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Engine Specific Info and Questions => TDI Engine -General Info => Topic started by: jimbote on January 18, 2007, 05:49:39 am

Title: TDI Piston Ring Placement and Rod Bolt Reuse....?
Post by: jimbote on January 18, 2007, 05:49:39 am

I'm building an ALH "parts bin" engine wondering what the correct piston ring placement is ....and has anyone reused rod or maincap bolts in an ALH? .....I know the manual says "always replace"......but has anyone "foolishly"  taken the chance on this.....if not I may be the guinea pig!...... :shock:

Title: TDI Piston Ring Placement and Rod Bolt Reuse....?
Post by: hillfolk'r on January 19, 2007, 01:37:17 am

i didnt chance the rod bolts or main cap bolts
i think the rod bolts were cheap,like 3 or 4 or maybe 5? bucks a piece??
 for the replacement main cap bolts,i went with a raceware stud kit for 155
what do you mean correct ring placement??
if i remember right the top ring is 1.75mm wide,the 2nd is 2mm and the oil ring is like 3mm

Title: TDI Piston Ring Placement and Rod Bolt Reuse....?
Post by: jimbote on January 19, 2007, 03:07:05 am

thanks for the reply hillfolkr'......what I mean by ring placement is how are they supposed to be "clocked"......of course you don't want to line up the gaps.....anyone know how they should be staggered? e.g. bottom ring gap at three o'clock second compression at five ....etc....

Title: TDI Piston Ring Placement and Rod Bolt Reuse....?
Post by: RabbitGTDguy on January 19, 2007, 12:50:03 pm

Couple tips...

Never reuse OEM harware :) I.E. rod bolts, mains, etc...all should be replaced. Dealer prices as already mentioned aren't that bad and are well worth the security of having new hardware in there. There is a debate about rod bolts...supposedly being able to be torqued twice in their service life...but I wouldn't...
Its all factory stretch stuff...def. replace for the price.

As for the rings, depending on the ring manufacturer they will provide you with instructions. Goetze I know does...and they recommend the rings clocked... 90 degrees off each other on proper installation. If memory serves me correctly without looking!

Joe

Title: TDI Piston Ring Placement and Rod Bolt Reuse....?
Post by: hillfolk'r on January 20, 2007, 12:25:04 am

Yea i think its 90 degrees
id have to grab my ring install chart
i think i went by what total seal said to do
i think they said 120 degrees,starting from the top....
close enough,,as long as the ring gaps are opposing each other

Title: TDI Piston Ring Placement and Rod Bolt Reuse....?
Post by: jimbote on January 21, 2007, 12:45:55 am

thanks for the advice.....did I mention that this is a parts bin motor?.....anyway.....I figured the top two should be at least 120 apart but when I took the pistons out I noticed on more than one piston a consistent pattern .....the top two ring gaps only fifteen degrees apart....followed by the oil ring another fifteen degrees counterclockwise from the second and lined up perfectly with one of the the divots just below and to the side of the pin....also on the one high mileage motor I noticed a trail of oil stain coming from the divot that had the oil ring gap above it.....it would make sense for the gap to be there so oil vapor could get to the rings.....on the ALH piston there are no oil "vapor" holes under the skirt as in the IDI engines.....I'm sure the rings were lined up that way for a reason....I'll post pics of one of the piston that suffered catastrophic damage that "locked" the rings into the factory position via "land crushing" force......also I'm reusing the pistons and rings from one engine in another block.....around 30k miles .....like new ring end gap.....

Title: TDI Piston Ring Placement and Rod Bolt Reuse....?
Post by: hillfolk'r on January 22, 2007, 10:04:30 pm

rings spin or turn in actual use,so sooner or later,the gaps do line up once in a while
but yea id oppose the oil ring gaps 180