The gasket needed between the Chevrolet head and plate on the 2ed one I had, would have had to get custom made which was another cost that I could not afford. I feel that any gaskets that would be used should be off the shelf items that can be gotten from any Ford or Chevrolet parts supplier ie; Ford over head gasket (I think RAJO) and standard Chevrolet gasket.
That looks great.
What parts are needed for a successful conversion, i.e. carb, in-ex manifold , ect.
Chevrolet head with rocker arms (preferable; 1928), Chevrolet intake and exhaust, gaskets, adapter plate, new exhaust pipe and muffler to fit Chevrolet exhaust, push rods, modified lifters, piece that goes between the Chevrolet head and Ford water outlet, updraft carb to fit Chevrolet intake, adapter to between the two or turn the the flange90 deg's, fuel pump, water pump, new connection between the carb an throttle.
Google mtfca; poor mans RAJO or Chevrolet over head.
what kind of power gains could one get from this setup?
That I can not tell you because a lot depends on the plate thickness and design of the opening over and around the valves. Off the top of my head would be around 4+ to 6 to 1 compression. Then you would have to factor in lift of valves, larger valves with 28 head and what carburetor you use. etc
The truth is I am not qualified to answer that question any more then what I suggested above.
John this make a poor man's Rajo
Performance about the same as Rado just not the costly