How to determine which head gasket to get (1,2,3 hole)

DaveLinger

Veteran Member
Joined
Apr 9, 2010
Location
Morgantown, WV
TDI
2001 Golf TDI
I know the obvious answer would be "get whatever is on there now", but I know the PO had replaced the head gasket and I'd rather not "trust" that he used the right one. Is that information printed or stamped anywhere?
 

Seatman

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Apr 23, 2010
Location
Scotland
TDI
2014 Skoda rapid elegance 1.6 cr tdi
There's something about measuring piston protrusion to determine which gasket you need. I don't know what the measurement is but there must be info around here somewhere.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
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Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
No, it isn't.
Pull the head, measure the piston protrusion above the block surface when at TDC. From that value a gasket of correct thickness can be selected.
(but I don't know what projection ranges suggest which gasket thickness, sorry.)
 

aNUT

Vendor , w/Business number
Joined
Nov 29, 2006
Location
Boulder, Colorado
TDI
'01 TT (ALH-ish), B7 Audi gasser, '05 Golf
Which engine code?

The HG selection is based on the piston protrusion as measured from the top of the piston to the top of the block when that particular cylinder is at TDC.

The ranges are specified in the Bentley. The ranges are engine code specific.
 

DaveLinger

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Joined
Apr 9, 2010
Location
Morgantown, WV
TDI
2001 Golf TDI
It's an ALH.

I was hoping to have the head gasket and kit ready before tearing everything apart to minimize downtime and whatnot, but apparently this isn't possible?
 

DaveLinger

Veteran Member
Joined
Apr 9, 2010
Location
Morgantown, WV
TDI
2001 Golf TDI
Thanks! Very very helpful.

It says to use the largest of the measurements among all cylinders. If I were to just throw a 3-hole gasket on there, aside from the forum telling me my car is going to explode, would there be any major negative side-effects, or just SLIGHTLY lower compression?
 

Franko6

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Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
Use the right head gasket. the "thickest head gasket" approach is really lame.

The simple way: Part of your head gasket protrudes from between the head and block. There are some holes in that part. The oblong hole means nothing. If you find BB-sized holes, one, two or three, then that relates to the head gasket you need.

The exacting and precise method: Pull out your Bentley book and turn to page 13a-17.

There is a diagram that shows a rather obtuse way of measuring the piston projection and a chart for the piston projection. Basically, I use a flat plate with a dial indicator sticking through it, but you can use a variety of measuring methods; vernier caliper, depth mike, shims... measure in line with the wrist pin on both sides of the piston.

The dial indicator is easiest as you zero the dial on top of the piston and look for the highest reading as you roll the engine over. Otherwise, find TDC and use one of the other measurement methods.

For an ALH, a measure of:

.91-1.00mm (.0358"-.0394")is a one-hole head gasket
1.01-1.10mm (.0398"-.0433") is a two-hole
1.11-1.20mm (.0437"-.0472") is three-hole

If you measure front or back on the piston skirt sides of the piston, you will get a false reading, as the piston can rock in the bore. Readings should be taken in line with the wrist pin.
 
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Vince Waldon

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Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
Since the gasket thickness is based on piston protrusion, head shaving has *nothing* to do with it. :)

A gasser changes compression ratios when the head is shaved because of how much of the combustion chamber is in the head... on our flat-headed diesels it's all in the piston depression and not dependent on the head.

Since you can't measure piston protrusion without pulling the head you'll need to pull the head before you can order the correct head gasket.
 

Golfakias_tdi

Member
Joined
Sep 12, 2012
Location
greece
TDI
1,9tdi asz
vw 1,9tdi(asz) -2,0tdi(bmm) head gaskets

HI

I have the 1.9tdi(asz)code with 130hp engine.I Have oversize the block to put new pistons from 2.0tdi(bmm)code with 140hp,the new sizes from BMM engine are: pistons 80,96mm and the cylinders 81mm.Also i have shaved the head of the engine where the valves are, if you didnt understanded.So i want to ask you,how
i will determinate which head gasket will i use to put on the engine?? which is the simpliset way to understanded???? the head of the engine which was shaved has any importance to all of this subject ??? the 2 blocks are same in everything only the diametre of the pistons change the BMM has 1,5mm pistons larger, last i want to ask you is ,if you know about the holes of the gaskets for ASZ and BMM engines, namely..how much milimetres must be the piston protrusive for 1 hole, 2holes and 3 holes??if you understanded what i mean!!!to put exacly the gasket it needs....so i will be waiting for your answer to help me with that because i will be crazy with that thing..PLEASE send me in my E-mail:Golfakias_tdi@yahoo.com

Thanks...
 

Golfakias_tdi

Member
Joined
Sep 12, 2012
Location
greece
TDI
1,9tdi asz
HI
I have the 1.9tdi(asz)code with 130hp engine.I Have oversize the block to put new pistons from 2.0tdi(bmm)code with 140hp,the new sizes from BMM engine are: pistons 80,96mm and the cylinders 81mm.Also i have shaved the head of the engine where the valves are, if you didnt understanded.So i want to ask you,how
i will determinate which head gasket will i use to put on the engine?? which is the simpliset way to understanded???? the head of the engine which was shaved has any importance to all of this subject ??? the 2 blocks are same in everything only the diametre of the pistons change the BMM has 1,5mm pistons larger, last i want to ask you is ,if you know about the holes of the gaskets for ASZ and BMM engines, namely..how much milimetres must be the piston protrusive for 1 hole, 2holes and 3 holes??if you understanded what i mean!!!to put exacly the gasket it needs....so i will be waiting for your answer to help me with that because i will be crazy with that thing..PLEASE send me in my E-mail:Golfakias_tdi@yahoo.com
Thanks...[/QUOTE]
 
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