Repair route

The Wonderbus overheated briefly last Saturday. This is a 1776 engine which has about 5,000 miles on it. It shows signs of having been
indifferently built. I've got the cylinders off and the pistons out.
Thanks to all the advice I've received here I have some idea of where I now stand, but don't know what are the most sensible next steps. I could use some advice.
My short-term goal is to get the bus running again for at least a few months until I can get a new stock 1600 for it.
Heads and Valves:
WHAT I GOT: The left head has a hairline crack between the intake and exhaust valve openings for #4, and both valve seats are cracked there too.
WHAT I COULD DO: Choose between getting the left head repaired, and install and lap new valves all around (?) -- or buy a new pair of 90.5mm bore heads from Aircooled for $330.
Pistons and Cylinders:
WHAT I GOT: None of the pistons show scuffing. Cylinder walls all show standard honing cross-hatching. These bits all appear to be in reasonable shape. But cylinder #4 has three fins broken (this is how the engine came to me).
WHAT I COULD DO: Given the broken fins on #4, which is also where the head was damaged, get new pistons and cylinders for this case ($200, Aircooled.net - 96mm case openings). Or just re-install the existing to get by with, and drive the bus lightly.
(My long-range goals is to sell the Wonderbus in much better condition than it was when I bought it, and get another ACVW to work on. A split-window, I think. And a bug for my wife. Pink. She'd like that.)
--
Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)
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On Mon, 31 May 2004 16:12:51 -0700, "Mike Rocket J. Squirrel Elliott"

...show picture of broken fins...
..Gareth
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Gary Tateosian wrote:

Right -- sorry. See http://www.ariaaudio.com/VW.htm , second picture from the top.
--
Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)
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You are loosing more cooling cause of the rust than the missing portion of the fins. The rust acts a bit like a heat barrier, lowering the heat transfer to the cooling air. You have to remove the rust and paint the fins with a very light coat of flat black paint. If I was building a new engine the best way I could, I'd use new cylinders, but in your case these cylinders should work fine. Having a machine shop hone the cylinders slightlly is a good idea.
I'd use the cheapest head I could find on this engine, probably a new bone stock head machined for 90.5 cylinders. Then measure the chamber volume to see if it matches with the other head you have. If there is a difference, you have to remove some material from the combustion chamber of the head with the smaller volume. The closer to equal you can get the chamber volumes the better.
You can enlarge the combustion chamber volume by removing material with a rotarry file attached on a drill. The area from which you may remove material from the combustion chamber (for example in cylinder 4) is left from the exhaust valve and right of the inlet valve, paying attention not to narrow the cylinder seating surface and not to grind the valve seat (the valves must be removed). Remove material in uniform passes, and CC the head frequentlly to check your progress. This process unshrouds the valves, which also enhances the breathing capability of the heads. These pictures show where to remove material.
http://poros.vlsi.ee.upatras.gr/~vspili/vw/heads/pic1.jpg
http://poros.vlsi.ee.upatras.gr/~vspili/vw/heads/pic2.jpg
Bill, '67 bug.
"Mike Rocket J. Squirrel Elliott"
wrote:

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On Tue, 1 Jun 2004 13:14:15 +0300, "Bill Spiliotopoulos"

...correction. It enhances the breathing of the one head you are wallowng out to match the other....again leaving you with a mis-matched engine. If a head differs very much at all from the other...find a different one. =-) I personally am a proponent of new heads...you have e better chance of them matching...and if they don't...hey they are new you can return em and try again. ;-)
..Gareth
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Good stuff, Bill -- thanks for the advice. I never tumbled to the rust on the cylinders being a problem until it was mentioned. Figured it was stock. The I received a loaner copy of Wilson's "How to build a high-performance Volkswagen air-cooled engine" and found myself looking at that nice engine on the cover and mulling over how important it is in electronics have nice black heatsinks - they radiate heat best.
The pictures of the removal of CC materials are very helpful. Those, combined with the information that Bob H. (and others) posted has given more than enough to get myself into trouble with.
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Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)
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....you cannot repair the head correctly cheaper than replacement. Very few do the proper pre-heating and cooling process to have the cracks repaired reliably anyways.

...I would not put new heads on top of that cylinder. Which leaves two options. Lower compression to acceptable level by shimming cylinders, and throw the engine back together as is and seeing if it will make yer two months.....or Buy pistons cylinders and heads. But wait....you will still need to set your compression...which means shims. But what compression should ya set? Definately not too high in a loaf. I'd pull the oil pump before making final decision and find out what cam you have. I personally generally talk to the cam manufacturer and explain usage and parts selection...their techs generally give pretty good advice regarding what would be best CR for a given grind, and what would be best grind for a given app. In fact I generally decide on a cam very early in the engine design stages....before buying lots of parts that won't work ;-) Hell if you *do* decide to get the cylinders and the heads,,,you might want to consider buying the bug me video on engine re-building to give ya confidence and taking the plunge, and taking it the rest of teh way down...replce bearings...make sure cam is specced for bus...balance parts..spec out rods..make yerself a properly re-assembled (notice I didn't say rebuilt) engine,....you can then pull it out when ya get the 1600 (if you do) and drop it into yer wifes beetle.
...Gareth
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Gary Tateosian wrote:

I've gotten a couple recommendations for shops with good reps. I'll call them tomorrow and at least discuss it with them. If the price ain't right or I don't get a good feeling then new heads, here I come!

Yeah, and the heads are rusted so they won't cool very well, either.

Which was what I was planning to do anyway.

"Engle 110" is what the receipt says. But should confirm, you're right.

Good advice. Will do.

I'll check out the Bug Me video. I am definitely planning to get this engine fully opened and fix whatever horrors I find within. But not right away: I do need to get this puppy running.

Get the 1600, put it in the bus, take apart and re-assemble the 1776 as well as I can for reliability, and then find bug for wife and install it.
Something like that, anyway.
--
Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)
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Mike Rocket J. Squirrel Elliott wrote:

Seats cracked too? Christ. That rarely happens. Are you sure? That would explain non-existant compression, or at least contribute to it.

The broken fins have marginal effect on things here. With the output power of the engine in question. Don't worry about it.
Piston rings: bend top and second ring out a little, as if you were goint to expand them for removal. If they don't "snap" back to shape when you release, but instead they stay "open"... it means you were able to bend them outwards, and it means they have very little tension left. Garbage. They need to be like springs.
Have seen this before on an overheated engine.

Everything considered, I'd just have the existing head fixed if it's cheap enough. Assuming it's identical to the other head (a matching pair). If they are different (like, different cc) then chuck it and get a new head, modify it to match the other one. Might need to use a machine shop.
Or if you can afford it, buy two new heads. Measure chamber volume and bring CR to desired value by either having the heads flycut (increases CR) or fitting spacers between cylinders and case (Lowers CR).
Jan
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Jan Andersson wrote:

Oh yeah. I don't have a closeup lens on my camera or I'd post it. But with inspection goggles and good light it's easy to see. I can't tell how deeply into the head the crack goes and am sorting out means to do so. The low compression was due to one of the valves having tightened up in the overheat. This crack is too hairline to bleed enough air quickly enough to affect the basic compression testing.
Note to self: visualize combustion chamber as capacitor. Leaks as resistors providing discharge paths. Charge up capacitor by turning engine over, as per basic compression test. Intake strokes pressurize chamber. If the leaks are small (high value resistances) then capacitor will not discharge much between strokes, so at the end of standard 10 stokes, you will have a sense of how much leakage resistance there is. Turning over by hand is so slow that even high-resistance paths to ground have sufficient time to discharge capacitor (chamber.) Normal leakage past compression rings is sufficient to prevent much pressurization.
Leakdown tester works like connecting a battery (i.e., a constant source of voltage/pressure) to the capacitor/chamber instead of a pulsing source. Then you measure the current/airflow which tells you how much resistance/leakage you got. In other words, how big the holes are.
That was me just putting this compression stuff into electrical terms so I could visualize it better. Maybe someone else will find this handy.

Hang on -- aren't you the guy that lives in a place where the phrase "hot weather" is used to describe a day that we here in SoCal would call a cool spring day?
I can increase the cooling of the cylinders by removing the rust and painting them black. Common practice in electronics, too: black surfaces radiate heat better than other colors.

If the hairline crack is deep enough, I will consider getting it repaired. That would be something I need to get done by a machine shop as I don't have the tools. I have a call in to a shop up in the Washington state area which came recommended, but they have not returned it. Anyone know of a good shop in SoCal / San Diego area (USA)?
New heads or keeping the old, I'm going to use the information that Bob H. posted and do what needs being done to adjust the CR to something reasonable for a bus.
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Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)
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Mike Rocket J. Squirrel Elliott

tightned up -> stretched -> DONT REUSE!
you probably were close to snapping the head off and wasting the engine complete...
--
Eduardo Kaftanski |
snipped-for-privacy@nn.cl | Freedom's just another word
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Eduardo Kaftanski wrote:

Roger that.
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Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)
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Hairline cracks at room temp get much bigger at engine op temp. When I really cooked my first set of heads I was embarking on a 1000mile journey. As long as I kept the engine running fast it had plenty of power and was smooth. I had to set the idle up around 1500 and leave it running at gas stations and convenience stores cuz if I shut it off I had to wait a couple hours for it to cool down before it would restart - either that or comp start it at around 40 in third! -BH
Mike Rocket J. Squirrel Elliott
in message wrote:

post it. But

I can't tell

out means to do

having tightened up

enough air quickly

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On Tue, 01 Jun 2004 17:01:28 -0700, "Mike Rocket J. Squirrel Elliott"

...so do ya ground the cylinder to chassis to release compression? I'm not sure but I don't think sprague makes VW cylinders. ;-)
...Gareth
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Gary Tateosian wrote:

Nah -- just short the cylinder out by unscrewing the spark plug :-)
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Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)
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Mike Rocket J. Squirrel Elliott wrote:

Ooh. I thought, it involved also putting a pencil inside the cylinder to prep the release process and the finally release the charge by pulling a head.
--
Olli

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Olli Lammi wrote:

LOL. No, that's the "short out the capacitor by inserting your wedding ring between the + and - terminals" approach. Only done once, and only by the very simpleminded.
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Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)
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