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View Full Version : Diesel vs. Gas Engine Rebuilding (~off topic)



gunbuilder
08-17-2001, 03:09 AM
If you ever find a Ford Tempo diesel do not hesitate to buy it. On a 35 mile commute mine would do 40 to 45 mpg with 200,000 miles on it. All I did was put a head and a timing belt on it and change the oil and fuel filters. I wish it was still running but after that last accident I haven't put it back on the road.

Paul

abn
04-09-2004, 03:26 AM
I've been looking around for a cheap truck.

I've never owned or serviced a diesel before but I've run across more than a few dead mid-eighties' diesels under a grand. When I buy cheap I expect having to rebuild. How does a diesel engine rebuild compare to a gas engine rebuild? Are there any wierd expenses that I should consider. Like one ad mentions needing "injector grinding"...what the heck is that?

Buckshot
04-09-2004, 06:17 AM
.......By "Mid 80's Diesels" you're talking about GM's warmed over Olds engines save your money. They were a disaster for the most part. I'm sure there are people who actually got some good use out of them and put many a mile on'em. However there were lots more who had nothing but trouble.

Diesel engines are more heavily constructed then a comparable gasoline engine so they weigh more. Diesel engines are also more expensive to buy from the git-go, and more expensive to work on if something goes wrong.

Due to some long drawn out circumstances I'm currently driving a friends 2000 Ford 3/4 ton crew cab 4x4 Diesel. I completed a simple service on it the other day. The oil filter was $14 and it took 16 quarts of oil.

A Diesel's forte' is to be able to work hard for long periods of time and to be economical with it's fuel requirements. Also in the Diesel's favor is it's general longevity compared to a gas rig. This same friend also had a 3/4 ton Dodge he had leased to Morgan Driveaway hauling RV's all over the United States and he put almost 340K miles on it without any engine problems.

He DID have to replace 2 clutches and rebuild the trans twice and driveshaft once. His Ford (auto trans) I'm driving has given 15 and 15.2 mpg so far. I'm driving it back and forth to work, 72 miles round trip, empty. I myself used to have a '96 Ford F350 crew cab with a 460 gas engine, auto trans. You were VERY lucky to get 12 mpg on the freeway with it. Around town or towing it was closer to 8-9 mpg.

The shorter your trips, and the more stopping and starting you do, the less you are a candidate for a Diesel. At least IMHO.

Regards,
Rick

spkrman15
04-09-2004, 08:25 AM
ABN,

I am with buckshot here. My dad owns a ¾ ton diesel, and the thing is a tank. I find it uses the same amount of fuel empty as it does loaded. Seriously. It is difficult to start. This one, international motor, is verry difficult to start in cole weather. Right now i have the heads off because the glow plugs seized in the heads.

20 hours to do the job and 5 hours at the machine shop to drill out 2 glow plugs, one on each head.

http://www.magma.ca/~idjs/machining%20pictures/dad's-truck-5.jpg
http://www.magma.ca/~idjs/machining%20pictures/dad's-truck-7.jpg
http://www.magma.ca/~idjs/machining%20pictures/dad's-truck-8.jpg

I really should get back to it. The heads are finally on the motor now and all i have to do is retorque everything and put-it all back together.

Rob http://bbs.homeshopmachinist.net//smile.gif

chkz
04-09-2004, 10:15 AM
pretty much agree with Rick up there on the costs and the stop/go driving thing.....don't know if I'd go with the warmed over Olds engines...don't know much about them but did hear they had their share of problems. Would definitely get a diesel though with a proven track record. A rebuild will cost ya for parts, IMHO wouldn't even bother rebuilding the injectors in a car/p.u. I'd replace them...I've mainly worked on heavy diesels..(12cyl Rolls, ...that type of stuff)so can't really comment on the smaller stuff...know the parts are pricey but on the plus side they'll "last forever" as a unit....

good luck and take care,

Michael Az
04-09-2004, 10:54 AM
I will relate my experience. I started driving big trucks about 30 years ago. In 94 I bought a new Dodge Cummins 4 X 4 and still have it. Really have loved the truck and will never part with it. The best mileage I ever got was 26 mpg a couple times on a trip when the engine was stock. I've done a lot to bump the hp up to 400 from 175 and even with that I still get 18 mpg everyday driving. No big problems with anything and I would do it again in a heartbeat.
Michael

wierdscience
04-09-2004, 11:16 AM
The 6.2 GM diesil is pure junk,the Ford/International 6.9/7.3 are great engines and the DODGE/cummins units are good also.

Main thing to consider with a diesil is change the fuel filters often.The only cranking problems I have experienced were due to people using ether to start them,a tiny amount isn't bad,but most folks use enough to wash down the engine instead of cranking it.The other hard cranking condition is due to either fuel system leaks or worn/damaged injectors or pump.

In my experience rebuilding diesils the first thing you check is the compression,320psi is absolute minimum for a diesil,if you don't have at least that on all cylinders then heads,rings maybe the case.If it does have good compression then the fuel system is the place to start.

I have seen people rebuild their engines only to find out that the pump/injectors were the whole problem not the engine itself.

For my bet I would pickup a 3/4ton Ford with a bad/blown 6.9l and drop in a modern fuel injected 351Windsor,you will have plenty of power,cheap parts,good gas milage and long life.But by fuel injected I mean multi-port not throttle body,if your gonna do it go all the way.

ibewgypsie
04-09-2004, 11:46 AM
Mid 80's olds diesels are not real diesels. They used the olds diesel block racing, it was better than the gas engine, used a lot of same design specs. I still have a vacuum pump from one around here I hook up to evacuate casting bubble in INvestment. (lost wax)

The INternational bus we had, it had a 7.3? diesel installed. It was basically a simple tractor motor, gas feed hooked to the injector pump. It cost me $116 to change the filters. These style diesels run forever if taken care of.

Raised the hood on a friends new truck, it had smog crap all over it, electronically controlled injectors. It has been in the shop every month since he bought it with electrical sensor problems.

I always wondered why they didn't instal a perkins 3 cyl diesel into autos. Simple and cheap to run, in everything from sailboats to tractors. That'd pull a 1/2 ton like nobodys business.

Diesel parts are a lot more expensive than gas burner parts. You can build 2-3 gas engines for what one diesel costs.

David

Carl
04-09-2004, 02:18 PM
The Cummins diesel in Dodge trucks originated as an industrial engine and thus has a well proven track record. I'm not sure about the engines in other brands. Most diesels have replaceable cylinder liners and parts are available in "cylinder kits" making rebuilds, even in-frame overhauls, very viable options.

wierdscience
04-09-2004, 09:58 PM
Dave,they did for a while put Perkins in the Ranger,think it was back in 84-85 somewhere in there,never actually seen one but they do exist.They also had a turbo 2.3l gas model,thats one I would like to have an extra 20hp wouldn't bother me at all.

Them Perkins 3cylinders are cheap to build too,did one for a friend last year in his forklift,head work cost $250.00 Gaskets,sleeves,pistons,bearings etc were $425.00,one day to tear down one day to put back.

PSD KEN
04-09-2004, 11:18 PM
Hard starting in Fords usually caused by a bad glow-plug relay, easy fix.
Beware shooting starting fluid into a glow plug engine, either you or the motor could take a hit.
Avoid the OLDS based diesel, and the 6.5'sfrom GM, ( a different POS) like the plague.

CCWKen
04-09-2004, 11:48 PM
I don't care what praise the diesel gets unless you have a bank full of cash, don't buy a used diesel anything for $1000. A pressure pump alone can run $1200. Add installation and the bill will top $2000. Very few people have the knowlege and tools to do the work correctly on a diesel. A $120 lift pump gone bad can cause Thousand$ in repair costs. The maintenance on a diesel is twice that of gas. If it hasn't been performed, count on spending a lot of money getting it back to where it should be.

Even some of the best gas mechanics will stand around with their thumb up their ass with a diesel. Don't get me wrong; the diesel has it's place and it does a good job in that place. Just don't expect to get a bargin in a $1000 diesel.