The Stovebolt Site Forums The Shop Area Engine Shop Patch or Rebuild or Remanufacture

The topic of how to deal with an engine for an old truck keeps coming up. In the day when these engines were new it was not uncommon to do a valve job or even a re-ring with the engine still installed. Now as these engines are 50+ years old and who knows how many times they have had work done the challenge comes up how to bring new life to it. The debate keeps coming up about buying a crate engine or a factory reman engine and having something with a warranty. This is a good choice for many reasons if the engine to suit ones need is available. Many guys will stand firm that they want to fix it themselves and that is a good choice for them also. On the other side of the coin many guys have no interest in working on the inside of the motor and would rather have someone else deal with it, all fine also.
I think that it would help everyone if we could start talking about some of the +'s and -'s. Then a good tech tip could maybe be put together to offer a guide towards engine issues. Lets see what we can do. Please keep posts close to the topic and keep the jabs and insults outside.
Thanks
Don

Frist, I think for the amount of time it takes to remove the engine or build it in the truck you can do a better job and easier out of the truck.

I like to build engines so for me it's a good time.I send the parts out to be machined and do the rest myself.It is a little cheaper doing the teardown and rebuild but not that much.

I've know people that remove the engine and take it to a shop and others who just bring the truck over and have it all done.As long as the shop does good work I don't think it makes any difference.

Money,of course is a large part of why you might want to do as much of the work yourself.

Pete

One good thing about a crate engine that in most cases you can pull you're old engine and put in the new one over a weekend with some help and you'll be back on the road.

I grew up around a very high-quality shop near the end of the era of the in-frame overhaul. A couple of situations contributed to that type of repair going out of style- - - -limited access to the engine due to the engines growing to fill all the available space under the hood, and the tendency for engines to wear out all over instead of being able to benefit from a "ring and valve job" repair. It was not uncommon to pull a 216 Chevy head, regrind the valves, replace the rings, adjust the rod bearing clearances, and reassemble the engine within the space of 2 or 3 days in the shop- - - - -total cost of less than $100.00, sometimes MUCH less!

About the time the 55 Chevy 265's started needing engine repairs, we ran into chronic low oil pressure problems after in-the-frame overhauls. Even replacing the rod bearings didn't seem to cure the problem. We found that the culprit was worn cam bearings which starved the rod and main bearings for oil. Replacing cam bearings required pulling the engine and a complete teardown. The Melling high-volume oil pump was still on the drawing board, which might have fixed the problem, but overhead valve V8 engines just wore out all over, rather than benefiting from a minor rebuild like the older engines. By 1958, it was virtually impossible to get the oil pan off most V8 engine cars without doing major surgery- - - -easier to pull the engine! Getting the oil pan off a 1970's era Pontiac required jacking up the engine, putting shims between the motor mounts and the frame, then unbolting the #1 main bearing cap and dropping it into the oil pan before sliding the pan off the crossmember.

Today's cars with main bearing girdle construction on the engines like most Cadillac V8's require splitting the block into upper and lower sections just to get to the rods to remove the pistons. That's definitely an out-of-frame job!
Jerry

I don't like to deviate much from the original design on an AD. The 6 cylinder is really native to it so I stick with that. I DO go to the next generation 235/261 (54-62) because they are full pressure oilers and insert bearings. I take the block and head to the local engine shop for hardened valve guides, cleaning, decking, magnafluxing, boring, etc. I like to buy the rebuild parts and kits from the same engine shop, then I assemble it all myself. No better feeling than starting it up after all that work and knowing you had total control of the quality, etc yourself. They are pretty straightforward to rebuild and something I enjoy. Not for everyone.

I still fix 6 cylinders like I have been doing for over 50 years. If I pull the pistons out of a GMC and the bearings still mike within specs, I tape up the rod journals and hone and crosshatch the cylinders. Quite often the original complaint was blue smoke and all it was is that the rings stuck since it was last driven. If I find aftermarket bearings that are worn beyond specs, I figure it is time for an out of frame. On a 6,I check the deck and if it is straight, I assume the line bore to be ok. If the block needs cylinders bored, I take that to a machine shop because I'm not equipped to do that. I pull the valves out. If they aren't burned and the stems mike good I reuse them. I narrow the seats a little with a 15° stone and a 45° stone. If the guides are bell mouthed, I press in new ones and ream them out to a little more than the minimum clearance. I have too many old jalopies to take all the blocks to a machine shop.

Deve, where do you buy hardened guides? Just pulling your leg, I know you meant seats. My machinist talked me into them as well. No more than I drive my truck, I doubt if matters that they are hardened. But since they are all new, they won't be recessed like they would be if he would have reground the old seats.
Carl

I do like many others. I do all the work, except machine work. This way, I know the care was taken to put it together properly and seal it up tight. If something goes wrong, it is my fault. Before assembly, I check the machine shops work to ensure parts fit properly.

My machine shop talked me out of hardened valve seats, I deferred. Stock 216 bored .30 over with aluminum pistons. Original babbit all good and got .002 clearance by just removing shims. Many of the rods still have a shim or two installed to maintain minimum clearance...amazing! Can't wait to start her up for the first time.

I'll pull a motor in a heartbeat rather than work on it while installed. My little L134 for example... adjusting valve lash on an L head in the frame is doable, but not a fun afternoon. By the time I take off the fender, exhaust, steering etc to get enough room make the adjustment, I could have spent an extra 30 minutes to take out the motor and do the work while sitting comfortably in my shop chair.

If you motor is matching, or a specific time period (aka 'early' vs 'late' features) the issue of crate vs DIY is not even an option. I think that is also an important consideration.

I'd pay good money for a proper 40's 235 motor for my truck. Babbit bearings, dippers and all.

x2 - I pass on the hardened seats of a mostly stock engine.

Most engine self engine assembly jobs are guess work. Most DIY mechanics have no clue about precision measurements required to do the job properly, or why its necessary, I think theres a few automotive shops that fall into that same category too I've heard some horror stories.

As the original post suggested:
Patch: If a simple fix will work with little downside then "Why not?" Consider, points, fuel pump, valve adjusting, No great controversy for those tasks.
Rebuild: Starter, Carb, Genny, Dizzy..you get the picture. So, what skills do you have? And how much can you spend? What is it worth to you when you know what you have and...what you can fix,.
Re-manufacture: Just so you know I hate this term. Hate it. What is the difference, Rebuild? Re-manufacture? OK so maybe that is another discussion. Any way, New or crate verses do it your self.. again match skills to the task. I don't know how or have access to do crankshaft grinding...so I get to choose a machine shop to do the work or buy a new crankshaft..I can use a micrometer so I can decide when the crankshaft is too far gone. You can see that the mix of skills is at least as big a part as as the choice to fix, repair or replace. I have watched some folks buy a truck all done and enjoy it well. Watched others do every thing that they can on that truck and enjoy it well. And some are in the middle.
Engine work is not a special case. How many of us do third member work?, Transmissions? Instrument work? Generators? Some of us will try any of it and some will say not.... So the upside? I know what I can fix and I know what I have. The down side? I am the warranty guy. Still I would recommend, do what you can, learn what you cannot, add skills as you go, and have some fun while you are at it.

Boo. Maybe true, but I believe to think that people who attempt engine assembly know what they are doing and know what to look for. Research is easy and almost any decent DIY'er can rebuild an engine. It is not rocket science. Just make sure the machine shop did not make a mistake and go from there. If in doubt, ask ask and ask some more.

I've sold a few 235's and gotten rave reviews. You DO have to know what you are doing, or in the very least, like when I started, KNOW what questions to ask. As far as hardened valve seats, doesn't hurt do just do it, so I just add the extra insurance on each rebuild. If there is anything controversial, I always err on the side of caution. But, its all about having fun doing it!

Well guys here goes my experience. My 235 in my 1956 3100 was totally locked up, so a patch was out of the question. I talked with a few car guys and after going to a lot of car shows and seeing all the v-8 conversions, I decided to keep the original 6 cyl. inline. First, I thought it would be cool to have what I think is the original motor at least it is period correct. Secondly, I think the floor "stomp" starter was a very cool thing that I hated to lose. Lastly, I saw a 1956 Chevy car with a painted 235 with an dual 2 bbl. carb set up with all the eye candy. I really fell in love with it.

My experience with motor repairing was nothing more than replacing the basic items such as brakes, water pumps, alternators, starters, thermostats, heater cores, etc. I wanted to rebuild my 235 and asked a friend to help me in the things I did not understand. My 235 was frozen and for a week I was trying to unseize the motor by removing the spark plugs and pouring oil in the block and rocking it back in forth in gear. After that idea did not work, I removed the engine and started the disassembly process. I was told by many I had a boat anchor. In the block I could not remove some of the lifters and the I left it to the machine shop for assistance. The machine did all the machining work , magnafluxing, reboring .030, head work, installing hardened seat and new guides, installing pistons on the connecting rods, resurfacing the flywheel, pressing on the camshaft gear and polishing and turning the crank -.010. I purchased all parts and assembled the rest.

Here are the +'s for me. I learned so much about the 235 not to be an expert but I now have first hand experience and I have a complete understanding of this motor. I even learned what a draft tube was. Once I finish the truck I know I did it, that's a huge plus for me. Yes I had help from the Stovebolter's here, parts vendors, machine shop, and sometimes my friend, however the truck was built the way I wanted it to be built, by me, and will be driven by me. I also get to buy new tools.

The -'s time, money and space. My garage is my workspace and my cars which used to be in them now are in the driveway. Yes it takes a lot of time as we all know especially waiting for things from the parts places or machine shops. Money I could have bought a crate sbc engine or had a sbc rebuilt a heck of a lot cheaper than the 235. I think with all the machine work, added eye candy, new parts, and upgradeds it was around 3500 usd.

Another huge plus for me I did something I was not sure about doing. Instead of going to bingo and playing the one arm bandits here in the casino, I found my money pit in the old Chevy and at least I have something to show for it. to sum it up.

+'s satisfaction, pride, enjoyment, and learned something new.
-'s time, money, and space

from this original head
235 before rebuild

to this
235 motor

I am doing it with my limited knowledge.

that is one CLEAN engine! looks great!

TJ - I think that is the worst rocker assembly I have ever seen.

tiny_jamie, very very well said. A lot of folks need to read your comments and stop bickering and arguing in another place.
...and you are right on with your engine. A couple years ago my nephew and I went all out building a 235 for a restoration we did for a fellow. Engine cost....$2800-$3500 depending on what you consider engine stuff. Regardless, the engine was $3500 and that is what the customer wanted..... and had been VERY well pleased ever since.

Good summary. Many bolters will appreciate it.

Yeah.. all that discussion, on a discussion forum... those people really should know better.

I still don't know what is so difficult about fixing a motor. You read the manual, a lot of times the fix is right there.. if X, do Y. If its more than that you can post online or find a shop to ask. People really like to talk about this stuff and are happy to help.

Other than needing specific machines (mills, lathes, grinders, boring machines) etc it really is as simply as unbolt X, bolt on Y.

Sometimes you do need to take a measurement, or torque to a specific value, and in the past those tools were very expensive. Not a days a micrometer, dial indicator or torque wrench can be bought for $20 each at any good hardware/tool store.

Let me ask.. what is the most difficult thing that people are 'scared' of?

For me the camshaft is the worst. You need a special tool to pull/seat the bearings. But other than that I find nothing so difficult that it would deter me from a DIY repair.

GM Jager thanks for the compliment.

5150scott yup I agree when I pulled the rocker cover off and then the side cover off I had to use a shop vacuum so I could see what was there, then I thought OMG what have I gotten into.

Achipmunk that was a very nice compliment also but the real credit really goes to this site. I still remember having frustrations trying to remove the clutch housing on that 235 with the pistons and lifters frozen into place. As I would make a little progress I would come here and post my question, and wait for all the wonderful responses. Even though I read the shop manuals but there was always a been there done it Stovebolters that was taking time to post a reply to help me with what I did not understand or knew what to do next.

I also want to add in the +'s column the cool factor of the 235. The first on I saw really took my breath it was such a beautiful site. Just about anytime I see an old timer I can make conversation about that old truck and I can listen to there stories about their experiences with old cars and trucks they had. One guy today was telling me about his car where he used the throttle cable for a cruise control.

Not to hog this thread but before I started the tear down I read Chevrolet, GMC & Buick Speed Manual by California Bill trying to get ideas on how to hop it up. Me I was so confused with really what to do with so many ideas I just jumped into it piece by piece and what I could not do I let the machine shop do. Here in Las Vegas before he sold his business I went to a local machine shop called Jack's. He told me of his old racing days on the dirt track where he said in the turns he would whip the v-8's and in the straights the v-8's would take him. he also stated in the 1/8th he always took a v-8. I heard all his racing stories and what he also told me that they forced him to run a v-8 put you could see the passion in his eyes when he talked about the old stovebolt engines.

After I finished my 235 and put it into the frame I really fell in love with the way it looks. My truck when I bought it came with a 350 sbc I am so glad that I sold it now. For me all the eye candy really is satisfaction on the 235. My last piece of advice is if someone is going to rebuild one like what I did I would read the book Rebuilding the small-block Chevy by Larry Atherto and Larry Schreib. Yes I know its not about the inline but most of the same principles apply. I did mine backwards I am usede to doing things the hard way, I rebuild mine 235 then read the book and it really hit home and brought closure to why I needed to do what I did on the rebuild. I am now reading Chevorlet Inline Six-Cylinder Power Manual. Its very interesting.

Lastly, I think to each is their own and you either love the 6's or not. If you want a v-8 that's cool too. I just knowing what I know now would not pass up the opportunity of rebuilding another inline 6. It may be an economic thing for some one wanting a crate engine but for me it was worth the expense, time and space for the 235. I understand the v-8's are cheaper but I really appreciate and admire the old technology.

I agree that the I6 layout leads to a very tidy and clean engine bay. You can actually see the motor.

Your story leads back to why I am so pro-DIY. How do you think 'California Bill' learned all those tricks? By doing it himself or buying a 'crate' motor? Nothing about a 235 (today) is so rare or expensive that you should not dive in and get it done yourself. We have the luxury to stand on the shoulders of the real 235 geniuses from the 50's when we work on the motors we have now.

I'm really don't care if you use an I6 or a V-6/8.. but if you say you ordered it out of a catalog you lose major 'motorhead' points. A 6 year old girl can order from a catalog. A smart 6 year old girl can build it herself. One is worth talking to, the other not so much.

And Henry Ford became an icon by building every Model T motor himself......He could push a button and have whatever he wanted, but he still had to know what button to push and what to ask for.
Same with old trucks, everyone can't do everything, but the guy who has the plan ends up with what he wants.

I really like the looks and performance of the 235/261s in the AD trucks. I posted a few pics today of the 261 in my current project to show how to plumb the PCV and fuel/vac lines. I plan on putting AC on the truck someday and I know with the overdrive trans it will do 70+ all day long. Nothing like the feeling that you get when you do it all yourself.

I've asked this at least three times and no one has really given an answer:

What is so difficult about rebuilding a motor?

Not counting machine work (which it could be argued unless you have an issue is not really required) why are people saying its hard to do?

I'm curious to hear what is supposed to be so hard that takes rebuilding a motor out of the realm of the DIYer with even a modest amount of skill.

Even though I don't do my own cam bearings (I can't justify a $300 tool when I can pay a shop $35 to install) if it came down to doing it I could easily seat the bearings using an ah-hoc tool.

No one is arguing that it is difficult, some people just don't want to, or they don't have the time, or they don't have the space. There are many people who couldn't do it regardless of how many manuals or tutorials they read. There are so many people just amazed at what I do, while I am amazed they can't figure it out.

A lot of people admire this kind of work but aren't as mechanical as others. Its really a huge thing for them to take the plunge and do something so foreign to them. No different than someone asking you to get your MSCE certification from Microsoft. Now that was just about as challenging as getting a pilots license w/IFR, or any number of other certifications having to do with the job.

If you can overhaul and engine, you have a special skill that lots of others would love to have. From a 235 in 1976 to a 289 in 1978 and on and on.. you have to start somewhere. Does that help answer what is so hard about it? After this many years of human interaction, I am a genius to some, a complete idiot to others. I just do my thing and hope others benefit.

Patch or Rebuild or Remanufacture

which ever is best for YOU.

I am not good at getting sheet metal perfect for paint, so I stop before I make it worse. I can't do drywall seams either. My oldest son cannot put the cap back on the toothpaste without cross-threading it. The only thing he can fix is a sandwich. In the immortal words of the Dirty Harry, "A man's got to know his limitations."
Carl

Exactly knowing limitations is the key. Bravo well said. Knowing how to do it and actually being able to do it is really two different things. I love the drywall example. I seen it done, I know how to do it but hiding the seems is just not my nack.

Now days you can just about Google or You Tube any info. Look at this site you just plug in your problem and you can get a bunch of replays. There is always a great tech tip here. What did they do back in the day before computers? I had to laugh if you read the old manuals for instance when installing king pins it said to use lard.

I vote for a rebuild however because I had the space, the tools, the money and an engine building buddy (like when you go swimming). I posted a lot of questions and read a lot of articles. I am so glad I did it and I am glad I did not miss the opportunity to learn how to rebuild it or miss the opportunity to learn about the 235.

I understand the patch for a temporary fix, and you gotta do what you gotta do.

I would not discard the remanufacture if I did not have the confidence or skills I guess that's where knowing your limitations comes in.

I guess I just grew up in a different generation. About 3/4 of the boys in my class grew up out in the country and they had to help their father's overhaul their old John Deeres, Farmalls and pickups as well. The rich kids who lived in town weren't allowed to get greasy. And then there were the hoodlums who weren't in ag, band or sports, who walked around with a cigarette hanging out of their mouth and a pack of Camels in their T-shirt sleeve. We all wanted to have the fastest car in town. I had a 50 GMC pickup that would blow the doors off of a 235 and would stay up with the Fords. When I got out of high school, I bought a Y-Block Ford and I seldom saw tail lights.

Then came the muscle cars. Rich kids who could talk their father's to buy them a muscle car could blow my doors off. And most of them didn't even know how to change their own oil. Even though I got a degree in accounting and pre-law, I never lost my passion for things mechanical. It will be 50 years ago next month that I bought my first semi. It was a GMC with an Olds block V8. I bought it in the town I went to college in and it took about a gallon of oil to drive it home 90 miles. I had two cylinders that were too bad to go 60 over, so I pulled the motor and had two salvage liners put in. For 5 years I had to pull the heads, hone the cylinders and re-ring it about every 100k miles. I then went to Cummins Diesels. Before the electronic engines came out about 25 years ago, mechanical engines had to have cylinder kits about every 100k miles and I did a lot of the work myself, but I had helpers who I had to show what to do. And I still spend a lot of time in the shop. I run all 2003 models because that is the last year of pre EGR. And they are all pretty rough when I buy them.

I don't trust machine shops to do valves on my old jalopies. Too many of the guys these days don't realize the clearance that valve stems need clearance to keep from seizing. In fact, I think every head for my old jalopies that I sent outin the last 30 years, I would up reaming the guides to suit me. I want them to use a quart of oil every thousand.

I have books for reference. But everything I learned was from having the luxury of watching old timers do it over 50 years ago, or from doing it wrong and figuring out what went wrong.

Yup, Cren.. you are a dinosaur. Just like me. I have the very same memories of the hierarchy in high school and beyond. We didn't have computers so we relied on something called human interaction. Its a bygone concept, but we used to decide who our friends were by there mannerisms, the way you were treated in person, and we shared information based on our instincts that the person we just shook hands with understood America the same way we did. Hard work, using your head, and compassion drove us to do amazing things. NOT the government student loan program. Oh well. All that's really left is for us to feel good about the fact that we were there when things made sense. Oh.. and REBUILD!! LOL!