745TD rebuild

[v8volvo]

This was a project that started earlier this year, just got it back on the road a few weeks ago. Here are some pictures.

Starting point, car was in disarray under the hood after a previous rebuild that didn't last and subsequent 5 years sitting with the head off after it got taken apart. Several major parts AWOL and the others in rough shape... Sorry for crappy phone pics.

http://imageshack.us/a/img856/9611/ov5g.jpg

http://imageshack.us/a/img23/761/0ehj.jpg

Disassembly and inspection, found a few issues. One functional problem that this car was known to have been having when it was last on the road was difficulty engaging a gear from a stop. Had been chalked up to maladjusted clutch but a more likely explanation was visible with the motor hanging in the air:

http://imageshack.us/a/img96/3135/5t4u.jpg

This was an aftermarket pilot bearing with no seal that was installed less than 20,000 miles ago during the previous rebuild; as expected with no way of retaining its grease the bearing had a very short lifespan, probably significantly less than the 20k the motor provided before it too expired.

Continuing disassembly many issues were found, including several failures that were quite unique and interesting which deserve their own thread for further pictures and description so I'll save the details on those for later. The single biggest concern was corrosion on the cylinder walls that occurred while the motor sat with the head off. Unfortunately I did not take a close picture of this but it is partially visible here.

http://imageshack.us/a/img6/7732/8jfc.jpg

Parts back from cleanup at the machine shop and the news was not good, #6 cylinder pitted deeply enough that there were areas the hone did not touch. Otherwise it was in nice shape with no real wear at all given the low miles it had run, but unfortunately since this motor was already bored to the max .040 oversize during the last overhaul there is no room to cut any further; this block has reached the end of the road.

http://imageshack.us/a/img546/9333/v6do.jpg

http://imageshack.us/a/img90/4461/erh7.jpg

[v8volvo]

As this project took place in Colorado, locating a replacement engine nearby proved to be a challenge; however, after considerable effort a candidate was found -- out of a Pinzgauer, bizarrely enough. :D It was not much of a motor anymore in its as-found state, but underneath the crust it looked OK, so it was worth a try... Some favors were bargained, and the motor was loaded up and brought home.

http://img690.imageshack.us/img690/4288/xs19.jpg

This second engine had previously suffered a water pump failure that sheared the timing belt and wrecked the head, see the valve head marks on the pistons; the motor got replaced and then become a yard decoration. Getting it freed up and pulled apart after spending several winters outside was a battle involving some caveman techniques, but the block looked promising after stripping it down. It still had room for overbore so it went in for machining to see what would happen.

Getting ready for final hone:

http://imageshack.us/a/img191/1269/qbhg.jpg

This time the results were a win; the block came out in the 2nd overbore (.040"/1mm) looking great. :cool:

http://imageshack.us/a/img191/8444/0a0b.jpg

http://imageshack.us/a/img43/6968/ilcd.jpg

[jbg]

This was an aftermarket pilot bearing with no seal that was installed less than 20,000 miles ago during the previous rebuild; as expected with no way of retaining its grease the bearing had a very short lifespan, probably significantly less than the 20k the motor provided before it too expired.


George,

Was this aftermarket pilot bearing purposefully designed without the seal? Or did the seal deform or break down causing the failure?

[v8volvo]

George,

Was this aftermarket pilot bearing purposefully designed without the seal? Or did the seal deform or break down causing the failure?

Two types of pilot bearings exist for the D24/T (as well as Audi engines of similar vintage which share the same setup): the original "good" type which has shorter needles and incorporates a grease seal, and the aftermarket-style "bad" type which has longer needles but no seal (and also, as far as I can tell, uses a plastic cage in some cases).

There has been some discussion of this in J.D.'s clutch thread here:
http://www.d24t.com/showthread.php?p=6854#post6854

And also here: http://d24t.com/showthread.php?t=1047

The bearing that exploded here was the second type.

Unfortunately it seems every pilot bearing you can get from an aftermarket source is the crappy cheapo kind with no seal, which is pretty much guaranteed trouble. AFAIK INA is the only maker of the high-quality OE type bearing, and they're not widely available from *auto parts* stores -- you can only find the other type in the aftermarket. Volvo used to sell the good bearing (a reboxed INA part) but discontinued it.

However, the INA bearing is still available at this time from bearing wholesalers -- just takes a little more digging than calling up your FLAPS. I ordered a dozen of them from Whisler Bearing in CO to distribute the cost a bit and still have 8 or 9 left that I have been meaning to send out to those who signed up for one in the above thread months ago. Need to do that here soon.

Fortunately, since your car has the ZF autobox rather than a standard trans IIRC, you won't have to worry about any of this. :cool:

[jbg]

Two types of pilot bearings exist for the D24/T (as well as Audi engines of similar vintage which share the same setup): the original "good" type which has shorter needles and incorporates a grease seal, and the aftermarket-style "bad" type which has longer needles but no seal (and also, as far as I can tell, uses a plastic cage in some cases).

Understood, thanks for the explanation!

Fortunately, since your car has the ZF autobox rather than a standard trans IIRC, you won't have to worry about any of this. :cool:

Exactly! I only have to worry about the ZF-related problems! :D

[Kraftwerk]

Hi,

Any updates on this build?