Diamond in the Rough - 91 Jetta project

[rs899]

I just picked up a 91 Jetta GL with an ME engine that has 140K on the clock.  This car sat for about a year not far down the road from me at a machine shop and I think it was the machine shop owner's car.  The owner died, so there's not a lot of good history on the car, except for what I can see.

The car presented itself this weekend with the head removed, but with new #1 cyl valves and all others reground and surface milled.  #1 piston has severe damage and, is in fact, cracked and leaking.  The other cyls have light valve hits, but nothing serious. A replacement for #1 piston was found in the car, along with all the other removed parts .  Camshaft(hydraulic) was lying in the leaking trunk and has severe pitting on several lobes- I do not think it wise to use it.  Injection pump was freshly rebuilt and installed.  What I heard from workers at the shop and surmised from looking at the car was that someone installed the IP and did not time it properly , causing the damage.

My plan is to re-ring/ re-rod bearing it with the engine in situ and I have a few questions and seek collective wisdom of the forum...

(1) Obviously, #1 piston and rod has to come out- would it be best only to replace that one?  I have a set or two of standard sized pistons/rods from CR engines.  Not sure if the ones I have have less than 140K miles- probably not.  Of course, I can measure the ones I already have to make sure they are in spec, but I don't know how good the ones are that are still in the car.

(2) Should I just pull all of them and rering the whole engine?  I am leaning toward this as when I was trying to spin the crank by hand #2 and #3 rings stuck pretty badly (the bores had all been sprayed heavily with Lubriplate to stop corrosion, but those two were at TDC and still stuck).

(3) What is the best type of hone to use?  I have one that looks like a large brake cylinder hone, but I see some that look more like bottle brushes with individual grinders for sale.  Would they be better for the desired cross-hatching?

(4) The cam is bad.  Can I use a solid lifter cam that I already have without damage? (I don't care if it isn't as efficient)?

(5) The lifters look good, but can there be some latent defects after such a collision?

I am new here, but I have a fair amount of diesel knowledge.  I drive an '82 VW Rabbit pickup that has about 180K miles on an engine I rebuilt myself 13 years ago.  I also have 4 Mercedes IDI diesels.

I am trying to do this at minimal cost, using parts from CR engines I already have.  I realize the best way to do this is pull the engine etc., but seems to me that if I get the re-ringing right, I could be getting another 100K miles out of this car with about $100 in additional parts (rings, head bolts, rods bearings, timing belt - the new head gasket came with the car) vs. $1000 to do it "right".  With that delta, I am willing to take on a bit of risk.

Any thoughts?

Rick

[Rabbit on Roids]

ok, so i got a free 1.5 engine of unknown condition. got it home, and the exhaust valve was missing its head on #2 cylinder.
but the piston had caught the chunk, and in turn gotten mangled. it bent the rod, broke the piston, took a chunk out of the block, and scored the bore. needless to say, i tore it down, because it was already out of the car. and i tllk all the pistons and rods out, checked them over, 3 were fine with 110k miles on them. just honed the block, went down to my grandpas, grabbed a used piston and rod with rings still on it, and threw it all back together. i used the stock rings that were on the other 3 pistons. even re-used the head gasket it came with. but uh, by looking at the engine from the outside, and from hearing it run, you would never guess its not factory correct. the rings took less than 1000 miles to re-seat, but after that starting improved and oil consumption went way down. runs like a top and starts the first time every time! btw, its been in my car for almost a year now un touched, just normal oil changes and such. my dad and grandpa both said its one of the best runnin VW diesels they have both ever seen. but everyone around me agrees on one thing... its fast for a VW diesel.

so i wouldnt worry about mixing and matching parts. i did it just fine and it is holding up great.

[arb]

Welcome rs899.  Are you in the medical field? Your choice of words sounds like it :-)

Yeah, I'd follow Rabbit on Roids advice and knock down the engine to see what else you need to do. A set of main and rod bearings are not that much money and you will not know if you need them unless you pull the crank.

Yes, this engine will eat valves and other important things if the crank and cam are not in time. Just the force from the starter cranking the first time after a timing belt is not put back on with everything aligned can cause the piston to smack the valve(s).

[rs899]

Nope-  not in the medical field, but I thought the doctor/patient thing was applicable in this case.

If I was not clear- the engine is firmly in the car- the head is off and ready to go on ( I will check to make sure it has new valve seals and wiggle the valves to make sure the guides are decent).

I will pull a bearing cap or two and perhaps plastigauge the crank if they don't look good- but I have no intention of pulling the block apart unless I see something really horrible in the oil pan.  Again- I don't want to spend $1K  (or the time) on this engine as I don't think its really worn out.  One reason is the (used) air filter looks clean.

Rick

[arb]

Only the Doctors I've worked with would say "The car presented itself " :-)

Yes, you can see what you need to under the car after pulling the pan. The 2 bolts between the flywheel and the pan can be a little challenging if you don't have a good selection of tools.

[Baron VonZeppelin]

1+2) I'd go for replacing just the one piston, but pull them all to inspect/measure clean grooves etc. You'll know what to do from there.
And install all new rings.

3) I forgot the pros and cons of stone hone versus dingleberry hone.
Used to know. But i've always preferred the stone hone. And since you have one ...
You control the cross hatch by how you work the tool up and down.
Slower is less degrees of cross - faster is more degrees.

4) No idea on swap. But the cam is hardened surface on lobes, a good effort with naval jelly and 000-0000 steel wool might could surprise you. The non critical areas could be cleaned with wire brush on drill - or similar.

Or perhaps could even have it thermal baked/cleaned at a shop such equipped.

5) Yes absolutely could be, but they probably addressed any factors like that when rebuilding the head.

6) Check operation of Gplugs while you're right on top of them.
Clean/lap the Injectors and install new heat shields.
An injector rehab link if you need it:
http://vincewaldon.com/index.php?option=com_content&task=view&id=20&Itemid=28

7) Verify piston protrusion - replacement(s) versus existing(s) after assembly and cross reference to the head gasket you have.

8 ) Pre-prime Inj Pump with ATF and let that soak for a day or so.
Rotate some by hand or air tool so often.

9) Welcome to a great forum. I'm new around here too.
But not necessarily a soaking wet rookie.

If all goes well on job, and the odometer was still working, at only 140,000+, another 200,000+ should be in the future. My 89 Jetta ME is over 340,000 and still daily driven with excellent MPG.

[rs899]

Thanks Baron-

I don't think the shop thought too much about the lifters- they were just tossed in a can in the trunk, but they were at least numbered.

The several of the cam lobes look severely pitted .  I will have another look at them, and maybe post a picture of it and the trashed #1 piston just for grins, but I think the cam would wipe out the lifters in short order.

Rick

[rs899]

Piston #1:



somebody didn't have a good day.  Does that look like a piece of valve stuck in the middle of the piston?

Camshaft:





too rusty to use?

I am going to try to drop the pan this weekend, if I can get out of my other chores.  I just ordered a bore gauge and will check ovality later.

Rick

[arb]

If you plan on keeping this ride for a while, I'd get a new cam, lifters, and a pistion. That pistion could last forever, but then again it might have a crack where the valve wacked it.

[rs899]

That piston has a crack in it (it's at 9 o'clock on the picture).  I poured some Marvel Mystery Oil on top of all the pistons and that one leaked quickly.

Anyone have any opinions on using a mechnical cam?  I have a pile of them. As Libbybapa said in one thread, the base circle is slightly different.  I measured about .050" smaller/thinner for the hydraulic.  I can't see any differences on the lobe tips where it would hit the lifters.

Rick

[zukgod1]

Replace the piston, Use a Bar/Stone style hone not a Ball hone.
Replace cam shaft.
Check piston protrusion and get the correct head gasket.

NEW Timing belt, tensioner also.
Water pump, T-stat.

Run that suka!!!!!

[arb]

Run that suka!!!!!

Prevet Dan, Kodula ?   :-)

Do you speak Russian too?

[rs899]

I think he meant "suka" as in "sucker".  I don't think "suka" is a very nice thing to say,  po-russki.

But "privet" yourself... I speak a little as my wife is Ukrainian.

Rick

[Rabbit on Roids]

im with dan. fix that one hole and just run it till she lets go again. it will be much longer down the road this time tho. i did the exact same thing as dan said. and i didnt use a ball hone. never have. i dont like them.

[zukgod1]

Yes "Sucker"  

Back to original topic, Its really easy to Over Think these engines.

Just remember the K.I.S.S. Rule, Keep It Simple Stupid...