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Old 01-26-2013, 01:04 AM   #1
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Is it possible ? Bad compression on SVT

Soooo, I had a compression test on my svt and found that my #3 cylinder isnt building pressure (100-125-85-125 ), I 'll proceed to make a leak down test soon to confirm but I think that there is blow-by around the rings (I saw smoke coming out of the tailpipe when I reved and engine sips some oil ). Seems like a need a rebuild ( my engine as now 160 k miles )

Many reasons lead my to think about a solution that I had never heard of on this forum : Could I use a stock zetec bottom end to replace my svt ? I mean is it physically doable ? I know the crank and block are identical. But I was wondering if the pistons would have enough valve clearance for when the vct would ret/adv the camshaft ? I've seen that the zetec pistons have deeper dishes so, given most of the CR raise is provided by the svt head, they should clear the high lifting valves of the svt head since the svt pistons are basically flat top pistons... Another way to look at this is : as anyone ever used high compression zetec pistons in a build svt motor and still use the vct ? I know I would lose the safety of the forged rods doing this but normal zetec rods have been proven for over 200 hp and I do not plan to boost/race/over-rev this car so I'm not worried about this weakness ( I'd still use arp conrod bolt just for the peace of mind )

Also, is there any gain/loss in the combustion efficiency because of going from a flat top piston to a dome/dishes piston ? Like flame traveling speed or whatever ...

I know i've asked a lot of questions... I've searched for these informations all over the forum but couldnt find it.

Thanks for the replies

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