16v pistons (standard)

25th February 2011, 23:34

Right I'm a bit puzzled

Is there different 16v standard pistons?

Basically, I've got a spare block that I'm rebuilding, and the pistons have only got the large cut outs on one side of the piston (I think for inlet valves can't remember) and that's it none for the exhaust, now one of the pistons was damaged whilst being stored by the guy who owned the bottom end originally and stripped it.

Now I've just got another set of pistons from a mate from his spare 16v engine and they have got both sets of cut outs for the inlet valves and the exhaust valves.

And it has confused me a bit as I thought there was only one type of piston which is the one with cut outs for both the inlet and exhaust valves, but it for me a bit worried it's not a 16v block I bought. Or I also thought it could be a jp4 bottom end but I always thought the jp4 pistons were domed on the top like the s1 106 rallye which helps with the slightly higher compression on the jp4's iirc which is kind of what makes me think it's not a jp4 block but you never know.

Can some one help me out a bit here please

Chris

25th February 2011, 23:47

Standard Saxo vts pistons only have cut out on the inlet side.

25th February 2011, 23:55

Hmm, well the pistons with cut outs on both the inlet and exhaust came from alexB's old engine from his diablo red gti back in the day before it got stripped lol. But that was the original engine so That's what made me wonder are the ones with just inlet cut outs wrong

26th February 2011, 00:08

the 155k beast engine? original engine tbh probably from snapped belt poss in past before I had it but when I got it was totally bog standard wouldn't be surprised if it was something like that as the guy I got it off didn't seem to have a clue really

26th February 2011, 10:50

Yet that's the beast gav, tbh though I did think snapped belt, but all 4 pistons have perfect cut outs and no other marks, they are all identical.
So i wouldn't have thought a snapped belt and valve to piston contact would cause cut outs like that, if that's what your saying? It would make a right mess of the piston but the exhaust cut outs on these pistons are all the same size in the same place. Like they've been machined there.

I'll get some pics when I get home from work

26th February 2011, 11:13

Got any pictures of the pistons?

26th February 2011, 11:18

it can happen just depends on circumstances and verocity. I can cetegorically state that in the time I had it no work was done to it at all, plus when Alex had it he just did the usual breather mods before he changed it.

26th February 2011, 13:37

Here's some pics then....

These are from the gti bottom end from alex

And one from the engine I bought..

But on the ones from the bottom I got from alex, the cut outs are pretty much all identical from what I can see on a quick inspection. I mean some do look a little rough though tbh.

But thing is I've had that head cleaned and worked on by a company I trust, and who have done work for alex in the past aswell as lex on his 16v head when he decided to sell the 8v turbo kit on. And other people I know have been there, but he said the head was fine all spot on an valves were straight as they got them put checked them and cleaned them up etc, plus I did say to do what ever necessary whether it meant paying more or not lol so I'd had thought anyone else would have seen that as a money maker but he just said he did what was necessary and that's what he quoted me.

So I find it strange if it was piston-valve contact as surely it would have bent the valves?

26th February 2011, 13:51

Just done a search on rallye reg and came across this...

http://www.106rallyeforum.com/forum2...hlight=Pistons

Hes got the 4 cut outs on each piston too they look exactly like the ones i got too

26th February 2011, 13:55

chris if the belt snapped and it bent the valves it would of been done before and fixed before I got it god knows when it would of happened but the engine had done galatic miles

26th February 2011, 14:03

I'd say those exhaust cut outs are from a cambelt going in the past

26th February 2011, 14:08

Ahh ok then, hmm may not use these pistons then, the only reason I'm changing them is cause one of the pistons is damaged withthe ones I bought with the bottom end, but alex has his other block spare so may get that from him tbh since they're on good nick still, and just use the 3 good ones I got with one from alexs, cause I don't want to risk anything and run into probs at a later date if these cut outs have been cause by valve contact.

26th February 2011, 14:18

I'd definitely not use the rods if it can be helped.

Hard to say about pistons, but for the price of good condition standard pistons, I'd scrap the ones with cut outs on exhaust side

26th February 2011, 14:26

considering I got the car on 150k did about 5k hard then sold it to alex who did a few k more they've lasted well

27th February 2011, 00:15

from the pics its does like valve contact as said, from the pic of the two pots side by side it looks like one of those cylinders took the brunt of it as the marks on one of the pistons pistons arent as deep looking as the ones on the next,

ive got a few sets of decent j4 rods if your looking to replace for cheap, no pistons though...

27th February 2011, 10:29

Yer I've decided to scrap it now, just dumped it at the top of the drive last night for the pikeys to take lol.
When you look closely the cut outs for exhaust do look quite rough like they've not been machined

Ive already got rods blackie, tbf I've got pistons but one looks Like it's been dropped and it's got loads of marks on top, but 3 are absolutly mint so really I only need 1 piston which doesn't help

How ever I think I've got some sorted now, thanks for the offer though mate