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*BREAKING* James Judd's Forged 1.9 Mk3 Ibiza HTA GT2868R Build *BREAKING*
- Thread starter James.Judd.1
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Nah its Pete's, its alot easier than dropping it onto a tyre like I did last time lol
(Cheers Pete)
Right a little update.
Lightly deglazed the bores ready for the new rings.
I then got to work checking if the bores were egged or tapered and then finally checked the piston to bore clearance.
Using this..
A bore gauge, which is pretty much the only accurate way to measure internal diameters.
It works by zeroing it at a known value (in my case 83mm) and the you subtract whatever is displayed on the dial.
E.g. the dial reads 0.49mm
83 - 0.49 = 82.51mm diameter.
Columns 1, 2 & 3 are three different axis through the bore :
Rows A, B & C are three different depths down the bore (top, middle and bottom)
Here are my results:
I am quite happy with that as there is only a maximum of 0.02mm difference in each bore and a max difference of 0.03mm across all 4 cylinders.
I then measured the pistons diameters and they were all 82.4mm on the dot.
This gives me a minimum piston to cylinder wall clearance of 0.1mm and a max of 0.13mm which again I am happy with.
Lightly deglazed the bores ready for the new rings.
I then got to work checking if the bores were egged or tapered and then finally checked the piston to bore clearance.
Using this..
A bore gauge, which is pretty much the only accurate way to measure internal diameters.
It works by zeroing it at a known value (in my case 83mm) and the you subtract whatever is displayed on the dial.
E.g. the dial reads 0.49mm
83 - 0.49 = 82.51mm diameter.
Columns 1, 2 & 3 are three different axis through the bore :
Rows A, B & C are three different depths down the bore (top, middle and bottom)
Here are my results:
Code:
CYLINDER 1 CYLINDER 2 CYLINDER 3 CYLINDER 4
1 2 3 1 2 3 1 2 3 1 2 3
A 82.51 82.51 82.51 82.51 82.51 82.51 82.5 82.51 82.5 82.53 82.52 82.52
B 82.51 82.51 82.51 82.51 82.51 82.51 82.5 82.51 82.5 82.52 82.51 82.52
C 82.51 82.51 82.52 82.52 82.52 82.52 82.52 82.52 82.52 82.53 82.52 82.53I am quite happy with that as there is only a maximum of 0.02mm difference in each bore and a max difference of 0.03mm across all 4 cylinders.
I then measured the pistons diameters and they were all 82.4mm on the dot.
This gives me a minimum piston to cylinder wall clearance of 0.1mm and a max of 0.13mm which again I am happy with.
Last edited:
Cheers mate, I like to know things are done right. Im going to take my time with it as there is no point in rushing to get it done for winter! Besides I still havent got a turbo!
I am going to try and document my whole build mate.
Haha have so many bits of wood lieing about the garage its just the easy option!
You measured this @ the dome or @ the skirt James?
replied to your email as well.
Yeh the dome is normally slightly smaller mate , normally half way up the skirt at 90 degrees to the gudgeon / wrist pin.
edit - just seen your picture - exactly like you did it !!!!!!
edit - just seen your picture - exactly like you did it !!!!!!
Something is wrong then.
find out if they are a faulty batch from the piston manufacturer.
If they are listed as 82.5mm then they should be 82.5mm not 82.4mm
I know the machine shop will only bore to the specified piston but just make sure.
Maybe the size isn't correct but that doesn't matter as long as all the pistons are the same size and the bores are bored / honed to the correct clearance.
In my case with the JE pistons that was 4 thou or 0.1mm in new money. Thats about what you have so
maybe search online for clearance specs for those specific pistons.Also dont forget, forged pistons expand / contract quite a bit with temperature change - normally the manufactures of the piston specify measure them at say 20 degrees C and also the block, measuring them in a freezing garage won't help.... Get them on the mantle piece
One thing are all the piston 82.4 dead or like 82.41 or 82.43 etc ???
That was my thoughts grahams81.. it doesn't matter as long as they are correct to the bores.
I took the 0.1mm piston/wall clearance from JE as I couldn't find much on Wossner.
The 20 deg thing is a good call, I was un aware of this... I am building the engine in the conservatory and it was a comfortable temp in there I cant imagine it being far off 20deg..
82.405 was the biggest variation I got.. I think I will warm them up and tripple check my measurements though!
Cheers guys
I took the 0.1mm piston/wall clearance from JE as I couldn't find much on Wossner.
The 20 deg thing is a good call, I was un aware of this... I am building the engine in the conservatory and it was a comfortable temp in there I cant imagine it being far off 20deg..
82.405 was the biggest variation I got.. I think I will warm them up and tripple check my measurements though!
Cheers guys
Love your attention to detail on all this work, nice one mate.
Just been catching up on this thread and read all your bad luck over the past few weeks - good to see it hasn't stopped you though. Onwards and upwards
These things never go as smoothly as you want but it's all part of the experience and at least now you know exactly what you're dealing with.
Interested to see how you find those cams too as I was always curious to try these. Keep it up
Just been catching up on this thread and read all your bad luck over the past few weeks - good to see it hasn't stopped you though. Onwards and upwards
These things never go as smoothly as you want but it's all part of the experience and at least now you know exactly what you're dealing with.
Interested to see how you find those cams too as I was always curious to try these. Keep it up
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