Re: SV: [T3] Is it salvaeable? a little long...

["Jim Adney" <jadney@vwtype3.org>]

On 29 Mar 00, at 9:25, Sandin, Karl-Olov wrote:

> Hi Jim!
> Do you have a minute for some engine rebuild questions?

Yes, but I'm going to post this to the list so that everyone can read 
it; I think it should be of general interest.

> Last night I took my poor original engine apart. No pictures produced yet,
> but I can try to describe the status of all the parts. 

> Left head is probably junk - lots of deep marks (1-2 mm deep) in #3
> combustion chamber. Can't see any cracks, but I doubt the head to be
> salvagable. Would require welding around the spark plug hump, and I am very
> suspicious to welding in these regions.

If the seats are okay, and there are no cracks, then welding might 
be an option. Ask your machine shop, and if they weld it make 
sure they preheat the whole head to avoid excess stress in the 
weld area.

> #3 P/C is definitly junk! A awful hole about 1" wide in the piston top, and
> a lot of minor hack marks in the cylinder wall surface. The piston wasn't
> stuck, so I believe the rod isn't bent.

This sounds normal and you would probably replace this part 
anyway. If the miles were low and you could locate a similar used 
P/C you could replace just this one and all the rings, however. Still, 
P/C sets are pretty cheap, at least over here; your local conditions 
may dictate otherwise.

It is possible that a "semi-hemi" cut in the combustion chambers 
might remove most of the damaged area. You'll have to be the 
judge of that.

> Right head and P/C:s looks fine (havent measured guide freeplay etc yet)

Valve job, and replacing the exhaust valves and guides would be in 
order all around anyway. This is just the right time to do it. Intake 
valves can be reused. Both valves in #3 should be replaced 
regardless; you don't want a slightly bent and weakened valve to 
come back and haunt you somewhere down the line.

> Well, splitted the case...
> 
> The case looks fine. It's a (old) AS41 dual relief case with 10 mm head
> studs. Eng.no: UO 507782
> No case savers. No cracks anywhere as far as I can see. Looked especially
> carefully inside and outside between cylinder holes and around the flywheel
> bearing journal. Should I have it examined by a pro? Is "crack indicator
> spray" a good method? (you know -the two-color spray stuff)
> No damage inside - seems like the valve head and most of the pieces from the
> broken piston stayed up in the combustion chamber. Just a few little pieces
> found in the bottom of the case.

Sounds normal and I wouldn't worry about the case. inspect the rod 
and crank carefully, however. Do you know how to "ring" a crank? 
Remove ALL the parts from it, suspend it vertically from 1 finger 
under a rod throw, and tap an unimportant place lightly with a 
hammer. If it is good it will ring like a bell; if it is cracked (or if you 
have left any parts attached to it) it will just go thunk. You can 
check any large single piece steel parts this way.

> The journals for the bearings looks pretty good, too. I am ambivalent about
> if I should have the case align bored... There a-r-e pressure marks in the
> journals after the back of the bearings, but very, very light marks - you
> can just about feel them by scraping with your fingernail. I intend to
> rebuild this engine as a total stocker, so I  am considering putting it
> together again with new bearings (loc-tited to the journals) and a little
> higher torque on the main studs (29 lbs, as I think Berg recommends). Just a
> thought... I guess it will snap back and bite me ;-)

Here's how to check the case: The problem area is at the # 2 
bearing so just look there. Look at the seating surface where the # 
2 bearing fit against the case and note that the back side of that 
bearing has a groove all around it to carry oil around to the other 
side of the case. Where that groove was there was no contact with 
the case, so that case material will not be distorted. When you 
look at the case you will see where the bearing pushed the case 
material back. If you can feel ANY step (the difference between 
where the case was pushed back and where it was not) there, then 
the case will not work again correctly as it now it. The problem is 
that the old bearing stretched with the case, but the new bearing 
will be loose there, which can be disastrous.

You also need to check the thrust face of the # 1 main bearing to 
make sure that that hasn't worn loose. Just use your old bearing to 
check that the saddle width is still snug in the bearing.

> Reading Berg's tech tips I got the impression that a sloppy re-boring often
> makes the mess worse, and a brand new case is the proper way to go, but they
> cost about 700$ here! *sigh* 

I agree about a sloppy align bore, but my personal opinion is that a 
good align bore can be done. The question is whether you have 
such a shop in Scandinavia. I think it is likely that a case that has 
been driven really hard and badly distorted (as in racing) might 
never be recoverable for racing again, but I have had numerous 
cases done for me here by RIMCO and have had nothing but good 
results from them in stock applications.

I ALWAYS have case savers added to my cases at the same time, 
not because I think there is a high possibility that studs will pull, 
but rather because RIMCO does such a good job of it, so cheaply, 
while it is there anyway, that I just can't see taking the chance. 
One of my early rebuilds was interrupted when the studs started to 
pull out as I was torquing the heads. That was a real bummer and I 
can't imagine how it would feel to have that happen in the car a few 
miles down the road. Adding 8mm case savers would probably be 
a good option, but I've always been too cheap to want to invest in 
the new studs, washers and nuts. My 10mm cases with case 
savers have all been wonderful for me.

> And I don't know how well the engine shops around can re-bore a VW case.
> Please correct me if I'm wrong.  
 
You'll just have to inquire around. Perhaps there's a shop in 
Germany that does this work? How hard is it to do an international 
shipment? RIMCO charges less than US$150 to do all this work, 
and that includes a main bearing set.

> I will try to get hold of a micrometer that can measure inner diameters.
> Then I know for sure if I need a rebored or new case...

Your fingernail will tell you everything that you need to know.

> Cam, cam gear and lifters looks fine. Lifters are a little worn, but nothing
> unnormal IMHO.

Check the lifter bores in the case; they should not be loose. Lifter 
faces are convex when new; if they have worn flat they should be 
replaced. Poor quality lifters are easy to find, good ones are worth 
the effort to search out. Best bet is to just buy from VW. I know the 
ones in the plain brown cardboard marked "Made in W. Germany" 
are junk.

> The crank looks good (not measured yet) with shiny, unscratched journals.

A machine shop can measure the journals for you and give you a 
verdict. Unless the crank is cracked, it is probably fine. Check the 
end threads and the dowell holes, too; should still be tight.

> The bearings doesn't seem to be unnormally worn.

If the case is fine and doesn't need to be bored, you might even get 
away with reusing the bearings. They might be better than new 
ones which had not been stretched and would be tighter in the 
case.

> The conn.rods looks fine, too. #3 seems to be undamaged, but possibly a very
> slight bend can occur. Can't judge by just looking at it, though.

Actually, they are easy to check! All you need is a very flat 
surface: a surface plate, or a piece of plate glass. Just place the 
rod down on the table and hold the side of the small end flat 
against the table the large end will be slightly elevated, but you can 
easily see if it is parallel to the table. Bent rods inspected this way 
become instantly obvious.

Check your pushrods for straightness on the same surface. Just 
roll them. If they are bent they won't roll evenly and they'll be 
clearly bent.

Good luck and keep us posted on your progress and questions.

-
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054

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