JE Pistons, 11.5 cr into a 3.2 flat 6?

[911hillclimber]

Peter is correct in what he says.
My plan for the valve to piston check is:

Dry install the piston/barrel/head/cam carrier with no barrel base copper gasket and torque down to spec
This brings the assembly to as close to the piston as possible.
The head (#1 and #4) will have the weak springs I have fitted, not the real springs. This makes the valve easily moved with 'feel'
Install the cam and rockers and set valve tappet to 4 thou as usual.

Fit the dti gauge to the carrier (as if you were timing the cam), and zero the dti off.
Bring the piston to TDC

Press the inlet valve down and read the travel off the dti gauge, needs to be about 80 thou on the inlet, 100 thou on the exhaust.

Repeat 3 times on head #1 and do the same on the opposite bank.

If all ok the addition of a fresh 0.25mm barrel seal shim adds a bit more 'confidence' to enough clearance.

I'm not expecting any issues, but the check has to be done at this stage.

The top of the engine can then be stripped and completed and the cams timed.

Trying to find out when the pistons will be here.

[gridgway]

Understood that process graham, but why bother with getting an 80 thou clearance and then add the gasket as insurance?

[Cortina]

Peter is correct in what he says.
My plan for the valve to piston check is:

Dry install the piston/barrel/head/cam carrier with no barrel base copper gasket and torque down to spec
This brings the assembly to as close to the piston as possible.
The head (#1 and #4) will have the weak springs I have fitted, not the real springs. This makes the valve easily moved with 'feel'
Install the cam and rockers and set valve tappet to 4 thou as usual.

Fit the dti gauge to the carrier (as if you were timing the cam), and zero the dti off.
Bring the piston to TDC

Press the inlet valve down and read the travel off the dti gauge, needs to be about 80 thou on the inlet, 100 thou on the exhaust.

Repeat 3 times on head #1 and do the same on the opposite bank.

If all ok the addition of a fresh 0.25mm barrel seal shim adds a bit more 'confidence' to enough clearance.

I'm not expecting any issues, but the check has to be done at this stage.

The top of the engine can then be stripped and completed and the cams timed.

Trying to find out when the pistons will be here.

Not sure what you are trying to do here !!
a) How far do you "press the valve down" ? Have re read your notes and am guessing that you use the cam to open the valve fully , then press down to see what clearance you now have ? ... fine ... but see b) below
b) Minimum valve to piston clearance with engine running does NOT happen at TDC , so it appears this "exercise " is almost worthless to me
c) I have not seen "talk" of actually measuring your compression ratio - as in doing it yourself. That is the first important step.

[RobFrost]

Just me but I would measure compression ratio and then shim to spec only if necessary. All those expensive parts, time and work, and you would give away compression needlessly? That extra 0.25 compression ratio could be the difference between winning and second place. You'll never get next racing season back. If you're racing to win you have to have the peak performance mentality.

[911hillclimber]

Looks best to time the engine for the valve clearance, my mistake.

The pistons will be posted to me from Performance unlimited tomorrow, they are in their warehouse.

I like this video, the valve clearance test is right at the end of the video.

https://youtu.be/KWtJNeqz1ZY

[neilbardsley]

What about squish?

https://tkart.it/en/magazine/how-to/imp ... of-squish/

Sent from my M2004J19C using Tapatalk

[911hillclimber]

Yes, mentioned before somewhere in here, the plasticine pellets close to the perimeter of the piston will give the squish distance once the piston had gone tdc and over.

Pistons are arriving noon tomorrow, nice start to the New Year.

[911hillclimber]

Going to re-read Peter's thread before touching these:

[PeterK]

I hate fitting the rings - so brittle and no warning. Take your time and double check which side you fit the first wrist pin circlip (don’t ask why I remember that )

[gridgway]

Nowhere near as bad as rebuilding my pinto race engine with new pistons where they have to be heated for an interference fit. You have one chance to get it on (as it were) and then you are buggered if you don't get it right first time!

[911hillclimber]

Not too many details here, but took piston #1 and set to with the ring gaps. Oddly, top and second were perfect gaps!

Came to the oil ring set, what an utter game. I was convinced the ring stack was too wide or the piston gap too narrow, but then they all 'pinged' into place and passed through my 360 degree Wilisco ring compressor.
Put the piston in the #1 barrel, barrel on the engine studs, advanced #1 rod to tdc and the pin slid in very nicely No clips yet as thi si the dry run. I know too well the clip 'pre-installation' Peter, been there myself albeit in 1994!

The barrel in place, just slipped the #1 head on.

Took to #2 piston and checked the top ring gap in #2 barrel. 15 thou, has to be more than 17.

The ring is rock hard for my swiss files....

So, New Year's eve, bugger it, sort it all on Sunday.

HAPPY NEW YEAR!

[AndrewSlater]

Great news that you now have the pistons!

Out of interest is there much weight variation between pistons?

[911hillclimber]

From lightest to heaviest, just 0.2 grams!!!

Impressive.

[PeterK]

If you can wait for the Post Office to open, I have a piston ring grinding rotary tool you can borrow Graham

[911hillclimber]

Thank you Peter, noticed that in your thread, please can I borrow it in case my dremmel grinder fails?
Will pm my address now.