DaveLinger
Veteran Member
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?
How to determine which head gasket to get (1,2,3 hole)
- Thread starter DaveLinger
- Start date
Lug_Nut
TDIClub Enthusiast, Pre-Forum Veteran Member
- Joined
- Jun 20, 1998
- Location
- Sterling, MA. USA
- TDI
- 2015 GSW 6M in S trim the other oil burners: 1967 two stroke Sonett 1988 Bolens DGT1700
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.)
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
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.
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
Veteran Member
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?
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?
Lug_Nut
TDIClub Enthusiast, Pre-Forum Veteran Member
- Joined
- Jun 20, 1998
- Location
- Sterling, MA. USA
- TDI
- 2015 GSW 6M in S trim the other oil burners: 1967 two stroke Sonett 1988 Bolens DGT1700
Got it (for your 2001 A4 in your sig):
http://forums.tdiclub.com/showthread.php?t=306773http://pics.tdiclub.com/data/500/Piston_Position_at_TDC.pdf
http://forums.tdiclub.com/showthread.php?t=306773http://pics.tdiclub.com/data/500/Piston_Position_at_TDC.pdf
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DaveLinger
Veteran Member
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?
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
Vendor , w/Business number
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.
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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davidm2232
Veteran Member
is this for a new head, or any head. how do i know if my head has been machined? is there any way to order parts before tearing the engine apart?
Vince Waldon
Top Post Dawg
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.
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
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...
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
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]
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]