Piston And Liners For 1.9 8V Engine Rebuild

[hoodygoodwood 70 3 Cars]

I have searched the forum for ages and not got the info I am after so can anyone help.

I will be rebuilding the std engine - D6B - in my Miami blue 309 GTI .I will be keeping the standard Bosch management so the only mods will be a Magnex manifold and system and a 57i kit plus an H + H rebuilt dizzy .

As part of the build I was going to replace the liners with new items as well as the usual rings, shells gasket set etc .I have seen a few sets of liners , pistons and rings on E-bay and elsewhere and want to make sure I bid on the right ones .I know the liners are the same apart from the ribbed Mi ones .

My D6B engine has the usual piston with the offset 'bathtub' pocket - I do not want to end up with low comp items - do they look different - flat top ? If I see a piston that looks the same will it be ok - no subtle differences .

Would 1.6 pistons give too high a compression for the standard management ?

I know the 16v engines have valve cutouts in the crown .

[welshpug 1,622]

1.6 pistons will work fine, though you may need to use a thicker gasket, especially if the head has been skimmed, pop a mild cam in there with a dizzy rebuilt with an advance curve to suit and you'll have a cheap "fast road" engine.

[hoodygoodwood 70 3 Cars]

What sort of compression ratio will this give me . The 1.6 pistons have a shallow flat depression in the middle ? - not like the offset deep pocket in the 1.9 piston .

I will be sending off a dizzy to H + H soon , I had better wait until I finalise the engine spec .They are quite good value at £115 for rebuilt dizzy , new vacuum advance , new rotor arm and cap including VAT and delivery .

[DamirGTI 323]

Around 11.1 static CR with 1.6 pistons ... they have 9cc volume dish (1.9 D6B pistons have 15cc dish) and different compression height (higher) , so on TDC they climb almost flush with the liner deck surface which improves squish effect massively along with boosted compression ratio ..

 

But , you need to use 1.9 conrods on 1.6 pistons .. so will need some pressing job which is a bit tricky and i wouldn't recommend doing that on a DIY basis without the aid of special tools for the job ..

 

The easiest plug an play option is using 1.9 DFZ pistons - they're identical 1.6 pistons combine with 1.9 conrods made from factory , and thus they're straight fit so no pressing job needed with these .. if you can find a set of these ones that would be the best/easiest option .

 

D

Edited March 16, 2014 by DamirGTI