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Sat May 17, 2003 5:41 pm

I'm not looking for someone to commit to an answer here, just your opinion and any experience you may have had. I have an '81 with a 2.0L. The van has good acceleration around town, but is very bad up hills or trying to maintain highway speed (maxes out at about 55mph on flat road, but will go faster downhill or slower uphill). I've replaced the heads (new), rings, plugs/wires, adjusted valves, and checked most other things.

The compression is still around 90-100 on all cylinders. I did a wet test on #2 (100psi) and it jumped to 120psi. I did a wet test on #3 (90psi) and did not see an improvement. I'm inclined to think that the cylinders and pistons need to be replaced and I would see a considerable improvement with the increased compression.

My wife is beginning to resent this investment and I need to shape it up or ship it out. *Assuming* she would concede to me purchasing new pinstons/cylinders, that is probably the most that I'm going to be able to get for quite a while for this van. I will not be able to take this engine or any parts (i.e. cam shaft) to a professional for an evaluation. The most I'll be able to do is have the pistons checked and weight corrected before installation (just because it is part of the job).

Here are my questions. Does the fact that I have decent pick-up around town give any indication that the cam-shaft would be okay? Can someone else who has driven a van or bus with similar compression levels verify that this is the type of driving behavior that is indicative of these compression levels?

Like I said, this is a touchy situation already. Either I gamble on solving the power problem with new pistons and cylinders or I sell the van. I bought this van to take family trips with, but so far we cannot even use it for that purpose. I just need to get it highway-way worthy so that family trips in it are made at a tolerable speed.

Thanks,

Hans

Sun May 18, 2003 12:48 pm

Helloooo.... Someone must have driven a bus with low compression before or dealt with a worn cam shaft.

I really need to get some 3rd party perspective and input before I discuss this with my wife.

Thanks,

Hans

Sun May 18, 2003 4:54 pm

You should have better acceleration than that on the highway. Take it to a decent mechanic and have them evaluate it for you, probably cost around $50 or so. They should be able to point out you problem. How many miles are on the engine? Did you mic the cylinders when you replaced the heads? Are they still round? Did you do a leakdown compression test? Have you retorqued the heads since you installed them? Is you exhaust system in good order?

Sun May 18, 2003 5:22 pm

Thanks Bajatacoma. Alas, I did take it to two VW machanics. The first said he wouldn't be able to diagnose without taking the engine apart (even I can do that to an extent). The second told me I had the wrong throttle body and disconnected a hose from the air distributor sending me on a wild goose chase only to find out that it is the correct throttle body. Mind you, the only thing these mechanics work on is VW.

I don't know what mic the cylinders means (I probably didn't). The heads are retorqued. I'm not sure about the roundness of the cylinders. As far as I could tell they were round, but you probably mean round as measured with a precision instrument.

The exhaust seems to be in good working order. No leaks and no clogs.

I can't do a leakdown test without a bit of spendy equipment can I? I didn't know what to specifically ask for when I took it to the mechanics, but now I recognise that they should have done leakdown tests.

I'm willing to go through a number of things on my own to narrow the problem down. The miles of the engine are unknown. It is a rebuild, but the speedometer cable was broken when I bought it. The odometer says about 32,000 original miles! Ya right!

I'm hoping to take this van out of state within about a month. My wife is going to be very resistant to taking the van to a mechanic again (the last misdiagnoses cost about $130 each). I'm wondering, given the compression numbers that I have and the trip I'd like to make, should I be considering the pistons and cylinders an inevitable replacement and then work on smaller problems from there? Or, given those compression numbers and the trip I'd like to make, would I be *okay* if it was running at the extent of its current potential?

Sun May 18, 2003 8:23 pm

okay, the problem, as i see it, is dealing with your wife as much as dealing with the van- she obviously feels that the van is simply a hole in the driveway that you are pouring money into, so she is wary of increasing your "investment' in the vehicle. explain to her the economics of having the engine properly diagnosed- right now, you can spend money on new pistons and cylinders, and find that the problem lies elsewhere, and then spend more money, etc, etc... or you can have a COMPETENT shop do the necessary diagnostics. I would be inclined to think that you probably need to replace the pistons and cylinders, but that may be only the tip of the iceberg, or you may be able to get away with just replacing rings. either way, the economics work like this- right now, the vehicle has a value to you of zero. with a little investment, you can have a vehicle which is priceless, a family getaway machine. bite the bullet, and find out what is wrong and fix it. if you do it right, then you will have to invest very little over the long haul, and everyone will be happy.
Or, plan B- find a good used engine, and take a weekend and install it. buy a good running parts van (now that you know how to compression test, you can look for a better runner than what you have, and junk/sell the rest)and do the transplant. Good running parts vans are common for less than $700. dune buggy guys will buy the tranny for $250- $400, leaving you less than $500 into the project. at this point, what have you got to lose?

Sun May 18, 2003 8:44 pm

An engine that feels peppy around town but bogs on hill pulls or freeways, suggests a high speed anomaly, such as subtle fuel starvation that occurs only under a lengthy demand, or perhaps an oxygen sensor that is going out of calibration under extreme heat. Pistons and cylinders would give you that anemic feeling every day all day. Time your 0-60, flog it just this one time.
Anything under 25 seconds is indicative of a healthy engine. Another high speed anomaly is centrifugal timing that is not advancing correctly.
Colin

Sun May 18, 2003 9:39 pm

Thanks guys. Very sound advice. Now that I think of it, the 2nd mechanic did mention that he advanced the timing to adjust for the improper vacuum action caused by me having the "improper" throttle body. Subtle fuel starvation also sounds reasonable. Perhaps the CHT sensor is not doing so hot. I tried removing the O2 sensor and got a bad reaction, so I'm thinking that it is working okay.

The wife is another issue. Even another $30 for a timing light is an issue when it comes to the van. I wish I'd bought one before I found out that she was upset about the van. Okay, so I'll check the above and try to rule out the lesser evils before committing to cylinders and pistons. I'm thinking that it needs cylinders and pistons regardless, but if there is any way to put them off for a while...I'll take it.

Thanks,

Hans

Mon May 19, 2003 1:06 pm

I have a bus which I love, and at times it takes money to keep it running well. We use it for camping and surf trips, a great family investment for our happiness and time well spent together. Ask your wife if she can bare the wait, until its done, and done right? If she can't, just ask her what would make her happy, because if momma's not happy, nobody is happy.

Mon May 19, 2003 2:23 pm

Hans, where are you located? You don't have any friends neighbors or co workers who may have a timing light to loan you to test and see if like Colin says the dizzy is not advancing properly?

or maybe someone on this site is near you or knows someone who can give you a hand... here's afew other possibilities....

Have you replaced the fuel filter? and made sure that the lines are not kinked or anything since the engine was put back in?

does the engine create alot of blow by? if the rings/pistons were that bad to make it only run 55 tops then you would see other signs.
you say "The exhaust seems to be in good working order. No leaks and no clogs." but are you certain? is there a catalytic converter on your system?
I would make certain it is not even partially blocked.
for 130 bucks work what did you get? (besides the run around?)

I am optimistic you have some other troubles either with the timing or the Fuel or something external that just needs to be properly diagnosed,

other than a flat cam , seems likely it is external.

I hope you get it figured out or can calm the little woman down, not a good place to be that's for sure!

Mon May 19, 2003 6:30 pm

keifer, check the compression numbers that hans posted- I don't think it is fuel or exhaust related, just based on the numbers. hans, check your pushrods, to see whether the cam is at issue. any smoke at start up/under acceleration? Have you got a bentley manual? there si some good info in there as far as trouble shooting goes.

Mon May 19, 2003 7:26 pm

Yeah BL I guess I skiped past the 90lb on the one.... still new rings and new heads? wonder how out of round they were and if he honed them, not timing light ? probably = no cylinder hone either.
still like you say hope for pushrod/ mis adjustment on old lifters or cam?
is it noisey? valve train that is???

Mon May 19, 2003 7:46 pm

hans, just a thought- when you replaced the rings, did you stagger the gaps?

Mon May 19, 2003 7:57 pm

BLJONES... super sleuth! LOL! MON NITES AT 9:00 ! ;)

Mon May 19, 2003 9:45 pm

Hans-
If your timing is too advanced, that'll do it. Also, have your wife get in it (if she's still speaking to you) and press the accellerator all the way down while you watch the throttle on the engine. As she holds the pedal all the way down, push the throttle farther open if you can with your hand. (Engine off, of course. If you can move the throttle farther by hand, you either have something blocking the accellerator pedal from going all the way down, or you have too much slack in the throttle cable. With the pedal all the way down, loosen the barrel clamp and push the throttle all the way open. Retighten the clamp with very little slack in the cable.
It doesn't sound like a camshaft problem. USUALLY if your cam is worn, the engine will start losing power at 2500- 3000RPMs. the dead giveaway is that it won't rev higher than about 3k max, even in the service bay. Another thing that can cause the problem you describe is the oxygen sensor leaning the mixture out too much. Do the throttle thing first. If that doesn't improve things, unplug your oxygen sensor and tape off the exposed male spade connector on the fat green wire. Drive your Bus with the O2 disconnected. If it goes faster now, replace the sensor. Finally, your bus may have an automatic timing device. It's a rectangular green box somewhere in front of the coil on the driver's side of the engine compartment. It has two fat round plugs going to it. Unplug both plugs and plug them together, bupassing the box. Hook up your timing light. Now, start the engine and check/ adjust your timing. If your bus has the green box, you MUST set your timing with it bypassed! Now, with the box bypassed and timing set, take another drive. If it drives OK now, leave it like this.
TWO THINGS you don't want to do: Run the engine too lean, or the timing too advanced.
My Personal Philosophy: If all the little basic stuff isn't correct, you can throw all sorts of expensive parts at a car all day long and it still won't run!
By the way, my wife is watching me type this, and she agrees with YOUR wife. She thinks we're all screwed in the head. I take it by your name that you're German too... My wife says to tell your wife "You can always tell a German... but you can't tell him much" Hope all this helps!
Bis Spaeter...

Tue May 20, 2003 2:24 pm

Thanks everyone. I did get the go-ahead on a timing light and a new CHT sensor. To cover some of the earlier questions: don't know what a push rod misadjustment would be other than off of the lifter cup, yes I did hone the cylinders, I'm sure that the offset of the rings is correct, no smoke at start-up or on acceleration, valves have been adjusted trying 1 - 1.5 - and 2 turns past touchdown on the valve spring, I did check the cat. and it didn't seem to have any clogs.

The timing is off for sure. I don't see how it couldn't be. The second mechanic advanced the timing to adjust for what he thought was an incorrect throttle body. I did notice before that the throttle is not hitting the little switch that is supposed to enrich the mixture for full throttle even when the pedal is floored. I'll deal with that ASAP.

I tried driving the bus without the O2 sensor (although I did not tape the connector), and there was no difference while driving, but the idle was different and a little rough when it was disconnected.

So, I bought a timing light (very basic) at Wal-Mart yesterday and tried to adjust the timing. I failed. I know where TDC is on the pulley by pointing the distributor to cylinder #1 and then aligning the set of three lines in the pulley with a point at exactly 90 degrees clockwise.

I have a degree indicator mounted, but it begins at 0 degrees and runs counter-clockwise to just before 270 degrees. I don't see a mark in this area on the pulley to use with a timing light. I can't just mark any spot because I know that it is not set correctly. I've never done this before and I felt really confused by it. I looked in my books and they explained the process briefly but not well enough for me to fully understand. Can anyone help me with this? Also, are there other things that I NEED to do this like a tach or dwell meter?

Thanks,

Hans

Tue May 20, 2003 9:57 pm

Hans: If you look at the timing mark like it's the big hand on a clock face, when the light flashes it sould be around 10: 30 or 11: 00. Sounds like you have a strange scale on your engine. I'd get an OE one from the dealer or a junkyard. If you have a white scale with black numbers there should be a red dot which is where you align the notch on the crankshaft pulley, (vacuum hoses to the distributor disconnected and plugged.) If you have a black plastic scale, there should be a dot stamped into it. Move the distributor clockwise to retard, and anti clockwise to advance. Then you time it to the dot just like the red dot on the white scale. Idle speed should be 750- 900 RPM. Don't forget to fix the throttle.

Wed May 21, 2003 2:39 pm

Hans:

I got a engine analyzer that has a tach and a dwell.

JEFFRO

Wed May 21, 2003 2:41 pm

I bought a tach/dwell meter. There were a lot of other fancy gadgets that were very tempting too. It will be nice once I have an arsenal of diagnostic tools at my disposal.

Hans

Wed May 21, 2003 2:43 pm

Hans:

Also I can get my points right on without the dwell when there new. But if there old I use the dwell. Just a thought!

JEFFRO

Wed May 21, 2003 5:20 pm

Okay...I checked dwell first and I'm at about 1/2 of the degrees than spec. Spec. is 44-50 and I'm at about 22 degrees.

I'm going to look for some info on what I need to do to fix the dwell before moving on to the timing. BTW I did find the timing mark. Thanks for the help with that.

Hans