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tips, technology, tools and techniques related to vehicle driveline components

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minorv8
Jukka Harkola

(161 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Piston ring land question
Posted by: minorv8
Date: April 16, 2019 06:44AM

I hit a slight problem when doing a dummy build of a stroker 4.6. The pistons protrude about 1/16" from the deck. That is basically an easy fix, put the pistons in a lathe and cut them. I do know that I have had the decks of the block machined in the past but donīt know if that was the first time or if it has been machined before.

But, these are forged stroker pistons with roughly a 1,2" compression height and ring land from crown to 1st ring is about 0,21". So not exactly excessive amount of material to machine.

What do you consider a safe ring land dimension given that it is a N/A engine ? Finding another 4.6 block is not the easiest solution.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Piston ring land question
Posted by: BlownMGB-V8
Date: April 16, 2019 11:17AM

The risk with any piston is too much heat on the top ring land, particularly adjacent to the exhaust valve. .210" isn't much but these are forged pistons right? So that is probably OK. Cutting it down to .150" probably isn't though, not if this engine is ever going to be run hard. Just my opinion, but if it fails, at best you'll have increased blowby and the consequences could be much worse.

Jim


MGBV8
Carl Floyd
Kingsport, TN
(3726 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Piston ring land question
Posted by: MGBV8
Date: April 16, 2019 04:18PM

That top ring will need a bigger end gap.


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