The GMC 248 has been the most reliable engine I've ever seen, and it's simple enough that even I could maintain it. It has failed to start three times in 25 years, and two of those were my fault. Now, the headgasket is gonzo, sweet smelling steam pours out the exhaust. One of the con rods goes clunk on cold starts. Rebuild, immediately; obviously!
But wait, I don't have a garage to work in, my truck sleeps in the rain. Furthermore, there's a clause in my lease that specifically forbids work that would render the vehicle immobile for more than 24 hours. Can't pull apart the engine in the parking lot.
Get an estimate from a shop! Inlines are way easier than V8's, right? Nah, they all say pull it and send it to a machine shop... total cost would be double my entire savings.
Okay, then, what options are within my budget? Different engine? Maybe an inline you can find parts for? That would require moving the motor mounts, but not much else in modification. I'd have to buy new intake/exhaust/pumps/pans but that will still be less than the shop (new pumps were included in the rebuild estimate as well).
BLASPHEMY! Destroying the purity of this vintage... um... work truck. When I first acquired the GMC panel it had a 228 laid to rest in the back with a rod poking out the side. The engine that's in it seems to be a wrecking yard find. Haven't a clue about actual miles or hours of operation, let's just say it's not original and well past its warranty. When it hasn't been used as a moving van by nearly everyone I know, it's been a rolling storage locker. I'd like to make it my wheelchair van, if I can find a lift that will clear the bumper and retract inside the doors. There's a place north of Seattle that harvests and resells wheelchair lifts, I'll see what they have. But, I digress.
What about the SM420 transmission? I've successfully ignored the input shaft bearing until the clutch throw-out began shouting even louder. I have a 4L60 automatic I'd love to see through a fresh-cut hole in the cab floor.
Hey, if you're gonna replace that GMC block with a bowtie, why not LS? Money, honey! I am a cripple with a very limited income, and if I can't afford to rebuild the inline, I sure can't afford a full LS conversion. Let's not forget this is a 3 ton vehicle, it will never be fast.
So, that's what's kept me busy during lockdown. How are you doing?
Can you find a shop on the dryside (Yakima, etc.) that would let you take it over there where it won’t rust overnight, rebuild the engine(a 270 or 302 would fit right in there, similar rebuild costs). 420 is a good trans, look up Novak in SLC for info. If you can drive a 420 with your disability, good for you.
It will still cost $. Spend a lot of time looking for someone who will not just gold plate everything.
Do you have any friends who can help you? I am sure there are clubs in the ‘wet side’ that might help you.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
Yeah, I got one reply from an inline builder near Bellingham, but that shop has a 10 month waiting list. I found a shop in Tacoma that will actually gold plate my valve cover and make my truck tap-dance with hydraulics, but they won't rebuild the inline.
I can either operate the clutch or brake, not both. I have power brakes, so I feel confident slapping it out of gear when I need to stop completely. Starting on hills (which is all we have in Seattle) is a three handed operation, getting the 4L60 installed would make it much safer.
Money is the one thing I'm not permitted. If a disabled person receiving benefits has more than $2K in cash it causes an automatic audit, and if I earn any money they will raise my rent and cut my benefits to compensate. I know a 270 or 302 will fill the hole, but unless you're going to donate a running engine it's not really useful info. I haven't considered the 270/302 for the same reason an LS is out of the question. I have to work with what I have, there is no budget for a wish list. Ironically, a tax subsidy will help pay for installation of the lift (modification for medical purpose), but the van itself is my problem to solve.
My friends and relatives moved out of Seattle when they got old enough to know better. Within minutes of retirement, they were packed and gone. If I didn't have a subsidized apartment and a cadre of medical specialists to support, I would have led the exodus. Seattle car clubs don't answer email, except the Greenwood Knights who informed me where to send membership fees. As a result, I have little info on local clubs beyond their webpages.
I don’t know how much work is involved but there may be some information on installing either a 235 or maybe a 250 chev engine in your panel ,if it is easier to find a good engine.
As I mentioned above, I'm looking at the 250 Chevy inline sold through Summit; it's within the budget and parts are still available. I don't have precise block dimensions yet, but I've been told the GMC block is longer than the Chev, so if I move the front motor mount it should drop in with room to spare.
I can't afford to drag the truck to Centralia. That's the nearest "dry side" shop that will touch an inline, and they're booked solid through 2021. Haven't looked farther east than that, TBH; I'd rather do the swap and worry about the GMC block later. Might rebuild, might sell, might stick it back in the truck someday.
It is at this point where Cunningham's Law comes into play, and those experienced with engine transplants administer the virtual dope-slap.
Actually that particular swap has been done hundreds of times, maybe by a few on Stovebolt. I would think if you have reasonable mechanical skills and access to a fair amount of equipment and tools it shouldn’t be too difficult.
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
This sound like an interesting project, can you post a picture of the Panel Truck? It sounds like you will put the wheelchair lift in the back door, why not front door? I have no idea how it would fit. You might be able to find a used 235 that someone no longer needs. Someone that swapped in a 350 and has that old running when pulled last year 235 sitting under a tarp in the yard, ahem…
See my signature line where your see the link to the build.
I already have an inline that needs a rebuild, I don't need two. Summit can drop a "freshly rebuilt" 250 in my parking lot for under $3K, which leaves me just enough money to do all the work myself. Thanks, anyway.
As I mentioned in the engine forum, Summit no longer sells GM inlines. As soon as they refund my money I am back to shopping for a "new" engine. That 4.3L V6 may be useful after all....
Right, here's an update on the wheelchair van project:
Got the GMC inline to Chevy auto kit from Speed Gems, but I haven't pulled the transmission out of the Blazer because I'm still driving it.
The only long-block inlines currently being sold are insanely expensive 292 Chevy blocks. EdPruss says he's got a 270 in Colorado that he can strap to a pallet, it ran when he pulled it and it's less than half the cost of any partial assembly with a warranty. I'll take it!
The current plan is to get Ed's 270 on a stand, bolt the adapter and 4L60 to it, then yank the 248+SM420 together and slide the 270+4L60 combo into the gap. Shorten the front half of the driveshaft, new trans mount location on the frame, and zip tie the trans cooler to the grille supports. Shouldn't need any mods to the engine mounts, no major changes to the cooling and fuel systems, the exhaust should even line up.
This eliminates the problem of an lease-breaking project occupying the parking lot, and I might even be able to afford to do have the swap done in a shop with a level floor. Safety forced!
Then the issue is getting rid of a 1996 Blazer with no gearbox. Any Henry Panza fans out there?
Thanks, but no. If I can't get a warranty on a fresh build, I may as well stick with the GMC configuration. As stated above, Ed's 270 will slide onto the existing mounts and it shares some parts with my 248.
Fewer changes means faster results, and a primary consideration is not getting caught in the parking lot with my crank dangling....
Adapting the 4L60 to the GMC will eliminate the bellhousing motor mounts on the SM-420 setup. There will be no way to bolt the GMC/4L60 in without fabricating new mounts, at least at the engine/trans junction point, possibly altering the bellhousing crossmember for clearance for the transmission, and fabricating a rear crossmember to support the tail shaft housing of the 4L60. Plan ahead! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
The GMC 248 has been the most reliable engine I've ever seen, and it's simple enough that even I could maintain it. It has failed to start three times in 25 years, and two of those were my fault. Now, the headgasket is gonzo, sweet smelling steam pours out the exhaust. One of the con rods goes clunk on cold starts. Rebuild, immediately; obviously!
