The Stovebolt Site Forums The Shop Area The HiPo Shop In over my head -- 1953 GMC 3100 project

A little backstory: I purchased a 1953 GMC 3100 as a project for a road trip for my wife and I for our 10th anniversary (Summer of 2016). I have some mechanical experience (mostly on motorcycles: '99 ZZR600, '06 ZX6-R, '00 CR250R, '03 XR100, '07 YZF-6. A previous unfinished 1957 Buick Roadmaster 75 project, and lots of DIY maintenance). The truck turned out to have a what I believe to be a 1955 Chevy 235 (.060 over, cracked block), a 1970 K10 differential, and an SM420 transmission. Since deciding to purchase, my wife has decided to stay home with our kids and we have had to cut expenses. I'm trying to get this project on the road, with an acceptable build quality and respectable dependability, as inexpensively as possible. This is meant to be an ongoing project with, possibly, a "shop truck" look.

Now on to the actual problem. On account of the block being cracked, I am looking for suitable swaps and have found the following options:

$1000 for a 235 pulled by a shop in Kerrville, TX (5 hours from me) out of a running truck for a diesel swap.

$125 for a '57-'62 235 that is seized. Unknown mileage or history. I would be able to swap some of my parts over and would hope to be in at around $1300 for a complete rebuild (IF the engine is rebuildable at all. The owner is not allowing me to pull off the head and inspect the cylinders/overbore of the engine).

$150 for a 2001 4.8 Chevy LS with no coils, water pump, or sensors. The computer and harness are available for another $150. I'm also aware of the MSD 6LS carbureted set-up ($700)and weld in motor mounts ($100). This puts the cost at $1100, plus coils, manifolds, and an exhaust. I could also go the fuel injected route and invest the $700 of the MSD system into a tank and pump. I would estimate the cost of this to be in the $1600 range, but I am unfamiliar with this process and would like some feedback on costs I may be overlooking in doing an LS swap. I'm also unsure of the necessity to switch the tank to the bed. If I could run an external pump and keep the tank, that would reduce the total cost by about $400.
I appreciate any input in helping me get this done.

How much to repair the crack in the block?

Option 3 sounds like the longest and more difficult to me.

Option 2 sounds like out of the frying pan into the fire.
How do you know it doesn't have a cracked block, needs sleeves or something just as bad?

Option 1 I'd consider if they could show me a video of it running before they pulled it, otherwise I'd see it as six of one and half a dozen of the other with option 2. Ten hours of driving is a lot of trust in some shops word...

With the investment of a mag drill(and maybe not even that) and the C series kit which runs about $350 and will do a 7" crack you could be up and running with a new tool and fresh skills to boot.

I'd call and talk with them and see whats up anyway.

Thank you. The engine smokes as it warms up, leading me to believe the cylinders may also be affected by this crack.

I'm considering offering the shop a trade for a Lincoln Electric Power Mig 255 I picked up at auction...

"'99 ZZR600, '06 ZX6-R, '00 CR250R, '03 XR100, '07 YZF-6" - this looks like an enzyme test profile to me.

CASO is spot-on & can help you over here in the Hipo- I just wanted to tell you good luck. Also, I have helped with several (3 or 4+) LS installs into classics... You probably won't make your anniversary going that route, is my only comment.

Brad

I appreciate the input and well wishes. What part of it is the most time consuming? I would tend to think it's the wiring, which the MSD kit is supposed to simplify greatly. I have also heard the steering rack/linkages are affected. Any word on this?

You say that saving funds are a high priority and you want to develope better old truck skills.
But buying other people's castoffs and then paying machine shops just seems a bit counter to those goals.

Will the guy who has your truck now let you pop the head and check things out for yourself so you actually know what your cylinders really look like?
You could even 'practice' doing a hone and ring set while your at it to see if that helps your smoke situation.
Either way what smoke I saw in your videos was nothing as far as "She's getting ready to blow captain!" So I say drive it till it does... pick up and rebuild your next one while you wait for that day to come.
And unless you have another welder why get rid of that one? They are way too handy to have around an old truck.

The part that takes place during the commercial breaks...

Transmission on the LS, or keep yours?

Wiring, yes, it was time consuming- I am not familiar with the MSD kit (or, if I helped with one, I did not know it).

I have never helped on an install of an LS series engine, in a classic truck or car, when the front end, steering, power disc brakes, and rear end weren't ALL changed/replaced/new parts.

The ones I helped with pretty much were like taking a frame and a body and making everything fit the engine & driveline. Not that it is a bad thing at all. Folks do it all the time.

Brad

CASO-----

Read here. Don't break for commercials...

edit-meant to be a joke, because the thread was a little lengthy, But where are these videos???
I never saw a video???

Brad

I've done some preliminary research and the sm420 fits behind the ls... But I have no idea how. I'm sure the 4L60 or 4L80 would be much better, but cost would take priority. Same with a brake/suspension upgrade. That would have to come around a few years down the road.
Caso, this has been a long process getting here. To save you some time, here's the jist of it: re-ring, partially rebuilt head, hone, found long crack on driver's side.
From the conversation this far, I gather this would be your most adviseable decision: have the shop check compression, oil pressure, and valve clearances on the "running" motor in Kerrville. I would consider trading the welder because, while I need it eventually, I don't need this size of a machine. A $400-$600 would do. This is a $1200 welder, but I got it for $600.

I must of been thinking of another thread...
I can't find it sooooo My Bad

Unfortunately, I live in a pretty isolated area. The only 235 in the area in the past 3 months has been this seized one. I'm willing to drive to the San Antonio, Houston or even Dallas area.

Keep the welder... It's like "Wear Sunscreen"

No you misunderstand me... I think you should fix the crack and drive what you have and drive it for at least 2000 miles before arriving at your final decision. ( I personally think it's going to clear up by then)
As said above below while you do that look for a replacement and rebuild at your leisure. If you can pick the next motor up while it's still connected to a decent truck body then BUILD THAT at your leisure as well. (you'll need that welder then for sure)

Before I comment, I can not seem to figure what motor you want, a 6 or a V8. That's first. I also do not see why a person who says they are over their head and want to go low budget, is looking at all those funky mismatch motors and trannys. Also would like to know what the difference is between a K10 diff and a c10 diff.
Sorry about the repost, was still typing.

Replacing the motor with the same era motor is by far the easiest. It's a bolt in! I have found if a person has patients and lives in a populated area and uses craigslist, you can find a running motor, still in the vehicle for $200-$500. Sometimes, if it is the right vehicle, I have purchased the whole vehicle and sold parts, got the motor free and made money. This is an especially way if the seller has no title. Hard to sell for him. If a seller says they just rebuilt motor, I walk away. There are plenty of sixes with plenty of miles left. Examine, run it, drive it, compression check, buy it. Find out what the newest, best internals, most reliable motor that will bolt in from Stovebolters here, they know.

I believe I understand you better now. The thing is, why is an external crack causing smoking. No one has been able to answer that yet. I think the crack is also in a cylinder(s). I don't see why risk getting stranded or running parts I could otherwise sell off this motor.

Gusco, I have been reading everything you have said about your Saga, so I feel I might have some insight on what your problem is. You are not focusing your thinking on a direct path to getting it done, you are conflicted so dividing your thinking into different paths which in the end will either drive you crazy or you will throw up your hands and just sell the truck. Take a deep breath, stop and think about what you can do to organize your thinking into a plan of action.

So far you have done much more harm than good in taking your engine apart and messing with ring gap and then finding your engine has a crack in it. Chances are, the ring gap is way out of tolerance causing your smoking problem. Since the engine is cracked, get another one. But of the same type. Forget all of this V8 stuff unless you have unlimited funding. Steering, suspension, frame mounting perches, it just keeps getting better and better! Make some calls to local salvage yards, Craigslist, Ebay, spread out your distance from home a little wider and find a rebuildable 235 engine for about $200 or so. If your head is good, all you need is the block. Stay focused on one path and watch all of the pieces of the puzzle fall together. If you lived closer, I could help, so I am sure there are people around you that can help too. Just concentrate on finding them. And, good luck on whatever you decide!

That's your belief not mine...
I think the rings haven't set.

The mismatch would be to keep existinting parts (i.e.-tranny). I don't care for the motor choice as long as it is a runner after the swap. I6, V6, V8, ls, 327, 305, 350 are all in the discussion and in the case of the v8s are all locally available. C10- 2wd, k10- 4wd.

I know what K and C mean, you said it has a K10 diff like you thought that is something special. Maybe that is my misinterpretation of why you said K10. I asked what the difference was between them, not what K and C means.
Also doesn't a cracked block cause water in cylinder and hydraulic lock? or water in the oil? What are the symptoms that make you think cracked cylinder.
Are you saying you want to keep the existing tranny or get a motor and keep it's 4L60 or 4L80? Those are mismatch to all the mounting of the motor and trans, mismatch to clutch, mismatch to driveshaft, mismatch to fan clearance, carb linkage, exhaust clearances, wiring...........fabrication, expense, headaches...
But I don't know what type of truck you see it becoming, how much time to do it, money and know-how.
Simple and good = wait for a motor. Don't forget to look at whole cars/trucks that are otherwise trashed with no title but run good. If you can't find that, there ain't a cow in Texas.

The K10 diff came on the truck. That type of advice is exactly what I'm looking for. It's not a simple "weld in mounts, run plumbing, and run it" swap. It requires a lot of fabrication, which I have no experience in.
The engine runs, and as ot warms up, water begins to weep from the nearly block-long crack on the driver's side. As it reaches operating temp, it begins to smoke. Lightly at first and progressively worse.

Post a video on YT and link us into it.
Show it on start up and warmed up and post one looking out the back window as you drive, from a stop as well as 'passing' speed. With this crowd you'll get a good consensus of what's going on with what you have and we'll all feel better going deeper into this thread.

Sounds like a plan! The truck runs, but does not drive (no brake plumbing yet). However, I'll try to get a video so you all can give me some more input.
The seller of the local seized 235 just replied today and may be willing to let me pull the head off.

If you can see a crack, The motor is toast/not worth fixing. Salvage the good stuff. Carb, intake manifold, exhaust manifold, water and fuel pumps, fittings, plugs, thermostat housing, valve cover, side covers, distributor, starter, generator, all that, when the times comes. Pull it out of there and get all ready for another. You don't actually need it right now for a family vehicle do you? Keep the harness all together and the voltage reg hooked up to harness. Label all wire ends and stuff harness out of the way. Don't detach harness anywhere you don't have to. Take pics of the accelerator, clutch linkage, hose hook ups and motor before taking out. Taking off front clip as one piece will really, really help in this process. Inner and outer fenders and front sheet metal all stay together as one piece. Take off front bumper. Plan ahead, roll it to where clip will be stored and roll it back to where the motor will be exchanged. Would not waste 2 minutes on a frozen motor. What are you going to do after you pull the head? Know if the rest is good? use the block? Know there are no micro cracks anywhere? The find a motor that runs and slap it in idea has risks also, but small money and small work to risk. Hear, see, smell, drive under load and compression test can only be done on a runner.
I DO NOT KNOW WHAT MOTORS WILL FIT RIGHT IN BUT:
http://sanantonio.craigslist.org/pts/5225542584.html
http://sanantonio.craigslist.org/pts/5182901571.html
https://houston.craigslist.org/cto/5244107143.html
WOW! here is a money maker for the right guy, me.
https://houston.craigslist.org/cto/5237793830.html

I hear you. The reason I'm willing to consider it is because at $125 bucks, I think the parts can get me that money back. In fact, I think just the 848 head may be worth the $125 on eBay. I'm most interested in seeing that the engine is not already at .060 over or greater since the largest pistons I have been able to source are .080 over. From there, I'd disassemble and be able to take it over to the machine shop to magnaflux it and go from there. I would think one could wire a starter and do a compression check on an engine on a stand.
I do agree with that the runner is less of a gamble. However, that's where I start to think that $1000 for an engine in unknown condition vs. $1300 for a rebuilt one sounds a bit expensive. Now, if that runner had good oil pressure and good compression numbers, that's the definite way to go based on my current options.

Yes you can do the compression test that way, it's always done not running. I guess if you are %100 sure you can buy everything, get machining and magna flux, new parts and labor, $1300 is not bad. If I had done that method several times and had good success and knew my numbers were correct, I would agree. But I have not. Have you? It always seems to come out more because you can't stop in the middle and those who are working for you know that too when they "quote".
Big heavy stuff on Ebay is hard to sell because of the shipping. It takes extra work to pack so as not to blow out the box. That's my experience.

I contacted that first listing in San Antonio.

I could not get the video to work on that ad. I guess it's a 250? It's in Lytle, TX. Will it mount up OK? You are correct, the 848 heads are worth that and more. One sold on ebay for $148 + $75 ship.

The one in Lytle looks valid from the vimeo and the last one is selling for what the machine shop charges were for my rebuild alone. I still had to put it together. . Bettrr option DO exist.

I don't have the money at the moment to purchase a whole truck and wait to recover some of the money.
The big money question now is: will a 250 match up to the sm420 and motor mounts?

The search here is your best friend. See the word search up top here? Click it and enter "250 swap" (with the parenthesis), hit submit and you will have many pages to read. You can PM the guys who have done it from there. The internet will be, likewise, full of info.
Example of what's in Stovebolt:
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=948368
And one with a mention of Langdons:
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=575613

The 250's are good motors. Sounds like you already have open drive, that's good. Do you have 12V yet? GMC was late on that and has some positive ground years. None of which is a problem to fix. 55.2 for Chevy 12V and maybe 56 for GMC?

I do have an open drive shaft. SOME of the truck is converted over to 12vv, neg. ground (alt., but no lights). It looks like this would not be abolt-in, but not a lot of fab work either: engine cradle and move radiator.

That's the impression I got also about the swap but I would have to read a whole bunch and know exactly what to make.

Bulbs are just changed to 12V.

There's a "rebuilt" 235 in San Antonio (4hrs away). Guy says he's selling for his father in law who was a school shop teacher who received it in the mid 90s and never assembled it. I'm waiting on pictures of the cylinders. He's asking $1400, which is too steep. He's open to offers. Any number jump to mind?http://sanantonio.craigslist.org/pts/5199655605.html
There's also a magnafluxed block in Houston (5 hrs) with a crank for $175.
http://houston.craigslist.org/pts/5186539152.html
Thoughts?

If they take this one in San Antonio to a machine shop and have everything they're saying verified for you, at no cost to you, sure- $1400 would be a good deal.

Otherwise, they're smoking crack.
Brad

Edit... don't touch that one anywhere near that price.
This is just my opinion, but I counted about $350-$450 in value.
What they say did not factor into my valuation.

But, this definitely did:

Yeah, San Antonio is too expensive even if it were half. Houston sounds promising. Now that you are focused on an engine, and your precise needs, things will start coming together quickly. Look over Ebay too. I have seen a few of them in the past few days. Hang in there!

..are you even considering the one in San Antonio???
if so be careful. Very careful.
The block was definitely not vatted, Head bolt broke off in the block and doesn't show like its been refaced, and the cylinder walls sure don't look bored or anything else. NEW valve's?? Look close, and why would a reconditioned head have the old gasket still hanging on it......plus you'd have to rebuilt the carb, maybe the starter and distributor as well as buy a new fuel pump. That's just my opinion, from what I see.

Houston is more "on the money" for what you get. Just my .02.

Edit- I deleted my follow-up comment on the San Ant. engine; gusco, if you can email me a video of your current engine running (short in length & zip-compressed) I'd be glad to post it on Youtube for you. It would just save you the account set-up hassle & download wait.

Brad

May not have to move radiator, I believe GMC has a longer engine bay. Those swaps are Chevy.

Sounds good. I'm going to see if I can avoid doing the fab work (engine cradle?) With this 235 in Houston. I'd the front mount something that can be transferred from my older 235 to this newer one?