Where to stop?

JFettig

Vendor
Joined
Aug 18, 2010
Location
Blaine, MN
TDI
B5 Passat, 2010 Jetta
if you know how to use them, telescoping gauges can work very well in combination of a good micrometer. I frequently see people mis-using them, it is sometimes hard to get a good measurement on them if you can't feel it just right.
 

Ski in NC

Top Post Dawg
Joined
Jul 7, 2008
Location
Wilmington, NC USA
TDI
2001 Jetta ALH 5sp stock
To accurately measure bores, I use three tools: A dial bore gauge, a micrometer, and a standard. The bore gauge has to be set using the mic, and the standard is used to make sure the mic is dead on. The bore gauge is handy as you can sweep the bore in numerous areas while watching the dial. Also, on little engines you can't get your hands in the bore with an inside mic, another tool that works. Inside mics are slow to take measurements.

Check ENCO in NV, they have good prices on measuring tools. I use name brands, but that took quite an investment. A bore gauge can be an off brand (usually) as you can check the performance of the tool with the mic. It really is just a transfer tool.

I've tried using bore snap gauges, but it is hard to get accurate measurements.
 

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
What is the down side to bore out the block? Cost of new pistons and the machine shop cost? At least you would know the bore is true. And you are going to buy some new pistons anyway, right?

Just asking - not advocating.

Also, what needs to be done to boost the power between 1000 to 2000 rpm??? Smaller turbo?
 
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JFettig

Vendor
Joined
Aug 18, 2010
Location
Blaine, MN
TDI
B5 Passat, 2010 Jetta
Here are a couple how-to use a telescoping "snap" gauge properly:
http://constructionmanuals.tpub.com/14256/css/14256_93.htm
http://bbs.homeshopmachinist.net/showpost.php?p=328010&postcount=2

Once it is tightened up inside the bore, carefully make sure you're in the center, then tip it like above. at this point, don't tighten it any more. carefully measure it. You will get some varying measurements but with practice you can get good at it. I can typically measure stuff to about .0005" with them.
 

Keebler145

Veteran Member
Joined
Jun 29, 2008
Location
Niles, Ohio
TDI
Jetta MKIV 2000, 2003, and MKV 2006 PD DSG
Ok - lots of comments to address here...

All of the other things that the car needs (suspension and such) are definately needed and way beyond overdue. Then combining the engine repair/replacement now and everything associated with that, I just wanted to make sure that I wasn't "polishing a turd" here. The overwhelming consensus is that it should be fixed and I agree with that. This car has done everything I've ever asked of it, thousands of miles pulling trailer, my dependable daily transportation, excelllent mileage (52+ MPG average over lifetime). I know what this car is/is not and buying something new/used would start that learning curve over and besides that I like the car :).

That said, now to decide how/what to repair this thing. It sure seems that lowering the compresion would help keep peak cylinder pressures and piston temps down. Lower compression will generally loose thermal efficiency but might prevent this from happening. ~18.5:1 would be about as low as I'd want to go to insure good starting in the winter. Any opinions on a thermal barrier on the tops of the pistons - Maybe keeping the 19.5:1 CR for good starting and a thermal barier would make the pistons live? I'm aiming to improve power in the 1000-2000 RPM range so this is the time to make any changes/improvements to support that.

I'm assuming that this failure was due to thermal stress on the pistons, most likely from towing and resultant operation at continuious high loads for hours on end. If I get it apart and find the oil squirter plugged on #3 pistion or some other evidence of another cause of the piston failure, I'll let everyone know. EMP's during the heavy trailer towing are equal to boost and IAT's are ~50F over ambient. A larger oil cooler would probably be a good idea (no oil temp gauge, but will be getting one).

My trusted mechanic is adamant that the block should be bored/trued up and that it's probably not round and would have trouble sealing the rings if it was just honed. I'm going to try and get a 3-4" micrometer and bore gauge to see if the cylinder is true enough to hone or not. Given the marks on cylinder 2 in particular it could be either way.

What about a complete engine swap? A PD150 and 6 speed from across the pond?

Are there any 16 valve motors that will more/less go in?

A CR without all the emissions stuff would be cool as well?



I guess all the statements I've made about "Well, it has not blow up yet" are no longer valid :).

I think it was pretty unanimous most of us said ASV with ceramic coating for stock compression and better thermal control or pd150 pistons to drop compression which have thicker crowns and would also have better thermal control. Matt makes a valid point on getting some rosten rods, it's cheap insurance.

I don't know that a 1756 will lower your EMP and EGT. You need to get a bigger exhaust wheel to really accomplish that. Not sure why you want to make more power in the 1000-2000 range, really not good for the motor. At that RPM you're really lugging the old girl and stressing the internals.

If you're going to do that definitely make sure you get an OEM weight or maybe heavier flywheel. If you're going to drive it like an old farm tractor you better build it like one.
 
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Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
What is the down side to bore out the block? Cost of new pistons and the machine shop cost? At least you would know the bore is true. And you are going to buy some new pistons anyway, right?

Just asking - not advocating.

Also, what needs to be done to boost the power between 1000 to 2000 rpm??? Smaller turbo?
If I can just hone the bores for new pistons/rings, then I don't have to remove the engine from the car saving a fair ammount of time/effort. If it has to come out, it will, but being generally lazy, I'd rather not if I don't have to.
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
Are the PD150 and ASV pistions interchangable? Bowls in the same location, etc?

I assume the PD150's have a larger bowl to drop the compression? Any idea what the CR drops to on with the PD150's

Swaintech for coatings I assume? Anyone else who does coatings like this?

I think I have all the measurement equipment lined up and will try and measure the bores tonight.

I've wanted to put a heavier flywheel in for a long time - figured it would smooth things out quite a bit.

Regarding lugging and stress on the internals, I think the pistons and rods should address a lot of that. I'm not looking to make 200 HP at 2000 RPM, but just extend the power curve down the RPM range. BMEP's are significantly lower (half) than some of the 200+HP 400+ft-lb TDI's out there.

Maybe to ask another loaded question....OEM head bolts or ARP's?
 

Keebler145

Veteran Member
Joined
Jun 29, 2008
Location
Niles, Ohio
TDI
Jetta MKIV 2000, 2003, and MKV 2006 PD DSG
PD150's drop it a whole point IIRC so 18.5. I never measure, but from the eye they look like they have a larger bowl.

Swaintech is about the only one I know of. ASV and PD150 pistons are interchangeable on rosten rods ;) but the OEM rods need tapered to fit a PD150 piston IIRC again.

When I bought my ARP headstuds they were only 80 bucks more than buying headbolts. Knowing I would be pulling the head again I bought something I could reuse. I had issues with the headbolts stretching and lifting on me at 24psi on a 17/22. My coolant bottle was always over pressurized and had soot in it.

Flushed the coolant installed the headstuds and the problem went away.
 

Whitbread

Vendor , w/Business number
Joined
Jan 21, 2007
Location
Johannesburg, MI
TDI
Several
Are the PD150 and ASV pistions interchangable? Bowls in the same location, etc?

I assume the PD150's have a larger bowl to drop the compression? Any idea what the CR drops to on with the PD150's

Swaintech for coatings I assume? Anyone else who does coatings like this?

I think I have all the measurement equipment lined up and will try and measure the bores tonight.

I've wanted to put a heavier flywheel in for a long time - figured it would smooth things out quite a bit.

Regarding lugging and stress on the internals, I think the pistons and rods should address a lot of that. I'm not looking to make 200 HP at 2000 RPM, but just extend the power curve down the RPM range. BMEP's are significantly lower (half) than some of the 200+HP 400+ft-lb TDI's out there.

Maybe to ask another loaded question....OEM head bolts or ARP's?
Yes, they are basically the same. PD150's are 18.5:1 CR, the ASV's are 19.5 like ALH's.

I've used both Swaintech and Polydyn, been very happy with both.

Do the ARP's, again very cheap insurance at this point. Literally I just did a head gasket on a car with a stock turbo that was pressurizing coolant yesterday. It'll never be easier than now to fix all the factory short comings.
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
Here's the cylinder bore measurements. I used a telescoping bore gauge and a 3-4" micrometer. The micrometer was ~0.0005" large on both the 3" and 4" gauge blocks at room temp. I let them set in the garage for a couple hours to get to the same temp as the engine (~40F). It took a few measurements to get the hang of it - I repeated the first 8 measurements I took after I completed the first set and got more consistent numbers with the other bores the 2nd time. I double checked most of them by the time it was all done. My guess is that the numbers are +0.0000"/-0.0010"

- means side to side across the bore
| means frint to back across the bore

Top of bore just below where the rings stop
#1 - 3.1320"
#1 | 3.1318"

#2 - 3.1310"
#2 | 3.1315"

#3 - 3.1315"
#3 | 3.1320"

#4 - 3.1300"
#4 | 3.1320" I did these two 4-5 times and it's about 0.0020" different

Bottom of bore just above top of piston
#1 - 3.1300"
#1 | 3.1310"

#2 - 3.1310"
#2 | 3.1310"

#3 - 3.1315"
#3 | 3.1310"

#4 - 3.1300"
#4 | 3.1305"


I don't have my bentley manual at hand (left it at my friends shop 250 miles away), but 79.5mm = 1.1299 inches so being 1-2 thousandths over and relatively round for the most part does not make me think it needs to be bored out/trued up.

Flex hone it in the car, new pistons, etc and get it back on the road?

Should the cylinders be honed with a torque plate?

I'm going to find accurate TDC and mark the flywheel as long as it's apart.

Anything else I should do while I'm here?
 

Keebler145

Veteran Member
Joined
Jun 29, 2008
Location
Niles, Ohio
TDI
Jetta MKIV 2000, 2003, and MKV 2006 PD DSG
definitely worth it. especially for low rpm higher egt running like you want to do!
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Does anyone have any data that shows coating pistons in a diesel helps? Diesels run relatively cool compared to gasoline engines. I've debated doing this for my track day Golf. I'm not even sure what data would be useful, but I wonder if it's worth the expense.
 

Ski in NC

Top Post Dawg
Joined
Jul 7, 2008
Location
Wilmington, NC USA
TDI
2001 Jetta ALH 5sp stock
No expert on coatings, but mighty skeptical. Detroit diesel sold coated piston kits for their high output two-strokes, and they failed. Coatings came off and the very hard and abrasive debris tore up the cylinder liners. And those pistons are iron, not al. Nothing seems to like to stick to al, at least in my non-metallurgist mind.

I would not go with coatings unless you are beyond the thermal limits with your tune and duty cycle. In the OP's case, I think it can be handled by keeping rev's up when towing. Snorting around doing heavy accels are brief and heat likely does not have time to soak into piston. But thermal stresses are high there due to the temp gradient...

High output marine engines handle the piston temp issue by lowering cr, as already discussed above. This does create more fuel smoke at light load and cold start, though.
 
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Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
Putting the cost aside for a moment, it's a two week delay in getting it back up and running again in my unheated garage.

I have time off work at the end of the year and plenty of holiday travels planned (I have other vehicles to drive, but not anywhere as economical as a TDI). Getting the coating done would put me in the 1st week of Jan instead of next week and cost an additional $250+ in fuel not driving the TDI.

I'm going with the PD150's which should drop compression by a point I'm told. I have no concers about the durability of the coating (maybe I should) - it's a logistics and principle issue. Like IBW asked, will it do any good practically?
 

mk1-83

Veteran Member
Joined
Aug 14, 2010
Location
Holland
TDI
LUPO 1.9 tdi 300+ hp
Pd Pistons and rods are pritty strong. It will hold just fine. I think you go with bigger nozzels to. hold the injection duration short. it make less thermal stress.
 

Keebler145

Veteran Member
Joined
Jun 29, 2008
Location
Niles, Ohio
TDI
Jetta MKIV 2000, 2003, and MKV 2006 PD DSG
I think I would have went rosten rods.... not a big fan of the IE rods....hope they work out, make sure you get the weights checked/balanced.
 

Whitbread

Vendor , w/Business number
Joined
Jan 21, 2007
Location
Johannesburg, MI
TDI
Several
If it's going to be a big delay in plans for you, skip the coating. The pd150 pistons will have much better thermal absorption characteristics than stock pistons do so I wouldn't worry about it too much. Between the lower top ring land, lower cr, and internal oil cooling channels, you should be fine.
 

TDIJetta99

Top Post Dawg
Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
If you're set on the low rpm power, as in 1000-2000, the lower CR will destroy those dreams... I went down to 18.7XX on my build and it has the torque of a 2.slow under 2000rpm.. 2500rpm+ is a totally different story however.. A bit hard starting in the cold but nothing major.. Some of my lack of low rpm grunt is from the 2260, but regardless of the turbo, there's NO off-boost power at all...
 

v8 coupe

Veteran Member
Joined
Sep 3, 2008
Location
bloomington, mn
TDI
09 rabbit 2.5L Gas
there is a place in MN that does coatings they can do them in a week or less usually.

From what I have read in all my tech articles it's hard to prove it works. Having said that a mentor of mine Joe Mondello use to say it's "free HP" he coated everything from briggs go-kart pistons to 2000HP tractor pull engine. Basically it doesn't give you anything extra. It only stops the heat from going where you don't want it, in the pistons and oil. Coating the head also helps, but to me the heat is needed to get the engine to operating temps.

FUB the place in MN is called TPIS here is a link good group of guys. They will be coating my modified ALH pistons.
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
Had a couple moments of motivation and went out to the garage and pulled the oil pan and all the rods/pisons.

Everything looks good so far

Does anyone know what kind of rings come on the pistons?

More specifically, to what finish or with what grit should I hone the cylinder bores?
 

Fix_Until_Broke

Top Post Dawg
Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
If you're set on the low rpm power, as in 1000-2000, the lower CR will destroy those dreams... I went down to 18.7XX on my build and it has the torque of a 2.slow under 2000rpm.. 2500rpm+ is a totally different story however.. A bit hard starting in the cold but nothing major.. Some of my lack of low rpm grunt is from the 2260, but regardless of the turbo, there's NO off-boost power at all...
Any theories on why a change in compression ratio would change the powerband?

Did you change cam's or anything else when you changed CR?
 

v8 coupe

Veteran Member
Joined
Sep 3, 2008
Location
bloomington, mn
TDI
09 rabbit 2.5L Gas
PD150 pistons need different squirters. ALH squirters will not line up with the hole in the piston to get optimal cooling.

PN is 038103157A
 
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