Hemi piston pop-up

nolongerracing · 11-01-2019, 03:42 PM

Ok, This is what he is asking.... Can I adjust the piston out of bore (above deck) to compensate for a thicker head gasket.
Yes you can.
Your running clearance as per NHRA is .518. That is .536 above block - .018 gasket. 518 is the number you must meet.
If you use a .027 gasket, your piston may be above deck by .545.

Piston CC's do need to be correct. There are some that are not and are still being used. Will they ever check? Most likely not!!!

HankN · 11-01-2019, 05:11 PM

Yes but this did cost me a block/pistons before.
As many years before I did use the Cometic's but one guy here in Sweden with connection to Gregg L said this was not Ok for a AB motor, so that did cost me a bunch ro fix it.
As I got, that was the rule before.
I know this is all Ok for wedge, but I wounder is this is still the case for a Hemi.
-If so, it's very odd.

What you are saying on the deck, piston/gasket's make all sense to me.
That's the question.

Race Clean · 11-01-2019, 05:37 PM

As I understand the rule as it once where "if it sticks out of the hole you can't compensate for the gasket" as you can if it's down in the hole.
I could be wrong, it may have changed, or they dont care.

HankN · 11-01-2019, 05:57 PM

Jepp, so who knows, do anyone cares ?
I like to read the book, if not why in ’stock’ eliminator class.
This is why I put helmet off, as I could not get the sence out if this and I been in it since mid 80’s.
Maybe one can do as the fat cam tunnels..

Tom Broome · 11-01-2019, 07:21 PM

Quote:

Originally Posted by Race Clean

As I understand the rule as it once where "if it sticks out of the hole you can't compensate for the gasket" as you can if it's down in the hole.
I could be wrong, it may have changed, or they dont care.

I agree on all points.

I haven't had to worry about dome height for quite a while. But as I recall it was "above deck"......nothing said about gaskets.
Apparently no one that currently races one of these combinations wants to give any "tips".

HankN · 11-01-2019, 08:32 PM

We has the rule book and Pat C don’t answer.
That’s why I ask here at CR.
My Swedish good ’byddy’ cost me allot before.
I asked Don Little over mail on aluminium heads but no reply back for 4 month.
Maybe he is more into super S theese days.

Rory McNeil · 11-02-2019, 02:47 AM

I can not offer any input to your Hemi engine question, but since you say this car was a 440-6 barrel car from Div. 6, do you have Wes Libbys old Dodge Challenger ? I have not seen Wes or the Challenger in at least 10 years, so the timeline fits.

HankN · 11-02-2019, 09:11 AM

Lets see if someone know who read this.
This is the car.
https://www.dragracing.eu/driver.asp?id=313

11-01-2019, 03:42 PM	#1
nolongerracing Member Join Date: Oct 2006 Posts: 173 Likes: 2 Liked 72 Times in 27 Posts	Re: Hemi piston pop-up Ok, This is what he is asking.... Can I adjust the piston out of bore (above deck) to compensate for a thicker head gasket. Yes you can. Your running clearance as per NHRA is .518. That is .536 above block - .018 gasket. 518 is the number you must meet. If you use a .027 gasket, your piston may be above deck by .545. Piston CC's do need to be correct. There are some that are not and are still being used. Will they ever check? Most likely not!!!

11-01-2019, 05:11 PM	#2
HankN Junior Member Join Date: Jul 2019 Posts: 18 Likes: 0 Liked 3 Times in 3 Posts	Re: Hemi piston pop-up Yes but this did cost me a block/pistons before. As many years before I did use the Cometic's but one guy here in Sweden with connection to Gregg L said this was not Ok for a AB motor, so that did cost me a bunch ro fix it. As I got, that was the rule before. I know this is all Ok for wedge, but I wounder is this is still the case for a Hemi. -If so, it's very odd. What you are saying on the deck, piston/gasket's make all sense to me. That's the question.

11-01-2019, 05:37 PM	#3
Race Clean Member Join Date: Aug 2017 Posts: 159 Likes: 18 Liked 129 Times in 53 Posts	Re: Hemi piston pop-up As I understand the rule as it once where "if it sticks out of the hole you can't compensate for the gasket" as you can if it's down in the hole. I could be wrong, it may have changed, or they dont care.

11-01-2019, 05:57 PM	#4
HankN Junior Member Join Date: Jul 2019 Posts: 18 Likes: 0 Liked 3 Times in 3 Posts	Re: Hemi piston pop-up Jepp, so who knows, do anyone cares ? I like to read the book, if not why in ’stock’ eliminator class. This is why I put helmet off, as I could not get the sence out if this and I been in it since mid 80’s. Maybe one can do as the fat cam tunnels.. Last edited by HankN; 11-01-2019 at 06:17 PM.

11-01-2019, 08:32 PM	#6
HankN Junior Member Join Date: Jul 2019 Posts: 18 Likes: 0 Liked 3 Times in 3 Posts	Re: Hemi piston pop-up We has the rule book and Pat C don’t answer. That’s why I ask here at CR. My Swedish good ’byddy’ cost me allot before. I asked Don Little over mail on aluminium heads but no reply back for 4 month. Maybe he is more into super S theese days.

11-02-2019, 02:47 AM	#7
Rory McNeil VIP Member Join Date: Jun 2007 Location: from Vancouver BC Canada, now in Nova Scotia Posts: 1,311 Likes: 317 Liked 1,103 Times in 301 Posts	Re: Hemi piston pop-up I can not offer any input to your Hemi engine question, but since you say this car was a 440-6 barrel car from Div. 6, do you have Wes Libbys old Dodge Challenger ? I have not seen Wes or the Challenger in at least 10 years, so the timeline fits. __________________ NHRA 6390 STK M/S 85 Mustang

11-02-2019, 09:11 AM	#8
HankN Junior Member Join Date: Jul 2019 Posts: 18 Likes: 0 Liked 3 Times in 3 Posts	Re: Hemi piston pop-up Lets see if someone know who read this. This is the car. https://www.dragracing.eu/driver.asp?id=313

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