Busted Bus By the Bay

[airschooled]

I know there could be hundreds of causes for any one problem, but something strange I saw recently was a distributor suddenly retarding itself 10-20* out of nowhere. What happened, was the drive gear had quite a bit of play in it, and the spring between the distributor and the drive had because sunk/pressed into the drive gear so far that it became useless. The spring helps take play out fo the drive gear, which makles timing consistant. Check to make sure you can pull your spring out and place it back in the center of the drive gear carefully.

Robbie
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[captincanuck]

That does seem to fit my symptoms. I will have a look at that. Thanks.

So I took a tour around town on the weekend (but skipped the skyway bridge in favor of the lift bridge) and had no problems the whole time.

I have a theory, and tell me if this sounds ridiculous but here goes;

I set the timing and tightened down the clamp with the engine running in the driveway.
I then got out and the highway and the engine got nice and hot.
Could the clamp have expanded enough from the heat to allow the distributor to rotate from the centrifugal force and through the timing out ?
I then checked the distributor in the morning after it was towed off the bridge and it was nice and tight, because the engine was cold again, maybe?

I put some paint on the clamp and dizzy shaft so that if it happens again I will know if the dizzy moved or something is up with the shaft/drive/spring or drivetang.

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[airschooled]

I've never heard of that happening, but I have found that many aftermarket clamps didn't grab as well as my OG clamp. As shiny as they were, I really had to crank them down to secure the distributor, so now they collect dust on my shelf. Good idea on the paint mark test.

I also see you have dual carbs? What kind/what vacuum nipple are you using?

Robbie
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[SGKent]

no - that theory does not work. A possible one is Wildthings suggestion that the dog may be out or was out. Also it is possible that the breaker plate or weights are sticking. Personally because I have seen the electronics fail this way I am inclined to think it is something going on electronically in the module or pickup. Also if the end play has changed radically that could shift the timing also.
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[captincanuck]

[captincanuck]

I am looking for some advice here on the damage I have on this piston, and what the cause might have been.

First off on replacement, the other 3 cylinders and pistons are in great condition and in fact the engine was running fine even with this damage. The cylinder with the damaged piston also shows no damage.

I have ordered Tom Wilson's book (This is my first time with the engine out, which is why I don't have it already) but its 2-4 weeks backordered. Must be a lot of engine rebuilds going on this Summer.

Back to advice;
Should I
1) just replace the piston?
2) replace the piston and do the rings on the other 3?
3) replace the 1 piston and cylinder that was damaged?
4) Replace all 4 pistons and cylinders?

I see a set of 4 pistons and (is PC term "Jugs") is around $400 from the usual places, and I don't mind dropping that if it is necessary but as the other 3 seem to be in great shape (still have the crosshatch marking and have no noticeable lip) I don't see why I should replace them with potentially inferior parts.

Cause:
It's all well and good to fix the damage, but if I don't know why it happened, then what's stopping it from happening again?
At one point there was a leak between the base of the carburetor and the intake manifold. Would this air leak have caused that one cylinder to run lean and over heat? Does that damage look like over heating damage to you guys?

P.S. Any sources on pistons and/or single piston and cylinder sets? I can only seen to find sets of 4.

P.P.S. Was the case originally painted or is that the PO's handy work. Really chunky in places like it was put on with a shovel? But it really doesn't come off easily.
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1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

[Wildthings]

At a minimum you need one replacement piston. You will also need to get the others 100% clean so that you can carefully check them to make sure they are in spec and so that all four can be balanced as a set.

You should also do the "V" notch modification to the rods so that they throw more oil out into the cylinders. Quick and simple to do. Also have the rods checked over by an automotive machine shop to see if they need to be resized and/or rebushed.

[captincanuck]

Thanks. I will defiantly do the V notch modification.
Trying to track down a single Mauhle 94 now to match the other 3 but it doesn't look promising. Might just go with a new set all around. Does anyone know if the size of the dish is marked anywhere on the piston, or are all the Mauhle's the same size?
Thinking I would go with the AA sets but the 94s are out of stock until who knows when, and I don't know if I should go with the 96's.
Maybe when Wilson arrives he can answer theses questions for me.
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1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

[aeromech]

You love your bus so fix it right. Replace the set of Pistons so that everything will be equal. Take a close look at the heads before you just slap them back on.
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[captincanuck]

So I got my new pistons and cylinders, my 3H, my Wilson book, and things are looking good. Been reading every post I can find on deck height and how to achieve your desired CR and it all looks achievable. I do have one question that might belong in the "stupid question" thread thou.
With my engine disassembled what is the best way to find what my stroke length is? I see stock is 71mm but who knows what the PO might have done to this engine in the past.
I also have the rods out in preparation of doing the V notch mod. and halted the reassembly when I decided to replace the rod bearings.
Weighting for my bearings I continued cleaning other parts up, which brings me to this question;
My alternator doesn't have a fan on it. The bus has a BA6, so it should have a 70 Amp alternator with a fan on it, correct? Could this alternator be 70Amp with no fan? And how can I check it? On the BD web site they say you can't replace a 55Amp with a 70Amp so I don't want to order one and it doesn't fit. If they aren't interchangeable than how did I get a bus with a seemingly stock BA6 system and a 55 Amp alternator engine?

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1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

[Xevin]

http://www.ratwell.com/technical/Alternator.html
If the BA6 runs well with the 55amp and if that is indeed a 55amp
Just leave it alone. Maybe easier to find 55amp parts and replacement in the future. This maybe a dumb question but I'm curious. Is the BA6 listed when you run the M plate?
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Keep on Busin'

[captincanuck]

Interesting. I do have a BA6 but no fresh air (ambulance) fans. To be honest I have never run the M code. I will do that tomorrow.
_________________
1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

[Xevin]

Did BA6 equipped buses have ambulance fans? I know BN4 only have the big orange plastic prop type fans in the back of the tube.
My guess is a PO put in a motor with a stock 55amp alt.
does your BN6 work proper?
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Keep on Busin'

[captincanuck]

The BA6 does work, once the mice were evicted. The motor being swapped out seems more likely than someone doing a perfect install of a BA6. Thanks for the input.
_________________
1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

[captincanuck]

[nathansnathan]

It's important to have thicker aftermarket gaskets for aftermarket carb intake manifolds. The stock thin paper gaskets will leak and you'll be running lean.

I'd hook up with a dakota digital cht gauge if I were you. Keep the temps below 400 or so and you should make it up that bridge without worrying about damaging your heads. It will tell you how slow you need to take it.

[surfwagonorangevw]

yep that valve does look deeper into the head than the others. Check the valve stem tips by placing a straight edge across all 4 tips , they should all be even . Remove that suspect valve from the head and if it is " sunken " you should see the mushrooming effect on the aluminum below the seat , actually if you take a look in thru the exhaust port perhaps with a flashlight you can inspect the back side of the valve seat , without removing the valve .

[captincanuck]

[captincanuck]

So with the engine out I wanted to give the empty bay some much needed TLC. It seems that the PO worked out some aggression on the spare tire holder that comes down into the engine bay on the left (drivers) side. Probably to get a big 2nd battery in there.

Just wondering what you all would do in this situation? Has anyone ever cut this thing out, as is doesn't do me much good in my closet?

Option 1: Cut that sucker out and weld a flat piece in? Sounds good. Bigger bay and I don't loose my socks in the hole when camping.
Option 2: Leave it alone. It's not hurting anyone. But looks ugly.
Option 3: Bang that thing back into shape? Might still look bad. And then my big ass battery won't fit.
Option 4: Cut one out of a bus at the junk yard and graft it to mine? Not to many busses up here thou.
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1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

[Wildthings]

If you don't want it there then removing it would be fine. Don't catch your fuel tank and thus your house on fire during the cutting and welding process.