pistons

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buckspet
Posts: 42
Joined: Thu Jul 16, 2015 12:24 pm
Your car is a: 1979 spider 2000 1980 spider 2000

pistons

Postby buckspet » Wed Oct 07, 2015 4:09 pm

The members have beaten me into submission, and I'm going to bite the bullet and do a high compression piston conversion. First..79 2L engine with 67k. No oil consumption, run smooth, no unusual noise. After I open it up,if things seem fine and no excessive cylinder wear, and main bearings look fine and are with in tolerances, can I reuse original items with just a light passing with a "dingle ball" to make for better sealing?or am I being foolish and to frugal? 2nd I have seen references relating to the 10.8. CR piston dome height causing some problems. Lastly I'm not planning racing just trying to find the seat of the pants feeling I got from my 73 years ago. After pistons single plane and 34ADF ,BETTER EXHAUST 2 1/4 THROUGH OUT, AND A REDUCED WEIGHT FLYWHEEL. Please advise on my concerns. I know you guys will be brutally straight forward. (AFTER MY CYLINDER HEAD EDUCATION) HAHA. as always your the best, thank you all for your time and patience

131
Posts: 672
Joined: Sun Nov 14, 2010 1:13 am
Your car is a: 1982 131 Superbrava warmed 2.0 litre.
Location: Tasmania, Australia

Re: pistons

Postby 131 » Wed Oct 07, 2015 5:47 pm

If it's only 67k, and the odo hasn't been around the clock, you should be able to get away with a hone and standard pistons, but don't buy pistons until you get the head off. Standard pistons come up occasionally on Ebay for reasonable prices, as there aren't many engines left that don't need reboring.
Mick.

'82 2litre 131, rally cams, IDFs & headers.

buckspet
Posts: 42
Joined: Thu Jul 16, 2015 12:24 pm
Your car is a: 1979 spider 2000 1980 spider 2000

Re: pistons

Postby buckspet » Wed Oct 07, 2015 7:50 pm

mick i'm interested in incresing the compression ratio. The 8mm dome slugs seem like a easy way to get substanial increase in power (along with other upgrades) My question in part was concerns about the 8mm dome units. Some have mentioned problems with these particular units. I'm hoping to hear from members who have either positive or negative issues with these pistons in the 2L motors

131
Posts: 672
Joined: Sun Nov 14, 2010 1:13 am
Your car is a: 1982 131 Superbrava warmed 2.0 litre.
Location: Tasmania, Australia

Re: pistons

Postby 131 » Wed Oct 07, 2015 10:20 pm

I have them in my motor, the previous owner said CR was about 10.5:1, don't know if he measured things to work it out, or if it's a guesstimate, with the head I now have on it, it's probably a bit higher. With IDFs, good headers and 290deg cams it runs well, but even with 98 octane fuel, if I load it up too much down low it will ping a bit, more noticeable in hot weather, so I have to drive accordingly.
Mick.

'82 2litre 131, rally cams, IDFs & headers.

fiatfactory
Posts: 506
Joined: Sun Jun 13, 2010 11:22 pm
Your car is a: 1970 128

Re: pistons

Postby fiatfactory » Thu Oct 08, 2015 8:16 am

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Last edited by fiatfactory on Tue Jul 02, 2019 1:00 am, edited 1 time in total.
nothing to see here... move along.

buckspet
Posts: 42
Joined: Thu Jul 16, 2015 12:24 pm
Your car is a: 1979 spider 2000 1980 spider 2000

Re: pistons

Postby buckspet » Thu Oct 08, 2015 2:17 pm

Thanks steve..good advice I'll go with the 4mm dome inits, which spec out around 9.6 I believe, but I'll do more research on <10:1 CR. anyone have good results with any brand or vendor for these inits. I have gotten excellent service from AR.

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focodave
Patron 2018
Patron 2018
Posts: 704
Joined: Sat Jun 30, 2012 10:35 am
Your car is a: 1980 Spider 2000 F.I.
Location: Fort Collins, CO

Re: pistons

Postby focodave » Thu Oct 08, 2015 3:10 pm

Buckspet,
Where are you located? What is the elevation with regard to sea level?
The reason I ask is that I am in Colorado at about 5000 feet elevation and higher.
I run a 2L, bored .030 over with 10.2-to-1 compression pistons.
I run about 12 degrees initial ignition advance, 91 octane fuel, stock cams, stock F.I. head.
I have absolutely no pinging, even when lugging up very steep elevation climbs through the mountains and canyons.
Why?
At elevation, 10.2-to-1 static compression really equates to about 9.1-to1.
My engine now has gobs of torque and just runs as sweet as can be.
Something to think about.........only if you are some distance above sea level.......
1980 Spider 2000 F.I. (my hobby)
1970 MGB GT (my other hobby)
2008 Ford Expedition (daily driver)
2019 Harley-Davidson Electra Glide Standard
2019 Harley-Davidson Iron 883 Sportster

fiatfactory
Posts: 506
Joined: Sun Jun 13, 2010 11:22 pm
Your car is a: 1970 128

Re: pistons

Postby fiatfactory » Fri Oct 09, 2015 8:43 am

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Last edited by fiatfactory on Tue Jul 02, 2019 12:58 am, edited 1 time in total.
nothing to see here... move along.

djape1977
Posts: 985
Joined: Sat Apr 21, 2012 6:08 pm
Your car is a: 1970 fiat 124bc
Location: Belgrade, Serbia, eastern Europe

Re: pistons

Postby djape1977 » Sat Oct 17, 2015 6:39 pm

where do we begin?

open the engine and see what you have...

then contact me on https://www.facebook.com/groups/fiat.an ... sic.parts/

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msjulian
Posts: 32
Joined: Thu Sep 03, 2009 1:19 pm
Your car is a: 1979 Spider 2000
Location: Newburgh, IN

Re: pistons

Postby msjulian » Fri Apr 08, 2016 1:21 pm

I have a '79 2L 124 with stock head and pistons and would like to go to something with a dome to get the compression up to something more respectable. I need something in the stock 84mm. Would have something that would work.


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