11mm block and 12 mm head?

[morgoon]

Hello to all, and thanks for such a great site



I am new as it gets to VW diesel, My wife and I just bought an 81 Rabbit (orig 11mm motor) 260 000kms

I have been reading like mad for a couple of weeks, and trying to get some idea of what to do next

The headgasket is blown, only a small leak at this point, the cause is unkown exactly, but the PO had some difficulty with over heating, and I think a hard time with putting in a new thermostat, from what I could gather, he tried it a couple of times, and it still seemed to over heat.

( I am not sure if it makes a whole lot of sense, but I read that it is best to fill the rad and engine from the top rad hose, not the coolant tank..the PO def used the coolant tank to fill it. It was never driven after that at all, so I thought air in the system might be a factor)


I will do a proper intro post tonight with pics, as I am on my way to work just now, but last night I bought a well used (it appears anyway) 84 engine and trans cheap...With the thought that if I was going to build a motor it would be better to start with a 12mm if I had that option


My problem comes from short term and long term planning


Short term I would like to get the car up and running, Long term I would like to rebuild the engine (never done it) and perhaps put a new Giles injector pump on



We have other electrical issues to sort as well, although so far it looks to be turn signal related


Ok too much to say all at once



IP, tripple square tools, and bently on the way


So can I use the 11mm short block in the car (it runs ok)..comp test comming too as a daily driver starter motor, but use the 1984 12mm head to get things up and running



Thinking that I would get the head rebuilt, and build the "new"  84 short block up over time as cash comes around


I have a leaky IP on the orig 81 motor that has to be factored into the cash flow



I hope this is not too confusing, I am such a newb with so many questions



Morgan

[Vanagoner]

Hi Morgan,
I am not an expert but I can share my experience related to that.
I bought a rabbit with symptoms similar to yours.  I figured I'd get lucky with a head gasket.  Unfortunately, mine had the internally cracked block that is so common in 11mm engines.  No way to solve overheating with that (unless your maxfax).  I gave it some work and a couple of head gaskets and it was still junk.  The 12mm engines are sturdy, great engines.  You might try hooking up the starter on your '84 engine and do a compression test on it just to see what you have there.  I highly recommend using arp head studs on whatever you work with.  They add a large measure of strength and intelligence to a sensitive area of the engine.  Personally, I'd work with the 12mm engine right away and end up with something better.

[burn_your_money]

Based on what the PO told you I would suspect a cracked block as well. Maybe the head is horribly warped and he didn't know to check for that. I *think* you can reuse the 11mm bolts so at most you are only out a headgasket. One of the main problems with the 11mm headbolts is they are too short. There are a lot of unused threads left in the block. This is where the ARP studs really shine

Before you spin over the 84 engine, prime the oil pump by removing the vacuum pump and spin the shaft coming up with a drill and 12 or 13mm socket. Make sure to reinstall the vacuum pump before turning the engine over.

Personally on a NA engine I wouldn't spend the money on studs.