After much thinking - and my head hurts, I've decided to take everyone's advice and put the car back together as it was originally built. I have another block now. I really need your help...
Question #1: I found a template for the 1st head gasket under the adaptor plate. It requires two holes drilled into the block for the chevy 348540.
Can I use this head gasket from Ebay and punch the two center water jacket holes? The adaptor plate will cover the unused "T" water jacket openings.
Question 2: Here is the heavy duty adaptor plate. Upon removal, two of the closest to the cylinder head bolts were filled in...with something gray? It wasn't lead. Can anyone guess what it was or what should be used?
Question 3: Here is a copper template for above the adaptor plate. Can I have a "real" gasket custom made with cylinder ring seals?
Here is the actual over the adaptor head gasket that was used...yikes. This leaves adaptor plate head bolts exposed to water jacket areas.
Here is what looks like an original gasket and the head for reference...
Any comments or advice is GREATLY appreciated!
Jim, I think you've pretty much have pushed past the interest on this forum with your last questions. I'm surprised no one has responded back with " if you want to use a Chevy head you should have bought a Chevy". You're better off on the H.A.M.B. or if your'e into social media on Facebook there is a group "Banger Hot Rods". There is a resurgence in interest in the 4 cylinder hot rod, Ford, Chevy & Dodge, so you shouldn't have an issue finding help.
I will say from the pictures that there appears to be no attempt on the adapter plate to accommodate the offset in the Model T cylinder bore and the Chevy head. I believe the new adapter plates made by the late Neal Jern did accommodate for this difference. Good luck
Okay, I think that I can use the Jern Thunderbolt head gaskets even though my adaptor is custom made. That should solve a couple of issues.
I'm still concerned with the clearance of two of the adaptor mounting bolts to the cylinder, the need to fill over them, and how retorquing will be accomplished.
Oops we were writing at the same time. Thank you for your honesty, Joe.
That wasn't called for Joe. In spite of your surprise, I've been following Jim's progress on this very cool MODEL T Racer with great interest. I just wish I had the answers he's looking for.
Please keep us updated on your progress.
regarding torqueing the adapter plate ...I used an aluminum plate (my own fabrication from 20mm ground plate)to adapt the chev. cyl head ...I used a .015 thick paper gasket between alum. plate and 27 T block ...torqued and retorqued to 60 lb/ft using a cross pattern in tightening the socket head screws that correspond to the T cyl. head bolts...the 2 drilled water passages at the center of the T block that are drilled to correspond with the chev. passages were drilled at 5/8" diameter and did not interfere with the counter bores for the 7/16 socket head screws ( if drilled at the 1" diameter as the chev. head casting they interfere) ...anyway , I would torque the adapter plate , fill socket head counterbores with RTV , let the RTV cure , then install the chev. head ...also I used 216" chev. pushrods ...shortened , with a ball end cut at the tappet end ...I used a 1/4" ballend endmill to cut a shallow spherical socket into the Ford solid tappet ...also the adapter plate was machined with the cyl. spaceing to match the Ford block with valve clearance cut to accommodate the chev. valves ...this works well , although I have only run this on the bench ...no long term road use as yet ...hope this helps ...always an optimist ...gene french
in addition to the basic aspects of installing the chev. head on the T block , it should be mentioned that the Chev. rockers / valve train use a felt plotter to oil the valve train members ...even antique chev. owners forget this sometimes ...you will get to be pretty good with an oil can ...always an optimist ...gene french
I'm curious for your progress as well. This forum has folks with a variety of interests regarding the T from proper and accurate restorations to full flight racing modifications related to the T. At least some of us will be interested in watching what you do with your car.
The adapter designed by Neal Jern used the standard overhead gasket you show in to top photo between the block and adapter plate. It also uses a standard 28 Chevy head gasket between the plate and head. Of special not is that the adapter plate has offsets built into it so that the top of the plate matches the Chevy head so the gasket fits nicely.
It rather looks like you will need a custom gasket between the plate and head. You may get by with the stock Chevy gasket but I'd be looking carefully at how it matches the plate. If there are fire rings in the gasket, will they really line up correctly? Depending on the final compression ration, you may get by without fire rings in the gasket. Sorry, wish I had a firm answer for that one. Would be interested in what you find that works.
No offense taken at all guys.
Gene French...Excellent info, and accurate my friend! My first pic shows the template with the new coolant holes to be drilled, that I believe to be 5/8" just as you say. (Still nervous about drilling holes in the new block and needed someone to chime in).
I ordered two overhead gaskets today.
You recommend RTV? There was something else in it's place that looked like lead upon removal of the adaptor plate 8 years or so ago...I had to dig it out. I'm thinking JB Weld or similar which I've read is good to 700 degrees. I thought of using USC All Metal but it isn't recommended past 400 degrees.
You are right about a custom upper gasket. The Jern top gasket is larger but $105 is a big chance to take to just touch it.
Gene, I should also add that this car was clocked at 65mph with this chevy head and it ran and ran and ran and ran on that original style '28 chevy gasket before failure. I just want more gasket coverage under the Chevy head and to seal off what you call the counter bores. I was also concerned about retorque AFTER counter bores are filled but thank you so much for addressing that. I've been reading about using a weedburner, retorquing or firing up without water, then retorquing.
Two additional holes had to be drilled on the outside of the block and the side of the head, and were interconnected with tubing to keep it cool. I have the felt pads too.
Walt, looking at the Jern site seems to reveal that they went to a fuller chevy gasket which actually encompasses all of the chevy head bolts unlike the stock gasket.
You are right though, the stock chevy gasket overlaps into the combustion chamber and intersects the "fire rings". It worked for a while, I just want to do just a little better.
Thank you guys. I'm building a second car for myself and have decided to keep Grandpa's legacy intact or "as is".
Here are those external water lines. I guess they worked although not beautiful. I think he ran a water pump with no fan.
That's one cool project. I enjoy reading about your progress. I look at the old Chevy head as a period style modification, similar to a Rajo or Fronty (made by the Chevrolet brothers, famous for racing Fords).
i am interested in watching this.
Great progress so far and interesting thread. Also great choice to remain true to the history of the car - if it was my grandfather's I would like to duplicate how he set it up. If you can do it so it is a tad more reliable, he would have been proud!
This is definately a part of Model T history and a known old timer approach to OVH conversion.
Jim, at a minimum my sarcasm brought your post back to the top. Attached is a picture and a link t0 a video of my car. It's an original the best I can tell, I can trace back through some of the previous owners but I have no history.
As far as your car being safe. The AARA organization in which your car ran required a fairly stringent safety inspection, albeit the drivers wear nomex and a helmet.
That is gorgeous, Joe. There's a lot to be ogled at there! Those are cool front friction shocks?
When I used to work in California, I remember packs of the old Cobras ( mostly replicas) flying down the 101 together. How cool would it be to see a pack of these old racers running together down the road!
Thank you Steven and Eric, I agree.
any new news on your speedster/racer project?
it is always interesting to see the innovation that went into others work , both the current examples and the period ...keep us updated on your work ...always an optimist ..gene french
Thanks for bring this back to the top, I missed it the first go round.
I am in the planing stage with most of the parts on hand doing the Chevrolet head conversion. I will be using the steel overhead valve T head gasket between the block and plate and steel Chevrolet gasket between the plate and head. I am planning on milling and putting freeze plugs in the water passages that are not used in the head. The large round ones are about 1 inch now. The outside water pipes, I was thinking along about the same line. Only I was going to run one from the water inlet tube to the back of the block. I will be using an Atlas water pump.
Right now we are re-working the valves for a Thunderbolt conversion on a Model A. It's having a problem with the top 3/16 of the valve stem shearing off, we think it's because of how the stem was shortened. Or, the springs and keepers may be part of the problem. The springs are not staying centered under the keepers or the springs are just too strong. My head hurts too!
Is it necessary to use a water pump and have those external water pipes with this conversion? i have the head but no pump or pipes.
Like I told Tom at the shop, some of these questions are hard to get replies too as there are a lot of us "in the process" but not on the road.
My thinking is because of the small water passages between the Ford block, plate and Chevrolet head, the ones that are actually used, adding at least a rear "extra" pipe to the back of the head might be a good idea. If you look at the photo above with the adapter plate mounted on the block, there are/should be two 3/8 holes in the rear *SEE NOTE, the 2 center holes and two 3/8 holes that are under and go into the front adapter block that the water outlet is mounted to. The other 4 holes that are between 1&2, 3&4 to the outside are not used. In fact (why I am going to install plugs) the plate to block mounting bolts are exposed to water if you use the Chevrolet head gasket on the one side. (The black dots in the two lower holes)
As far as a water pump, time will tell. The Atlas seem to do a good job of pumping and because it mount on the front of the engine with a longer pipe between it and the stock water inlet, makes it easier to try the extra piping off there.
*The instructions from Thunderbolt says to add one more hole to the rear of the Chevrolet head, if you don't you only have one 3/8 hole for rear water passage as one of the holes in the head ends up being over a mounting bolt and hole.
Sorry guys, I just got back from a missions trip to Mexico a couple of days ago, then got tied up buying more shop space at a real estate auction.
Prior to that though, I did drop the engine off with Kevin Prus and his gang here locally. They had some good suggestions.
This set up was tried and true. It was raced and stayed cool using a water pump and no fan.
One of the things we're going to do differently this time around, is that instead of drilling the side of the block for the external water cooling passages, they're going to tap and use screw in plugs in the 3 existing "freeze plugs" in the side of the block. There was concern as to drilling and tapping that area just below the head. The casting there is very thin. Tapping the freeze plug passages will give me an alternative to run the external water jackets.
I'm impressed by my grandfather's adaptor design because it does not expose the adaptor edge to the combustion chamber, which can potentially cause a preignition issue(hot spots). I plan on using ebay RAJO gaskets with 2 additional water passages in the center.
I'm waiting for the engine to be rebuilt, then I'll have the transmission alignment checked in the pan.
Just wanted to report that I'm back at it again. I mounted my adaptor plate today. I used My Niagra punch to put the two water jacket holes in the Ebay Rajo overhead gasket. I chased all of the threads on the engine and adaptor, cleaned, and sand blasted all of the head bolts, and only the 4 recessed holes in the adaptor plate that will be filled in before the next head gasket goes on (I'm hoping for good adhesion). Torqued to 55 lbs with light oil on threads, but crept on it in stages..
Just being cleaned up makes it look a ton better. Keep it up!
Nothing wrong with the all copper head gasket, clean it up anneal it and go again. A lot of the old diesels used solid copper head gaskets with a lot more compression than a gas engine. Nice project, good luck. KGB
The pics may be deceiving. I have my engine back from being rebuilt. I used the permatex spray copper gasket adhesive over a new steel gasket and steel adaptor.
I did this conversion last winter and used Mr Jerns steel plate and his lower and upper head gaskets, without any problem, been driving a lot this summer. Water and compression tight, but i pre heated the steel plate several times and re draw the bolts. Also used studs instead of bolts to bolt the chevy head down. I do not use a waterpump but have a new radiator. Check for steam pockets when filling radiator/engine. I run without a thermostat.
Perfect info Thomas. That's why I'm documenting, so that others may catch what I may miss. This morning I went out to the shop and put a little heat(not much) on my adaptor. I retorqued, and had lost as much as 10lbs overnight. I'll keep thinking up over the course of a couple of days.
Question Thomas...did you see the copper tubing in the pics of this thread running from the block to the head? Are you running any cooling connection externally other than the cooling holes in the adaptor?
Jim, i do not run any externally cooling connection except for the kidney formed one coming up from T block, going thru the steel plate and into the Jern fabricated thermostat housing. Your plate do not seem to have those holes.
I tried to laborate with the original Chevy head gasket and the model T OHV copper gasket but felt that the easiest way was to use Jerns gaskets.
Greg Sabourin, a companion with Mr Jern, took over the business, you can have his email address if you PM me.
You're right, I don't have that front water port. I'll have to tap my freeze plug ports and route them to the head. Thank you for your help!
In my opinion this is a proper Model T racer project. As it was (in period) so it shall be. I am over blokes telling me just how good their T racer/speedsters are that are modified & modernised to great effect no doubt but are they the real deal, not in my book. A big noter turned up at an Australian historic race meeting with a T fitted with an A crank, a modern distributor and 2 1.5 inch SU carbys and called it a 25 T. I still had his measure with my bent wire and as built 18 engine, if the Chevy head was built pre 27 then go for it just as a young hopeful would have done in period.
My thought is if you want to go fast buy a fast car don't take the heritage from a real car.
The standard Chevrolet gasket has a circular hole for the bore...why does the gasket shown have an offset section at the plug area? So does the Jern gasket...perhaps the same as shown.
That is a Jern gasket and i have been wondering my self about the offset section. Someone?
Is the chevy head placing the spark plug away from cylinder bore and you do not want the plug to spark above the head gasket..?
If you are following this thread, you may become inspired to install one of these yourself. There is one complete kit for sale in the classifieds.
Thank you, Doug. I will take that as a compliment. I'm not a purist by any means. Just putting Grandpa's car back together as he built it. It's kind of an emotional journey for me as I struggle to figure out how everything works and is put together. He used home made gaskets, and adaptor and it worked.
I found this AARA tech inspection sheet under the seat yesterday. It is a real treasure for me...
I rechecked my adaptor torque this morning and everything has finally stabilized at 55lbs.
Today I nervously, and after practicing on another block, drilled and tapped the freeze plug ports for 1/2" NPT. This will give me more water flow options since the head is externally tapped.
I also received a new '28 Chevy head gasket today that I think I'm going to try. I don't ever want to have to take the adaptor off, but the head gasket I'm willing to experiment on.
That looks like a great Chev gasket....where does it come from?
Ebay was out of stock so I got it from BronxAutomotive.com
It got here quick, and it's a super nice gasket compared to the others I have for the Chevy.
This morning I went back to "the hoard" looking for my missing water pump and FINALLY found what he used to fill the adaptor head bolts, and possibly coated the head gaskets with.
"Caterpillar High Temperature Manifold Sealer"
I've been guilty of making fun of people who use JB Weld, :P but here I am using it to fill the adaptor head bolts. It seems like the best candidate at a 550 degree rating, and sands well. I've used epoxies quite a bit and I just don't trust them in this application. I'm adding a second coat to fill any imperfections.
Here is the new head gasket on the plate. She is offset but this configuration has worked and has been raced...
Been going through the entire fuel system as well, Including cleaning the tank. It was entirely gummed up solid.
Wish I knew what this seat shell came off of...
Well after 22 years of sitting, we got her fired up and she ran and idled like a kitten for half a minute(no water). Looks like I got the mag timing correct. Tach, kill switch, fuel pressure, everything worked as it should. We were going to tow her but got her started on the starter. I'll retorque the head, build external water passages, and start attending to the little details. I left as much dirt as I could on her. Thank you guys for all of your insight and help!
Good to see. Thanks for the update.
Thanks Kep, how's yours coming? Any progress on your end?
Looking good! Congratulations. I think your grandfather would be proud! Having a family piece of history in the form of an antique car is special. A race car like that is very special.
Drive it proudly, and carefully, and enjoy it. W2
Not yet. Materials are scarce.
I have parts if you have cash lol ;)
you have a WAY COOL car ...i don't know if there is any intent to operate this car on the street or any extended periods of operation BUT , i would like any observations regarding the usefulness of this conversion for road use ...i plan to use my own design for road use , but only have about 3 hours total operation on the engine ...this being in a test stand with a combine radiator and electric fan to assure cooling ...keep us posted , and Happy New Year ...gene french always an optimist
I will keep you posted Gene. I'm finishing up rerouting the external cooling lines from the block to the head. I've considered making this street legal (barely), but may let her run in the shop and wait until spring to drive her illegally on extended dirt road trips now and then and a few parades. I will say that this engine sounds awesome!!!
Thursday I pick up a '26/27 roadster body to put on my other car. That will become the priority then. Just don't know what direction to go on that one. Hoping to make my OWN creation.
I purchased a 28 chevrolet head to build one of these several years ago but since acquired a C35 Rajo. I still had plans to build a Thunderbolt but waited too long, now that Mr. Jern is deceased. Perhaps I'll find a plate and continue the build for another project. Too many projects and not enough time!
Noel, my adaptor wasn't a Thunderbolt. It was a steel plate which appears much thinner than the Jern. My grandfather designed it and had milled elsewhere. He had a Dick McKee adaptor but decided to build his own. It wouldn't be hard to have a bunch made up. The rajo gasket fits great on the lower half, and stock Chevy on top fits but is a little awkward.
I know where a rajo is, bit the gentleman doesn't want to let it go
Wow Jim ! what a car! you do some very nice work .I keep getting sidetracked ,but made some good moves today . my buddy fixed up my battery cables and starter button . then cleaned up the nuts for timer wires ...no more missing runs smooth ,and starter cranks nice .Im stoked! but still no cooling system so ran a couple minutes then shut her down .
Jim, The seat back looks like the seat parts I had with a 36 Chevy 2 door sedan I had years ago. I have seen them used on several old racers, and they are popular with the rat rod bunch today. I really enjoy this build. Your grandpa would be proud. Im glad you chose to keep it as close to his build as possible. You will never regret doing it that way. One thing that in my opinion, that is not mentioned much, is that these type of cars were built well into the late 30s and even still being built to some degree in the 40s till WW2. So parts from 30s era cars are period correct. A lot of folks think to be period correct on speedster you need parts from 1927 or before. That would mean using some parts from "new cars" Most hot rods even today are made from "old used cars" not "new cars" keep us posted on the build.... have fun and be safe .... Donnie Brown ....
Great Michael, and I've been keeping up with your build!
Thank you Donnie for the info on the seat. I've seen some close matches on the seat after looking on eBay...thank you. Can't wait to drive her.
Now if we could just start racing again
I have two 4 cylinder 28 chevy engines for sale if anyone is interested. Send me a PM....I could deliver them to the Bakersfield swap meet.
I have seen and rode in a model T that had a 28 chevy block & head mounted on a 4 dip T pan using the T transmission. The engine is on display in the Evans museum in San Diego. Going that rout, you get a much stronger crankshaft, oil pressure to the mains. The chevy block fits nicely on the model T pan....re-drill the mounting bolt holes, reshape the nose some. The chevy block also has rear support holes similar to the 26/27 model T block. A simple adapter was made to bolt the 26/27 hogs head to the chevy block. Ford 292 pistons were used which provide better compression over the chevy stock pistons. The chevy wrist pin holes were reamed to fit the 292 piston pins.
I was going to duplicate the set up but too many other projects and age has prevented it from happening. I also have new old stock 292 ford pistons & rings that could be included in a package deal.
Les, I ache for your 2 engines!!!! I ain't that brand sensitive. I love it all! Yeah, I've thought about the Chev head on my T block and the Chevy on the T pan.
All three of my '28 Chevy engines have bent cranks, how does a fella get around that? Peening?
Jim, thank you for this thread!
A bump from the recent past! Any up dates?
Use a T crank.