Larger pistons vs stock head gasket - 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 06-27-2016, 09:06 PM   #1
Junior Member
Thread Starter
 
Join Date: Jun 2016
Location: Wichita, Kansas
Posts: 93
Total Cats: 3
Default Larger pistons vs stock head gasket

Hey guys, I am starting my first build and have come across a question I can't find an exact answer to. I am going to run 83.5 mm supertech pistons and have had my cylinders bored out to match. Will a OEM head gasket cause any problems? My pistons shouldn't be over the deck as I haven't had material milled off. Additionally, I have read mixed information that you shouldn't have to worry about the head gasket unless your pistons are more than 1 mm over stock (mine are only half a mm.)
Jmanwork is offline   Reply With Quote
Old 06-27-2016, 09:13 PM   #2
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,175
Total Cats: 2,578
Default

you'll be fine
18psi is offline   Reply With Quote
Old 06-28-2016, 12:21 AM   #3
Senior Member
iTrader: (1)
 
Join Date: Sep 2008
Location: Tucson, Arizona
Posts: 889
Total Cats: 55
Default

I went up a couple sizes and used a regular gasket 18 is right.

Also food for thought. If you have an 01+ motor you should get a 94-00 head gasket and do a reroute. If you have no clue what I'm talking about happy reading.
krissetsfire is offline   Reply With Quote
Old 06-28-2016, 12:40 AM   #4
Junior Member
Thread Starter
 
Join Date: Jun 2016
Location: Wichita, Kansas
Posts: 93
Total Cats: 3
Default

I appreciate the feedback, it's been helpful. I'm running a 95 block and head. I still plan on doing a coolant reroute 100%, although I'm leaning more towards the diy option. I've seen the kits on 949 for example but they look way too expensive for what it is in my opinion. Not trying cut any corners though, any thoughts?
Jmanwork is offline   Reply With Quote
Old 06-28-2016, 02:07 AM   #5
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,796
Total Cats: 248
Default

OEM gasket should be fine, I'm running 84mm pistons on a stock gasket and all the boost with no problems. I have a DIY reroute, many do, and they work great when done right and are cheaper as you already know.
patsmx5 is offline   Reply With Quote
Old 06-28-2016, 12:48 PM   #6
Senior Member
iTrader: (1)
 
Join Date: Sep 2008
Location: Tucson, Arizona
Posts: 889
Total Cats: 55
Default

I also did DIY. I hope I don't have to change my thermostat for a while though lol... The kit makes serviceability better but that's it.
krissetsfire is offline   Reply With Quote
Old 06-28-2016, 09:15 PM   #7
Senior Member
iTrader: (1)
 
Join Date: Jan 2011
Location: Chattanooga, Tn
Posts: 1,038
Total Cats: 157
Default

I have an 84mm bore and have unshrouded the valves which are over sized. If I used a stock gasket there would have been just the slightest "ridge" in the areas where the valves were unshrouded.

The max limit of the unshrouding was determined by bolting the head to a block with no crank rods or pistons, turning the motor upside down and marking the edge of the bore with a scribe. The unshrouding work was then performed in a CNC mill.

The Cometic 84mm gasket fit perfectly.
TNTUBA is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Questions for Best Setup Megasquirt Install drizzay222 MEGAsquirt 0 04-26-2016 04:18 PM
Hey, NA8 here, long time reader/referrer to turbo kitty knowledge NickelNDiminIt Meet and Greet 0 04-20-2016 02:24 AM
Stock 96 new MSPNP2 install - lean stumble Chobo MSPNP 2 04-18-2016 10:12 AM
Hey guys! New to the page! Damon Sharp Meet and Greet 2 04-18-2016 04:44 AM
Half-Car suspension simulation Alumilo Suspension, Brakes, Drivetrain 0 04-10-2016 02:34 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 07:21 AM.