Rod stretch and Squish area

Festa

Veteran Member
Joined
Aug 14, 2016
Location
South east uk
TDI
Vw t5 van
The squish area that I should have is .61-.63mm but with a decked block and ceramic coated pistons it appears I will only have a squish area of .34mm, this possibly isn't enough. Now I understand the possibility of rod stretch at 5500rpm and expansion in the engine, but would 4340 h beam rods stretch as much as an oe rod ?
I may have to get a head gasket made up to allow for extra clearance but thought I would ask on here first as the worst that could happen is piston to head contact.
Think I should have removed material off the piston top...
Thanks in advance
 

mk3pd

Vendor , w/Business number
Joined
Nov 14, 2006
Location
Norway
TDI
Passat Quattro :)
The squish area that I should have is .61-.63mm but with a decked block and ceramic coated pistons it appears I will only have a squish area of .34mm, this possibly isn't enough. Now I understand the possibility of rod stretch at 5500rpm and expansion in the engine, but would 4340 h beam rods stretch as much as an oe rod ?
I may have to get a head gasket made up to allow for extra clearance but thought I would ask on here first as the worst that could happen is piston to head contact.
Think I should have removed material off the piston top...
Thanks in advance
Easiest solution,and perhaps cheapest would be to remove the coating,machine the pistons and then coat again
Almost no difference in stretch for the rods
 

Mongler98

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Mar 23, 2011
Location
COLORADO (SE of Denver)
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98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
the title of this thread sounds like a cheep, bad, gay, porno lol
 

turbovan+tdi

Top Post Dawg
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Mar 23, 2014
Location
Abbotsford, BC.
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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
Easiest solution,and perhaps cheapest would be to remove the coating,machine the pistons and then coat again
Almost no difference in stretch for the rods
I would think that would be expensive, having a head gasket made would be cheaper, or make your own head gasket by using 2 different ones and making the thickness you need.
 

mk3pd

Vendor , w/Business number
Joined
Nov 14, 2006
Location
Norway
TDI
Passat Quattro :)
I would think that would be expensive, having a head gasket made would be cheaper, or make your own head gasket by using 2 different ones and making the thickness you need.
Nah,making a custom headgasket is not cheap,if you even find someone who does it
Many companies claim they can make custom headgaskets,but in reality they only do it in large quantities
Believe me,i have been down that route a few times before :)

Edit,i assume the measured squish is with the thickest headgasket......
 

martin33100

Veteran Member
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Oct 13, 2015
Location
UK
TDI
VW T5 2.5
I known in the past the OP Festa has bought two VW head gaskets and de-laminated them and then made a thicker one with the different layers.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
On a serious note, though, i was interested to know about custom head gaskets as well, from what i have seen, you have to make your own, metal supply and machine shop supply companies can order you any thickness in copper, stainless, ect.. get the thickness you need and have a machine shop make it or you make it with some fineness and lots of measuring or just trace a head gasket and cut it out. high performance engine builds v8 and what not do it, why cant we? What about putting in fire rings on the head or block?
I was told that the measurement of the coating is nominal and not even worth measuring before and after.
 

Festa

Veteran Member
Joined
Aug 14, 2016
Location
South east uk
TDI
Vw t5 van
Thanks for the input guys..Yes Martin is right I have made a gasket up with two gaskets in the past but I was trying to avoid this as it seems bad practice.
No I can't get a gasket made as it's not enough volume as I only want one.
I'm trying to keep it simple and if things go wrong (which they do for me) I want to go to an auto store and purchase off the self items. It's not always possible as that where I am now..I did think about topping the pistons but then I would have to do the valve reliefs and maybe the combustion bowl, again I may as well get some forge ones made to order as these will be lighter.
I bought the pistons and had them ceramic coated before the rotational stuff went for balancing just to spped things up a bit, thats where things have gone wrong. I've now stripped the head off the engine and rechecked the tolerances, I have a piston projection of 1.03mm and I have ordered another gasket so I can get a 0.2mm leaf out and then add it to the 1.43mm gasket.
I have done Two engine rebuilds last year of which both lasted a combined mileage of 1800 miles so this now better work as I could do a lot more with 20k gbp
 

Festa

Veteran Member
Joined
Aug 14, 2016
Location
South east uk
TDI
Vw t5 van
On a serious note, though, i was interested to know about custom head gaskets as well, from what i have seen, you have to make your own, metal supply and machine shop supply companies can order you any thickness in copper, stainless, ect.. get the thickness you need and have a machine shop make it or you make it with some fineness and lots of measuring or just trace a head gasket and cut it out. high performance engine builds v8 and what not do it, why cant we? What about putting in fire rings on the head or block?
I was told that the measurement of the coating is nominal and not even worth measuring before and after.
I think imo that a copper gasket will always leak and the insertion of 'o' rings is a must but a v8 petrol has less compression over a diesel.
I'm running 18-18.5:1 as it is and I don't want to strip the thing down every year to replace a copper/stainless gasket because it leaks.
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
The standard assumption here of several people including myself is that you're already at the end of the road with the thickest OE gasket? Then ya, you need more creative solutions.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
Nah,making a custom headgasket is not cheap,if you even find someone who does it
Many companies claim they can make custom headgaskets,but in reality they only do it in large quantities
Believe me,i have been down that route a few times before :)

Edit,i assume the measured squish is with the thickest headgasket......
Take apart your new one and a used one, use one of the thinnest shims from the used one mixed in with the new gasket parts
they have a thick flat plate, then two bellevilled plates for sealing, then the thin flat shim plate for the various thickensses.

ETA: ah, I see you've already come to this conclusion
 
Last edited:

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
On a serious note, though, i was interested to know about custom head gaskets as well, from what i have seen, you have to make your own, metal supply and machine shop supply companies can order you any thickness in copper, stainless, ect.. get the thickness you need and have a machine shop make it or you make it with some fineness and lots of measuring or just trace a head gasket and cut it out. high performance engine builds v8 and what not do it, why cant we? What about putting in fire rings on the head or block?
I was told that the measurement of the coating is nominal and not even worth measuring before and after.
copper sucks
know why old engine guys do it? because composition gaskets suck even more

mls is god-tier
you can run stainless fire rings with MLS with lower than normal projection, my friend does it with his DSM making 1500ish hp from a 2 liter
needless to say he doesn't care about unimportant details like small coolant leaks
 

Festa

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Joined
Aug 14, 2016
Location
South east uk
TDI
Vw t5 van
Thanks guys again I really appreciate the help :)
Fix until broke....thanks for the link..
We're here for one reason and that is to extract what we can from an engine.
Most have been in a position which we kinder know what's going to happen or want clarification but you don't always have someone in the workshop to bounce ideas off.
Hoping that most of you know this is agear driven 5 pot that's been fitted in a toe rag and it seems that there's not many have tuned this lump as it had a short life compared to the 4 pot 1.9/2L
The gear driven timing isn't a proplem and is reliable which is more than I can say for the rest of it, but I do have a soft spot for it.
It didn't really help that I had some machine work done which didn't turn out right so that's why I'm here as to get over a problem.
Topping the pistons.....next time as now I know what direction to go as I have another set that's seen sign of a load of metal been thrown around the crankshaft area but with a bit of tlc and coating will be fine.
Forge pistons I believe grow more than the oe piston.
Gasket....I have gone the route of 486. I've ordered a 3 hole thickest gasket and will take a piece of the new/old only compressed gasket that's not had a heat cycle yet and going to insert within the new head gasket and hope it doesn't let go.
I did run with a inserted leaf a couple of builds ago but took it out because of the white smoke at cold start issue...It looks like an old coach starting.
Really starting to miss driving the old girl now as it's like a pair of old shoes.:)
 

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
Thanks for the input guys..Yes Martin is right I have made a gasket up with two gaskets in the past but I was trying to avoid this as it seems bad practice.
Its not bad practice at all. I buy Cometic's for my Turbo Caravan's and customers turob Daytona's, GLH's etc, and that's how Cometic does it, but they do use a thicker shim but we've done that for years with Cometic's, mixing and matching to get the required compression, and they hold fine at 30+ psi of boost. :D
 

Festa

Veteran Member
Joined
Aug 14, 2016
Location
South east uk
TDI
Vw t5 van
Its not bad practice at all. I buy Cometic's for my Turbo Caravan's and customers turob Daytona's, GLH's etc, and that's how Cometic does it, but they do use a thicker shim but we've done that for years with Cometic's, mixing and matching to get the required compression, and they hold fine at 30+ psi of boost. :D
Thanks for the heads up..I was a bit worried of the reed effect of a thinner leaf

and they hold fine at 30+ psi of boost. :D
I'm over that but I think it should still be fine:D.
Engine is mostly now back together and just waiting on some stuff back from the powder coaters..trying to work out how to upload pictures?
 

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
Thanks for the heads up..I was a bit worried of the reed effect of a thinner leaf


I'm over that but I think it should still be fine:D.
Engine is mostly now back together and just waiting on some stuff back from the powder coaters..trying to work out how to upload pictures?
You can use a photo host site or save them on here.
 
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