Christmas Build, 3.2 Short Stroke, 10.1 CR

[snbush67]

Taking things slow.

[G450X]

Thanks for the info, I’ll check with Mahle, but I think the new P&C 3.0 to 3.2 ring sizes are different. I thought you had reconditioned an old set.

[dedyplay]

Very nice

[snbush67]

Had a few hours today to clean and prep the camshaft housings.

[trond]

i too got new cylinders from Mahle. And I had a problem to get a good seal to the heads, because my cylinders were not chamfered. While the cut in the heads is radiused. Put the heads on in the vertical. Also do leakdown to verify they seal before proceeding. I ended up chamfering the cylinders. Fixed it

[snbush67]

Originally Posted by trond

i too got new cylinders from Mahle. And I had a problem to get a good seal to the heads, because my cylinders were not chamfered. While the cut in the heads is radiused. Put the heads on in the vertical. Also do leakdown to verify they seal before proceeding. I ended up chamfering the cylinders. Fixed it

Dang it, I wish I had read this earlier. I just put the heads on and the cam housings this morning. I’ll check before I proceed further.

[snbush67]

I don’t see any issues with the heads sealing.

[trond]

agree. maybe I was unlucky. When I installed my heads 1-3 was installed vertical. None of these leaked. Heads 4-6 were installed with engine flat. 2 of these leaked. Maybe my issues came from my heads had been recut 0.25mm and radius could be different.

[snbush67]

Originally Posted by trond

agree. maybe I was unlucky. When I installed my heads 1-3 was installed vertical. None of these leaked. Heads 4-6 were installed with engine flat. 2 of these leaked. Maybe my issues came from my heads had been recut 0.25mm and radius could be different.

I appreciate the “heads” up it was a good idea to check.

[snbush67]

A little progress, chain boxes installed, cam shafts and sprockets are on.

[Ovis]

Nice work, looks beautiful! I am hoping to catch up to you with my build here in a few days, just waiting on a few more parts.

[snbush67]

2 shims on the left and 4 shims on the right.

Left side:


Right Side:

[snbush67]

Originally Posted by Ovis

Nice work, looks beautiful! I am hoping to catch up to you with my build here in a few days, just waiting on a few more parts.

Thanks. I hope your parts arrive soon and your build goes great.

[trond]

following this ! I have similar build and also the same k75 cams on order. One question on ring gap you have 0.0175 ring gaps. A lot more than porsche build specs. Why ? Asking because I was confused with the CP/Carillo gap specs compared to porsche specs. I am thinking air cooled aluminium cylinders vs cast iron and different thermal expansion. Circumference (length of piston ring that expands) of a 98mm bore vs a 95 mm bore is insignificant

[LukasM]

Very nice work with great attention to little details Shane and Ian! Taking notes for my engine building file, will be spending some extra time for parts prep to avoid leakage and scratches in these very expensive P&Cs!

Originally Posted by trond

i too got new cylinders from Mahle. And I had a problem to get a good seal to the heads, because my cylinders were not chamfered. While the cut in the heads is radiused. Put the heads on in the vertical. Also do leakdown to verify they seal before proceeding. I ended up chamfering the cylinders. Fixed it

Hi Trond,

Can you please explain or ideally show a picture where you would place a chamfer on the cylinder? I get it for the heads since the chamber is sized for a 95mm bore, so that it matches the bigger bore below.

Cheers,
Lukas

[Ovis]

Originally Posted by snbush67

Thanks. I hope your parts arrive soon and your build goes great.

Got my missing ring and moving along. Hope to have the chain boxes and cams installed today.

[snbush67]

Originally Posted by trond

following this ! I have similar build and also the same k75 cams on order. One question on ring gap you have 0.0175 ring gaps. A lot more than porsche build specs. Why ? Asking because I was confused with the CP/Carillo gap specs compared to porsche specs. I am thinking air cooled aluminium cylinders vs cast iron and different thermal expansion. Circumference (length of piston ring that expands) of a 98mm bore vs a 95 mm bore is insignificant

Good question, the rings were gapped at 0.0175” right out of the box, so I couldn’t get less gap if I wanted to. Fortunately that is right where we needed them and on the edge of Mahle recommendations. The gap determination involved Ian’s experience and consultation with other renowned builders.

[snbush67]

Ready to get timing.



#1 valve lash adjusted.



Mechanical chain tensioners in place.



Verified TDC and all timing marks.



Old school degree wheel mounted to the fly wheel. Wheel of fortune style.

[snbush67]

The plan was to get timing done tomorrow, but things went smoother and quicker than expected and I’m done or I screwed something up and I’ll figure it out tomorrow.

A quick call to William Marshall got the Cam card and directions to set these up at 0 valve lash, 050” at 27 degrees before TDC.



Both camshafts installed with the key ways pointed up and sprockets pinned.

Left side (1,2,3) From TDC I turned the crank until #1 valve was at .050” then removed the pin, rotated the crank until the degree wheel was at 27 degrees before TDC, and put the pin back in. Checked by turning the crank two revolutions while verifying on the second rotation that at 27 degrees before TDC the intake valve was at .050”. It was.





Then to the right side (4,5,6) key way was pointed down. Installed rocker on #4 and dial gauge, adjusted valve lash to zero. Rotated crank until crank until #1 valve was at .050” then removed the pin, rotated the crank until the degree wheel was at 27 degrees before TDC, and put the pin back in. Checked by turning the crank two revolutions while verifying on the second rotation that at 27 degrees before TDC the intake valve was at .050”. It was.



I’ll adjust valve lash to running spec tomorrow and check that each side is at .047” at 27 degrees before TDC. degrees. I’ll double check everything and valve to piston clearances as well.

[snbush67]

Timing is done, rockers installed and valves adjusted.