The Stovebolt Site Forums The Shop Area Engine Shop 235 engine rebuild

I have a 235 motor which has about 77k miles I believe, I dont know if that is leaking oil also. However it is too much work to put the engine and find out it needs rebuild. Since it is that old, I thought it is better to rebuild.

How difficult is rebuild the engine and I have no experience in rebuilding - I have to read books and rebuild and people have told it could cost about 2000k min.

Any thoughts please, I would really appreciate.

Ganesh

If you have no experience, i recommend that you take it to a qualified mechanic. The $2K-$2.5K will be money well spent. Cecil.....

Thanks for the advise 51Jimmy

If you feel confident enough to disassemble it it could be a very rewarding experience to do some of the work yourself. Take it apart, have the parts cleaned commercially, Have the machine work done professionally and them put it back together with new parts. It's not like it's rocket science or anything and you can always bail out and turn it over to a pro if you lose your nerve.

Doing your own work is a huge part of the experience of owning an antique vehicle so if you don't need it right away and you feel adventurous, go for it.

I agree with Czechman. I was in your shoes just a few years ago. I had never done anything on an engine other than an oil change. They are not that tough to rebuild. Just take your time and follow your manual. If you run into trouble everyone here on the Stovebolt site is ready to help.

It's a great experence to learn something new. Don't miss out.

Good luck
George

Man thatz the inspiration I needed. I know it was not easy but I can always stumle through and get something done.

Thanks guys, I appreciate.

Ganesh

Just a suggestion....before you start tearing it down....line up your machine shop who will "dip" the engine, clean all the internal passages, mic everything, check the head for cracks and do the hardened seats and valve job, grind the crank, bore the cylinders, check the balance of all the rotating components, dress the flywheel, and several dozen other necessary operations, and see if he is willing to work on an engine that comes to him in pieces.

If you can find a shop that will take on this kind of job, you're lucky. Most, in my neck of the woods, will pass on this kind of work. Once he finds out you're in the O.J.T mode and are planning to get "experience" putting it back together and having it run, he'll be "too busy" to even do the machine work.

When you figure up the retail cost of a full rebuild kit and the cost of his machining, the $300. he gets for assembling it correctly and backing it up with a warranty is money well spent. There is no single manual in print that will take a newbee through an engine rebuild. Building engines, requires some pretty specific hands-on skills as well as equipment to get it done right. Save yourself some heartache (and money) in the long run and focus your energy on something more realistic.

I don't mean to sound overly critical, but I would be remiss if I didn't point out the many pitfalls you may/will encounter.

Dave

Dave,

That is a very detail and good information, one of the question I was going to ask was what should machine shop do and what should I do. I think you pointed me into the right direction.

Thanks once again.

Ganesh

One of the most important functions of a machine shop is to evaluate the true physical condition of the engine block to verify that it is a candidate for rebuilding. A 50 year old block can be subjected to a variety of conditions. Blocks crack, heads crack and warp, engines are put together with mismatched parts and it would be a shame to waste your time and money without determining you had good sound cores to start with.

When the shop disassembles the engine they can visually note trouble areas that are obvious to them but you might overlook. After they "boil out" the block there are several methods of checking for cracks, misaligned surfaces and points of wear that will effect the life of the rebuilt engine. They have the equipment and expertise to insure you aren't wasting your money on a defective block, crankshaft or cylinder head.

Something that you might be overlooking; does your engine even NEED to be rebuilt? You might be jumping the gun without getting some expert advice and wind up spending big bucks on an engine that might be brought back into decent running condition without a major overhaul. Getting a compression test to determine ring sealing and condition of the valve train and checking for decent oil pressure, is warranted. Also, oil leaks, as long as they aren't from the rear main seal or excessive "blow-by" from stuck or worn rings can be corrected by new seals and gaskets. The rear main seal can be a real challenge!! These are some things you can visually check out. If it is determined that the engine has weak compression, burned valves, low oil pressure, and some lower end noise it's time to dig deeper into your pocket and have it rebuilt. I'd highly recommend seeking some professional help in doing this preliminary evaluation....you might just get lucky.

Dave

My first rebuild was the B61T's 711END...came out well as i put 75,000 miles on it than i had turbo added it's still holding up very well. . . My first rebuild was a high compression non turbo disel that's now holding a turbo's boost. . . year's later truck will still haul a D9 cat 67mph and not bat an eye. . .

It took me 10 hour's to pull it out of the truck and about 14 bout's to get it back in and running. . . I spent 2 month's working on it nerviouse the whole darn time oit's when you don't get nervouse on the first start up of new engine that you should worry. . .

i wish ya the best of luck there is hunder's of good guy's to help ya out. . .

Mike. . .

Fla54Chevy3100,

So you're saying that the very first step of a rebuild should be to take it to a machine shop and have them evaluate it? If it passes muster it sounds like you're saying they do everything? I mean if they inspect it, disassemble it, grind the crank, do the valves and "square up" everything... what's left to do when you pick it up?

I don't know where your located by in So Cal. They have a web site that specilizes in old engines. Egge or Egg. They have and can do should you have the need. I personally would go for for the do it yourself route, however as mentioned it really may cost alot more in the long run, But you won't get the experience. Then again think of what your really good at and concentrate on that. Put like that have it done. But then look at the fine mess I've gotten myself into. I don't follow my own advice HA.
Wizard 50

I am located in Varginia and lot of guys out here say that they dont rebuild old engines much or otherwise they give a eastimate like 90$/hr and they dont know how long it will take

Just to swap motor they wanted 1500$, so that is the reason why I am trying to do in do it yourself route. Dave has given lot of information, but if I could find a engine rebuild manual, if one exist - that will help me to look at the rebuild process and what specific tools, I would need to tear and rebuild and what specific jobs I have to go to machine shop. These are some of the things I want to list it down.
I will see if anyone has more ideas.

Ganesh

Not necessarily...if you've got a compression tester (and know how to use it) you can get a good idea as to whether you've got a ring problem or a problem in the valve train. Smoke on initial start-up could be a seal or valve guide problem. Smoke after warm-up and under load would show up on the compression gauge as a ring problem. Reading the plugs is also a good diagnostic tool. Lower end diagnosis, is basically getting an accurate picture of the oil pressure and noting noise from the rotating assembly. If you find that your problems are in the head and valve train you and an experienced friend could tackle that job.

Once it's been determined that a rebuild is in order and you've delivered the engine, the machine shop takes over with the evaluation, machining, and assembly. If you've got the necessary equipment and expertise, this is where you can save a few bucks and reassemble. If you're short on either of the "E's" you'd be wise to let the builder do the assembly.

What's left to do after a shop rebuild?.....well Woody, hopefully you've prepped the engine compartment, gotten the correct clutch disc and pressure plate, installed a new pilot bushing, installed the clutch disc and pressure plate, added new motor mounts, bolted up the transmission and clutch linkage, added the starter, water pump, intake and exhaust manifolds, got your distributor set with static timing, and ready to pull for pre-oiling, added a new thermostat, hoses and charged (and burped)the cooling system, installed the fuel pump and lines, rebuilt or replaced the carburetor, added fluids, pre-oiled, primed and fired the engine to run in the cam, adjusted the timing and carb.....when all of this comes together and there are no knocks, or vibrations, and the engine idles down to a purr, you can sit back and feel good about your success.

Dave

Thanks Dave, that's a great help... It all sounds pretty straightforward and logical. I figure in a year or two I'll be thinking of a 235 upgrade and pretty sure I'll be doing as much of the rebuild as possible.

Stay tuned

Woody...There are a few improvements to the basic 235 that should/could be performed....and a few areas that are critical to getting the most out of your rebuild. Aside from verifying that the engine is a good candidate for the expense of a rebuild, the machine shop can drill and tap it for full-flow oiling, drill your crank for installing a SBC harmonic balancer bolt, drill/tap the front main cap for installing the 2 bottom timing cover bolts from the outside, insure your crank thrust surfaces will give you the proper end-play as well as the same for the cam. The crank rear main seal area may/will need some surfacing if you want to run an upgraded rear main seal.

As I think about it.....you could save a few bucks by having the shop install the lower end and pistons...basically build you a "short block" and you'd be safe as a novice, with plenty of care, to install the head and the other bolt-on components. This and getting it running and tuned will give you plenty of experience and the folks on the STOVEBOLT can help with any little bumps in the road. With that done, you'll know that the bearings are all properly installed, your end plays and ring gaps are correct and that she's make oil pressure when you finish buttoning her up.

There's nothing any more frustrating than to pour your time and money into a rebuild and have to lay on your back and try to figure out why you've got a "knock" or low oil pressure or a few other problems that could take the joy out of your rebuild.

Doing a total rebuild and is a satisfying experience, if you have the necessary equipment and expertise, but it can weigh heavy if you over-estimate your ability and get into a bind. Too me, the peace-of-mind is worth the extra cash you pay the professional.

Dave

Dave,

How much do you estimate it would cost just to have a short block built with those upgrades... including parts?

I had my 1960 235 done by a pro builder....the total was $2300. for name-brand parts....no cheap stuff and it included the full rotational balance, replacing 6 mismatched rods, drilling for full-flow oiling, drilled for SBC crank bolt, timing cover bolt mods, bored .060, crank turned .020, new hydraulic torque cam, zero gap rings, hardened seats, new valves, milled the head, decked the block, and resurfaced and installed the flywheel and bellhousing.

So what did I get for my $2300? An engine that is as smooth as goose-grease and peace-of-mind!!! And at this stage of my life....that's priceless!

For a short block....I'd venture a guess of $1600-$1700 with the balance job. It was $250. and the balancer threw in the set of replacement rods. However, even though my engine will probably never see 3500 rpm's I would advise getting it balanced. Part of the expense factor involved getting a builder, who is familiar with, and willing to take the time to do the little operations that make my engine run a little smoother and function in a highway environment, a whole lot faster pace than when it was manufactured.

Dave

Thanks Dave,

Please don't misunderstand what I'm about to say because I'm only saying it for the sake of discussion but it sounds like what you're describing is more than a rebuild and more like what we used to call "blueprinting"... bringing a stock engine as cose to optimal tolerances as possible.

Rest *assured that your advice has not fallen on deaf ears. I respect your approach but I don't think that much dedication to perfection is necessary to "rebuild" an engine. If you look at what a rebuild is logically, consider that a "suitable candidate" for restoration has already run what... 70,000 miles from a factory that initially *assembled it with much less care that what you're describing. If it'll go that far under those circumstances I would think it would go that far again with an "average" rebuild.

What you've said has been very enlightening and perhaps when I get to that point (and have the money) I'll go your route but I still think a reasonably intelligent person with an above average understanding of an internal combustion engine (and the help of a good machine shop) could accomplish the task of rebuilding a 235 with excellent results.

But that's just me and my what-the-hell attitude speaking, while in the back of my head I'm hearing the words of a respected mentor saying "Woody, there few things in the world more dangerous than a fool with enthusiasm".

*Since when is [censored]embled and [censored]ume considered foul language?

Fla54Chevy3100,

Dave, I have followed your photo albums with great interest, and have learned many finer points from your postings, I frequently go to your site just to re-read what you have done with your engine & T5 tranny - I thank you for taking the time to prepare and post those photos. It seems that I have more to learn.
My 261 is at the machine shop right now, stalled while we await the arrival of a cam from the US (it has been nearly 4 weeks since order). Why do you recommend putting an harmonic balancer from a Small Block V8 (SBC) on an I6 ("bore the crank for a SBC bolt) and also drilling / tapping the main cap to allow installation of the timing cover bolts from the outside. I have already drilled and tapped my block for full flow filtration - that was interesting getting that chunk of iron mounted in my drill press!

Thanks in advance - to all for a good discussion here

Woody...I truly understand where you're coming from and the spirit of your responses. My feeling is that I, as well as everyone else should get the very most for their rebuild dollar. We've, in many cases, become a society that is satisfied with the statusquo and the younger folks aren't even aware that a little bit of attention to detail can make a big difference in the end result. I applaud those who take the time and effort to develop the skills to tackle "mechanical things." Having devoted a good portion of my life to encouraging young people to explore and master technology, I often cringe when I see the cavilier attitude displayed by many of our so-called artisans. [censored]uming that both you and I are at about the same place on life's path, I can truly understand why you would enjoy doing your own [censored]embly. However, I think it's important to share with those younger folks who read the posts, who might not have the expertise or the dedication to tackle projects, with some insights that might prevent them from failing. That's probably why my posts are "long-winded"!!!

There are a multitude of things in this life that we can't even attempt to control. Engine building shouldn't be one of them. I guess I come from the Ol'Skool where I want things right and I recognize that there are still a few folks out there in the shops, who share my sentiments. Luckily, I found a guy who would do it my way and was as concerned with me being totally satisfied as getting my check into his bank account.

A few of the things I pointed out for the machine shop to do, in addition to the normal machine work, are meant to make life easier for me down the road. My Chevy project is meant to be dependable, economical, and most importantly, fun to operate. If I can help some young guy with more enthusiasm than expertise avoid a pitfall, then my journey has been worth the extra keystrokes.

Dave

Well said Dave... and thank you.

I agree with Czechman. Most of us don't need a motor that has had all that exotic work done on it. I couldn't imagine missing out on the hands on enjoyment of putting a motor together. It is such a thrill to see the result purr away.

I think it is the correct approach to rebuild a vintage motor with 77K on it before installing it. These 235s are one of the best motors to learn on. I say go for it!

I must be missing something somewhere....exotic work; drilled and tapped so you don't have to beat the balancer on with a hammer, drilled and tapped so you can change a leaking timing cover seal without pulling the pan and dropping the front main cap, or drilled and tapped so that you can supply your rods and mains with 45 psi of oil pressure and filter all the oil instead of 10%. As far as the balance job...the PO of my core engine was tooling around with mismatched and unbalanced (13 gram spread) rods....I guess a 50 year old, 135 horse engine doesn't warrant some tweaking to make it easier to maintain and run a little more efficiently. I'm hoping I misinterpreted something along the way!!! Wouldn't be the first time!

I guess the point I'm trying so miserably to make, is that if you know what you're doing, have the necessary equipment and the time to do it right, I TOTALLY AGREE that the experience can truly be enjoyable. However, if you're lacking in one or more of the above, it can be frustrating and expensive. Being able to determine your own limitations should be a priority.

Dave

Since the idiot who maintains this site (that's me) can't figure out how to do it correctly. (I'm looking at it now.)

Ok, now I'm assessing the results. Hmmm...looks like it worked....wait, WT [censored]???? [censored]. [censored].

OOOOOOOKKKKKKKK.....Houston, we have a problem.....I'm going to have to report this to the developers.

Now my question would be, what exactly do you drill and tap to turn a low pressure 235 into a 45 psi motor. If it were that simple, we would all do that at rebuild time.

Paul, I understand that rebuilding at home is not always a choice. My point is I wouldn't want to discourage someone from enjoying the experience if they wanted to give it a go.

Fred

This article explains exactly how to drill and tap a stovebolt six for full pressure oiling.

I may be more fortunate than others but I have 2 motors, soon three. One which runs and I'm gonna use or have reworked by a professional if needed.

I was told by a mechanic that he could rebuild one at half the cost as long as I brought only the motor to him, compared to it still being in the truck. I was under the impression he would do it for about 700 to 800$ as long as he was just rebuilding the motor on a stand and was not fooling with the other assesories or installation.

I have been given two motors because nobody wants these "boat anchors". One motor which is only promised, i've not yet recieved, has been freshly overhauled and runs great. The current owner has already purchased a high performance crate 350.

The 235 in my truck, I shouldn't need and I plan on tearing it apart and putting it back together for experience. Maybe I can get it to run.

To make a long story short. I wouldn't surprise me if you could find a free 235 some where and get all the experience you need. While not being dependent on it for transportation.