1981 Rabbit Diesel - poor power!!

[MattRabbit]

Hey all!  I have a 1981 Rabbit Diesel that has been in my family since it was new.  I started driving it when I was 16 years old (back in 1990), and I've always had a sort of 'attachment' to it.

The thing is, this car has never had power.  Ever.  Like, it can't pull the hat off your head, weak.  It does 0-60 in... well, sometimes it'll do 0-60.  It's really pathetic.

I used to forgive it when I lived in Colorado, as high altitude isn't good for these cars, but when I moved to Florida it still felt like it just didn't have any get up and go!

Engine is the stock 1.6L.  The injection pump was replaced at one point due to leaky seals from a j/y unit (back in the way early 90's).  I think it's a pump off a vanagon, though I can't be sure.  I did a ring job on it back at around 240K miles, and it seems to make excellent compression (a compression test would tell more).  I just checked timing... it's set to .89mm, or as I like to say, dead on.

I'm not sure when the injector nozzles were replaced (if ever), nor am I sure when the valves were last adjusted.  I never did either when I owned the car and drove it in college.  I haven't done these two things either since I've had the car back (1999).  It's not my primary vehicle (I have a 2001 Golf TDI).

It has 317K miles+ on it. 

Other than these two things and short of throwing a turbo on it, what else can be done?  How hard it it to check the valves in this thing?  It's the original head, so it should be mechanical.

Any ideas are much appreciated.

[RustyCaddy]

To start you could try bumping the injection time up a bit. Mine is set closer to 1.00 (these pumps are old). Check the threads about turning in the fuel aka smoke screw, very carefully a little bit at a time and see what you think. i found a really big difference can be had by setting the idle rpm to spec, much smoother idle and seems to have helped the overall power (surprisingly).  Check threads for the governor mod.  There is a great area for look ups in the "Making your NA faster" (or something like that) in the FAX section.

[ORCoaster]

300 K plus and never a valve adjustment or injector cleaned.  I would surely be changing that.  But first I would do the cheap stuff.  Up the timing, and adjust the valves, or at least check them.  Without the special tools to press the cam followers down and the pliers to pull the shims out you will play heck on changing the adjustment.  CAUTION MATH INVOLVED.  You have to know the clearances for the intake and the exhaust are different.  And then know that the outside valves are the exhaust and the next is an intake.  IF you look at the manifolds you can pretty much see what is what. But I simply remember EIEI OH?   That works for both sides of the head.  Although from the right is the mirror of that IEIE, still working from the outside in to the center it is EIEI. 

In order to change the clearance you need to measure the distance you have, consult the spec and see if you are plus or minus to that spec.  Then you need to pull the shim off the top of the cam follower and see what it measures of says depending on wear.  Then you need to add a thicker shim if the measured gap is too large.   That will close up the gap.  And if you are too narrow then you need to put a skinnier one in instead.  This is where having a bunch of used engines comes in handy.  We have lots of shims to choose from.

I would also be doing a compression test because at that number of miles it may very well be worn to the point where you are not getting the 23:1 you need. 

I swap out the injectors at about 120 K miles and send the old ones off for new needles and breaking pressures.  But you say it never had any ommph so perhaps it has always run a bit behind.  You can have the dial gauge telling you it is .89 mm but what is the timing really doing.  That is why I so love the meter I bought that picks up on the flash of the burn in the cylinder.  No fooling that. 

So get to work.  My 1.6 won't drill you to your seat but it does jump up and go if I want it to.  So something is amiss on yours.

[MattRabbit]

Thanks for the info, you guys!  I'll be looking into getting the tools/parts to check and adjust the valves.

I'm also starting to have a look at injectors, as I bet that's most of my trouble right there.  I still remember driving it around when I was 16 thinking it was really damn slow, but we lived in Estes Park, CO which meant 7500 feet above sea level.  I'll try to get the engine all squared away and then start looking at compression/etc.

First thing, though, I lost my lower steering bearing.  The column needs some work!

[air-cooled or diesel]

And then know that the outside valves are the exhaust and the next is an intake.  IF you look at the manifolds you can pretty much see what is what. But I simply remember EIEI OH?   That works for both sides of the head.  Although from the right is the mirror of that IEIE, still working from the outside in to the center it is EIEI. 

i love your puzzle of exhaust and intake here; eiei, ieie, eiei; same in the book, or to complete or's puzzle from cyl #1 looking from left to right, or 'front' to 'rear' of motor, as pulley end is front, or left, EIEIIEIE, i think is it.

yea dude after so many MONTHS the valve adjustment needs to be checked, so if theyve never been checked since 81 or even 90, Check and adjust them!! injectors usually need to be swapped out about every 4 to 5 years or so, or at least pop tested. only things id add are change fuel filter & air filter. when you get all straightened out run a bottle of lubromoloy to a full tank or fuel and get a good fuel flush.

[MattRabbit]

Well, the other day, I pulled the breather tube off the engine while it was running to see what was being blown out.  As it turns out, a small amount of oil was coming out as well as a bunch of smoke.  It looks like I'm getting some cylinder blow by from somewhere.  I doubt it's the rings, but it could be the head.  The head hasn't had anything done to it... ever. 

Would pulling the head and replacing the valve stem seals/valve guides/whatever else can be replaced make a difference?  I guess I could just rebuild the whole damn thing, but money isn't great right now.

[libbydiesel]

Blowby is almost always the rings and on a non-turbo engine is guaranteed to be the rings.  The only other leakage I can think of that would result in smoke in the crank vent would be past the exhaust valve stem seals.  Leakage past the valves themselves just goes into their respective ports.  On a turbo engine the ports are pressurized so its feasible that it could leak past the valve stem seals, but not on a non-turbo.  If there are over 300,000 miles on the original bores/pistons, then the bores are virtually guaranteed to be very much out of spec.  In fact, it would be a miracle if they were not wildly out of spec at 240,000 miles when you did the re-ring.  After another 75,000 miles after the re-ring (when the bores were already out of spec) it would be another miracle if the new rings were not worn out after doing the funky chicken dance in the oval and tapered bores. 

A 1.6 non-turbo vanagon will do 60+ MPH on flat ground with no wind and it weighs twice as much as a rabbit and double the drag.  If you rabbit will not do 60 easily you have issues.  Getting it running right is easiest with a systematic approach rather than a shotgun method.  I would recommend doing a valve adjustment first as it affects compression.  After doing the valve adjustment, check the compression just to get it out of the way.  If it's really bad then there isn't really much point in doing anything else to the current engine except either a full rebuild or a stop-gap measure toward replacement.  If compression is good, then move on to injectors and pump adjustments.

[MattRabbit]

Yeah, the bores were out of spec when I replaced the rings.  I was a poor college kid, so I just replaced with oversized rings and filed them to get to the right gap.  That was a great stopgap measure, but I bet you're right... The engine probably needs some work.

I guess at 34 years old, it deserves it!  My head isn't (wasn't) warped, so I could probably reuse it.  I could just pull it and have it reworked.  I'd still need to get a shortblock, though. 

thanks for the info!