To repair or not to repair. That is the question!

little_waters · Posted: Wed Jul 22, 2015 2:04 pm Post subject:

a2d2 where was it that they took it apart and didn't tell you first? Eek!!

zippyslug31 · Posted: Wed Jul 22, 2015 2:09 pm Post subject:

Merian · Posted: Thu Jul 23, 2015 11:46 am Post subject:

some more info:

I just looked at the factory flat rate labor manual for a 912 engine (4 cyl.) - a complete rebuild on a removed motor is 20.0 hours

obviously more if you are not a factory trained mechanic, but a rebuild on an air cooled bus motor is not an insurmountable DIY for a neophyte who is motivated and is the low cost way to go (assuming you don't eff it up)

a2d2 · Posted: Thu Jul 23, 2015 1:28 pm Post subject:

little_waters · Posted: Fri Jul 24, 2015 10:19 am Post subject:

Thanks a2d2, I appreciate that! Gives me a good ball park for costs with this.

So what the mechanic said is #2 cylinder is low (25), #1 is at 90, other two are 115 and 110. Said there's an exhaust valve leak for sure when they tested it's leaking at 95. He said to be able to go in and see what's up he'd have to drop the engine to get to the cylinder head to see what the problem really is and that i might need a new cylinder head. I dunno, it's all confusing,

I guess I don't know why they'd need to drop the engine to do that? Just to look at it and see what's the problem is 4 hours labour. I'm holding off for now and I need to think about it. $1000 at least to repair/reuse the cylinder then I might as well invest in it and get the engine rebuilt is what I'm thinking..

a2d2 · Posted: Fri Jul 24, 2015 11:01 am Post subject:

Disclaimer: Keep in mind that I'm still learning myself so take my thoughts with a "grain of salt".

There are much more knowledgeable people on this forum who will hopefully chime in...

The biggest issue is the low compression in #2 and a new cylinder head will fix that most likely. The problem is that the rest of the numbers are fairly low as well - this means more issues are coming soon for this engine. It most likely could use new rings at minimum or a complete top end rebuild.

Do you know the history of the engine? If it is not original and has been rebuilt sometime in the not too distant past you could probably get many more years out of it with just a top end rebuild. On the other hand, if it is original or a rebuild from long ago, there is a good chance that the cam and bearings are wearing out as well. In that case it would be wise to get the whole thing rebuilt or replaced.

The shop is right that they won't be able to see exactly what is needed without pulling the engine. Sometimes an issue with a valve will destroy a piston as well but my guess - since you still have some compression and not zero - is that you have caught it in time and the damage is only in the head. A new head only would get you back on the road but if you want dependability you should probably go deeper that that.

Good to hear you got a diagnosis before the point of no return!
_________________
1981 Vanagon, Aircooled 2.0 AFC
1978 Baywindow Bus (R.I.P.)

little_waters · Posted: Fri Jul 24, 2015 11:03 am Post subject:

Wow I just talked to Ed from the Bug Shop again and what a nice guy. Took the time to talk with me about some options and suggestions, pros and cons of each. Said he'd fit me in sooner than 3 weeks if I can tow the van over next week. The guys at Adria seem really nice too but with all the good things I've heard in the forums about Ed's work I think I'll be bringing it over to him.

little_waters · Posted: Fri Jul 24, 2015 11:09 am Post subject:

a2d2 yeah I don't know the full history of the engine. One of my mechanics mentioned it looked like it had a bit of work on it but that's all I know. Patching it up probably isn't the way to go I'm realizing.

Thanks everyone for all the suggestions! If I didn't post this and get all the feedback from you I'd probably have gone for the cheaper fix. I realize now that's probably not the best option for my pocket book or my van long term Smile

Randy in Maine · Posted: Fri Jul 24, 2015 11:54 am Post subject:

Actually it is pretty quick to pull the engine at around 4 hours for a novice guy.

The weak link on a type 4 engine (and notably in a bus or vanagon) is getting the valve guides too hot, then too cool and they can fall out. That is bad. The fix is to install "improved heads" that have more Zn in the valve guide alloy to allow it to cool down slower as you come down the hill.

It is a judgment call weather to spend the real money to rebuild a head (and improve the hardware that goes with it) on a head that has a million hot/cold cycles on it or to buy new heads to improve them with no heating and cooling cycles. Most people just buy new AMC heads and improve them.

I would suggest adding a good cylinder head temp gauge so it doesn't happen again. I like the Dakota Digital one myself.

The other weak link in a Type 4 is the camshaft can go flat for some reason. Hydraulic lifters/camshaft motors seem to run a bit hotter than the mechanical lifter version. Make sure your FI system is all 100% before you re-install it. Clean and calibrated injectors and new injector seals as well as new fuel lines. Improve the electrical connections while you are waiting for the mechanical stuff to come back in time well spent.

I usually suggest staying away from the AVP engines as they really are a "budget rebuild" and have more QA/QC issues than I want to deal with.

Just my 2 cents....


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