PD pistons - all 4 meant to be identical?

devonutopia

Top Post Dawg
Joined
Dec 1, 2003
Location
Devon, U.K
TDI
PD300 Skoda Fabia
Hi

Just wondering if anyone knows in a PD engine if there's any difference between the 4 pistons? e.g, are 1 & 2 different to 3 & 4 in some way. My head for some reason says all 4 would be the same, but then I am neither an engineer or a mechanic, so asking the question. :)

In power enhancements as relates possibly to a 2 litre rebore upgrade.
 

-zamppa-

Well-known member
Joined
Jan 13, 2010
Location
Finland
TDI
Audi Allroad 4BH V6 TDI/6M, Compound charged Golf 3 AHU, Passat 3B5 TDi 4motion, Typ1 & 636B
If you imagine how intake/exhaust ports&valves are located in the cylinderhead you will find it out very easy.

So, 1 & 2 pistons are same, and top of 3 & 4 pistons are reflection of those.
 

devonutopia

Top Post Dawg
Joined
Dec 1, 2003
Location
Devon, U.K
TDI
PD300 Skoda Fabia
If you imagine how intake/exhaust ports&valves are located in the cylinderhead you will find it out very easy.
So, 1 & 2 pistons are same, and top of 3 & 4 pistons are reflection of those.
Thanks - question answered.

I am hoping the supplier of my pistons ensured the above was the case in the ones I got. All in the hands of my tuner now though :D
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
2.0L bore out will help a little, no replacement for displacement but most of the gains will be a nice, new bore with new rings.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
don't overbore if you can avoid it
just run more boost

do cut the bowls before you put them in, wish I'd done mine when it was apart
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
don't overbore if you can avoid it
just run more boost

do cut the bowls before you put them in, wish I'd done mine when it was apart
Why cut the bowls?
 

sam-

Veteran Member
Joined
Oct 1, 2008
Location
Belgium
TDI
Golf mk3 tdi AFN
alu head, weak
4x12mm studs per cyl, weak

high compression plus good amounts of fuel (with the air to burn it) makes coolant fart out
Hi, is that reasonable to do it on block without taking piston apart like p0wer did on his golf mk3 but without having experience ? I can practice on dead pistons before.
If yes do you know the formula to know how low the CR will drop with the volume we take off please ?

Or its only a machine shop work ? To get the 4 pistons perfect identical ?

Thanks :)
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
alu head, weak
4x12mm studs per cyl, weak

high compression plus good amounts of fuel (with the air to burn it) makes coolant fart out
Hard to beat that logic, ;)
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
Hi, is that reasonable to do it on block without taking piston apart like p0wer did on his golf mk3 but without having experience ? I can practice on dead pistons before.
If yes do you know the formula to know how low the CR will drop with the volume we take off please ?

Or its only a machine shop work ? To get the 4 pistons perfect identical ?
Dunno, man. Try it and find out.

I'd pull mine and do it in the mill, because I got it so why not use it. I only really plan to take the ring off the top of the bowl. Valve reliefs are 'wasted' air, but you need them if you want to run a meaner camshaft. I don't really intend to.
 

devonutopia

Top Post Dawg
Joined
Dec 1, 2003
Location
Devon, U.K
TDI
PD300 Skoda Fabia
I kind of need to rebore though, as 2.0 pistons are going to be a bit stiff trying to work in a 1.9 block :D
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
Hi, is that reasonable to do it on block without taking piston apart like p0wer did on his golf mk3 but without having experience ? I can practice on dead pistons before.
If yes do you know the formula to know how low the CR will drop with the volume we take off please ?

Or its only a machine shop work ? To get the 4 pistons perfect identical ?

Thanks :)
I wouldn't hack it, do it properly. If you don't get it even, you'll have 4 different compression ratio's, won't make for a smooth, clean engine.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
I wouldn't hack it, do it properly. If you don't get it even, you'll have 4 different compression ratio's, won't make for a smooth, clean engine.
ehhh, not something I'd worry about too much
power balance is out the window anyways if you're running any sort of non-boutique injector calibration
I kind of need to rebore though, as 2.0 pistons are going to be a bit stiff trying to work in a 1.9 block :D
Aww, just heat up the block and cool off the pistons. :p
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
ehhh, not something I'd worry about too much
power balance is out the window anyways if you're running any sort of non-boutique injector calibration
Maybe, I like to backyard things but pistons I don't mess with, do those right or don't bother. My 1/2 cent. ;)
 
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