The Stovebolt Site Forums The Shop Area Engine Shop What to do with my 235?

I have a '58 235 in my '49 1/2-ton. When I bought the truck, the engine would turn over, but was not running. The PO swore it was running the previous week. You know the story.

Now it's time to start rebuilding the engine. Question is, what should I do with it? My goal is to have a very clean, reliable driver when I'm done, but I don't have an unlimited budget either. I measured compression on the cylinders before I removed the engine. From front to back, compression was 120, 130, 80, 110, 120, and 105 psi. My understanding is that 130 psi is spec for this engine. I'm having all new valves, seats, and a rebuilt rocker assembly installed. The shop wants over $500 for this exercise. The price is high, but it seems worth it to me.

My question is what to do with the bottom half of the engine? The price for a complete re-build makes me gasp for air at $3,000. I removed the head myself, and inspected the cylinders. I can turn the crank from the main pulley with my bare hands, but just barely. It's a struggle. I used a $19 micrometer from Harbor Freight to measure the cylinders. All of them seem round and within a few thousandths of each other. When I run my finger up and down the cylinder walls, I do not feel any kind of a lip at the upper stroke of the pistons. This leads me to believe the bottom half of the engine is not too bad, but I'm hardly an expert. I've never done this before.

Any advice? I'm told the shop I work with is the best in town, but they only seem to know one price: very high. Should I hone the cylinders, put new rings on, and call it good? How important are a new crank, cam, and bearings to performance and reliability? Seems like there should be some options here besides a second mortgage on the house. Help!

What your experiencing is what I call inline shock. Chevy sixes are just expensive to rebuild and especially the older 216-235's. The cranks have shims and are sort of tapered from end to end and I think that scares a lot of rebuilders or at least provides an excuse for high charges. The parts are expensive too as compared to a SBC for example.

I'd suggest you pull the rod caps and have look at the journals. If they seem good then chances are the mains are too. You certainly can hone the cylinder walls yourself with the aid of a Shop Manual which should be your first purchase. If you replace the cm then do the lifters and gear also.

Sounds like your fairly handy so go for it. You can do it as thousands of others have. Lots of experts here (not me) to help you out of a spot. Incidentally...$3K sounds high to me too but repair costs are regional. Is that for ALL new parts and labor?

Was there any evidence of burned or stuck valves in the cylinders where you had the low compression readings? If so, you've probably found the source of the problem already. The engine might run just fine with nothing but a valve job and a good lower end cleanup. Be VERY cautious with any honing operation, as if even a slight amount of abrasive is left in the cylinders, it will wear out a new ring set in a short time. I did an in-the-frame ring and rod bearing job on a 1960 Rambler flathead six many years ago, just before driving from central California to Tennessee. By the time we arrived in Nashville, the engine was using 3 quarts of oil to every tank of gas, and the oil ring expanders were rubbing the cylinder walls. In 2,500 miles, I had worn out a brand new ring set! The cylinders were washed down several times after the hone job with solvent and clean rags, and then washed again with lacquer thinner. There was still enough hone grit in the cylinders to wear the rings out. Hot, soapy water and a scrub brush is the only way to clean up after a hone job, followed by a pressure wash or at least almost-boiling rinse water, and it's much better if you've got a bare block out on the shop floor while you're doing that.

I'd suggest soaking the cylinders with plenty of penetrating oil, and spin the engine with the starter to see if it frees up. If so, drop the head back on and drive. If the performance doesn't suit you, you're only out the cost of a head gasket set and a little labor time.
Jerry

Take it apart. Once it is apart take the head and block and have them inspected. I took the cam, and crank in also. But use good judgemnet. After you find out what you need and don't need to get, then start having fun with it. Put it back together. You will learn alot about your engine and be proud of it if you can tell people you built it.

Hmmm... I like Hotrod's advice. Put the head on it and try it. I can always do more work later.

Let me ask a couple of questions though. 1) With the head off, should the crank and pistons turn freely by hand? If so, then I probably have a problem. Like I said, my crank turns very hard by hand. 2) If I put the head back on, and compression is uniform and increases to within 10 or 15% of spec, my engine is good, right? If I have a crack-free head with good compression, what else is there?

I also like the idea of tearing into the engine myself, but I wonder how badly I could screw things up. If I really mess up, it's probably not a life safety issue, right? It's more like a wrecked engine issue. Can it get any worse than Hotrod's experience?

What kind of special tools do I need to do the job myself? I have a shop manual, and it refers to all sorts of special tools for special jobs. I don't have any of them. It looks like my first obstacle is getting the main pulley off the end of the crank. I'm not sure how to do that.

Here is an article from Chevytrucks, http://www.chevytrucks.org/tech/engine1.htm

It's what got me started. It is kind of vague in places, assuming you know what they are talking about, and it has no pictures. But it is pretty good.

The Chilton's repair manual gave me all of the specks. You can get one from amazon for $30

http://www.amazon.com/gp/offer-listing/B000GZZFJA/ref=dp_olp_used?ie=UTF8&condition=used

I also used the shop I go to. I did spend a lot there for just getting the block bored and cleaned, and getting the head cleaned and valves in. But I was there almost every day with questions. They even let me borrow a tool here and there. But I'll bet you'll learn more about your motor than you ever thought you would, and half way into it you'll start to think it's not as hard as it looks.
You also have this forum with a bunch of people happy to answer anything. I was in the same boat a month ago.

There are some things to consider here. If it is the original Chevy motor, it probably has a fiber timing gear on the camshaft. If you do any work on the bottom end, it would be a good idea to replace the gear. Have a look at the rod bearings. They will be babbitted directly on the rods, so if the bearing surface is worn out, they have to be repaired. Usually the best route here is to have them machined to take insert bearings.

The motor should turn freely without the head. I would guess that the pistons and rings need some lubrication. You can also lubricate the main bearings by driving the oil pump with a drill.

I have the same truck and engine. I had Advanced Auto rebbuild my longblock, $1200.00. That was a year ago. I thought it was the most econmical professional overhaul I could find. The engine is perfect

After reading Davidn's article, I decided to tear apart the lower block myself . I think I can, I think I can. In one afternoon, I got the pan off, the oil pump out, and the harmonic balancer and timing gear cover off. Stay tuned. I'm sure I'll be back begging for help.

Meanwhile, the cylinder head came back from the engine shop today. It looks so pretty I think I want to eat breakfast off it in the morning. I can almost hear that engine purr!

I think you are ok with just being able to barely turn the crank over by the balancer with bare hands. If you were having trouble turning it with a socket wrench that would be another story. If you left the distributor in, you are still fighting the friction of it, the oil pump, the camshaft, the front and rear main seals, and the rings. You don't want it to be too easy. Both my 261 and 302 I can just barely turn over by hand with the spark plugs out, and they have normal compression and oil usage. I would just install the head and run it. If you want to pull the pan and replace all the seals that's fine, but if you put the new head on and you have good compression and don't burn oil then you just saved yourself 3 grand.

I just read through this whole dialoge. I have a 50 3/4 ton with the 216in it. I have no idea how good the 216 is and the neighbor gave me a 235 to stick in the truck. Got it home yesterday. Anyone out there try any of that free-up miracle oil and run an engine afterwards? Any preferred poison? Tinocker

Stuck engine treatments have been the subject of a lot of threads lately. Please do a search, you'll find a lot of info on miracles.

i would pull the pistons take a ring off to see the end gap look everything over you will be able to tell if anything is worn or scuffed run a finger nail over the journels to see if you feel any lines if you havent built a motor before try and find someone who does it for a hobby and the fun of it thats what these trucks are about fun!!!!

Thanks folks. I'm still collecting information and trying to decide what to do. I inspected the old valves fairly carefully. All of them are covered with black carbon soot, and one of them appears to be slightly out-of-round. Maybe this one came from the cylinder that was giving me low compression (see my first post). Would a burned valve appear slightly out-of-round?? Sorry for the newbie question.

The timing gears have a lot of dried, caked oil inside the cover. This got me to wondering how the gears are oiled. Is oil sprayed between the gears and then drained back into the block by gravity?

I have not removed the caps from the rod and main bearings yet, but I'm thinking that will be next. Can I use plastigauge to check the clearance on the existing bearings? If existing bearings are not way out of spec, there should be no need to remove the crank and replace the bearings.

I'm also planning to borrow a better micrometer to check the cylinders. If the cylinders are not out of round by more than a few thousands (diameter and taper), I would think there would be no need to replace the pistons. Do rings wear out even if the cylinders meet spec (another newbie question)??

Finally, when I removed the engine, I noticed a lot of oil caked on the transmission. I'm assuming this means a leaking main seal should be replaced. If the bearing journals and cylinders meet spec, I'm thinking I'll just replace the seals and gaskets, button the thing up, and drive. If bearings and cylinders out out of whack, more work will need to be done.

If you're gonna take it apart that far you should, at a minimum, ball hone and re-ring it, assuming it has straight bores. You can take the block to a machine shop and ask them to measure the bores with a dialbore gauge and a mic. Especially check the cylinder with low compression. Also, it seems like you are not sure where each valve came from cylinder-wise. You need to keep track of each part you remove, either so you can accurately determine what's wrong, or to ensure they go back in the same place they came from (if you're going to re-use them). Also, mark them for orientaion, ( front-rear, top-bottom) and make sure they go back the same way they came out.

Btw, the rings can and do wear out, even if the bores are straight, and the pistons are good. If you replace the rings you need to resuface the cylinders lightly with a ball hone. this need to be done in a particular way, so that a certain cross-hatch is achieved. This requires complete dis-assembly, and a thorough cleaning afterwards, as Hotrodlincoln said. I wash them repeatedly with HOT soapy water, scurbbing with the rags as hard as I can, then immesiately afterwards spray them with WD40. Then I use white paper towels and more WD40 to wipe them, until the paper towels come out white. If you do not clean them properly, you will have abrasive particles in all of the nooks and crannys, and will wear out your rings in no time!

used 235 are pretty cheap. you might get lucky
ya might go that direction, swapping engines might be easier than whole rebuilds.
see inliners 4-SALE , craiglist etc.

Update: I removed the cam, lifters, and pistons from the block. No problems so far. The casting number on the block indicates it is a 1958 235, and the engine has mechanical lifters. Apparently, this means the engine was donated from another truck, because I think I read that all cars had hydraulic lifters by 1958. I've read on this forum that hydraulic lifters are quieter and provide better valve operation at all temperatures. So, my first question is, CAN I replace the mechanical lifters with hydraulic lifters (i.e. are the blocks identical for both types of lifters)? My second question is, SHOULD I replace the mechanical lifters with hydraulic lifters? Is it worth spending a couple hundred bucks on a new cam shaft and lifters? Aside from a little noise, do hydraulic lifters provide more power, durability, or performance?

have your machinist look at the valve and if its bad replace it and button up the engine and go! the one thing that seemed to kill these motors were cracked water jackets from freezing. fixed quite a few cracked blocks when i was working with zero budget.

Another update: The rings on Pistons #5 and #6 are busted! I didn't notice when I first removed them. Of course, this discovery is like payday! If I hadn't torn the engine apart, I probably would have been very disappointed with a power-plant that runs poorly and burns oil.

Time to crack open a cold one and feel proud of myself. Maybe I should quit while I'm ahead.

Since my last post in December, I completely disassembled the short block and took all the parts and pieces to a local machine shop. They planed the deck, bored the cylinders, machined the crank and cam, and fitted new pistons and rings. I reassembled the entire engine myself and installed it back inside the truck.

Today was a red-letter day. I stomped on the starter and she turned over like nobody's business. I don't have the fuel lines hooked up yet, but after 2+ years of working on this truck, it's exciting just to hear the motor turn.

I also performed a compression test today prior to the actual start-up. My gauge registered 165 to 170 psi at each of the six cylinders. That's a vast improvement over the original compression values (80 to 130 psi)! I'm surprised the compression readings are this high. The engine spec says 130 psi (min). Is this normal? Can I expect the numbers to drop significantly after the rings are slightly worn, or will the numbers stay high as a result of modern equipment and machining? If the rated horsepower on the engine is 145 HP, does higher compression mean I get more horsepower? If so, how much?

Another week or two and I should be ready to actually start this thing. Sweet!

norcal49er,

My handy chart sais that 160 psi compression is aprox 9 to 1 Compression. Thats still regular fuel. Good job. Advise Petronix ignition moduel. No way to tell how much hp without dyno runs. What cam are you running?

Norcal,

Congrats on getting your engine to turn over. I just fired up mine last night after sitting for 25 years. The feeling you get when you hear that engine roar for the first time is better than losing your virginity. I am still shaking with excitement! Good luck in the next week or so.