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mahle 2.8 piston questions

Old 10-09-2014, 09:46 PM
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SamGrant951
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Default mahle 2.8 piston questions

So I came across a set of NIB mahle 2.8 stroker pistons dated 1995. Have a few questions...

Markings on the box say 100,470? The quick measurement I got with my (harbor freight ) digital caliper was ~99.95. Am I measuring wrong? I just took a measurement across the top of the piston.

Does anyone know what the markings on the top of the piston reference: 26/0? The bottom marking of 100P35+?

Why would these have valve reliefs – a normal turbo piston doesn’t have that or was that just an option when buying them and some did / some didn't?

Any insight/thoughts appreciated.

Looking at a recent thread from hp18racer: https://rennlist.com/forums/944-turb...-for-sale.html These look a bit different (dish, reliefs) and his have markings on the side by the wrist pin whereas mine do not. On the bottom mine read Mahle 100P35+ and his read 100P32.

I bought them on a whim along with a 3L crank but really have too many other projects already going on so may throw them on the shelf for down the road or if anyone is interested...lets talk.

Thanks,
Sam









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Old 10-09-2014, 09:54 PM
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blown 944
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Need to measure the skirt.

The reliefs may be to create a non interference design.

No idea on the other numbers
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Old 10-09-2014, 10:15 PM
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Maybe they are higher comp ratio than standard with a shallower bowl hence the valve reliefs ?
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Old 10-09-2014, 11:15 PM
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Do you have to get the specs from the manufacturer on the pistons to figure out compression ratio or is that something that can be measured (by someone thats knows what they are doing)?
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Old 10-09-2014, 11:23 PM
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rlm328
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The 100P36 is the casting number, the 100 is the piston range, P is the piston type with the 36 I think is the batch number. The 100.470 is the cylinder size if I am not mistaken, they usually have a stamp on the skirt by the wrist pin that has the OD of the piston. The arrow points to the front of the engine.
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Old 10-09-2014, 11:28 PM
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Call Mahle, I did when I needed the clearance spec for my 3L. They're very helpful. IIRC they're in NC.
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Old 10-09-2014, 11:34 PM
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Contact Mahle NA. They'll respond.

This guy: Tony Ford
MAHLE Engine Components USA, Inc.
MAHLE Motorsports

270 Rutledge Road
Fletcher, NC 28732
Phone: (828) 650-0814
[email protected]
www.us.mahle.com
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Old 10-09-2014, 11:43 PM
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Tom M'Guinn
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Originally Posted by SamGrant951 View Post
Do you have to get the specs from the manufacturer on the pistons to figure out compression ratio or is that something that can be measured (by someone thats knows what they are doing)?

You have to cc the motor. The compression ratio Mahle/Andial advertises for its 104mm pistons is way off... So even if they told you it was X, I wouldn't trust it... The FSM shows where on the piston to measure . I don't remember the original Andial stroker pistons having valve pockets like that, but its been years since I've seen one in person, so could be wrong...
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Old 10-09-2014, 11:57 PM
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Thanks guys, Ill call Mahle!
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Old 10-10-2014, 12:10 AM
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Don't be vague when talking to Mahle. When I spoke with Tony Ford, he divulged more pertinent info when challanged with more specific questions.
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Old 10-13-2014, 10:44 AM
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Tony wrote back and said 100.5 and 9.7:1 so sounds like a n/a application. Up for sale they go - no use to me.
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Old 10-13-2014, 04:54 PM
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You could have the bowl machined to drop the CR.
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Old 02-01-2018, 09:33 AM
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Seffen944
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Default Mahle Stroker pistons 2.8

Hi,
I like to build a NA 8V stroker with an S2 crank, and i´m looking for a set of those pistons 100p35 with stock NA compression. I know, i´m a little late, Please text me if anyone here has those or others on sale
With best regards
Steffen
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Old 02-08-2018, 02:39 AM
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boost feen
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I believe these exact pistons are on eBay for sale with a 3 liter crank good luck
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