2.2L vs. 2.4L "S" Pistons - How to ID??

[vntgspd]

Title says it all -

How do you tell the difference between 2.2L and 2.4L "S" pistons?

Couldn't fine anything in the "search".


thanks,

David

[BURN-BROS]

2.2 S piostons should have more pronounced valve pockets. I'll look for some pics...

[tom1394racing]

The piston identification number is located inside the piston either on the skirt or beneath the dome.

These pistons will have a number like 84PXX

84V51 are 2.2E pistons.

84P8 are 2.2S pistons.

84072 are 2.4E pistons

84p11 are 2.4S pistons

[vntgspd]

Tom,

Great info.

Any idea what 84V54 is???


David

[tom1394racing]

84v54 is a 2.4T piston.

Here's a copy of my piston cross reference listing (still incomplete):

Porsche 911 Piston Reference numbers

yr/model size Mfg CR P/N
2.0 65-67 80mm Mahle 80v37
2.0 E 69 80mm Mahle 80v79
2.0 S 67-68 80mm Mahle 80P26
2.0 S 69 80mm Mahle
2.0 906 80mm Mahle 10.3 80P26
2.0 T 68-69 80mm Mahle
2.2 E 84mm Mahle 84v51
2.2 S 84mm Mahle 84p8
2.2 T 84mm Mahle 84V48
2.2 T 84mm KS 84072
2.4 T CIS 84mm Mahle 84v58
2.4 E 84mm Mahle 84072
2.4 S 84mm Mahle 84P11
2.4 T 84mm Mahle 84V54
2.4 T 84mm KS
2.7 CIS 90mm Mahle 8.1
2.7 CIS 90mm KS 8.1 90202
2.7 CIS 90mm Mahle 8.5 90L58
2.7 CIS 90mm KS 8.5 90208
2.7 RS 90mm Mahle 8.5 90P27
3.0SC 95mm Mahle 8.5 93L7
3.0 SC 95mm Mahle 8.5 95L70
3.0 SC 95mm KS 8.5 95136
3.0 SC 95mm Mahle 9.3 95L67
3.0 SC 95mm KS 9.3 95152
3.0 RSR 95mm Mahle 10.5 95P30
3.0 SC 95mm Mahle 9.8 95L70
3.0 Turbo 95mm Mahle 6.5
3.2 Carrera95mm Mahle 9.5 95p36++
3.2 Carrera95mm KS 9.5 95175
3.2 Carrera95mm Mahle 10.3 95p36++
3.2 Carrera95mm KS 10.3
3.3 turbo 97mm Mahle 7.5
3.6 100mm Mahle

[vntgspd]

Thanks Tom!

[BURN-BROS]

Ditto!

[tom1394racing]

I've got quite a photo gallery of 911 pistons showing all of the ones listed and more.

I've been thinking about doing a post on the Engine Building forum showing pictorial comparisons of the various pistons. What do you think??

[arrivederci]

I have an 84V53. Is this also a T? See pic - I thought the T's valve pockets weren't this deep.

[Manipou]

great info, does anyone know if the 84mm 2.2S piston used the same nikasil cylinder as the 84mm 2.4S?

[chiroracer]

I think they are BIRAL steel sleeve with alum. fins cast around them for all but the T's Steve

[Flieger]

Originally Posted by chiroracer

I think they are BIRAL steel sleeve with alum. fins cast around them for all but the T's Steve

Yes, first Porsche use of Nickasil was for 90mm cylinders on the 917 4.9 and 5.0 liter engines in 1970.
The factory then put them on the 2.5 short stroke 911ST and then the 911 Carrera RS 2.7

The 90mm bore is beyond the capabilities of Biral construction. The wall is too thin to hold the cylinder pressure reliably.

[tom1394racing]

The 84V53 is a 2.4E piston. These motors came from the factory with biral cylinders.

[arrivederci]

Thanks Tom. That's what I suspected based on the valve pockets and all the pictures I've seen of T and S pistons. Any idea why that doesn't match the 84072 that you noted above?

[tom1394racing]

I've been constantly updating my list.

I believe the 84072 us actually a 2.2T piston not a 2.4E piston as I has originally listed.

[BURN-BROS]

84p13...looks like a 2.2S but with more comp.

[arrivederci]

Interesting, looks similar to these. 92mm 2.8L.

[tom1394racing]

Aaron

I believe the 84P13 is a 911ST piston.......10.3 CR and 87.5 mm diameter

[bavaria911]

Nice find. I noticed the 4 drilled holes each side on the inside. I have only seen three holes as a common mark.

Bavaria911

[BURN-BROS]

Originally Posted by tom1394racing

Aaron

I believe the 84P13 is a 911ST piston.......10.3 CR and 87.5 mm diameter

Yes, I measured them this morning 87.5 here is a comparison pic of a normal 87.5 and the modded one..




Another partial set I have are
84p8W2 that measure 86.7mm