Volkswagen Owners Club Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
85 Posts
Discussion Starter #1
I have 1981 Caddy with 1.6l diesel. I have got it to start, I though it was the fuel pump, changed it and same old thing. I can spray starting fluid and it will run until that is gone. I took it to a Volkswagen mechanic and he said that the engine did not have enough compression to pull fuel to the injector pump and run. He said it showed 290 on 3 and 350 on the other one. Is this right???? If so what should I do first?
 

·
Registered
Joined
·
302 Posts
First thing you do is find a new mechanic! One that understands how this VW of yours really works.

I will give him credit for measuring the compression of the cylinders and telling you they are low. I believe the minimum PSI is 400 but that one at 350 being your best shows you have a ring and a bore of the engine in your future. Those 3 at 290 are just so far from doing the job I can see why you need the a can of coercion to keep it running.

The air flow into the cylinders has nothing to do with fuel delivery. That comes from the injectors, it is sprayed in when the cylinder hits TDC. The injection pump has a low and high pressure side. The big part of the body contains a wheel that has four little squares of metal equally spaced around the edges. That is the vane pump, it is what pulls fuel into the IP. It pushes it to a second part of the pump where a 9 mm or larger plunger then compresses the fuel and pushes it into the correct delivery tube to the injector. All a very nicely coordinated dance for the diesel.

If you have decent fuel delivery and it sounds like you do as it did run in a manner of speaking, I would be rebuilding the pistons, cylinders, head and once you have the proper level of compression, 480 PSI/ cyl. Then start measuring the amount of diesel being pumped out at idle. That is about 1 liter per 90 seconds if I remember it right.

How many miles on it? Timing belt and tensioner pulley in good shape? Any records of past maintenance?
 

·
Super Moderator
Joined
·
10,586 Posts
IIRC the minimum pressure is @ 400. Max being @ 495. There should only be 75 psi difference between cylinders. He measured 2 cylinders? To measure the pressures yourself be sure that you buy a diesel gauge that goes to 500-600psi.

In the days prior to the interweb when I owned my Diesel Bunny, I had a fueling issue, So I bought a used pump, that didn't work any better and decided to tear my original one down. I didn't buy a rebuild kit. I tore it all apart and cleaned everything, I even polished the vanes on the injector pump...which is where the issue was I had 2 vanes that didn't slide. When I reassembled it I had to bleed it at the Iron Manifold as there was air trapped at the Injector Stand-offs.

Think no interweb no digital cameras, I just drew pictures of things...to get them back correct.
I had that car running in about 4 days, and it kept running for another 8 years before I sold it.

Timing belts are tricky, there is no error allowed in timing. One tooth off and you can have massive ca-ca to occur.
The Diesels are interference engines, where the Gassers are not.


http://vwdiesel.net/forum/index.php/topic,4353.0.html
 

·
Registered
Joined
·
302 Posts
Briano His mechanic measured 290 on 3 different cylinders and 350 on the other. I know I had to read it twice to figure it out but it does make sense the way it was written.
 

·
Registered
Joined
·
85 Posts
Discussion Starter #5
Thanks for all the info, sorry for not writing so you can understand . Measuring from the injectors from left to right-dry- the first three injector showed 290 compression and last one showed 350. The motor has 121000 on it. Ok I am going to pull the head off and we will go from there. thanks again Allen
 

·
Registered
Joined
·
85 Posts
Discussion Starter #6
One more thing---I have another engine that the block corner is broke off around the bolt hole. Could I use any of parts off it??? It has only 79000 miles on it. It was still running when I took it out. thanks Allen
 

·
Registered
Joined
·
336 Posts
Yes. All the internals are interchangeable even between the fuel types but the diesel ones tend to be more sturdy.
Is possible to even make a "Giesel" ie gas block with diesel internals...got one that came with my Some Assembly Required Caddy that afaik as I know is healthy but will never use it like it is since the block itself won't be as robust. Fortunately have a couple bare blocks to choose from.
 

·
Super Moderator
Joined
·
10,586 Posts
I have seen a diesel perverted to gas, (different head, and added a dis instead of the vacuum pump)...I wouldn't of done it.
I have seen 16V gasser heads installed on a diesel and Turboed (shoot it was part of an aftermarket turbo kit you could buy)

But never seen a gasser converted over. :)

The above 16v turbo kit was sent to me in a Mailer after I had bought my 81, and I was really tempted, but the 4K price and only making 220/week was too much. It even came with a 10 gallon bladder tank that fit in the rear wheel well, and they said on 20 gallons of fuel you could drive coast to coast on 20 gallons.... I forget the HP gain but I think it was doubled....Can't remember the name of the company that was making those kits, but IIRC they were German Based, and had a good rep....
 

·
Registered
Joined
·
302 Posts
It even came with a 10 gallon bladder tank that fit in the rear wheel well, and they said on 20 gallons of fuel you could drive coast to coast on 20 gallons.... I forget the HP gain but I think it was doubled....Can't remember the name of the company that was making those kits, but IIRC they were German Based, and had a good rep....

I doubt the mileage claim. That would be over 110 Miles per gallon. We would have all heard about that by now. I think the horsepower gain from a turbo is modest at best unless you really build for boost. If you are running a standard 8 or 10 PSI gain then you are adding something like 18 or 20 HP. Given that the initial HP of a 1.6 is near 53 then it does help for heavy loads or excessive starts. Or just more fun to drive.

I have yet to convert my Caddy over to turbo, always something getting in the way. Like brakes or alternator charging gremlins. I will be on is soon I hope. The extra air into the engine is claimed to bump the MPG to the 50 mark on the highway.
 
1 - 9 of 9 Posts
Top