[1993JLX]

I have a G16a 16V block and a G16a 8V Head. Are they suitable to put together as is or will I need to change pistons to suit? Everything else seems to line up just unsure if they will go together without any damage being done. Cheers

[Jezzer]

I supplied a 8 valve bare block to someone rebuilding a 16 valve. Apart from a couple of casting differences on the out side it worked so I’m sure it will work the other way.

The tops of the pistons are different between 8 and 16 valve.


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[sideways]

You can put your 8V head on a 16v block but it will drop the compression to 8.42:1. G16a 8v is 8.9 and G16b is 9.5. I believe it also makes it an interference engine.

You could skim the head about 0.1mm to make up the difference in compression. You could also put in 8V pistons, they are around $160 a set last time I looked.

[1993JLX]

I do have the head in the machine shop at the moment for a recondition and new valves, will the compression ratio being that much lower cause many issues? Do you know if the valves will hit with the 16v pistons as the valve reliefs are differently located. What would be the best way to test this?

[sideways]

1993JLX wrote:

I do have the head in the machine shop at the moment for a recondition and new valves, will the compression ratio being that much lower cause many issues? Do you know if the valves will hit with the 16v pistons as the valve reliefs are differently located. What would be the best way to test this?

You will lose a very small amount of power/torque with the compression drop.

You wont have valve clearance problems with the engine running but if you lose the timing belt it wont be good. Personally I'd change the pistons for peace of mind.