Piston to Bore Clearance using OEM Mazda 83.5mmPistons - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 12-08-2014, 05:47 PM   #1
Junior Member
Thread Starter
 
Join Date: Dec 2014
Posts: 89
Total Cats: 1
Default Piston to Bore Clearance using OEM Mazda 83.5mmPistons

Hi,

Any suggestions on piston to bore clearance when using OEM Mazda 83.5mm pistons? NA application.

Factory manual I have states standard clearance as 0.0010" to 0.0025", and max as 0.006". Some discussion here Piston to Wall Clearance which seems to conclude between 0.002" and 0.003". I will be using the OEM Mazda .5mm rings, which I have not seen yet, but assume are pre-gapped (i.e. not file back), so the more I open the bore up, the more I will open the ring gap up.

Mostly track usage, and more concerned with max performance than anything else.

Currently I'm thinking of aiming for around 0.002 to 0.0025" which is the towards the upper end of the OEM "standard clearance".

Any input appreciated.

Cheers.
Neddy is offline   Reply With Quote
Old 12-09-2014, 08:10 AM   #2
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,660
Total Cats: 1,559
Default

Naturally aspirated with stock pistons? Use stock clearance values. If what you have been reading online is about forged pistons then it is useless if you are using stock cast pistons because the expansion values are different. And if it is for a turbo application then the temperature range will differ as well.
sixshooter is offline   Reply With Quote
Old 12-09-2014, 09:30 PM   #3
Junior Member
Thread Starter
 
Join Date: Dec 2014
Posts: 89
Total Cats: 1
Default

Quote:
Originally Posted by sixshooter View Post
Naturally aspirated with stock pistons? Use stock clearance values. If what you have been reading online is about forged pistons then it is useless if you are using stock cast pistons because the expansion values are different. And if it is for a turbo application then the temperature range will differ as well.
Hi,

Thanks for the reply. I do understand the differences between the requirements of different pistons, and NA vs Turbo.

Mazda set OE clearance values with many factors in mind, many of which I am not concerned about. I am specifically seeking advice regarding optimum bore clearance for NA track car performance using OEM pistons / rings.

Cheers.

Last edited by Neddy; 12-10-2014 at 01:02 AM. Reason: Fix typo
Neddy is offline   Reply With Quote
Old 12-09-2014, 09:59 PM   #4
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,660
Total Cats: 1,559
Default

Talk to Emilio at 949 Racing if you want some really technical advice for a race engine. There is a big difference between a 10 hour race engine, a 100 hour race engine, and a 2000 hour dual duty track/street engine. Bore clearance, ring tension, and a whole lot more play into it.
sixshooter is offline   Reply With Quote
Old 12-10-2014, 01:18 AM   #5
Junior Member
Thread Starter
 
Join Date: Dec 2014
Posts: 89
Total Cats: 1
Default

Quote:
Originally Posted by sixshooter View Post
Talk to Emilio at 949 Racing if you want some really technical advice for a race engine. There is a big difference between a 10 hour race engine, a 100 hour race engine, and a 2000 hour dual duty track/street engine. Bore clearance, ring tension, and a whole lot more play into it.
Cheers sixshooter, I will try to follow up with Emilio at 949 Racing then.

You are of course correct that there can be a dramatic difference in engine running time between refreshes, depending on a huge number of factors. I would not be overly concerned by a relatively short time between rebuilds if it means reasonable hp extra. However at the expected power density, using OEM Mazda pistons and rings, I think there will be quite a while between rebuilds.
Neddy is offline   Reply With Quote
Old 12-10-2014, 06:23 PM   #6
Junior Member
Thread Starter
 
Join Date: Dec 2014
Posts: 89
Total Cats: 1
Default

Tried to PM Emilio through the forum but it appears that I can't.

Anyone?
Neddy is offline   Reply With Quote
Old 12-11-2014, 09:28 AM   #7
Elite Member
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 2,399
Total Cats: 200
Default

His website?
ryansmoneypit is offline   Reply With Quote
Old 12-11-2014, 09:38 AM   #8
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,660
Total Cats: 1,559
Default

You could make a telephone call during west coast business hours, maybe?

He'll sell you some better power than stock rings for your application if you let him. And I'm sure he can offer some other suggestions while you have it apart.
sixshooter is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Garrett Turbo, 1.8 Oil Pan, & Misc. Stuff nbdooey Miata parts for sale/trade 9 08-30-2017 10:50 PM
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 57 07-19-2017 05:11 PM
1994 Spec Miata Race Car SM/SM2/SSM For Sale Quinn Cars for sale/trade 6 10-23-2016 08:58 AM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 04:02 PM.