Newly Rebuilt Engine Questions 1980 Vanagon

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cegammel
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Newly Rebuilt Engine Questions 1980 Vanagon

Post by cegammel » Sat Sep 20, 2014 5:19 pm

Hi all,

I've just finished my 300 mile break in on my newly rebuilt engine. I'm running into a couple of annoying and potentially serious issues that I need help with:

1) 3 of my rod tubes are drip-drip-dripping. On my last partial rebuild, I put them in dry with no leaks. This time, I put some white grease around them, and they drip like sieves. Is there any easy fix, or just pull the tubes and replace the rings?

2) I pulled my plugs Friday on a lark. Three look good. The number 1 cylinder, however, is black with dry soot. While working on the rod tube issue, I also noticed a suspicious oil drip right on the head-side edge of the lower baffle. I'm concerned about a head gasket failure. I have not performed a compression check yet. I assume that to be my first step. If the gasket is to blame, Will it be my best bet to replace it with the engine in the van? Am I missing something big that would prevent a (relatively) easy head pull-replace gasket-replace head?

3) I also just replaced my brake hoses, my clutch slave, and clutch hose. In the process, I managed to mangle two of the wheel side steel brake lines. Other than my personal inability to properly bleed brake lines, that job was a bear, but finished. The clutch slave, on the other hand, is an issue.
The clutch functions...but engages just about all the way off the floor. Previously, it engaged about 1" off the floor, so it's a strange feel. Is this normal? Do I still have a massive air bubble in the slave cylinder? I did not bench bleed the cylinder....was I supposed to? Is it true that vanagon clutches will bleed themselves if left cracked over night? I tried just cracking mine, and fluid gushed out. My initial bleed was with a vacuum bleeder; I do not have a pressure bleeder.

Thanks for all your help.

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SlowLane
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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by SlowLane » Mon Sep 22, 2014 11:42 am

cegammel wrote: 1) 3 of my rod tubes are drip-drip-dripping. On my last partial rebuild, I put them in dry with no leaks. This time, I put some white grease around them, and they drip like sieves. Is there any easy fix, or just pull the tubes and replace the rings?
Pulling the tubes is the easy fix (considering the ease of doing so on a T4 compared to a T1).
  • Use Viton rings
  • inspect and remedy any burrs or rough patches in the case and head bores
  • inspect and remedy any dents or irregularities in the tubes where the o-rings sit. New tubes aren't that expensive, so consider replacement if yours are looking ratty
  • use just clean engine oil for assembly
  • gently use an appropriately-sized socket to seat the tubes during assembly
  • last, but definitely not least, make sure your spring retainers are correctly installed with the flat bits resting on the ends of the pushrod tubes, not sitting inside the tubes. The proper positioning of the retainers is essential to keep the tubes from creeping out of the case bores as the engine expands and contracts.
cegammel wrote: 2) I pulled my plugs Friday on a lark. Three look good. The number 1 cylinder, however, is black with dry soot. While working on the rod tube issue, I also noticed a suspicious oil drip right on the head-side edge of the lower baffle. I'm concerned about a head gasket failure. I have not performed a compression check yet. I assume that to be my first step. If the gasket is to blame, Will it be my best bet to replace it with the engine in the van? Am I missing something big that would prevent a (relatively) easy head pull-replace gasket-replace head?
Umm, you ain't supposed to have head gaskets on this engine. The cylinders should seat directly against the head.
cegammel wrote: 3) The clutch functions...but engages just about all the way off the floor. Previously, it engaged about 1" off the floor, so it's a strange feel. Is this normal? Do I still have a massive air bubble in the slave cylinder? I did not bench bleed the cylinder....was I supposed to? Is it true that vanagon clutches will bleed themselves if left cracked over night? I tried just cracking mine, and fluid gushed out. My initial bleed was with a vacuum bleeder; I do not have a pressure bleeder.
I've never had to mess with my clutch, so I can't really answer from direct experience here. I'm not a big fan of either vacuum or pressure bleeding, however, Both techniques seem to have a potential for introducing entrained air into the brake fluid. The old pump-and-fill method has always seemed safest to me, even better if you have two people to coordinate pumping and nipple-twisting. :blackeye:
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

cegammel
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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by cegammel » Mon Sep 22, 2014 12:44 pm

Come to think of it...there were no gaskets...this head is an AMC. Als, compression is 115 on 1 and 3. So, maybe there is no issue. I pulled plugs again, and everything now looks normal.

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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by cegammel » Wed Sep 24, 2014 4:26 pm

Ok...this clutch is really messing with me. Before replacing the slave cylinder, it worked flawlessly. The slave developed a drip, and with a trip planned, I replaced it. Now, the pedal doesn't engage until more than half way up its travel. The clutch disk and pressure plate have about 450 miles on them. I stalled the van out twice today...that's never happened before...

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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by Amskeptic » Wed Sep 24, 2014 6:31 pm

cegammel wrote:Ok...this clutch is really messing with me. Before replacing the slave cylinder, it worked flawlessly. The slave developed a drip, and with a trip planned, I replaced it. Now, the pedal doesn't engage until more than half way up its travel. The clutch disk and pressure plate have about 450 miles on them. I stalled the van out twice today...that's never happened before...
Re-bleed. Have assistant press and hold the clutch pedal down. Crack open bleeder just enough to allow tell-tale spit (evidence that there is air in the fluid). Have assistant release clutch pedal and give it time at the top to replenish the clutch circuit. The brake fluid in the reservoir cannot be allowed to drop more than 1/2 inch at any time during bleeding. This is more critical than when bleeding the brakes, because the clutch system takes its fluid only from the upper part of the reservoir (so a clutch failure does not drain out all that nice brake fluid from where it is critically needed). Repeat above until you get only fluid out the bleeder and the release arm moves in 1:1 correspondence with the clutch pedal
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

cegammel
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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by cegammel » Thu Sep 25, 2014 3:27 am

Thank you. I will try again tonight.

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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by Amskeptic » Thu Sep 25, 2014 5:39 am

cegammel wrote:Thank you. I will try again tonight.
Did you get the push rod tube leaks squared away?
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by SlowLane » Thu Sep 25, 2014 11:11 am

If the clutch problem persists after sorting out the slave bleeding, don't rule out the pressure plate. Even though it's new, there have been reports of utterly awful early failures of (mostly Chinese manufacture) pressure plates. I helped a young friend sort out his Beetle awhile back and the diaphragm spring on his nearly-new pressure plate had essentially no spring to it. It had collapsed completely. Hope that's not the case with yours.
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

cegammel
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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by cegammel » Thu Sep 25, 2014 5:24 pm

I bled again...and again...and again...the clutch is better, but still not what it was before the slave swap. As for the tubes, I haven't done anything yet. Will I need to reset the valves afterwards? It seems the settings should remain...

It does look like I will purchase a pressure bleeder to deal with this silly clutch.

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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by Amskeptic » Thu Sep 25, 2014 7:45 pm

cegammel wrote:I bled again...and again...and again...the clutch is better, but still not what it was before the slave swap.


Just because it feels *different* does not mean that it is "worse". For the record:

Air in the lines makes the clutch less efficient. You would have a pedal that disengages the engine down close to the floor, and it would take up as you pull away close to the floor, as well. After bleeding, the clutch disengages the engine closer to the top. **This mimics a "worn" cable-operated clutch**, but is a sign that the hydraulics are working well.
cegammel wrote: As for the tubes, I haven't done anything yet. Will I need to reset the valves afterwards?
Yes. You will. Don't not.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

cegammel
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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by cegammel » Sun Oct 05, 2014 5:30 pm

To all of those happy VW owners who have encouraged this madness, my lovely wife has many, many nasty words for you.

I've just completed my 700 mile on my new engine. This last trip, of about 250 miles, was going swell...until the bucking started. Running up a long but gentle hill, the van just started bucking like crazy in 4th at about 50 mph. I slowed down to 40 and dropped into 3rd. Van ran fine for about 10 miles in third, then started bucking again. We stopped for some wifi, and saw a post about the OXS causing such a thing, and so unplugged it. We ran another 10 miles, bucking all the way, in all gears, at all speed ranges. I stopped, and plugged the OXS back in...no change. We pulled into another wifi friendly establishment, shut the engine off, and let it sit for a while. Started her up, the OXS light came on and stayed on, but the van ran great. We cut out 4 night camping trip to one and headed on home. Van ran great the whole way (110 miles).

So, is this a case of a bad OXS? This is the original-to-me sensor, so no idea how many miles are on it. My catalytic converter is a straight pipe, if that matters. Will replacing the OXS make a difference? Will the light turn itself out, or will I need to find the reset button?

Thanks for all your help. I'm ordering those Viton tube seals with the new OXS...and a sink faucet, since that also died this weekend...

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SlowLane
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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by SlowLane » Sun Oct 05, 2014 9:18 pm

cegammel wrote:To all of those happy VW owners who have encouraged this madness, my lovely wife has many, many nasty words for you.
And a big ol' howdy to her too. :flower:
cegammel wrote: So, is this a case of a bad OXS? This is the original-to-me sensor, so no idea how many miles are on it. My catalytic converter is a straight pipe, if that matters. Will replacing the OXS make a difference? Will the light turn itself out, or will I need to find the reset button?
Since you don't know the age of the O2 sensor, it's prudent to replace it, if only to rule it out of the bucking equation. In the absence of a catalytic converter, the O2 sensor is still a critical part of the FI system, as it provides feedback to the ECU.

As far as I know (and Bentley seems to back this up), the OXS light is simply on a milage counter which trips every 15,000 miles. It has no "smarts" to diagnose the condition of the O2 sensor. You should just need to press the reset button on the plastic box which is in-line with the speedometer cable. It's buried under the front of your car somewhere (sorry, can't be more specific at the moment).

Bucking problems can be be of the most depressing things to try and diagnose, because there are so many potential causes. About the best one can do is to go over every subsytsem in the engine room and make sure they are functioning within spec. Good spark plug cables, smoothly-operating mechanical-advance, eradicating all vacuum leaks, well-sealed exhaust, etc.

One potential culprit which I believe Colin discovered was worn or out-of-balance rear tires which would set up a harmonic resonance with the AFM wiper at certain speeds. Not sure if that was a Bay-specific problem or if Vanagons are susceptible as well.

Good luck. Sorry that it's spoiling your family's camping trips.
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by Amskeptic » Mon Oct 06, 2014 7:22 am

cegammel wrote:To all of those happy VW owners who have encouraged this madness, my lovely wife has many, many nasty words for you.

Started her up, the OXS light came on and stayed on, but the van ran great. We cut out 4 night camping trip to one and headed on home. Van ran great the whole way (110 miles).
See, no problem. :flower:

Adding to Slowlane's prescriptions, check grounding of battery to car, grounding of engine/transaxle to car, and the little fuel injection ground spade terminals.

Bucking that occurs only when the engine is hot and under acceleration can be a sign of a rich mixture. You can check the TS sensor cold for 2500 ohms at 68* and see that it drops down to the 200-400 range as it arrives at engine operating temps. You can run the engine without the O2 sensor if you do not have a catalytic converter, but you may need to adjust the AFM.

If your spouse is sending out excessive electrical spikes, that can make your ECU electronics misfire. The fact that the car ran great on the way home suggests that you might need to install a mind wave shield.
Colin :bom:
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

cegammel
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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by cegammel » Tue Oct 07, 2014 4:50 am

Checklist so far:
1) grounds: all cleaned, lubed, and replaced (did not ohm test every wire, so could be issues in the bundle, I suppose).
2) O2S ordered
3) o2S switch reset
4) Checked plugs and ohm tested all wires...all good
5) rechecked timing and idle...idle speed had crept up to 1100 rpms (how, I don't know...I set it to 850 a month ago). Idle was at 8* ATDC. Idle now at 900, timing at 5*ATDC (tops out at 28* at 3400).
6) AFM: Budging the needle 3/8" CCW causes the engine to level out, then sputter. Budging 1/4" CW causes sputtering.
7) I hear a hiss from the intake, but I can't localize...will try propane today.
8) I'm having trouble getting a consistent ohm reading on the Temp sensor...it jumps all over the place, but seems to be low. I hope this doesn't contribute, but I installed my VDO gauge sensor under the T2S, since putting it under the spark plug would have destroyed it. That may be causing too much interference, I suppose... the jumping readings seem to be 1300 cold, and 130ish warm. The sensor is relatively new...installed last spring.

Thanks for all your help...another trip planned for this weekend.

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Re: Newly Rebuilt Engine Questions 1980 Vanagon

Post by Amskeptic » Tue Oct 07, 2014 1:24 pm

cegammel wrote: 7) I hear a hiss from the intake, but I can't localize...will try propane today.
8) I'm having trouble getting a consistent ohm reading on the Temp sensor...it jumps all over the place, but seems to be low. I hope this doesn't contribute, but I installed my VDO gauge sensor under the T2S,
Hiss is normal air passing through idle screw gate, but I'd never say no to a propane leak check (with a temporarily leaned mixture so the engine will react to the propane).

I know that seemed like a neat solution, but the temp sensor should have a dedicated ground path to the head. Read up on how a single little washer was the solution for L-Jet warm-up leanness, just a little washer between the head and the sensor increased warm-up times.
You need 2500 ohms at 68*, dropping to 200-400 ohms when warm and even lower when hot.

Is your 5* ATDC reading totally separate from the 28* @3200 rpm reading by virtue of the 5* ATDC reading has to be with the vacuum retard hose on, and the 28* reading has to be with all hoses off the distributor? just checking . . .
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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