Main bearing orientation - Check

[Tom Fenton 1,542]

Personally I’d re use your original pistons. Yes it’s at tolerance, but not above it.

[Andy 105 1 Cars]

2 hours ago, Philpooma said:

Hi Andy, sorry I may not have detailed the situation properly.

The pistons that don't fit are a secondhand set that I bought, not realising that I needed to check 1.9 or 1.6.

 

The measurements detailed are from the original Pistons and are fine apart from No.2 having a slightly larger top ring gap.

 

So right now, my rebuild has stopped. 

Ah.Now I see. The rods are a press fit onto the pistons, which is a bit of a nuisance as it is a machine shop job to press the pins out and refit. As you must have your 1.9rods attached to your 1.9 pistons , if you are really worried about the ring to groove clearance , you could get a machine shop to press out the 1.6rods from the pistons you have installed into,your liners and press in your 1.9 rods. Option 2 is to follow the advice given by Tom. My vote goes for option 2 . Oh, I am assuming that you have fitted new rings and gapped them .Did I also mention that if I were you I would take Tom’s advice ?Silly me,must have forgotten that I had already suggested that you take Tom’s advice . Must be my age . 
Regards,

 Andy

[Philpooma 30]

2 hours ago, Tom Fenton said:

Personally I’d re use your original pistons. Yes it’s at tolerance, but not above it.

Its definitely an option Tom. If swapping the 1.9 pistons over to the 1.6 rods is going to be too much hassle then thats probably what I’ll do.

Its just that I’m trying to build a really nice engine, that will give good reliable power and I just hate cutting corners or making do. However as you suggest, it is in tolerance and I’m sure that the effect on the engine will be very small if at all. 

[Philpooma 30]

14 minutes ago, Andy said:

Ah.Now I see. The rods are a press fit onto the pistons, which is a bit of a nuisance as it is a machine shop job to press the pins out and refit. As you must have your 1.9rods attached to your 1.9 pistons , if you are really worried about the ring to groove clearance , you could get a machine shop to press out the 1.6rods from the pistons you have installed into,your liners and press in your 1.9 rods. Option 2 is to follow the advice given by Tom. My vote goes for option 2 . Oh, I am assuming that you have fitted new rings and gapped them .Did I also mention that if I were you I would take Tom’s advice ?Silly me,must have forgotten that I had already suggested that you take Tom’s advice . Must be my age . 
Regards,

 Andy

Hi Andy, yes, You are right, these are the two options that I’ll consider.

If swapping pistons and rods over is too much hassle, then I’ll have to swap the rings over to the old pistons.

If this is the route that I take, I’ll have to clean up the old pistons as they didn't go in the parts washer due to the fact that they were not going to be re used.

Currently this engine rebuild seems to be a lot more faffing around than actually building.

I should have had the engine and gearbox completed by now as the car is due back from the paint shop soon.

 

[Leslie green 111]

I seriously doubt most people measure that gap as nearly everyone seems to reuse pistons in 205 gti's on resto threads on here  so put a NEW  ring in your old piston no 2 and see whats what , measure them all first as they won't all be exactly the same size and use the thickest , job done . a 1.9 crank would see you with a bigger engine but its not quite that simple and other bits would be needed. 

Edited January 3, 2020 by Leslie green

[welshpug 1,661]

you wouldn't want 1.9 pistons in a 1.6 engine unless you add a turbo, the dish is larger in the 1.9 piston which would result in a drop in compression.

[Andy 105 1 Cars]

Hi Phil,

 from my perspective, the penny has finally dropped. Your engine is a 1.6 and you have accidentally got some replacement pistons with rods that are from a 1.9. . I had not realised that and should have done from the photo of your installed piston/ rod combination. As Mei says, you must use your 1.6 pistons and rods with new rings , so I am afraid you need to pull out your newly installed pistons from their liners, retrieve the rings ,  clean up your 1.6 pistons and rods, install the rings and replace in the liners. You knew all this already I am sure. Option 3 is to buy a new set of pistons , in which  case you would also get new liners as they are relatively inexpensive . Together, that  becomes  an expensive option . Sleeves rolled up time and crack on with option 2 

[Philpooma 30]

2 hours ago, Leslie green said:

I seriously doubt most people measure that gap as nearly everyone seems to reuse pistons in 205 gti's on resto threads on here  so put a NEW  ring in your old piston no 2 and see whats what , measure them all first as they won't all be exactly the same size and use the thickest , job done . a 1.9 crank would see you with a bigger engine but its not quite that simple and other bits would be needed. 

I think that you are probably right Leslie. I’ll strip the old pistons, clean them up and try the new rings and see what happens. I have to admit, I hadn't seen anyone measuring the ring grooves on any of the resto threads that I had seen on the site.

thanks for your comments 

 

 

[Philpooma 30]

1 hour ago, Andy said:

Hi Phil,

 from my perspective, the penny has finally dropped. Your engine is a 1.6 and you have accidentally got some replacement pistons with rods that are from a 1.9. . I had not realised that and should have done from the photo of your installed piston/ rod combination. As Mei says, you must use your 1.6 pistons and rods with new rings , so I am afraid you need to pull out your newly installed pistons from their liners, retrieve the rings ,  clean up your 1.6 pistons and rods, install the rings and replace in the liners. You knew all this already I am sure. Option 3 is to buy a new set of pistons , in which  case you would also get new liners as they are relatively inexpensive . Together, that  becomes  an expensive option . Sleeves rolled up time and crack on with option 2 

LOL, yea I’m with you there Andy.

Looks like its option 2 then.

I do have new liners and did try to find a new std piston and liner set but couldn't find what I needed.

As you say, sleeves rolled up and crack on  

[Philpooma 30]

2 hours ago, welshpug said:

you wouldn't want 1.9 pistons in a 1.6 engine unless you add a turbo, the dish is larger in the 1.9 piston which would result in a drop in compression.

Brilliant Mei, I didnt know that, thanks.

Thats whats so great about this forum ,there is so much knowledge about the 205 here