pistons

[buckspet]

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]

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.

[buckspet]

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]

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.

[fiatfactory]

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[buckspet]

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.

[focodave]

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.......

[fiatfactory]

.

[djape1977]

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/

[msjulian]

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.