Need a new block

[Lando]

I am the new owner of a 1.5D in my 1980 rabbit.  I am fairly new to VW diesels, but not to IDI diesels.

I recently discovered the block is cracked through one of the head bolt holes.  I am picking up a short block tomorrow, the guy says it was running before he sold the head.  I am planning on reusing the head, and upgrading to ARP studs to prevent the block from cracking again. 

I'll be bringing a set of telescoping gages and micrometers, and checking out the block for cracks especially around the head bolt holes.
Does anyone have a link to where I can find specs for all the key measurements?

I am planning on re-ringing, replacing the bearings, HG and all gaskets.  I've got a new water pump, timing belt and tensioner.  I've rebuilt the injectors (new nozzles and needles) and shimmed them to spec.  I have also rebuilt the vacuum pump. 

So is there anything I am missing on my list?  I wanna get it done right.

Also, are elring head gaskets a good choice?  IME, they are the best for european cars, and often the OES.

Thanks in advance,

David

[shwak23]

Don't bother rebuilding a 1.5... Find a 1.6TD... The only vwdiesel worth rebuilding made pre 1992.

[Lando]

Don't bother rebuilding a 1.5... Find a 1.6TD... The only vwdiesel worth rebuilding made pre 1992.

I suppose I didn't mention my goals.  This will be a commuter which will see 90+ miles a day.  I do not care about power.  All I want it to do is get 50+ MPG on the highway and for it to be reliable.  The only major problem I have heard of on these is the block cracking, and ARP studs should seriously reduce the chance of that happening.  With that in mind, would you still recommend replacing the motor with a newer 1.6 when I could get this one running as new for less than $300 bucks?

[Toby]

What causes the blocks to crack through the bolt holes is water and oil in the bottom of the bolt holes. When the bolt goes in the oil has nowhere to go so it splits the bolt boss when the pressure gets high enough.

[Lando]

What causes the blocks to crack through the bolt holes is water and oil in the bottom of the bolt holes. When the bolt goes in the oil has nowhere to go so it splits the bolt boss when the pressure gets high enough.

The ARP studs bottom out in the threads, leaving very little room for oil or water to accumulate.  Also, when torquing, the bolts push outward on the threaded area of the hole as they resist the friction of the threads and the tension in the bolt.  ARP studs only put the tension of the stud on the threads because the friction is dissapated in the threads between the stud and the nut.

[shwak23]

Don't bother rebuilding a 1.5... Find a 1.6TD... The only vwdiesel worth rebuilding made pre 1992.

I suppose I didn't mention my goals.  This will be a commuter which will see 90+ miles a day.  I do not care about power.  All I want it to do is get 50+ MPG on the highway and for it to be reliable.  The only major problem I have heard of on these is the block cracking, and ARP studs should seriously reduce the chance of that happening.  With that in mind, would you still recommend replacing the motor with a newer 1.6 when I could get this one running as new for less than $300 bucks?

I would at the very least go with a 12mm 1.6. Then you won't have to worry about block crackage. I would also suggest going with a turbo anyway. It's not like it makes it a rocket ship. It just makes it so that you can pull out on the highway and not be crushed. Keeping up with the flow of traffic is pretty nice. Just saying.

$300 is a good price but if you can do a 12mm N/A for the same price. I would.

[Lando]

$300 is a good price but if you can do a 12mm N/A for the same price. I would.

$100 for the shortblock, $75 for factory rings, $90 for ARP studs.  Gaskets are already bought and paid for.  I can't imagine I could get a 1.6 for that price.  What other problems may I encounter with a 1.5?

[fatmobile]

You can put those 1.5 guts in a 1.6 block,.. but the small oil drain hole on the front of the head won't match up.
 The bolt holes usually crack because the bolts don't go deep enough, too much stress in a small area,
 not because the bolts are so tight in their threads that a fluid can't even escape past them when bolts are tightened slowly.

 The 11mm block is a good option as long as you have the head studs,.. I boosted past 30psi with the old VNT-15 with the vanes locked closed, a couple times
  and 11mm headstuds are cheaper than the 12mm ones.

 If you do decide to use the 1.5 block; use a hose from the block to the intake to help vent the block. The front oil return is too small and returning oil can be blown back into the head.

 I don't know what measurements you'll need, other than making sure the cylinders aren't bored too big.

[Toby]

too much stress in a small area, not because the bolts are so tight in their threads that a fluid can't even escape past them when bolts are tightened slowly.

The problem comes when there is enough oil and water left in the bottom of the bolt hole that it is being squirted out the spaces between the head bolt and the threads in the block. Especially if you do it slowly. All of the air escapes and you have a completely filled hole when the threads pull tight as you take up tension on the bolt. And then you put another 1/2 turn or better as you bring it up to the final torque setting. I have watched this happen while watching someone else torque a head of a 1.5D. I watched the bolt click the torque wrench and then there was a little pop and the bolt went another 1/4 of a turn and oil was weeping out the minute, new crack in the block.

I expect that this only happens with good smooth threads in the block and the bolt, but it is real.

[745 turbogreasel]

I can't remember assembling a motor without blowing teh
gunk form the bolt holes first....

[Lando]

I can't remember assembling a motor without blowing teh
gunk form the bolt holes first....

^This

Hello fellow TB'r

[libbydiesel]

While proper bolt hole prep will reduce likelihood of the block cracking, it still happens frequently regardless of bolt-hole prep.  They will still crack even when using ARP studs.  BTDT.  IMO, the 11mm blocks are not worth assembling.

[R.O.R-2.0]

What causes the blocks to crack through the bolt holes is water and oil in the bottom of the bolt holes. When the bolt goes in the oil has nowhere to go so it splits the bolt boss when the pressure gets high enough.

no, thats not the only thing that splits these blocks..

the bolts only engaging half of the threaded boss works against them as well

i cracked a block from boost..

the head had never been off before i got it, and i removed it with extreme drive pressure..

To the OP:

ive built/rebuilt more 1.5Ds than i care to count, and they ALL crack..

the 1.5Ds are not really worth messing with. thats why i got rid of all mine.

get a 1.6. the 1.5 only gets like .2mpg better, and is way harder to get parts for.

[camboscams]

Well the clock is ticking on my setup but i'm running 1.6 internals in a 1.5 block (due to my lack of knowledge in my early days) with studs. It sees 15psi daily along with 1300degrees occasionally. It has been this way for  over three years and the only issues i have had is keeping head gaskets on it. So if you wind up with no other options it won't be the end of the world to use a 1.5 . But i do agree that a 1.6 is far superior in many ways.

[Lando]

Picked up the block today, it was too good of a deal and I couldn't find any used 1.6 motors with 12mm head bolts.  I also got a set of these for $75 bucks:



Got the studs ordered, now I just gotta measure for the head gasket and bearings.