2002 Jetta TDI ALH, Pistons projection HELP. First thread on this forum

[fleuryperformance]

Hi everyone !

I'm new on this forum, this will be my first thread.

To begin the story, I've bought a 2002 Jetta 1.9TDI from an old lady few weeks ago. Clean title, low mileage (Around 130k miles), no broken TB, never been modified. I've bought the car mainly to go to my job (I made 400+ miles only for my job every week). That was the perfect car for this !

I wanted to make the car hyper reliable for years to come and deceided to change all the seals and head gasket even if everything was OK. I did not want to get in trouble on the road while traveling to work (especially during those cold Candian winter.)

So I took apart everything to get the head off, turbo, intake etc. After cleaning all of the mating surfaces, i've mesured the pistons projection to make sure that everything was in spec. The original head gasket was a ''2 holes''. The mesurements are the following (taken at two places on the piston following the pin axis) :

Piston 1 : Average : 0.041''
Piston 2 : Average : 0.018'' (One mesurement is 0.012 and the other side of the piston is 0.024, pretty crooked IMO)
Piston 3 : Average : 0.022''
Piston 4 : Average : 0.039''

Head is in perfect shape, no bent valve, no sign of wear, NOTHING WRONG.

So pistons 1&4 are in specifications but what about 2&3 ?

Engine was starting fine, no smoke, running fine. Power was OK.

What would you guys do ? Do I put the new gasket and studs and close this out since the car was running fine before ?

Thanks for you time and you advise !

 

[fleuryperformance]

Any ideas guys ? Would the engine work without any issues ?

 

[csstevej]

If your measurements are correct , it looks like you have two slightly bent rods , probably from a slight hydrolock from a runaway..
How does the bottom of the head look and the top of the pistons?

Your gonna have to pull those two pistons out. and double check that they are bent.

If the are then I recommend you pull all 4 out and contact member Franko6 on here as he is one of the most respected members on here , talk to him and send him all four.
What he will do is verify that they are bent and match and balance the rods and pistons.

You will need new piston rings, new connecting rod bearings and new bolts ( they are a one time use the bolts ) A piston ring compressor tool and a ball hone tool.

I had to do this on one of my cars I purchased for my daughter, on that one the PO mechanic dropped a valve after he botched a TB job. It bent two connecting rods and damaged 2 pistons......

If you don’t have a Bentley MM I would highly suggest you get one.......this isn’t a difficult job to do...

 

[fleuryperformance]

Thanks for the answer ! Bottom of the head & pistons look perfect. No sign of wear of sign of the piston hit the head. So I’ll guess I need to pull the motor out and do the complete job !

Thanks again

 

[Genesis]

Engine does NOT have to come out for this.

 

[fleuryperformance]

Ok thanks for the precision !

 

[Vince Waldon]

I'd suggest looping in a TDI machinist like member Franko6 (that's an "oh" not a "zero") and find out what the acceptable tolerances are. Some variation is expected.. there will be a scientific answer as to how much.

 

[csstevej]

Yes as genesis says you do not have to remove the engine, just remove the oil pan and loosen the connecting rods there and pull out the pistons .
Yes frank is a wealth of knowledge and is willing to help, he also sells everything you need so it can be a one stop shopping and he is very reasonable .

 

[PakProtector]

Yes as genesis says you do not have to remove the engine, just remove the oil pan and loosen the connecting rods there and pull out the pistons .
Yes frank is a wealth of knowledge and is willing to help, he also sells everything you need so it can be a one stop shopping and he is very reasonable .

Are you really recommending doing a hone to an engine that won't have its crankshaft removed?
cheers,
Douglas

 

[jokila]

Before you do all that, consult Frank's TDI in Missouri and see what he thinks.

Are you really recommending doing a hone to an engine that won't have its crankshaft removed?
cheers,
Douglas

Yeah. You can do it in situ. Just cover the crank from debris from the hone. Also, be mindful of the oil squirters at the bottom of the cylinder when you hone it.

 

[zslnk]

I just went through this with an ALH.

If your piston numbers are accurate, you would not have liked how that engine would have started in the cold. A compression test would have been a good place to start though.

Being in Canada, ALH engines are a dime a dozen with lots or cars sold, lots of bad auto transmissions and lots of rust taking these cars off the road with good engines. I ended up finding a good bottom end and using my low mileage head. This let me do a full re-seal and inspection on an engine stand which was pretty painless. I have a dry engine with 500PSI x4 that runs like new for the cost of gaskets, seals and TTY bolts. I can find ALH blocks for little money locally. Quebec should be the same as there are lots of TDI's there.

 

[fleuryperformance]

Thanks everyone !

 

[csstevej]

Are you really recommending doing a hone to an engine that won't have its crankshaft removed?
cheers,
Douglas

Yes what’s the issue with doing it that way, it’s been done many times.
You protect the crankshaft at the bottom of the bore , do you honing, clean up afterwards, all you are doing is breaking any glaze on the cylinder walls......it’s not rocket science.

 

[fleuryperformance]

Do you guys recommend a product in particular to hone the cylinders ?

You can link it if you want to !

Many thanks

 

[jokila]

Do you guys recommend a product in particular to hone the cylinders ?

You can link it if you want to !

Many thanks

I used this and sold it on this site after I was done with it.

Flex-Hone Tool-GBD31418 Brush Research Cylinder Hone, GBD Series, Silicon Carbide Abrasive, 3-1/4" (83 mm) Diameter, 180 Grit Size: Amazon.com: Industrial & Scientific

Flex-Hone Tool-GBD31418 Brush Research Cylinder Hone, GBD Series, Silicon Carbide Abrasive, 3-1/4" (83 mm) Diameter, 180 Grit Size: Amazon.com: Industrial & Scientific

www.amazon.com

 

[csstevej]

That’s what I used too.
I used WD-40 as the honing lubricant.

 

[fleuryperformance]

Do we need to do multi step honing (like 120, 180 then 240) or just few pass with 180 grits is enough ? ?

 

[csstevej]

No , just one step, I need to check which one I used, but I think that’s the one I used also.

 

[fleuryperformance]

Thanks, if someone can confirm that the honing grit is 180 i’ll buy the tool now.

 

[wonneber]

Are you really recommending doing a hone to an engine that won't have its crankshaft removed?
cheers,
Douglas

If the rings are replaced you do have to hone the cylinders to break the glaze.
A ball hone does not increase the bore size by enough to worry.
Crankshaft shouldn't interfere with this.

 

[csstevej]

Fleury... just checked what gritt I used on my rebuild, I used a 240 grit as I was only breaking the glaze and I had a light scratch on one wall.......after a few minutes Cross hatch pattern was back and no more scratch.

 

[Vince Waldon]

OP: sounds like you've decided you're going to replace the rods anyways, since you're now focused on honing.

You probably know this already, but rods are generally sold in matched sets of 4 (since the tolerances are so close). That said, the aforementioned Franko6 keeps an inventory and may be able to sell a set smaller than 4, if sent an original rod to match with that will work with his stock.

 

[wonneber]

I would send the 4 rods and pistons.
Let Franko6 check them and match as needed.