Zetec turbo headgasket
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Zetec turbo headgasket
i'm Building a 2.0 zetec turbo engine at the moment and thinking of what headgasket to use.
Thought about a cometic one.
Gonna be running about 21 psi for now.
what do you guys recommend?
Thought about a cometic one.
Gonna be running about 21 psi for now.
what do you guys recommend?
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Put the cometic and standard Focus 2.0 gaskets side by side and you will not see much of a difference. Cometic has a wider selection of thicknesses though with Ford only having two to choose from.
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It's for a silvertop zetec but i guess i can use the focus one or is the mondeo gasket the same?
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Wich one is stronger is more inportant or is strong enough for some reasonable boost ( minimum 21psi )
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It's very unconsiderate to make statements based on false assumptions. The difference in the compression rate is not made with the head gasket thickness. The ST170 gasket is on the order of 1.0mm and the other 2.0 gaskets, including RS, is on the order of 0.6mm thick. The thickness should be chosen so that the piston crown to cylinder head plane distance is optimum. Usually this is between 0.7-1.0mm depending on application. If you then end up with the wrong compression ratio, then you have an unsuitbale piston dish/dome volume.
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It's very unconsiderate to make statements based on false assumptions. The difference in the compression rate is not made with the head gasket thickness. The ST170 gasket is on the order of 1.0mm and the other 2.0 gaskets, including RS, is on the order of 0.6mm thick. The thickness should be chosen so that the piston crown to cylinder head plane distance is optimum. Usually this is between 0.7-1.0mm depending on application. If you then end up with the wrong compression ratio, then you have an unsuitbale piston dish/dome volume.
Thats why you can buy various thickness` of gaskets which makes up the "extra material" from having your head skimmed.
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Its right what you say about the pistons having a clearence to the head face but the thickness of the gasket does alter the compression ratio, the thicker gasket will create a larger squish area lowering the compression while the thinner gasket will reduce the squish area and increase the compression ratio. It wont make a huge difference but it does...FACT!
Thats why you can buy various thickness` of gaskets which makes up the "extra material" from having your head skimmed.
Thats why you can buy various thickness` of gaskets which makes up the "extra material" from having your head skimmed.
Back to the point: The whole engine should be specced as a whole, including the gasket thickness. Extra care should be taken when mixing pre/post -95 or euro/us zetec parts.
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If you are running low comp they should be well clear anyway, its high comp engines where you tend to get the most problems.
Place sum plasticine or mouldable wax on the highest part of the piston (if they arent flat), smear a small amount of oil on the head chamber, place the H/Gskt on, drop the head on, nip up the headbolts slightly, rotate the engine thru 2 revolutions, whip the head back off,slice through the squashed wax/plasticine in sections and mic up the thickness, try not to pull it off too hard (oo er!) as it will stretch and become thinner. (do this for all 4 to be on the safe side)
You are looking for around the 1mm mark, this allows for heat expansion and rod stretch at high rpm
Good Luck!
Oh...just to add, if you think the valves may come into contact, its the same principle but you will obviously need to put the cambelt on etc.... (solid followers would also be advisable to use as we all know the Hydraulic ones creep back in which will mean the valves wont be moving as much as if the engine were running!
Place sum plasticine or mouldable wax on the highest part of the piston (if they arent flat), smear a small amount of oil on the head chamber, place the H/Gskt on, drop the head on, nip up the headbolts slightly, rotate the engine thru 2 revolutions, whip the head back off,slice through the squashed wax/plasticine in sections and mic up the thickness, try not to pull it off too hard (oo er!) as it will stretch and become thinner. (do this for all 4 to be on the safe side)
You are looking for around the 1mm mark, this allows for heat expansion and rod stretch at high rpm
Good Luck!
Oh...just to add, if you think the valves may come into contact, its the same principle but you will obviously need to put the cambelt on etc.... (solid followers would also be advisable to use as we all know the Hydraulic ones creep back in which will mean the valves wont be moving as much as if the engine were running!
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If you are running low comp they should be well clear anyway, its high comp engines where you tend to get the most problems.
Place sum plasticine or mouldable wax on the highest part of the piston (if they arent flat), smear a small amount of oil on the head chamber, place the H/Gskt on, drop the head on, nip up the headbolts slightly, rotate the engine thru 2 revolutions, whip the head back off,slice through the squashed wax/plasticine in sections and mic up the thickness, try not to pull it off too hard (oo er!) as it will stretch and become thinner. (do this for all 4 to be on the safe side)
You are looking for around the 1mm mark, this allows for heat expansion and rod stretch at high rpm
Good Luck!
Oh...just to add, if you think the valves may come into contact, its the same principle but you will obviously need to put the cambelt on etc.... (solid followers would also be advisable to use as we all know the Hydraulic ones creep back in which will mean the valves wont be moving as much as if the engine were running!
Place sum plasticine or mouldable wax on the highest part of the piston (if they arent flat), smear a small amount of oil on the head chamber, place the H/Gskt on, drop the head on, nip up the headbolts slightly, rotate the engine thru 2 revolutions, whip the head back off,slice through the squashed wax/plasticine in sections and mic up the thickness, try not to pull it off too hard (oo er!) as it will stretch and become thinner. (do this for all 4 to be on the safe side)
You are looking for around the 1mm mark, this allows for heat expansion and rod stretch at high rpm
Good Luck!
Oh...just to add, if you think the valves may come into contact, its the same principle but you will obviously need to put the cambelt on etc.... (solid followers would also be advisable to use as we all know the Hydraulic ones creep back in which will mean the valves wont be moving as much as if the engine were running!
CR wil be about 8.5:1
#32
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Well, went to the ford today,
They said the st170 was the same as the other 2 liter engines and only the RS was different.
Ordered the RS one and we'll see how it goes
Thanks for all the replies.
They said the st170 was the same as the other 2 liter engines and only the RS was different.
Ordered the RS one and we'll see how it goes
Thanks for all the replies.
#33
Colossal Pervert
As I said in my reply to your PM, the RS is 3 layer (as is the normal 2L) and the ST170 is 4 layer..
Part Numbers
2L/RS = 1105772
ST170 = 1071744
I think your parts dept. needs a kick up the arse!
Part Numbers
2L/RS = 1105772
ST170 = 1071744
I think your parts dept. needs a kick up the arse!
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#36
Me and a mate are currently building a zetec turbo, he has had it bored out to 86mm and has vauxhall c20let pistons fitted, the head has had one skim, he would like a cometic headgasket, there are currently four different thicknesses to choose from, does any one know which thickness is correct?
#40
What sort of compression ratio would be good to aim for?
Edit:
Ive just found this information over on fiestaturbo.com
With forged pistons there are a number of options for the Zetec. The cheapest is to use those originally designated for another type of turbocharged car. In this case the most common source for 2.0 pistons is the Vauxhall C20LET from the Cavalier and Calibra Turbo. Fitted to a Zetec these will give a CR of 7.4:1
The C20LET bore is 86mm, compared to the 2.0 Zetec’s 84.8mm, so a slight overbore of the block is required. This presents no problem as the block is likely to have some wear on it and there is enough material to maintain the wall thickness. This will take the original 1998cc to 2045cc. Also required is modification to the rods to accept the 21mm wrist pin.
The metal Series 3 (Focus) Zetec head gasket is fine for turbocharged use and has been used without problems a up to 2 bar boost. As far as I have been able to determine. The turbocharged Focus RS uses the same gasket as the NA engines.
Edit:
Ive just found this information over on fiestaturbo.com
With forged pistons there are a number of options for the Zetec. The cheapest is to use those originally designated for another type of turbocharged car. In this case the most common source for 2.0 pistons is the Vauxhall C20LET from the Cavalier and Calibra Turbo. Fitted to a Zetec these will give a CR of 7.4:1
The C20LET bore is 86mm, compared to the 2.0 Zetec’s 84.8mm, so a slight overbore of the block is required. This presents no problem as the block is likely to have some wear on it and there is enough material to maintain the wall thickness. This will take the original 1998cc to 2045cc. Also required is modification to the rods to accept the 21mm wrist pin.
The metal Series 3 (Focus) Zetec head gasket is fine for turbocharged use and has been used without problems a up to 2 bar boost. As far as I have been able to determine. The turbocharged Focus RS uses the same gasket as the NA engines.
Last edited by Cameron; 02-10-2014 at 09:11 PM.