does a std abf piston protrude the bore?????

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Darrien
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does a std abf piston protrude the bore?????

Post by Darrien »

looking to find out if a std abf piston protrudes the bore? and if so by how much? reason being is i want to tighten the squish clearance without touching the bottom end,so i want to make a custom headgasket to do this,thanks in advance.
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Re: does a std abf piston protrude the bore?????

Post by PapaJo »

Darrien wrote:looking to find out if a std abf piston protrudes the bore? and if so by how much? reason being is i want to tighten the squish clearance without touching the bottom end,so i want to make a custom headgasket to do this,thanks in advance.
Afaik yes. Don't do it. Custom headgasket will bring you headaches. Bent valves and repairs on a 16v is expensive. Valves, guides, gasket set and replacing pistons, rings and bearings.

Best bet is to strip your head off and measure if you want to get the correct neasurement. We can give you values, but we don't know if your motor was opened up before and if head was skimmed or block decked. Might still be unopened though.
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Darrien
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Re: does a std abf piston protrude the bore?????

Post by Darrien »

motor is unopened as far as i know,well im under that assumption as well because the intake gaskets and tappet cover gaskets were still original when i opened it up to sort a leak
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Re: does a std abf piston protrude the bore?????

Post by Darrien »

thats just an assumption though,assuming all is std,just wanna get the squish down to 0.8,ive done it on the 8v plenty of times with larger cams than i plan to use on the 16v (268intake-272exhaust) and never had a issue,papajo -thanks for your responsse
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Re: does a std abf piston protrude the bore?????

Post by PapaJo »

0,35mm would be the amount of protrusion above deck on a std ABF motor. 0.8 on a 16V is not advisable as you risk hitting intake valves unless your valve timing is spot on. Stretched cam chain and floating valves and kaboom!! I would not go less than 1,6mm valve to piston clearance.

Thinner headgasket does up the compression ratio by a small margin, but ask yourself if it is worth the risk. The thinnest headgasket available is 1,6 mm or 1,65 mm when torqued down. Victor Reinz head gasket. Guys are yousing the 2e steel headgasket too, but I don't have specs on the 2e headgasket.
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Re: does a std abf piston protrude the bore?????

Post by Torker »

I'll just leave this here:

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Re: does a std abf piston protrude the bore?????

Post by Darrien »

i meant 0.8 clearance on the squish,not piston to valve clearance
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Re: does a std abf piston protrude the bore?????

Post by Darrien »

if you say that the piston protrudes 0.35 above bore and with a 1.6mm head gasket,its safe to say my quench/squish clerance is now 1.25mm,lowering that even by the slightest bit will help the motor perform more efficiently,and the only ways of lowering it is either deckind the block and using std pistons,getting aftermarket high comp pistons or fabricating a thinner gasket

-so the gasket is the only way i see without touching the bottom unless you can advise me otherwise
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Re: does a std abf piston protrude the bore?????

Post by -=sT3V3=- »

You really cant risk advice from other members, the best builders wont even risk giving advice.

clay your motor first and make your own measurements, thats the only safe way to do it.
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Re: does a std abf piston protrude the bore?????

Post by chucker02 »

Darrien wrote:if you say that the piston protrudes 0.35 above bore and with a 1.6mm head gasket,its safe to say my quench/squish clerance is now 1.25mm,lowering that even by the slightest bit will help the motor perform more efficiently,and the only ways of lowering it is either deckind the block and using std pistons,getting aftermarket high comp pistons or fabricating a thinner gasket

-so the gasket is the only way i see without touching the bottom unless you can advise me otherwise
How much do you expect the cr to increase by? You wont notice the difference anyway
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Re: does a std abf piston protrude the bore?????

Post by PapaJo »

Darrien wrote:i meant 0.8 clearance on the squish,not piston to valve clearance
Smalker clearance on squish result in smaller piston to valve clearance too. Thinner head gasket bring the valves closer to piston.
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Re: does a std abf piston protrude the bore?????

Post by PapaJo »

-=sT3V3=- wrote:You really cant risk advice from other members, the best builders wont even risk giving advice.

clay your motor first and make your own measurements, thats the only safe way to do it.
:iagree:
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Re: does a std abf piston protrude the bore?????

Post by Darrien »

thanks for all the replies
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Re: does a std abf piston protrude the bore?????

Post by citi87 »

Torker wrote: Wed Jul 27, 2016 12:11 pm I'll just leave this here:

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What sort of compression ratio are you getting with this set up?
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Re: does a std abf piston protrude the bore?????

Post by Trishen94 »

I hope im not been rude but I'd really like to know is the reward greater than the risk ? Does this setup really make such a big difference ? There are so many other mods that can give u much more power with much less risk ...
Current :2008 S3 8P (panic mechanic +thanas) 227kw /309hp 473nm
viewtopic.php?f=11&t=217296

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Previous :too many to list
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Re: does a std abf piston protrude the bore?????

Post by ICE King »

Trishen94 wrote: Fri Nov 09, 2018 4:32 am I hope im not been rude but I'd really like to know is the reward greater than the risk ? Does this setup really make such a big difference ? There are so many other mods that can give u much more power with much less risk ...
Check out Torker rides threads, he built motors to extract every single kw out of it.Was/Is a fully built Ethanol motor eventually he craved more power and ended up going turbo
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Re: does a std abf piston protrude the bore?????

Post by ICE King »

citi87 wrote: Mon Nov 05, 2018 12:21 am
Torker wrote: Wed Jul 27, 2016 12:11 pm I'll just leave this here:

Image
What sort of compression ratio are you getting with this set up?
The sort that needed ethanol.

Here's a link to one of his ride thread https://vwclub.co.za/forum/viewtopic.ph ... &start=925
1992 Mazda 323 B3 - Masala Mods
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