Would This Work?

[david932 0]

ok i need to get this confirmed before i try it and potentially ruin my engine.

 

asumming the big ends in my gti6 are ok:

 

s16 rods and pistons removed straight from the s16 engine rings included mated to an 88mm mi crank,

 

then straight into the gti6 block(no honing) with arp bolts. will this be ok? am i likely to raise the compression to high or wreck the valves?

 

my other question is about an 8v crank. i've read that this is 88mm but not fully counter balanced. is this the 1.6 or 1.9? and if i was to get this balenced could i use this instead of an mi 88mm crank?

 

thanks

[Richie-Van-GTi 70 2 Cars]

Im not too sure but I think you will be alright on piston clearence as far as I know they are the same as gti6, you will need to swap the rings over from the old pistons if your not planning on having the bores honed to the new rings.

 

the 1.9 crank is the one your thiunking of, 1.6 is a shorter stroke crank IIRC. It is balanced, justy not counter balanced. Not something which can be added in a cost effective way. Better to use the MI crank.

[Bono 0]

This is a similar setup to my planned engine.

Couple of points:

1. I would use new rings regardless of whether its honed or not. However if the blocks worn there could be a lip at the top of the bore. This would be fine for 86mm crank but the extra 1mm upwards travel on an 88mm crank is likely to wreck the rings as it will constantly be pushed over this lip

 

2. I think the GTi6 head has a smaller squish area than the S16 head so the compression may be too high?

 

As said the 8v cranks are balanced but not counter-balanced, so basically at high rpm they would whip.

[petert 554]

It will be ok provided the bore lip is ok as pointed out. CR will be 11:1, perfect. Valve to piston clearance will be ok for a std to small cam, but you'll need to verify it for anything else.

[david932 0]

ecellent

 

what do you mean by verify it?

 

to what sort of tolerance should i allow for a lip?

 

could you recommend some cams which wont have too much lift but are uprated from standard?

 

bono, the desiel cam your thinking of is that a 306? and is it counter-balanced?

 

sorry for all the questions

[Bono 0]

the crank i have is apparently from a diesel, its fully counterbalanced. not sure exactly what engine it came from.

[petert 554]

what do you mean by verify it?

 

to what sort of tolerance should i allow for a lip?

 

could you recommend some cams which wont have too much lift but are uprated from standard?

 

Verify - You need to measure the valve to piston clearance at TDC. There needs to be a minimum of 0.080" on the inlet. The exhaust will be fine as you'd use the standard cam.

 

If you can feel a lip with your finger nail there's too much.

 

My Stage I inlet cam will work without modifying the pistons.

[david932 0]

whats the duration of your stage 1 inlet cam? where abouts in the rev band is the power? and whats the cost?

 

i spoke to 205spares today in hunt for a mi 88mm crank. the chap explained good ones are like rocking horse poo. i mentioned the spec i was weighing up and he suggested running a 1.9 88mm crank would be fine as long as the car isn't reving over 8k. he explained the differences are very minor. would any of you engine building guru's agree with this?

 

also is there a link or post or any books i can get to give me the tightening torques of the gti6 engine and s16 engine?

Edited March 15, 2007 by david932

[DrSarty 90 1 Cars]

I'm biased but go for Pete's cam! I know there are others (like the Catcam), but I have Pete's and can testify to its performance and value. SuperJosh, Kyepan and Maxi have launched in it too, so you could ask them.

 

Personal opinion, but one read of Pete's very informative web site should be enough to indicate he's one man worthy of investment and trust.

 

Rich

Edited March 15, 2007 by DrSarty

[brianthemagical 1]

1. I would use new rings regardless of whether its honed or not. However if the blocks worn there could be a lip at the top of the bore. This would be fine for 86mm crank but the extra 1mm upwards travel on an 88mm crank is likely to wreck the rings as it will constantly be pushed over this lip

 

if new rings were used in unhoned bores then the rings wouldn't wear in, leaving them not sealing efficiently. i think.

[petert 554]

whats the duration of your stage 1 inlet cam? where abouts in the rev band is the power? and whats the cost?

 

All the info is here - www.taylor-eng.com.

[david932 0]

does it need vernier timing?

[petert 554]

Not necessarily. I use offset keys with various combinations of pulleys to get the cam in the ideal position.

[david932 0]

what pulleys and keys would i require for this? do you provide them in the kit? is the kit made to run on a standard map or will i have to remap?

[petert 554]

Ideally the Stage I cam needs to be centred at 109 degrees. The std. S16 inlet cam is centred at 114 deg., so you have to advance the cam 5 degrees. This can be achieved with an offset key and the std. #2 pulley. I'll PM you with pricing details.

 

The Stage I cam runs perfectly on the standard mapping.

[david932 0]

It will be ok provided the bore lip is ok as pointed out. CR will be 11:1, perfect. Valve to piston clearance will be ok for a std to small cam, but you'll need to verify it for anything else.

 

i was just thinking the pisons on a gti6 are a flush deck so if i was to just change the crank for an 88mm and the rods for s16, keep the oringinal gti6 pistons would the extra mil of travel be an issue even if the block wasn't honed? a complete stab in the dark but the ring's on previous pistons i've seen havent sat within a mm of the piston to anyway

[petert 554]

i was just thinking the pisons on a gti6 are a flush deck so if i was to just change the crank for an 88mm and the rods for s16, keep the oringinal gti6 pistons would the extra mil of travel be an issue even if the block wasn't honed? a complete stab in the dark but the ring's on previous pistons i've seen havent sat within a mm of the piston to anyway

 

Without seeing all the bits it's too hard for me to comment on, but I think it's a problem mixing and matching as GTi6 pistons are pressed pin, not floating.