My friend needs to now how to bleed the fuel system on the 5.7 gm diesel. the motor has been put in a old 50's gmc truck so its not in the original body, not sure if that matters. I dont know anything about this motor since its the only gm diesel that i have never owned. any advice would be great, thanks Aron

I would imagine you crack the injector lines at the heads, while cranking with the pump unpluged and bleed just like the brakes

:exactly:
Thats how I did mine back in the day. Takes two people or a remote starter switch.

I think High Sierra has one and might know of a better way.

My friend needs to now how to bleed the fuel system on the 5.7 gm diesel. the motor has been put in a old 50's gmc truck so its not in the original body, not sure if that matters. I dont know anything about this motor since its the only gm diesel that i have never owned. any advice would be great, thanks Aron

Doesn't bleed any different than any other Roosamaster/Stanadyne rotary injection pump - like what is used on the 6.9/7.3 Fords and 6.2/early 6.5 GMs. Anything beyond the pump, e.g. the injectors, do not need to be bled - they will bleed themselves. But, you can save a little cranking time by loosening them until fuel dribbles out. Keep in mind, it won't be much (less then 1/100 of a teaspoon every fire-stroke).

What must be bled is the fuel source that goes TO the pump. Bleed at the fuel filter, and then bleed at the feed line where it hooks to the injection pump. Unhook the shut-off wire from the pump, then crack the fuel line loose where it hooks to the pump, then crank it until fuel spurts out, then tighten, and rehook the power to the pump and start it.

If you have a lot of bleeding to do, you can save your batteries and starter - by first unhooking the glow-plugs (or controller). If you REALLY want to save the starter and batteries, you can also remove a few glow-plugs from the heads to lower cranking compression. Not necessary though, unless you are stuck out in the middle of nowhere and your batteries are going dead.

Having owned several 5.7's for hundreds of thousands of miles, I fashioned a fuel cap, drilled and tapped 1/8" pipe, fitted with a Schrader (tire fill valve) fitting. Add just enough air to the top of the fuel in the tank to force it out the lines. Less than 10 psi. Add slowly, at low pressure, not full force shop air from the compressor, you could blow the tank/lines.

With slight positive pressure in the tank, loosen the fuel filter fitting at the inlet of the pump until fuel comes out, then crank it over in short bursts until it starts. Ten to fifteen seconds at a time, cool the starter between cranking cycles.

I've used a shop rag, wrapped around an air nozzle to pressurize the tank in the absence of the above-mentioned tool, just be careful you don't put too much pressure on the system.

As mentioned above, the 5.7 Rossa-Master/Stanadyne system is self-priming, it just takes a while. With a good electrical system, a big battery charger, and patience, they will self-prime if just run out of fuel and no other problems are present.

I think High Sierra has one and might know of a better way.

I haven't gotten that far yet with my 5.7... Still working on the buildup in my spare time. I've still got both of the heads taken off of it.

I'm going to say that bleeding the fuel system should be pretty much the same as bleeding a 6.2. I always bleed diesels which aren't equipped with manual fuel system bleed pumps or electric fuel pumps using air pressure with a method similar to the one Fred482' described. As he noted, you do have to be extremely careful not to use to much air pressure so you don't damage anything or blow a hole in the fuel tank (particularly if the tank is old and rusty).

i hope you have a return line too the tank 1

pull the main return line off near the ip after the injector returns t in and pressurize from there just a small amount and catch the excess in a clean container from the other side of the line you just connected the simplest way imo then with it still pressurized pull the glow plugs and crank her for a few then replace the glows and start her up might take a few cranks but she should pop off when the return line catch tank is full remove the air fitting and reconnect your return line should be good too go

dont forget too vent your tank and pour the fuel back in the tank lol every lil bit counts

i am very opinionated about the 5.7 imo he is better off getting a squirrel cage and tying it too thetourqe converter and buy a ton of mice too keep the tc turnin seein that the 5.7 is going too give you nothing but problems in the near future from broken block too blown head gaskets too prematurely wearing rocker arm pivots lol

if you do blowa head gasket get a arp stud kit for the heads and get the mr gasket head gaskets not the felpros they have weak sealing surface between the cylinders

and yes it will be cheaper if you get the 5.7 gasser pivot but it is exactly the same best of luck with your future project from hell

sorry about the rant hahahahahhaha

I think the 5.7 was a pretty good engine by '82 or so, but they weren't making many of them at that point (and nobody would buy one anyway). I've got one torn down here and it seems to be pretty well built. This engine I've got doesn't have a gasser block. In addition, I've found out during the build that pretty much nothing from the gasser bolts on to this diesel...

I understand that many people had problems with the 5.7 and that most of the early ones were junk, but I think this later model engine has potential. I'm thinking of installing mine in an S-10 when I get it done and if I do it should be a pretty nice truck... I'm expecting power similar to the 4.3 that was originally put in the S-10 while getting about 35 mpg.

I think the 5.7 was a pretty good engine by '82 or so, but they weren't making many of them at that point (and nobody would buy one anyway).

I worked in a diesel shop doing warranty work for GM when those 350 Olds diesels first came out. To compound the issue, I worked with three guys that bought brand new 1/2 ton Chevy trucks with them - including my boss. The 350 Olds diesel - as first designed, never made it to production. It was supposed to have a much stronger block, forged-steel crank, etc. But, after it was first designed - it went through massive cost-cutting.

I won't outline all the details - but all-in-all, they were absoltutely terrible engines. And, doing warranty work was frustrating. GM, over and over, would come up with new "computer designed" head gaskets, head bolts, better casted crankshafts, revised fuel injection pump parts, revised glow plug systems, and for the most part - NONE of those things worked.

Then, after GM got hit with a large class-action law-suit - they upgraded the 350 diesel and we replaced many engines with "Goodwrech" updated replacements. Better block, better injection system, better quality control with casting crankshafts, etc. They certainly were better - but even so, they did not, and do not last anywhere near as a good 6.2 will. I know of many - newer updated Goodwrench 350 diesel V-8s that lasted to 150K miles - which is quite a gain. Then, they often snap crankshafts. The original 350 diesels rarely made it past the magic point of 70K miles.

We'll see. I don't personally have much experience with the 5.7D so I can't say for sure how it's going to run or how long it will last. It looks like it should be a decent engine, though. I know it has a really bad reputation, but I'm guessing it'll be a decent engine nevertheless... We'll certainly see, though.

I don't disagree with anything JD has said; the earlier ones were junk from the beginning and the 82 - 86 Goodwrench had their weakpoints and would never compare to the 6.2 but I always wanted to put one in an S10 anyways. I'm jealous:rolleyes: !

The 5.7 was built as an interim engine to meet Corporate Average Fuel Economy (CAFE) standards, allowing GM to continue to sell big, heavy vehicles without paying penalties to the Gov. It was designed as a light duty, fuel economy engine. GM's development of fuel injection/gas engine technology was progressing but would not make the time line needed.

It allowed them to continue with body/chassis designs currently in production while progressing on the new front wheel drive fuel injection technology for the future without all the big dollar penalties.

It also allowed continued production of more large light duty trucks. By adding the 5.7D to the 1/2T 2WD chassis, they were able to sell a bunch of fuel economy trucks without monetary consequences.

If all the "homework" had been done and testing had been successful prior to release of the engine, things could have been much different. As it was, it worked, for GM, for a period of time. The backlash was another issue. They may still be paying for that one!

I, too, spent my years in the dealership working warranty on the 5.7. It later became a cash cow that I think was the biggest GM Job Security program I ever had. The 700R4 was second!

My biggest earning years, according to my latest Social Security Statement, were '79 - '84. Gee, that's when I worked on loads of 5.7's and 700's! Working in a small town dealership, I was able to swap dozens of 5.7's over to gas 350's. That's where the earnings came from, not the warranty, for sure!

JD and Fred,

Sounds like you guys have a ton of experience with those motors, Where would you say the major weak points were? I know the rear main seal was a leak issue, and the Head bolts stretched blowing head gaskets. If a guy found one and wanted to use it what would you reccommend they pay close attention to when they are building it?

( Besides paying close attention as it tumbles down the hill into the river):D

JD and Fred,

Sounds like you guys have a ton of experience with those motors, Where would you say the major weak points were? I know the rear main seal was a leak issue, and the Head bolts stretched blowing head gaskets. If a guy found one and wanted to use it what would you reccommend they pay close attention to when they are building it?

( Besides paying close attention as it tumbles down the hill into the river):D

I have a lot of experience with the early ones - but when 1981 came, the the local Chevy dealer started doing his own repairs instead of sending all his bad diesels to our diesel shop. Somewhere around that time is when GM - as part of the law-suit settlement - started replacing the failed 350s with upgraded engines with DX blocks. You are absolutley wasting your time and money if you try to fix any 350 that is NOT a DX.

In regard to GM not doing their homework with the 350 diesel - I suspect that is not entirely true - but it depends on who you want to believe. I read several articles written by the two engineers that created the engine. They state the original design was MUCH better than the production model. GM did a lot of cost-cutting before putting it into mass-production.

Here's some unsorted info you can read through. It is NOT my writing - so don't give me credit- or blame - for any of it.


The overall engine design used 22.5-to-1 compression, indirect injection, pre-cups and glow plugs, with the Oldsmobile gas engine carry-over 4 head bolts per cylinder. The bolts couldn't take the pressure, and would stretch almost on a whim. Head gasket leaks were repaired and the engine torqued down with the old head bolts, causing a cycle of unreliability. This caused egregious sealing problems in the early years; eventually GM went to a 1/2" head bolt in 1981, but this was an engine that just screamed out for head studs due to all the head gasket failures. There were also problems with crank breakage in the earlier models due to inadequate main bolt depth in the block; this was also improved in 1981 with the introduction of the DX block, which also featured hydraulic roller lifters. The troublesome early pencil injectors were replaced with a new poppet design midway through 1980. The injection pump is rumored to be substantially the same as used in the GM 6.2 engines (which were designed as diesels from the beginning) and is not the worst pump ever made if the fuel is kept clean. Further improvements to the 5.7L came in 1983 including piston pin and rocker arm redesigns; by that time, GM had solved most of this engine's problems but the soured reputation was too much to overcome and the engine was discontinued after the 1985 model year


STORY OF HOW THE 350 OLDS WAS CREATED

Winter 1976 - As a winter project, the engineers at Olds took the 350 gasser block, cast it from high nickel iron, stroked the crank, cut reliefs in the pistons, reworked the heads with a Ricaro prechamber and installed detroit pencil injectors. Found a Roosa Master 8 cylinder pump from the local tractor dealer and machined an adapter plate to mount the pump. Made five copies and put them on the dyno to do the tests.

So the story goes, two months later, Mercedes announced that they had put a turbo on the 300 and finally had a diesel that could keep up with the traffic. With the fuel crisis still in full swing and Detroit stumbling along with their two ton lead sleds, GM marketing went looking for a solution only to find that their own engineers had a hobby. Olds was given 18 months to get the prototype into production (about 24 months shorter then normal, especially for a new engine design).

January 1978 - After working many overtime hours the engineers had developed an engine, that at the time had the best power to wieght ratio of any production automotive diesel ever made, but discovered the accountants all held a deep desire to be designers. Nix the dual exhaust, heavy duty version of the Roosa Master, the hardened head studs and the high nickel block. The result was a 120 hp diesel that got almost 40 miles to the gallon (IMP) and only 70 lbs heavier then it's gasser counterpart. Unfortunately you had to drag a magnet behind the car to catch all the parts that flew out of the engine.

Granted some of the problems were related to a totally uneducated buying public but most of it stemed from letting the accountants play with the design and that it was literally an untested engine.

August 1981- After almost breaking the bank with warrantee claims, and after many hours of exhaustive testing GM introduced the "DX" block with stiffer webs, high nickel block, roller cam, new stronger crank, 27 modifications to the Roosa Master (now made by Stanadyne) (lets face it, it started out life as a tractor pump), better cooling channels, improved injectors and a better head design.

While they were forced to de-rate this engine to 105 HP, it still gave great mileage and reasonably acceptable power for the vehicles it was installed in. None the less, the previous three years had written paid on it's reputation and nothing Madison Avenue could do could revive it. The engine stayed in production through the 1985 model years but was quietly laid to rest. In order to get rid of the over-stock, many GM cars had these engines installed as standard equipment and you had to special order them to get the gasser.

While they were still plagued with head problems (cracking between the valves and gaskets) the DX engines were reasonably trouble free as long as you knew how to operate a diesel.

Dude, You are full of usefull information.
So sounds like a guy would want an 82 - 86 DX block. If he used it in something light like an S10 and did not drive it like he stole it should do okay. Use ARP studs and good head gaskets, do the seals right and NOT cheap, anything else? I'll probably be looking for one in about 6 months. Too many irons in the fire right now.:rolleyes:

Thanks JD!

So sounds like a guy would want an 82 - 86 DX block. If he used it in something light like an S10 and did not drive it like he stole it should do okay. Use ARP studs and good head gaskets, do the seals right and NOT cheap

:D

The information JD posted seems to be the same as most of the information I have read about the engine. It seems to me I had a book around for a while that had the whole history of the engine in fair detail, but I don't know what happened to it. I'll be interested to see how my engine performs. I've never messed with one before, so it'll be an interesting experiment for me...

That's pretty much the story. I've built several with the studs and several with good grade ARP bolts. I prefer the studs, the newer ones with the allen socket hole in the head, so you can remove them easily (or easier!). The studs make it a little hard to change a head gasket in the chassis but, if the block and head machine work is done correctly, the interval for head gasket changes gets tolerable.

Unmistakeably, if you own and drive a 5.7D long enough, you will gain experience putting head gaskets in. There is much talk of MLS technology, solid copper gaskets, o-ringing the block, etc. I would think these would be a step toward better sealing of the high compression. I have no experience with this technology, except in a drag racing application. With the decline of interest in the 5.7D, the cost of this technology for that application will be quite high.

The later blocks are the most desireable for buildup. Attention to detail and good, quality machine work will help longevity.

I belive with correct parts, good machine work, careful assembly, attention to detail and reasonable driving technique, the 5.7D can and will continue to be a viable, fun project for the diesel enthusiast.

The best thing about the 5.7 diesel is changing it back to gas. It makes a heck of a gas motor.

The best thing about the 5.7 diesel is changing it back to gas. It makes a heck of a gas motor.

I've heard that before. Can you just bolt gasser heads onto the block or does it need some mods to work? I imagine gasser pistons are a must.

I've heard that before. Can you just bolt gasser heads onto the block or does it need some mods to work? I imagine gasser pistons are a must.

Actually, I've heard that's part of the cool thing about it... The diesel pistons make it a really high compression, high performance gasser. Whether or not there's any truth to it I don't know. As I noted above, I have very limited experience with these engines.

Honestly, I don't think the gasser heads would fit on my 5.7. I don't know about the early model, but I don't think any gasser parts will fit on the later diesel.

I've heard that before. Can you just bolt gasser heads onto the block or does it need some mods to work? I imagine gasser pistons are a must.

Yes, there are several gas heads that bolt on with no mods. You can keep the diesel pistons also. Compression winds up being anywhere from 9.5 to 1, up to almost 11 to 1 - depending on which heads are used. A different cranks is sometimes used also. There are a lot parts to changed. Only gain is a somewhat stronger block -over a stock gasser.

None of it makes sense to me - but I'm not an Oldsmobile enthusiest. I drove a brand new 1970 Olds 4-4-2, and didn't like it anywhere near as much as my 396 Chevelle. Olds tends to run different - with long stroke, moderate revs - whereas HP Chevys tend to be short stroke and high revs. Then - there were the HP Buicks - some of which were promoted as being "square" - meaning bore equals stroke. I had a 69 Grans Sport and liked it. Back then, they were all different with their own engines - which made them all unique. That's been lost.

Funny thing - about engine conversions. I collect old - 1960s vintage 4-stroke 55 horsepower outboard motors (on boats). They were made by Homelite, Bearcat, and Fisher Pierce. The engines are modified Crosley car engines - tilted on end with an increased bore. And now? There are Crosley midget racer enthusiests (cars, not boats) looking to buy up all the outboard motors they can find - and convert them back to car use - because the blocks are better and also have bigger bore. It's driven the price up on the boat engines. Seems the same sort of thing has happened with the Olds diesel DX blocks.

I did one these conversions years ago. When i heard about i did not think it would work.
My grandfather bought a farm and the pepole who had lived there left about 10 of the old 5.7 diesel engines laying behind the barn. A few weeks later i ran into a guy who was wanting one of those engines so i was corious what he wanted it for.
That is when he told me he was going to convert it back to gas and put it in his race car. So i loaded up 2 of those engines and took them to his house and hung around wile from time to time wile he was building this motor. the only things he used was the block,crank,pistons and rods.
When he was done that car would run 8.10's all day long in a 71 olds cutlass.
So about a year later a guy gave me a 70 olds vista cruiser wagon that had a 350 rocket with a crack in the block where this guy was to cheep to buy anti-freze. I pulled the motor tore it down and put all of the parts on one of those 5.7 diesel blocks. The only thing i used from the diesel was the block,crank,rods and pistons. All i did to the parts was clean then up and buy a gasket set. For that car to be so big THAT THING WOULD FLY. and would absoutely fry the rear passengers side tire off.
I played with that car for awile before i sold it, and it was still running great.

i done a 5 7 conversion once :eek:


converted it too a 6.2 diesel:grd:

oh yea i forgot heres a link too a 350 olds diesel forum have fun dont make too much fun

http://forums.delphiforums.com/n/main.asp?webtag=350Diesel&nav=start&prettyurl=%2F350Diesel%2Fstart