The Stovebolt Site Forums The Shop Area Engine Shop Seized up 235

I pulled the head off the 235 engine that I picked up about a month ago. As you can see by the pictures, it's pretty ugly.
Cylinder #2 is full of water. I dug down to the water and found a disk of rust that likely came off one of the valves. The bits are shown in picture number 2. Cylinders 3 and 4 are just about at TDC, and have some significant crud in them also. Cylinder #1 is dry, but has quite a bit of "sand" in it. No. 2 cylinder walls are pretty barnacled, and there's a pile of crud on top of the piston. The other cylinders have some fine rust on the walls. I drained the water out of all of the cylinders and put some ATF in them, but I doubt that even Carl's "boiling oil" trick will help. I may need to use Jerry's hole saw on the piston crowns to get them out. My plan is to pull the pan and the crank (destroying the cam gear to get the front engine plate off) and work on each cylinder individually. I expect that a few of them can be driven out (likely 3 and 4, being near TDC.) What I want to salvage from this engine is the crank and rods and possibly use them in my 216.

Yep, that one sort of qualifies as "butt-ugly"! If you do the hole saw trick and then smack the tops of the pistons with a block of hardwood and a BFH, you'll probably be able to turn the crankshaft once the stuck piston ring area separates from the pistons. I'd also suggest using a coarse bristle cup brush in a high speed drill motor to clean up the cylinder walls. The block might be worth saving, but it's going to require a few sleeves, most likely. Good luck!

www.ebay.com/itm/186274717593?

Jerry

Got the pan and timing cover off today and ran into a little surprise. It has an aluminum cam gear, which is going to be a little hard to break apart to get to the thrust plate screws like a fiber cam gear. Also, both lifters on cylinder 1 are currently stuck, but that's not a big deal as I can drive them out from below if they don't cooperate. My next approach is to pull the crank gear and see if I can get the cam to turn so I can get to the thrust plate screws. Unfortunately, my balancer puller won't get the bolts close enough to screw into the crank gear. I'll run down to the FLAPS and see what they have. I thought about pulling the cam gear, but both my other pullers are just 3 arm instead of being convertible to 2 arm. Not enough room to get behind the gear except through the two holes.

That crank snout looks like it’s been knurled to increase it’s diameter.

For a gear puller, if you have any heavy plate, you could drill and tap the center hole to match one of your pullers then drill holes to match the gear.

I drill and tap two 5/16-18 holes in the cam gear and use a steering wheel puller to remove it from the cam. That avoids destroying the gear, and gives me easy access to the cam thrust plate screws. The same puller will also work on the crank gear. Why rent or borrow a puller when you can have your own for less than the cost of a Burger King Whopper combo?

www.ebay.com/itm/292290247337?

Jerry

Is it still standard bore? Or already overbore?

Haven't measured the bore yet, but will check that. Cylinder #2 is probably heavily pitted. The intake valve for that cylinder was stuck open, and rainwater got into it even though there was an oil bath air cleaner on the carb which is also rusted shut (but it's a Rochester B, so no real big loss.) The air cleaner was actually a "water bath."

Jerry, I have a much stouter OTC Stinger harmonic balancer puller than what you linked to, but the slot spacing doesn't go down to the 2" spacing on the crank gear holes. Your idea of drilling and tapping could work on the cam gear, but the FLAPS rental (actually free) puller will probably hook in the two screw access holes.

Phil, I've built a steering wheel puller with a piece of steel plate. I'd have to modify that to use the screw from one of my pullers, but probably don't have a tap of the proper size to do that. Just using the bolts screwed into the wheel works for steering wheels, but I doubt they'd stand it on a crank gear without stripping the threads.

I was referring to the center screw from your existing puller to tap into the plate. Probably in the vicinity of 1/2”-20.

I understand about the center screw. One puller I have might be that small (and I do have a 1/2-20 tap,) but I haven't checked, and it seems a little puny for the task. I have another that's way bigger than that. But that brings a thought to mind, that I could just buy a nut and tack weld that to the plate to engage the center screw.
Currently using that plate as a steering wheel puller, I just set the plate against the end of the steering shaft, tighten the bolts and tap on the plate to get things moving.

Gosh... I have all the Stovebolt respect in the world for you... but that's a whooool lot of work for a questionable outcome. I know, I know... if it casts a shadow, it can be restored... but restorable 235's are cheap, even in Alaska, I'll bet. Plenty of good parts in that engine, though.
On the other hand, if you have the resources to do the work yourself, then go for it. The final outcome will be something to be proud of.
I'm sure that We, in the Stovebolt Family will support and help in anyway We can.
Jethro.

Jethro, seriously, I'm not considering rebuilding that 235. My end goal with it is to harvest the crank and rods from it to put in my 216 with Buick Aluminum pistons, resulting in a full pressure 216 with a slightly higher compression ratio, and more dependable rod bearings. If I wind up giving that block away or burying it in the back yard, that's OK.
That and I needed a winter project after I burned out a rod bearing in my 216. My '51 needs to be outwardly original as a restoration of an Alaska Road Commission truck from back in the day.

"Jerry, I have a much stouter OTC Stinger harmonic balancer puller than what you linked to, but the slot spacing doesn't go down to the 2" spacing on the crank gear holes."

Have you considered using a die grinder or a rat tail file to move the inboard ends of the slots closer together? Just because somebody else decided how close the slots are doesn't mean you have to take their idea as gospel.

Yeah, that's a good use for that old engine. Should keep you busy in a warm shop while the wind howls outside. Keep the heater stoked!

I took a look at that puller and lengthening the slots is a no-go as there's a thrust bearing that's nearly that large in diameter. The slots would have to go in to the space where the bearing is. I'll go with a rental puller for those gears.

In that case, I'd be tempted to drill and tap a disc of 1/2" or 3/4" steel plate for a puller screw and make a dedicated puller just for crankshaft and/or camshaft gears. Of course, I'm always thinking of doing several engines with the same tooling. Got a dedicated drawer in the tool box for home-brewed toys like that!
Jerry

I borrowed a puller and got the crank gear off, the lifters and cam out (lifters and cam are badly worn), the front plate out. Today I pulled the bearing caps and pulled the crank up enough to get to the oil pump pin out (it wasn't accessible where the crank was frozen.) Then hoisted the crank out and put some blocks in so I could get the clutch and flywheel off. I was able to get all the pistons driven out. Number 2 was pretty tight. I broke the crown of the piston out and cut thru the ring area with a sawzall to relieve some of the pressure, then was able to get it the rest of the way out. Here's a couple of pics. Crank was 10 under and may need to be reground a bit smaller, a little worn. Rods are removed from the pistons and should be good to use.

Well Done Kevin! Persistence pays off. I'll go off track for a moment and share a perfect story on persistence. We were keeping our 3 year grandson recently, my bride was having trouble getting one of Charlies favorite shows to play, Kathy was getting very frustrated. The interface between operator and TV remote wasn't working properly. Charlie was setting quietly taking it all in when he very softly said "My Daddy says to keep trying, don't give up". He repeated it for Mrs. Kathy's benefit in the same very soft voice. She persisted and won the battle. For the record 3 year old Charlie can tie his shoes and write his name and knows his address.

OK, back on track. Looking forward to more journey updates with the soon to be new engine.

RonR

Ron, You need to put that line in your signature. Nice story.

I'm hoping this pans out and I wind up with a full pressure 228 (that was originally a 216) with Jerry's assistance.

Those Buick pistons are also available in .060 oversize, that will make that "216" a full grown 235 with aluminum pistons. Silv-O-Lite part number 1718-60.

www.summitracing.com/parts/uem-1718-060

That's an 8 piston set, but the price isn't terrible, even with a couple of leftovers. Many years ago, J.C. Whitney sold a "high compression head gasket"- - - -a solid copper gasket .030" thick that was supposedly designed to make a tiny difference in the combustion chamber volume. I've been in contact with a machine shop that claims to be able to use a water jet CNC mill to duplicate stovebolt head gaskets from a thin sheet of copper. Using studs instead of head bolts, and a solid gasket will probably avoid the potential problems with using 70 year old OEM gaskets with the increased compression gained by increasing the displacement of the 216 engine. Some "quick and dirty" guesstimates suggest it might be possible to build a 235 cubic inch engine that looks like a 216 from the outside, with around 8:1 compression!
Jerry

By my calcs, the Buick pistons will be about 0.063" below the deck at TDC using the 235 crank in a 216. The stroke difference is 0.188, and half of that is 0.094. The compression height of a 216 piston is ~2" measured as close as I can, and the compression height of the Buick pistons is 1.843", with a difference of 0.157".
One slight issue is the piston pin diameter. 216 and 235 use 0.866" pins, while the Buick pins are 0.875", a difference of 0.009, which can probably be taken care of with a light reaming of the small end of the rod, although that may not even be needed with the split small end on the 216 and 235 rods.
The Buick pistons have a slight dish (0.15" deep) on the crown, which would lower the compression ratio a bit, essentially increasing the combustion chamber volume. It'd take a bit more ciphering to figure the exact compression ratio.

When I want to ream a split end rod like a stovebolt, I clamp a piece of soft aluminum into the gap and ream to whatever size I need for a particular piston/rod combination. I'll probably use my Sunnen hone instead of a reamer to resize the stovebolt rod ends, since the difference is pretty small. The shim would keep the reamer flutes from hanging up in the slot and possibly damaging the reamer. It would also be possible to deck the block a little to reduce the error when using the Buick pistons. The stroker crankshaft version of the 216 I'm thinking of using will be equipped with pistons for a Japanese Diesel forklift, and a custom length big block Chevy V8 connecting rod. That one will have a little over 250 cubic inches in a 216 block. 235s and 261s with the same stroker crankshaft can get around 270 and 300 cubic inches, respectively.

www.ebay.com/itm/163130694013?

Jerry

I did a few more calcs with closer numbers and it turns out that a standard bore 216 with a 235 crank, rods and Buick 215 pistons winds up with a compression ratio of 6.25:1, down from stock 216 6.6:1. That's because the Buick pistons land 1/8" below the deck of the block and have a recess in the center.
Probably not a huge thing in the big picture. If I go that route, I'll likely get the crank reground offset to 40 undersize on the crank pins which would increase the piston height by about 0.015 at TDC. Decking the block a bit would help as well.

Here's the numbers.

Compression height on 216 pistons, 2.0625”
Compression height on Buick 215 pistons 1.843
0.2195 shorter
Add back increase of half stroke difference +.094
puts piston crown ~0.125 below deck.

Stock 216compression ratio 6.6 to 1
Stock 216 Stroke volume per cylinder 36.08 cubic inches.
Compression volume V
6.6= 36.08+V V=36.08/6.6 = 5.46 cubic inches.
Add 3.5^2*0.125*pi/4 plus dish volume in Buick pistons (2.812^2*pi*0.15/4) = 1.20 ci + 0.56 ci
New compression volume =7.22 cI
New stroke volume. 3.5^2*3.938*pi/4 = 37.89 cubic inches.
New compression ratio (37.89+7.22)/7.22 = 6.25

Will you use the same spark plugs or do you need longer reach plugs?

The head isn't going to change, so why would I use longer reach spark plugs?

I thought the piston was going to be farther away from the top of the cylinder.

What connecting rod and bearing do you plan to use to compensate for the reduced diameter of the rod journal when you change the stroke?? A 90 MM Diesel piston that's available on Ebay solves the low compression height problem, but you'll need to put a bushing in the piston pin bore to make the stovebolt wrist pin fit. A 292 chevy six rod will also work with a 235 piston, but there are also some dimensional differences that need to be addressed there.
Jerry

Edit: Check this one out:
www.ebay.com/itm/255759757459?
90.5MM=3 9/16"
The piston crown is thick enough to machine it level with the top of the block.

If you bore the 216 60 over with the 235 crankshaft and use an oversize Buick piston, the "216" becomes a 235 in a 216 block. That will also compensate for the lower deck height and raise the compression ratio. It's also possible to deck the block a little.
Jerry

Yes, oversize pistons would increase the compression ratio a touch over the calculated 6.25, but that requires additional machine work. The oversize Buick pistons would still be 1/8" below the deck. I doubt it would be possible to take that much off the deck. If I were to use a stock 216 piston, it would be 3/32" ABOVE the deck. I'm investigating whether it would be possible to cut that much off the crown of a stock piston. I haven't looked at 292 rods, but I don't have any of those. I can get 40 undersize rod bearings for the 235 rods, and would be able to increase the stroke by about 15 thousandths. [on edit]It looks like even the standard size Toyota diesel pistons would require boring the cylinders. When I don't have the machine tools like you do, Jerry, it gets real expensive.

Otto, the spark plug position doesn't really have anything to do with the piston height, as the fuel air mixture should be essentially uniform throughout the combustion chamber, and the spark plug can ignite it wherever it is.

No, it's not possible to machine that much off a stock 216 or 235 piston without seriously compromising the strength of the crown. The piston will crack or burn through almost immediately. (not conjecture- - - -I've tried it) Offset grinding and using a 40 under bearing will give your machinist fits- - - -I haven't met a "machinist" in the past 40 years who will try something like that- - - -which is why I own TWO crankshaft grinders.
Jerry

I talked with a machinist the other day about offset grinding and he said "sure I can do that." He builds racing engines. I haven't committed to doing that yet. If it's that much trouble, it doesn't really give that much increased stroke.
I didn't think that a 216 piston could be cut down, but I have that question in to a piston supplier to see what they say. Another option would be to offset the piston pin bores lower in the pistons, but again, more machining cost.

I've got one of those 90.5 MM diesel pistons on order. I'll have a test block mocked up soon to do some actual measuring on- - - -not a WAG from a parts catalog. Of course, I've got the equipment on hand to actually produce some of these exotic parts- - - - -lathe, mill, boring bar, Sunnen hone, line bore machine, etc.- - - - -all I need is enough time to use them!
Jerry