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GM "Industrial" vortec 4.3l gurus? Need to swap engine in forklift. What can we use?

huleo

Hot Rolled
Joined
Feb 12, 2014
Location
UT
GM "Industrial" vortec 4.3l gurus? Need to swap engine in forklift. What can we use?

Have a forklift (96-97 vintage) that will need another engine. Other is not worth rebuilding IMO. I am having a hard time finding information on the "Industrial" engines. What is different? What is the same? How many flavors exist? Does it matter?

So far, it seems like the old engine was only rated to less than 100HP. Issue is getting something that has a reasonable power curve to work with a fork. I have also heard about the "hardened valve seats" for LP and not sure how others might stack up? I don't need to stack the hours on this machine. Maybe 100hr/yr. I just need to do some cross checking here before I do a transplant.

Would a pickup engine be cam'd about right? Would compression ratio be too low to really take advantage of LP?

Just need some good info on these 4.3's! All I can find is guys playing with their toy trucks and not much about industrial applications. I guess there are marine engines, which is probably on par though. No talk about compression, or cams though.

Our fork has electronic spark timing so I have concerns we will run into issues if we have something cam'd radically different. I am not sure if we can just alter the mechanical advance to cheat or not. So little info.....
 

john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
The performance is the last thing I d worry about.....Continentals with 5 to 1 compression run on LP,valve seats for unleaded are OK for gas......biggest issue with engines is the power takeoff for accessories.....where is the hydraulic pump drive?,the steering pump?.....and the biggie...is the crank flange the same?is the block drilled the same for the housing?......only way to find out is to compare the parts-pull you engine and the replacement and compare.
 

bsg

Titanium
Joined
Jan 17, 2003
Location
Imlay City, Michigan
Have a forklift (96-97 vintage) that will need another engine. Other is not worth rebuilding IMO. I am having a hard time finding information on the "Industrial" engines. What is different? What is the same? How many flavors exist? Does it matter?

So far, it seems like the old engine was only rated to less than 100HP. Issue is getting something that has a reasonable power curve to work with a fork. I have also heard about the "hardened valve seats" for LP and not sure how others might stack up? I don't need to stack the hours on this machine. Maybe 100hr/yr. I just need to do some cross checking here before I do a transplant.

Would a pickup engine be cam'd about right? Would compression ratio be too low to really take advantage of LP?

Just need some good info on these 4.3's! All I can find is guys playing with their toy trucks and not much about industrial applications. I guess there are marine engines, which is probably on par though. No talk about compression, or cams though.

Our fork has electronic spark timing so I have concerns we will run into issues if we have something cam'd radically different. I am not sure if we can just alter the mechanical advance to cheat or not. So little info.....

I'm looking at doing this also!

I have a 1980's Hyster with the 4.3 and 1990 Chevy pickup with a 4.3 that I will use for the donor. I wasn't planning on doing anything other than freshening up the replacement motor, possibly a new cam and lifters........I wonder if the compression is lower for the propane fuel?

The performance is the last thing I d worry about.....Continentals with 5 to 1 compression run on LP,valve seats for unleaded are OK for gas......biggest issue with engines is the power takeoff for accessories.....where is the hydraulic pump drive?,the steering pump?.....and the biggie...is the crank flange the same?is the block drilled the same for the housing?......only way to find out is to compare the parts-pull you engine and the replacement and compare.

No power steering pump to worry about, done with hydraulics. Unlikely the crank flange would be any different than a passenger car/truck would have? Same thing with the engine block, I'm sure a standard Chevy bolt pattern? I wouldn't think Hyster would pay for the cost of casting a new block to fit just their trucks?

Kevin
 

Cole2534

Diamond
Joined
Sep 10, 2010
Location
Oklahoma City, OK
Have a forklift (96-97 vintage) that will need another engine. Other is not worth rebuilding IMO. I am having a hard time finding information on the "Industrial" engines. What is different? What is the same? How many flavors exist? Does it matter?

So far, it seems like the old engine was only rated to less than 100HP. Issue is getting something that has a reasonable power curve to work with a fork. I have also heard about the "hardened valve seats" for LP and not sure how others might stack up? I don't need to stack the hours on this machine. Maybe 100hr/yr. I just need to do some cross checking here before I do a transplant.

Would a pickup engine be cam'd about right? Would compression ratio be too low to really take advantage of LP?

Just need some good info on these 4.3's! All I can find is guys playing with their toy trucks and not much about industrial applications. I guess there are marine engines, which is probably on par though. No talk about compression, or cams though.

Our fork has electronic spark timing so I have concerns we will run into issues if we have something cam'd radically different. I am not sure if we can just alter the mechanical advance to cheat or not. So little info.....

That's in the Mercury service manuals. If you have a marine engine in mind, gets its serial number and head over to mercruiserparts.com to learn more.

Sent from my SM-G973U using Tapatalk
 

ewlsey

Diamond
Joined
Jul 14, 2009
Location
Peoria, IL
How bad is "not worth rebuilding"? A short block should be easy to get. You can reuse your heads and cam if you choose.

In my experience, the only difference between the propane and gasoline engines is the carb and the ignition timing. And the gasoline engine ignition timing will get you close enough to get it running.

It's not like diesel versus gasoline. The pistons, valves, cam, etc should be same on gas or propane.
 

m16ty

Hot Rolled
Joined
May 11, 2016
Propane runs better and offers more hp with higher compression. That being said, a gas engine will run fine on propane. Years ago they built propane specific engines, in modern times they just use the exact same engine for both.

I’d just find a donor 4.3 out of a pickup or buy a reman engine. I wouldn’t worry too much about performance. Unless you are racing the thing, you’ll never notice plus or minus a few hp.
 

PocoLoco

Aluminum
Joined
Oct 8, 2019
This is the beauty of a Chevy, it all bolts right up, if you have the right parts. I agree they probably did not design a new block for it. My friend has a 327 forklift block in a 69 Camaro. Bolted right up. Just use the intake, carb, and distributor from your old motor. The cam may be optimized for the aplication, but the truck cam will work. Its not going to be that much different. Propane conversions used to be common, and in some places still are, no one changed the cam, pistons, etc when making these conversions of gassers to propane. I think you will be fine, just buy a doner truck or van, pull both motors and compare what you need and what is different. Chevy has not changed much from 1955 to the ls motors. Chevy is the most swapped motor in history, I have seen them in buldozers, tractors, car crushers, snow blowers, and every make of car. Get a good running donor truck and keep everything till the swap is done. You will do fine.
 

huleo

Hot Rolled
Joined
Feb 12, 2014
Location
UT
I do have the free donor in possession now but the donor is slightly newer and this is complicating things. No one knows a thing about them and its no wonder so many engines get built wrong when there are 500 variants.

The engine I have in the fork I believe to be a 93-95 era engine with the standard GM TBI intake. The propane carb bolts right to that carb.

However, the donor is a year newer as the "vortec" engine even though the fork engine says "vortec on it". I always remembered the auto vortec engines as the ones with the two piece intake, which thewer donor has.

This engine has the injectors and lines inside the intake, with a throttle body at the front. The intake also has 8 bolts instead of 12. Looks like I need a different intake....yay!

The donor has no detectable blowby, instant oil pressure, and seems to run just fine.
Someone asked why the other engine is "not worth rebuilding", it actually is to the right guy, but I don't have the time right now and that engine needs COMBED because the morons that built is punched it 30 over and installed STD pistons! There is also a valve stuck in a guide that is TIGHT! Like real tight. All things that tell me the numbers were not checked, it was just slapped together.

I think the valves, guides, and seals are all could make a good engine, but it needs checked out.
 

PocoLoco

Aluminum
Joined
Oct 8, 2019
Thats what I mean about having the right parts. Chevy builds em in generations, or seasons. Some parts interchange from season to season, others dont. That intake and heads is one of those seasonal changes. The forklift heads will bolt onto the truck block, so if you fix the sticky valve, that is one option. Fixing the sticky valve is not difficult. An auto machine shop should be able to do it, even if they end up putting in replaceable guides and new valves. Another is to find a 1995 or earlier doner, which will have the correct heads. Yet a third, is to get a set of used heads from a junkyard or craigslist and use them on the truck block. I would still take any used heads apart, check for wear on the stems and guides, touch up the valves and seats. Reasemble with new seals, good to go. Loose guides are better than tight, though really loose guides can pass a lot of oil. I think I would keep looking for a doner in the right year range, with the tbi intake. That would be the fastest and easiest swap.
 

huleo

Hot Rolled
Joined
Feb 12, 2014
Location
UT
Its hard to argue with a free, good running donor..... There are other intakes, just none that have a TBI bolt pattern so I will have to adapt to anything I do.

I would say finding an older TBI engine that is low hrs will probably be a stretch, as is accepting someone's "rebuilt" status. I can see how that rebuilt thing looks on the current engine. I used to build engines for a living so I know the hours involved to get one right and I just don't have the time right now.
 

Street

Hot Rolled
Joined
Apr 16, 2015
Location
Melbourne Victoria Australia
pay someone to rebuild the engine properly and install it,test run it.get a warranty. 30 over go 40 if need be no big deal. seized valve in guide no big deal.
If you don't know about hardened seats you need to learn a lot more and tick every last detail off if you do a swap one missed detail will end up in the crapper and you have wasted maybe 2 weeks of time and back to doing a rebuild.

heck give them 4 weeks to do the job and you will be still ahead with all the wasted time searching here and everywhere else.

then piss and moan about the cost while you drive your forklift, just don't post it here i don't want to hear.
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
Where s the guys say it all bolts straight up cause its Chevvy......they ll come over and do it for ya.Before the beer runs out.

Yep. There's no higher level of interchange with GM. There's a whole lot of looks pretty close, but doesn't fit stuff.

They all pretty much build the cheapest shit that makes it past the warranty period. Some do certain things better than others, but most vehicles and engines are just built for one thing- To sell.

I think the vortec 4.3 came out long before 1995. 1996 was the first year for the vortec 350 thing, but the 4.3 had it for more than a few years prior to that. You gotta go back pretty early to get a non-vortec 4.3

On a side note, had a good friend who fixed forklifts for Pape machinery. He said the vortec 4.3's were a pile of shit Propane engine and Hyster had a huge pile of warranty work when they started using the new "vortec" style 4.3 engines on propane. They wouldn't make the same power as the old 4.3 and used way more propane and had overheating problems. Something about the fancy vortec head combustion chamber wasn't playing nice with propane. Propane likes a shitty slow moving bathtub combustion chamber.
 

PocoLoco

Aluminum
Joined
Oct 8, 2019
4.3 interchange

I hear ya about the free doner, and you can still use it, just need the right heads. And yes, it will bolt right up. And yes, Chevy has made some crap over the years, but its still the most interchangable engine around. The bellhousing flange on that 4.3 is the same as the first 265 v8 made in 1955, the same as a 454, the same as a 250 inline six. The op asked what will work. I gave him 3 solid options, let him choose one, or make up one he likes better. In any case, he has a better understanding of the situation.
 

CATERPILLAR

Plastic
Joined
Mar 6, 2021
Gm v6 lpg in cat fork lift

the performance is the last thing i d worry about.....continentals with 5 to 1 compression run on lp,valve seats for unleaded are ok for gas......biggest issue with engines is the power takeoff for accessories.....where is the hydraulic pump drive?,the steering pump?.....and the biggie...is the crank flange the same?is the block drilled the same for the housing?......only way to find out is to compare the parts-pull you engine and the replacement and compare.

im struggling with a v6 vortec smelling of oil in a caterpillar gc45k forklift we checked compressions all in spec, do you suggest valve stem seals?
 

matt_isserstedt

Diamond
Joined
Dec 15, 2003
Location
suburbs of Ann Arbor, MI, USA
This is an old thread but to answer some of the earlier questions, in MY1996 there's a breakpoint to the "Vortec" cylinder heads. The TBI motors that preceded it were torquey but at the cost of HP.

Where things could get squirrelly is in the intake lower to the cylinder heads. My guess is that if you were trying to cross that part from one generation to the next, that's where I think you'd be most likely to have an issue.
 

1yesca

Stainless
Joined
Jun 1, 2004
not all 4.3 are the same there are FWD , RWD , roller cam none roller cam some have counter balance shafts some don't like the guy above was saying this is an old post but you have four things you can do 1-fix the motor you have and if its org then you know what you have and it will work 2-put a used something unknown may work may not motor in there who knows you may get lucky 3- new will fix it most of us would never do that as we are to smart ya to smart for are own good and 4 - do nothing that's the cheep thing to do tell something goes wrong like some one gets hurt over trying to save some money . i work in an automotive machine shop i assemble motors all day long unless the motor was run nu-tell it locked up or never had the oil changed more then likely its not that bad ya the shop will try to sell you a bore job and pistons but if you have the time and the skill to do some of the work your self like dissemble it cheek the wear in the bore mike the pistons and crank cheek the big end of the rods and if it all looks good your looking at some rings , rod and main bearings maybe cam bearing timing set gaskets oil pump and a valve job you can get an overhaul kit from summit hell go find a used motor to put in there tell you and your kid or grand kid spend some time together fixing your org motor hell i have seen more motors put together from used parts then you could or would believe sometimes if it was not for used parts we would not have any parts at all but what ever you do or did do good luck
 

john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
Best forklift story I got ,is raising the forklift using blocking under the mast.....I used to do it five times a day to fix flats......anyhoo ,the idiot boss sees me doing it ,and bignotes himself to the golden ones how to jack a forlift......he blocks under the carriage ,and the wheel stays put on the ground......the golden ones have a joint IQ of 30 ,but even they arent impressed........So ,next time I jack one ,boss come out and says "Safety issue ....next time I see you doing that ,youre fired"........Questions ...how come morons are rich?
 

DaveKamp

Titanium
Joined
Oct 3, 2004
Location
LeClaire, Ia
FWIW, the difference between the 'industrial' and the 'automotive' 4.3, is just what the thread history suggested. The TBI and carbeurated industrials were made on a separate line, with different equipment, which is why his manifold, injectors, etc., didn't interchange as expected.

There were two distinct iterations of 'Vortec' heads. The initial design used a 'ramp' in the intake port, whose function was to force a swirl motion on intake mixture to improve atomization of liquid motor fuel for better economy. Totally irrelevant, and counterproductive on a gaseous (lp or ng)application, and the ramps(and the swirl they generate) become very restrictive as it creates a laminar 'wall' (like an 'air curtain' at your grocery store) which incoming charge cannot find it's way through... Later version of the 'Vortec'concept did away with the ramp, and went to port injection, roller cam, and entirely different chamber.

The industrial, however, was a conventional port, with conventional combustion chamber, and fitted with a cast-iron intake (rather than plastic). Even after the roller cam came out, industrials used industrial heads.

They ALL have hardened valve seat inserts. The misinformation of'leaded-end' era carries on in perpetuity it seems... ANY engine designed for gaseous will have hardened inserts... as there was never such a thing as propane with tetraethyl lead.

If one wants a GM Industrial, the closest source will be a GM Marine... the difference between the two will be customer spec details. Marine engines will be fitted with corrosion inhibiting hardware, salt-sediment protection, brass drain plugs, and explosion-proof electricals, and a camshaft with profile suitable for idling well against submerged exhaust. The 4.3 industrial V6 MIGHT have a different camshaft as a result, but they might have just kept it as a minimal-overlap marine grind.

The industrial will have a different thermostat housing system, and be set up to run at a higher temp. Marine cooling using raw water will rarely be higher than 160F on the thermostat, because doing so will result in hot spots from boil-off. Raw water cooling is not a pressurized system. It runs closed-circulation until cooling is needed,then flows incoming raw in proportion to need. All excess raw water gets flowed out through exhaust manifolds and sent overboard with exhaust gasses.

Industrial engines (pre-electronics era) are usually fitted with mechanical or velocity governors. Boats are NOT fitted with governors... just sometimes a rev-limiter... but usually not.
 








 
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