The Stovebolt Site Forums The Shop Area Engine Shop Engine Rebuilding, 270 GMC, Who Still Rebuilds?

I need (multiple) 270 GMC straight six engines rebuilt. My truck(s) are DOA
until I get an old school engine rebuild. There are still 30 plus engine shops
in my city, but apparently none of them still do such work. I found one place
in Los Angeles, $ 5K, but don't put any of the "appliances" back on the engine
and get it running, fuel pump, water pump, gen. or alternator, etc. One shop
would rebuild, even paint it for me. $ 9k. That shop is a thousand miles away.
Can't register the truck with a newer model running engine in it. Yes, I could
move out of state. That would cost more than $ 9k. I want a driver truck.
Does anyone know of a real engine rebuilder who would get an engine
running for me? The closer to 95204 the better, but anyplace USA? I don't have
the tools or the skills to rebuild an engine. Lots of things I can do, but not
that. Anybody want to open an engine shop? Thanks for any ideas.

Putting the add-ons on the engine isn't that tough. And $5k for rebuilding a long block isn't that bad. I just had a 7.3L diesel rebuilt and it cost me ~$8k for the long block returned to me. Myself and a buddy bolted everything else on and reinstalled it. Yes, it was some work, but nothing super technical.
We could probably talk you through installing the stuff on a long block. I'll bet the shops local to you could rebuild your 270(s).

When I lived in CA ages ago, engine swaps could be registered with DMV. And that should only matter if the registration was done with an engine serial number instead of vehicle serial number. But that was before smog checks. Your trucks are likely old enough not to require smog checks. Call DMV and ask about it.

I've been doing that kind of work for 60+ years, but Middle Tennessee is a LONG way from the San Joaquin valley! I left Merced in 1980!
Jerry

I had my 248 rebuilt about 6 years ago. It was close to 4,500. That was in Sherman, Texas. You just have to keep in mind that the GMC is a different animal than the Chevy motors. Shake a tree and 235 parts fall out. Not so much for the GMC’s.

I'm up in Grass Valley and the machine shop here has a labor rate of $160 per hour. The last engine I had them do just the machine and component balancing was $3000, that was probably 10 years ago. So that's not over priced. I assembled the engine and put it in and the guy I did it for was a happy camper. If you are interested P/M me and if you are interested I can do the grunt work, I'm a retired auto mechanic and have all the tools needed.

5k to 8k for a GMC rebuild by a reputable machine shop is the going rate. If you want to play you got to pay. Nothing more expensive than a cheap rebuilt GMC engine.

Thanks all for the comments, keep them coming. I am going to write FAST55. He is close to me.
Sounds like $ 5k or maybe a bit less IF the block and all my parts are not very bad, and rebuildable
may be as good as it gets. That's useful. YES GMCs are different that Chevys. Both are great, but
I just like the GMCs. Heaven help me, I guess.
RE DMV, you can't get the truck registered and licensed until it runs AND gets inspected by DMV or
CHP. Actually, I will take mine into CHP if I can get one running. You file the initial paperwork
after purchase, but can't complete process until running and you schedule an inspection. It is
the way it is. Thanks guys. I will keep trying.

Other than a few of the basic parts like crankshafts, heads, blocks, camshafts, and sheet metal, consumables like bearings, rods, pistons, and other stuff can be substituted from different engines. All it takes is a machinist who is willing to measure, modify, and substitute non-standard parts. Just today, I picked up a 235 crankshaft that I had modified to run big block Chevy V8 rods and rod bearings. That one's going into a 261 block with pistons for a 292 Ford V8 and valve lifters for a big block MOPAR engine. The engine will have a 4" stroke, 275 cubic inches, and H beam connecting rods rated for 1K+ horsepower. I'll have less money invested in it than if I bought all original stovebolt parts.

There's no reason the same approach can't be made to building a GMC engine.
Jerry

Locally, I've talked to people in about 15 of the shops. They don't rebuild old engines. At all.
They say their work is mostly insurance related work of various types. They work on engines
to repair nearer ones. They seem to have a lot of foreign model cars that younger drivers
might like. I am told lots of cash goes into such cars for side shows, street races, and such.
Everybody tells me that none of the local shops rebuild old engines. But I have spoken to all
of them directly yet. Still trying... Thanks for any constructive comments. I know I will have
to pay. So far, no one wants my money, lol. Can't give it away.

That just doesn't sound right. Parts might be more difficult to find for older engines, but machine work is just machine work, no matter how old the engine is. The basic engine hasn't changed for 100 years.

Go to local cruise ins and car shows. Talk to everybody, especially people with rebuilt engines. You likely won't find a shop but might find an independent hotrodder who does the work himself and/or knows somebody who does machine work for him, etc.

Regrinding the cam and the lifters would be the way to go if needed.

Doing an overhaul or rebuild will take a bit of time no matter who does it, like mentioned the parts could be a huge issue. Not many doing that rebuild want to spend the time hunting for parts, and is likely why no one wants to do it.

A quick check I guess there are some parts around for these, and prices ??? So that is a huge help

One of the big problems encountered when rebuilding GMC engines is the very difficult task of locating suitable pistons. I have found a few sources for metric diameter pistons for Japanese Diesel engines (forklifts, etc.) that can be adapted for use in GMCs. They're available and affordable from various Ebay vendors. For instance: these pistons can be fitted to a 302 GMC with a little creative metal butchering:

www.ebay.com/itm/156414489925?

Jerry

What year are the engines? Anything known about them? Are they rusted and don't turn, do any of them run?

If I was doing that job I'd want it complete, so don't understand shops not wanting to do that. Hmm if its for a driver maybe the HEI is the way to go as well.

What Jerry said about finding pistons. Even Egge machine doesn't list pistons for a GMC 270. They seem to have everything else.

There's also a Japanese Diesel piston that will work in a 270- - - - -don't remember the metric bore equivalent right now, but the very thick piston crown (about 1/2") can be whittled on to get the right compression height and eliminate most, if not all of the oddball contours. They're still lighter weight than a stock GMC piston.
Jerry

So is this a do it inexpensive type job or ? The shipping is the main problem for anyone out of your area, and ruins the inexpensive part quick.

It's a fairly simple job for anyone who has the unmitigated gall to call himself a "machinist"- - - -but the guys who really qualify for that term are about as scarce as a chicken with lips! The wrist pin hole size in the piston, and possibly the crankshaft stroke would need to be altered. With the proper piston/rod combination, the stroke on a 270 can be increased by about 1/4".
Jerry

You say you don’t have the skills to rebuild it yourself, but it might be worth your time to at least pull the head and do some quick measuring of taper. There a tech tip article here. Super easy to do.

It’s possible your cylinders are in reasonable enough shape to get by with a hone, thus avoiding the nightmare of locating GMC pistons. Pistons could be knurled to take up some excess wall clearance as well.

Not sure how stuck you are on using the engines you now have, but might keep an eye on Marketplace. GMC sixes do occasionally show up for sale. Buying a decent running engine is likely to be much cheaper and less headache than a rebuild.

The simplest (not least expensive) method of building engines with scarce pistons is to bore and sleeve the cylinders and reuse the same pistons, assuming they're not severely damaged. As with any kind of 75 year old equipment, refurbishing it is not for cheapskates, or someone who wants to find the "easy button". "Buy once- - - -cry once" applies in these situations, at least most of the time.
Jerry

Here's a Nissan Diesel piston that's the same size as a 270 piston. (96MM) There's also a flanged sleeve available that fits with a little creative whittling that allows the engine to be rebuilt repeatedly without reboring it again.

www.ebay.com/itm/195096233829?

www.ebay.com/itm/154178552143?

Jerry

As a youngin, I had no $ to do fancy overhauls, I never had problems with them, yeah since dad was a machinist I had access to precision tools instruments. Yeah the good old days. Did lots of things on the cheap and worked for many trouble free years. Even did a few leak free corvairs in the day.

Mike if a 235 would work for you PM me I will also be passing on a 4 speed open drive still in its crate..