The Stovebolt Site Forums The Shop Area Engine Shop 216 with 235 Crank

Last week new member pk10 posted his hello with a link to pictures of his 48 3804 that he got from his grandpa-in-law. Cool Truck! Some of the pics were scans of an old Chevy brochure with handwritten notes on it. This one particularly caught my attention. Near the upper left he wrote "235 crankshaft in 216 block 3/32 - cut off from top of pistons..." I have a reprint of California Bill's book and back in the day putting a "Hi-Torque" (235) crank in a "standard" (216) motor was quite the thing. Special pistons were available back then to do this... I wonder if Egge or one of the specialty manufacturers could still make pistons like that? I have a solid 216 that's about ready for an overhaul, and I have a good 235 pressure crank... If I did it right I could have a full pressure 216 (227?) sleeper with a little more umph.
Any comments?

Frank,

I took auto shop during my high school years '60-'64, and I remember the teacher put a 235 crank in a 216 and stacked two head gaskets together. I don't know if this ever ran but I thought it was a pretty funky deal...anyway, that's my comment.

Stuart

Maybe someone else with more experience with the 216 than I have will chime in - but I'm thinking the 216 block isn't cast or drilled so that it would be "full pressure" even though a 235 crank was used.

Full-pressure means high-pressure and refers to 54-63 235/261 truck engines (and mostly similar years of auto engines). The major change for high pressure had to do with insert rod bearings and internal lubrication of the rod bearings.

Using a different crank in a 216 would not change the lubrication to the rods.

I have received a Private Meessage from another member that corrects my statement above:

". . . if the 235 crank used was from a precision bearinged engine, it would change the oiling to the rods, as the oil comes from the main bearings through rifle drilled passages in the crankshaft down to the rod bearings. So you could also use precision bearinged rods with that crank also.

So, maybe someone who has first-hand experience with this "conversion" will post information on what modifications (if any) need to be done to the high-pressure 235 crankshaft.

If I was a low-pressure 216/235 owner/user and I wanted to keep my 216/235 that needed a rebuild, I'd be saying (or thinking) "this option is too easy to ignore".

Tim

It would be no problem putting a 1941-52 splash 235 crank in a 216 with proper pistons, apparently some Canadian engines came that way. The problem with putting a 1953-62 full pressure crank in is the thrust bearing is narrower. I looked into having a block machined for the narrower bearing but could not find anyone set-up to do this.

Dave,

So, the use of a low-pressure crank would not result in a "full pressure 216" but would result in "a little more umph".

Frank,

When California Bill was referring to a a "Hi-Torque" 235 crank, he was most likely referring to what GM called the "Loadmaster High Torque" low-pressure 235 (pre-53/54 235).

Tim

The real problem with these early inlines is the compression ratio was very low, difficult to improve and custom pop-up pistons cost a fortune. So after lots of swapping cranks etc etc you still have a low compression motor. Best is to get a later 235 or 261. Believe me I've been through this, it's not worth the trouble.

There are shops that will drill a splash crank for full pressure oiling, but I'm not sure it's worth the cost.

My '46 235 high torque (in my coupe) has a later 235 full pressure crank, a friend machined the block to accept the later crank and bearings etc. There are some of these type modified early 235s around. Again now wish I'd gone the 261 route.

Thanks for the comments.

Hello Franck
I have read your message ( because i want to make the same modification).
Did you manage to do it ? What is the solution that you use for the different stroke ?
Thank you for your answer.
Raphael

I’m not sure that you are aware, but this post is 13 years old. Some of the members that posted may not reply. I would start a new thread and you will get better responses.

I’m sure that Hotrod Lincoln would respond as he has a current project to upgrade a 216 to a full pressure, increased cubic inch sleeper.

Hi Raph. This is a blast from the past. No. I never did anything with the 216. I learned that “late” 235’s designed for oil pressure to the rod bearings have different width main bearings and the crank will not drop in a 216 block. There were and are shops that can drill your crank for oil pressure to the rods. As far as increasing the stroke by using an “early” 235 crank, you have to do something about the compression height of the pistons, since the 216 block is 0.09375 shorter than a 235 block.

Currently, I have two 235 crankshafts modified to fit 216 blocks. All that's needed is to widen the #3 main bearing thrust faces to fit the 216 main bearing, being sure to remove the same amount of metal from the front and rear faces to keep the timing gears aligned properly. If the original connecting rods are used, the pistons will stick out of the top of the block due to the increased stroke. A 292 six connecting rod is the right length, but it has the wrong size bearing, so the crankshaft rod journals would have to be reground to 2.100" to accept the 292 rod bearing. Then you'll need to put bushings in the top of the rods to fit the smaller dfiameter 216 wrist pins, and fabricate thrust buttons from aluminum or teflon to keep the wrist pins centered in the cylinders. The rods are too narrow for the crankshaft journals, so weld thrust washers onto both sides of the rod caps to keep the rods centered on the oil holes in the crankshaft. Recondition the rods to eliminate any misalignment welding the spacers created. You might as well go ahead and bore the 216 cylinders 1/16" oversize and use the 235 aluminum pistons while you're at it. Now you have a 235 engine in a 216 block.

Now, you're going to need more oil volume to keep the rods oiled. I make an adapter bracket to run a pump for a 250 six, along with a shortened drive shaft for a big block V8 oil pump to connect the distributor shaft to the pump. The adapter has bronze bushings to keep the drive shaft centered. Then remove the spray oiler plumbing from the oil pan, or find a pan for an early 235 with a straight rail on the passenger's side. Then plumb new tubing to the oil pickup screen and the oil galleries in the block. Plug off the oil port that used to supply the spray oilers.

If you're still interested, I'll share a way to make that 216 engine a 247 by using a different connecting rod and offsett grinding the 235 crankshaft. Bring money- - - -lots of it!
Jerry

I will be posting some photos later this evening of the modifications necessary to make these engines run with parts not normally intended to work together. Anyone is welcome to attempt to do this type of work, using my experimentation as an example, as long as you attribute the source of the information appropriately. In the past, some less than scrupulous stovebolters have plaigarized my information, and try to sell it as their own knowledge. I have "minimum high regard" for a thief, whether they steal physical or intellectual property. These modifications are not simple, easy, nor inexpensive. They are a great challenge for someone who no longer needs to work every day to put food on his table and a roof over his head!
Jerry

OK- - - as promised, here are some pictures of the modifications necessary to put 292 connecting rods on a 235 pressure-oiler crankshaft. The first problem is the width of the rod- - - -it's way too narrow. This problem can be addressed in one of two ways- - - -widen the rod cap, or install thrust washers inside the piston to keep the rod centered on the crankshaft journal. Either way works, but here's how I chose to solve the problem. The rods pictured are a spray oiler 216 rod with a cast iron piston, a modified 292 rod with spacers TIG welded to the cap, and a recycled NASCAR rod with spacers to make it the same width as a pressure oiled 235 rod. It will be used in a long stroke full oil pressure "216" with a 235 crankshaft with offset rod journal centers that will have almost 250 cubic inches.

Other projects I've got in the pipeline are a 270 cubic inch "235" and a 300 cubic inch "261" using similar modifications.

More pics:

None of these rods are finished, BTW- - - -the weld beads will be smoothed up with a die grinder, and all the pistons, rods, and other moving parts will be weight-matched down to an accuracy of 1/10 of a gram. (A dollar bill weighs one gram). That was standard procedure on all the race engines I built. An inline six is inherently dynamic balanced, so changing the weight of the rotating and reciprocating parts won't require dynamic balancing, as long as all the parts for each cylinder have the same weight.
Jerry

On the 235 and 261 stroker engines, I've devised a method of reducing the diameter of the stock stovebolt connecting rods to use a smaller bearing intended for a 2.4 Liter Nissan engine, allowing the stroke to be increased to 4 5/16"- - - -a 3/8" increase over the standard stroke. The 235 engine can use a 3 5/8" diameter piston for a Ford 223 6 cylinder, and the 261 can use a Chevy 283 V8 piston after some block height decking. The Nissan rod bearings have been used successfully in 600+ HP turbocharged engines, so a stovebolt at 4K or so shouldn't be much of a challenge!
Jerry

Thanks Jerry for your comments and for sharing your knowledge and experience.

Hello everybody
Thank you for your answers and thank you Jerry for sharing your great knowledge.
I just bought 292 connecting rods on ebay to Start the engine work

Jerry, I've noticed it's fairly common as we get a bit long in the tooth with our broad knowledge base to imagine what's possible. Good to see someone actually act on those thoughts.

Keep up the good work!

RonR

I had a very good example to follow. Back in the early 1950's, my father was building dirt track cars with flathead Ford V8's, with stroker crankshafts and big oversize pistons, even moving cylinder centerlines apart to avoid thin spots in the block where the exhaust passages ran, and fueling them with an alcohol/peroxide mixture. He was getting around 300 cubic inches from a 239 engine, and making V-12 Lincoln Zephyr distributors run on V8 engines. Like Hank Williams Jr. says- - - -"It's a Family Tradition!"
Jerry

Hello Jerry
I hope you are well
My machine shop just start the modification that you have explain to me for the 216 to 235 conversion the last month….
Everything is done on the the block, and the Crankshaft. The last thing that we have to do, is the oil pump modification and
Welding the spacer on eatch side of the connecting rod.
I have a question please : do i have to make a treatment for the crankshaft to make it more stronger ?
My mechanic told me that, if the Crankshaft was originally mounted with the Babbitt and now transformed to the bearing,
the crankshaft steel will be not enough stronger ?

I hope you will understand what i want to explain.
Thank you for your help

Raphael

That crankshaft is forged steel, and it's tougher than the lips on a woodpecker! All you need to do is be sure the oil clearance between the crankshaft and the insert bearing is correct, by grinding/polishing the crankshaft journals to get a clearance of around .0015 inches. (0.04MM) If you're using 292 six connecting rods, the standard shaft diameter is 2.100 inches (53.3 MM), and the rod bearing is the same one that's used in a 350 Chevy V8. They're plentiful and cheap, and made to survive in engines that produce over three times the HP of a stovebolt engine. There is a hardening process known as "Tufftriding" which we used on full competition engines on the dirt tracks, but it's very expensive, and won't be needed on a relatively low horsepower, low speed engine like a Chevy six. Good luck with your project!

Edit: I have found that a Melling M-29 oil pump is a direct bolt-in fit to a 216 engine block. It was used in early 235 engines, and it supplies sufficient oil volume and pressure to lubricate the 216 with the 235 crankshaft and pressurized rod bearings. That is much simpler than modifying the engine for the 250/292 oil pump.
https://www.jegs.com/i/Melling/689/...62onFhQMV0jjUAR3EqQiVEAQYAiABEgIeUPD_BwE

Jerry

Hello Jerry

Thank you for your quick answer and the good news for the oil pump.
I hope the engine will start this year

Raphael

I have another question Jerry

My mechanic have made the modification for adapt the pistons wrist pin ring (circlip)
You have told me that i can ( for centered the connecting rod) weld spacer or use thrust washers.
I am afraid to weld on the connecting rod, if i use the thrust washers it’s not less reliable than the welded washers ?

Thank you
Raphael

Thrust washers at the top of the connecting rod around the wrist pin will keep it centered on the crankshaft journal. Use brass or bronze washers and fit the clearance on both sides to around 0.25 MM or so. I think you should find a "mechanic" who isn't too timid to do things the easy way. A short TIG weld in a few places to hold a spacer onto the connecting rod cap won't damage anything, and it's a much simpler process than making a dozen precision thrust washers.
Jerry

Thank you Jerry, i will see what he want to do
Do you think i can found the oil pump at the rockauto store, may be it’s cheaper ?

It's possible that different vendors might have better prices. The oil pump you will need was used on 1954 and early production 1955 235 engines. The later model, larger 235 oil pump that was used from midyear 1955 through 1962 pumps only fits engies with an offset in the engine block oil pan rail on the passenger's side. It's too wide to fit inside a 216 or early 235 oil pan.
Jerry

Hello Jerry
I have take a look on other saler but the price is more or less the same for the oil pump
This is the picture of the piston with the spacer
Now, we must mount everything on the engine and check the clearance with the valves and the head because the piston exceed
1,5 mm to the upper block line ( the connecting rod are not very more shorter than the original one)
If there is a problem we can remove a little material on the top of the piston, if there is enough clearance with the valves, it will be great for the compression ratio.
The last and big modification is, adapt an 5 speeds gearbox from an m35 truck. I have found the gearbox in germany ( very cheaper 300 €)
I will send somes pictures of the modification

The 216 engine block is about 3 MM shorter than the 235. The taller block is how Chevy chose to compensate for the longer stroke 235 crankshaft, rather than manufacture a shorter connecting rod. The 292 rod should prevent the 235 piston from sticking out of the top of the block, but the piston can be machined a little if necessary. The intake valve will be the only one to be concerned with for clearance purposes- - - - -the angle of the exhaust valve makes it virtually impossible for it to touch a piston. The quick and easy way to check piston/valve clearance is to place a small piece of sculptor's clay on top of the piston, assemble the engine temporarily, adjust the valve clearance, and rotate the crankshaft at least twice. Remove the head and measure how far the clay has been compressed. You should have a minimum of 1.5MM clearance or a little more between the piston and the valve at the closest point. Good luck!
Jerry

Another option for pistons would be ones for a Rover 3.5L V8 engine. Silvolite part # 1718. (based on the GM 215 cubic inch Buick/Oldsmobile engine from the 1960s) They are the same bore size as a 216, 3.5 inches/89MM. with oversizes available that approach the diameter of the 235 pistons. They have a slightly shorter compression height and a small dished-out area in the piston dome for extra valve clearance.
Jerry

Thank for those informations Jerry, i will check and tell you the result

Hello Jerry
We have finally decide to put the spacer on each side of the connecting rod.

I made a welding jig to hold the thrust washers I made onto two connecting rod caps bolted together, welded them on, and cut the caps apart with a thin slotting saw. Everything was clamped into proper alignment that way, and quick, short TIG welds attached the washers to the caps with minimal distortion of the material. The alignment fixture was made of aluminum to "heat sink" the welding heat away quickly. Then the rods were reassembled and reconditioned for a proper bearing fit. Only the rod cap section needs a thrust washer to keep the bearing centered on the crankshaft journal.
Jerry

Raph, There was a problem for a short period of time that caused the original pictures to not display. It's fixed now. Maybe you can re-POST with the images.

Hello
thank for your message
This is the pictures of the connecting rod, everything Jerry told me is done.
Now we must Check the clearance with the valves.
The mechanic who have made the job is : ventoux moteur ingénierie (VMI) at carpentras it,s a Bugatti specialist

Wow! I fell in love with Type 55 and Type 57 when I was around 7 or 8. There are no words to adequately describe the beauty of those cars.

The Schlumpf brothers are my heroes.

Hello
I have finally recovered my engine at my machine shop.
After all this time…
Everything is done, like you have told me Jerry( thank a lot 😊)
Except for the oil pump, I have a question.
Can I use a 235 oil pump, in my block, or it’s the same
model than the 216.
Thank for your answer