VW 1.6L Marine Engine

[DeadEye]

I have just inherited a Shamrock Boat that was recently retrofitted with a engine from an 81 Rabbit. The refit is a not quite finished project (the bugs are not yet worked out). Its now up to me to tune this super fuel economy boat in. This engine was marinized with parts special shipped in from england . A wet exhaust/heat exchanger and bell housing with a 1.5:1 borg warner velvet drive transmission. Its the only boat Iv ever even heard of with a good ole 1.6 VW diesel.
The engine refit has a few bugs to be worked out. It was being run on a 50 50 mix of diesel and SVO and had enough power to get on plane, recently power dropped and a flustered owner passed the project to me (Quote~ time to cut losses and roll).
Thinking OK this is a fuel issue with the SVO and such I changed both fuel filters and vacuumed the fuel tank refilled with good diesel and flushed all fuel lines ect. Ran like a charm! well at the dock it did anyway. Still in sight of the dock the engine started loosing power so turned back. Engine got weaker and weaker slowly till it died. Back on shore an hour later with a garden hose feeding the raw water supply it fired up and again ran like a charm ( darn an intermittent problem ). With engine at full operating temp 195 F. AND at higher then idle the problem returned on shore. RPM dropping just like in the water. Im thinking gotta be the injection pump _ Your thoughts?

A few other tid bits. The lift pump is a universal electric fuel pump rated at 9 to 12 psi like you would use on a gas engine, what is lift pressure (feed to IP) supposed to be for these engines.
Looking over the Heat Exchanger install / plumping, there is a coolant fitting on back of head that is hose to water pump and a T off the thermostat housing direct to water pump. Seem perhaps wrong like it was for the car heater and now loops the pump. What is normal operating temp for the 1.6?

If I need a new IP what would be an upgrade? A few more HP would be grand

Many Thanks DE

[82vdub]

Welcome to the forum. My first thought for something like this is fuel starvation. There's a restriction somewhere (likely a plugged inlet screen or something) and the fuel turns to foam under a certain amount of vacuum. Engine dies, air goes back into dilution with the fuel, and there's fuel for it to start and run again. Fatmobile has a thread on here about adding a vacuum gauge to the inlet of the IP. If you can somehow rig up one of these to make sure your pusher pump isn't dieing and causing a restriction (or some other issue), that would be a place to start. THese VW engines don't use a pusher pump from the factory. If you have to replace it, it needs to be replaced with a very low psi pump as it effects internal IP timing with too much pressure pushing fuel to the IP.

[DeadEye]

Thank You. Yes that was my thought as well starvation. If I disconnect the fuel line at the IP and turn on the pusher fuel flows real good,it dos not seam restricted but who knows could be a small leak in the line sucking in air I guess. I will go out and hook the engine to a fuel can and try it that way to eliminate a plug or leak issue with the fuel lines as well as to see it will run without the lift pump. Update later Many Thanks

xx

11:25 Hooked up a gravity feed system and again the engine runs like a charm cold and as soon as temp get up it acts like its starved. Will take off the bango fitting and inspect that now but its a long shot. Looks like a new IP is in order.

[TylerDurden]

11:25 Hooked up a gravity feed system and again the engine runs like a charm cold and as soon as temp get up it acts like its starved. Will take off the bango fitting and inspect that now but its a long shot. Looks like a new IP is in order.

A clear hose on the IP outlet can help determine if the IP seals are sucking-in air. Lots of foamy output indicates air in the IP. Common to see some after startup, but should diminish after a while. If foamy output increases after time, the IP seals or fittings are prolly leaky.

Using Lubro-Moly "Diesel Purge" (DP), you can clean a lot of crap (like polymerized SVO/WVO) out of the pump, by running the engine and circulating the in and the out to the IP from a container of DP, as if it were the fuel tank.

Any pump having seen SVO/WVO should be cleaned with DP as a first measure, IMO.

[DeadEye]

Many thanks on this tip. I will try to clean /purge pump as recommended. Yes I used a semi clear fuel line (translucent yellow) The return emits very very little fuel when running, like a drop per minute almost non existent return, not what I would call flow at all. Any thoughts on the LOW flow of return.

[TylerDurden]

No fuel in the return line is likely a plugged OUT bolt in the banjo fitting. Flow should be >1/2 cup per min @1500rpm(?)... I gotta check, but deffo not a few drops...

The OUT bolt has a small orifice to maintain IP internal pressure - a calibrated pinhole. There is also a screen in the bolt to help keep debris from clogging the orifice.

If the OUT bolt is clogged, the IP internal pressure will be high and the IP will not get cooled by proper fuel circulation. Hot pump!

I would carefully remove the bolt and clean it thoroughly with brake-parts cleaner/solvent.

Replace, run w/ DP and look for bubbles in the return line.

[DeadEye]

No fuel in the return line is likely a plugged OUT bolt in the banjo fitting. Flow should be >1/2 cup per min @1500rpm(?)... I gotta check, but deffo not a few drops...

The OUT bolt has a small orifice to maintain IP internal pressure - a calibrated pinhole. There is also a screen in the bolt to help keep debris from clogging the orifice.

If the OUT bolt is clogged, the IP internal pressure will be high and the IP will not get cooled by proper fuel circulation. Hot pump!

I would carefully remove the bolt and clean it thoroughly with brake-parts cleaner/solvent.

Replace, run w/ DP and look for bubbles in the return line.

You are DA MAN. and yes it was a rather hot pump before all this. Cleaned the bolt and got flow. There was a load of brown gunk in there polymerized oil I suppose. Had to repeat procedure about 15 times so far as it keeps re clogging. Found a few other problems along the way. A leaking injector body and a missing plug on last injector body.

Update later THANK YOU ALL

I think the pump is now operating properly but I have created a new problem. One of the injector bodys was leaking due to it getting unscrewed by not holding the lower part when removing the injector line. I removed the injector and tightened it reinstalled it (Not knowing about the heat shield). Still leaked took it out again and took it apart cleaned things a bit with carb cleaner. Reinstalled again now no leak but an unacceptable fuel knock. Guess it dumps to much fuel. Read up some more and found out about the shield. Cant seam to get it out does this look right? See picture below~ hope I did not flub up more than the injector

Were to order new injector and shield?

[Fatmobile]

You can run with a regular banjo bolt (like the one on the front of the pump) in place of the "OUT" bolt for awhile to flush everything from inside the pump.
You can't run around like that because there won't be any internal pressure,... and fuel flow through the pump will be incredible and cause air in the fuel.

Is that a picture of a broken heat shield? First time I've seen that.

Injectors don't just come apart when you remove the line. They are torqued together pretty tight.
The previous owner was probably messing with that injetor and didn't screw it back together tight.
Look at the injector end while you have it out, see how concave it is around the tip. Gives you an idea how old they are.

[DeadEye]

Thank You

Is that a picture of a broken heat shield? First time I've seen that. Ummmmm not sure. I have worked on diesels before but never a VW. That is the hole the injector unscrewed out of, at the bottom of the hole is what looks like a 1/3rd of the hole was never drilled all the way out/ er ahh part of the aluminum casting sticking out there: What looks to be the heat shield under it.

Something dont seem right with that hole but it did run/ hit on all cylinders. I guess I could pull another to compare with.

[CarlosA]

Looks like it could be lead, used to try and seal up the injector. I had a injector seat deteriorate and leak and pretty much do what you are talking about - I swapped the head out and problem is gone.

[mtran]

If the OUT bolt is clogged, the IP internal pressure will be high and the IP will not get cooled by proper fuel circulation.

What about hot or cold WVO campare to Disel in viscosity,it will make difference right?
in presure thing I think.

[TylerDurden]

Is that a picture of a broken heat shield?

I thought it was glare on a pool of fuel in the bore.

If the injector was opened in place and poorly re-assembled, it would not surprise me to see fuel all around.

What about hot or cold WVO campare to Disel in viscosity,it will make difference right? ... in presure thing I think.

Straight VO needs to be ~160F to match the viscosity of diesel. Colder straight VO can destroy pumps and injectors.

Blended diesel/VO is more complicated, but many have used 50/50 in summer.

Problems with VO can arise when it sits unused in the system and gets gummy.

[DeadEye]

Ok fellows I pulled the injector beside it to get a comparison. WELL WELL the hole was as it should be in the #2. The hole as pictured in #1 is FUBAR to say the least. This was is a defective machine job on the head. The hole in the casting was drilled at an angle compared to the rest and was not even punched all the way through thus the shiney part you all see. Worse yet it is above the heat shield preventing its removal (how the heck did they get it in there). Perhaps this is a shade tree job of a sleeve to repair threads damaged in the past.

I might be able the dremel grind that aluminum out in order to replace the shield.
Is the threaded part a replacable insert on the head?

No way as a mechanic would I have used a head with a bad hole like that.

Thanks Fellows

[82vdub]

The injector boss is not replacable, or designed to be. The threads are integral with the head. How did the heat shield get in there and underneath the aluminum? Are you sure some filings didn't fall in and over time become somewhat solid?

[TylerDurden]

Freaky.

Might be possible that an injector was cranked into the bore crooked, the end of the injector shaving the wall of the bore down onto the heat shield.

When installed, was that injector on a slightly different angle than the rest?