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TDI 101 Got a simple/basic TDI question? Are you a newbie (new to the forums). Feel free to post your question here.

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Old August 27th, 2017, 16:13   #31
Franko6
 
Join Date: May 2005
Location: Sw Missouri
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I think I have more than my share of engines that we have rebuilt and tested for bent rods. For clarity, I will start at the top.

One of the first checks is to see if the turbo shaft is broken or the compressor wheel is touching the compressor housing. Oil in the intercooler that pours out is a very bad sign of a ruined turbo.

Next, with the injector pump fuel shut off wire removed, and the battery fully charged, all glow plugs out and the vacuum reservoir out of the way, you can test compression. Do not overtighten the glow plug test element. Many of the test plugs are made of brass and will easily strip in the hole. Lightly snugged is all you need.

Run compression until the needle stops rising. It usually will be between 10 -15 strokes. The variation between cylinders should not be more than 10% and the minimum compression would be 390, however, we personally think anything under 420 is relatively poor. The compression on a perfect engine is between 500-515. If it's 490, I would surely be satisfied. Be fair warned, if you have no comparison, gauges can be off and comparative values are important. I'd rather have cylinders registering 450psi across the board than 500 on some and 450 on others.

As for replacement of rods, we have stock replacement rods that we have organized by weight and LENGTH. Unfortunately, not all engines are the same. Although most will be fairly close, if you install rods that vary by as little as .004" in length is to vary compression ratios by .5, when the expected compression is supposed to be 19.5. Just so you know, from the shortest to the longest rod we stock, it's .040" difference.

The other issue we regularly note with piston/ rod assemblies is the variation in weight. Apparently, VW allows 8 gr between reciprocating sets and as much as 12 grams for opposing sets. In other words, if 1-2 piston set weight can be lighter or heavier by almost 1/2 oz. In my feeling, this is a lot and although the engine can run, it runs much more smoothly with balance weighed piston/ rod sets.

As for aftermarket rods, we have such sets in the H-beams we feel are superior, however, if the intent is to reassemble the engine for stock performance, there is no need to use big rods. We can effectively match from our sets of stock OEM rods to suit.

Once it is determined if the compression drop merits cylinder head removal, we measure the piston projection to confirm it is a bent rod. Once confirmed, drop the oil pan (we have some good hints, tricks and tips..) remove the offending piston/ rod and it's reciprocating piston/ rod. Mark for pistons cylinder location. We will balance sets to within .1gr, which is maybe a bit anal, but more than that, because we can. We check pistons for damage, as a badly bent rod can cause piston scarring. We stock sets of good used pistons also.

Then, it's a matter of checking bore dimensions. If there is more than .001 taper, we recommend honing, but not more than .003" from stock bore dimensions. Otherwise, you bore to the next oversize.

Replacing rods is not so much 'drop in', as there can be variations in length, the CRAP rods will not only vary in big-end size, but in taper and length. Tolerance for a well-made rod is .0002", so accuracy counts. If you get a short set of rods, the block would need to be decked. Long rods... you got trouble. You would have to mill the piston height.

As for the Bentley manual, they are the best, but have mistakes for the pistons for a 1.9 TDI engine. The measurements in the book are based on a stock piston of 79.46mm, but almost every TDI we have ever seen, the pistons are 79.44. .01mm = .0004" or roughly .0008" deviation from the book measurements. Again, that doesn't sound like much until your engine burns oil and the rings won't seat.

If we can be any additional help, feel free to contact us. I don't think I would want to do this job under street lights, especially in Alaska. Days are already rapidly getting shorter and although you are more protected as far South as you are, I'd say rain, rain, rain, would hamper your 'outdoor' environment.

Good luck.
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Frank's VW TDI's, LLC
1007 Olive St.
Lockwood, MO 65682
417-232-4634
FranksTDIs@sbcglobal.net

'02 80k grey leather, 99.5 R.I.P 153k
'85A2 NA 375k, '91 A3 290k Always Silver, Always a Jetta

Last edited by Franko6; August 27th, 2017 at 16:17.
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Old August 27th, 2017, 18:49   #32
csstevej
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Wished I could've helped you, I was just in Ketchikan this past week on business.......never seen so much rain in my life in the week I was there.

Frank's advice to you is golden, he helped me with the one bug I've been putting back together. I had one bent rod and one damaged piston....two different cylinders.
I pulled all 4 pistons and rod sets and sent them to Frank to be matched and balanced.
He did a great job and was fast on returning them.

It's really not that bad of a job to do. I also can't do mine in a garage, but did it in the driveway.

All I can say with the twins are good luck ! Enjoy them now for they grow up too fast and you become the village idiot and don't know anything when they get older����
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Old August 31st, 2017, 00:35   #33
Franko6
 
Join Date: May 2005
Location: Sw Missouri
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Hey Steve,

thanks for the compliments.

I spoke with Mo and I do think it's possible to do the job, maybe under a TENT! heh. Actually, that's not such a bad idea...

I think in discussion, it's very likely that this is just another blown timing belt and Mo and I talked through the twins (one crying and one babbling in the background) to the point I felt it was fairly obvious the head is likely to come off, but removing the cam will prove the point.

I wish you the best of luck, Mo. Don't feel bashful about asking for help. I'm happy to do so.
__________________
Frank's VW TDI's, LLC
1007 Olive St.
Lockwood, MO 65682
417-232-4634
FranksTDIs@sbcglobal.net

'02 80k grey leather, 99.5 R.I.P 153k
'85A2 NA 375k, '91 A3 290k Always Silver, Always a Jetta
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Old September 8th, 2017, 13:56   #34
Mocontreras
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Join Date: May 2017
Location: Hoonah, AK
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Ok. So I took my car on the 3 hour ferry ride to Juneau. Which is the closest town with repair shops only to find out that the shop unspoken with that said they would do the work is now not going to do it. It's looking like i might have to ferry my car back here and do the work myself. I'm hoping a can do it. If it's a head rebuild. What's it going to cost?
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Old September 8th, 2017, 17:40   #35
UhOh
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Join Date: Dec 2014
Location: PNW
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Did someone say to work under a tent?

First real work on a TDI -timing belt- in the midst of winter (PNW- no snow at the time). Perhaps not quite as involved as pulling pistons/rods, but not exactly a piece of cake either. It's do-able; and given the wonderful help that's available from folks here I'd have to say that anyone who puts for the effort IS going to be able to get things done.
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Old September 17th, 2017, 07:36   #36
Franko6
 
Join Date: May 2005
Location: Sw Missouri
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Our town got all bent about some of the junk cars around town a few years back. One of our buddies didn't have the time to work on a little truck he ended up reviving. Rather than getting a eye-sore nuisance ticket, he hid the truck in a tent! There wasn't a law about tents being eyesores. Kept the city off his back...

Mo,

The average cylinder head repair we do costs $600- $650. Our built head ready to install is $880 and we buy your core cylinder head after evaluating it. All the parts to reassemble are about $85. Timing belt kit, Dayco belt, Hepu water pump: $290. If rods are bent, it depends, but maybe another $200. Is the turbo shot? That could be a deal-breaker, but around $650 for the stock turbo. Shipping to AK sucks, but you already know that.

That shop makes you boat your car all the way there and then turn you down? Not good business ethics, in my opinion.
__________________
Frank's VW TDI's, LLC
1007 Olive St.
Lockwood, MO 65682
417-232-4634
FranksTDIs@sbcglobal.net

'02 80k grey leather, 99.5 R.I.P 153k
'85A2 NA 375k, '91 A3 290k Always Silver, Always a Jetta
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