I wanted to thank you racebum for taking the time to assist me with this, I ordered the Mahle pistons today.

 

your welcome, let us know how the build comes together

 

Any advice on p2w clearness?

 

i was gona say SRP makes pistons that should be what your lookin for

 

2 weeks ago....

 

now that you bring it up yes. follow the directions exactly. when they say .0025 to .0030 they seriously mean it. if you go looser they rattle more. have the machine shop aim for anywhere in the middle of those two numbers

 

Looking at Hitting

0.0025"-0.003" p-w

# 1,2,4,5 0.0018", #3 0.0020" mains

0.0020" rods

 

Looking for a lightweight wrist pin 21mm x 1.950", I have looked in about every catalog I am able to get my hands on. Looking for something in the 70gr range, my Mahle pins weigh almost 100gr and to me that is totally unnecessary for my build. The closes I have been able to find are my old Wiseco pins that are 2.002" and weigh a touch over 67gr, I tried fitting a Wiseco pin in my Mahle piston but its a hair too long.

 

if i remember right the mahle and wiseco pistons weighed within a couple g of each other with the pins installed.

your clearances look great on everything

my only worry is if there's a reason mahle used such a strong pin. when it comes to things like piston strength i never try to outthink the manf. 30g is quite a difference though. that of course tells me it's either different steel or thicker.

 

Mahle are .200" wall

No Picture......

The wiseco's are a tapered design.



67gr vs 84gr Wiseco

 

hmm im not feeling that tapered pin design, might as well taper it all the way through its only as strong as its narrowest point. The pins Arias sent me for my new motor weight 130g a piece haha.

 

same here, that thick pin is a LOT stronger by visual. if it were my motor i would run what they sent you.

just my vote though, i can understand your point of view on weight

 

Then you clearly don't understand how stress is applied to the pin...

Seems to work well in the C5R

 

which mahle ironicly makes the pistons for

 

And the Vette has twice as many pistons, pins, rods and bearings to spread the load/stress per cylinder out, and its a low reving NA pushrod equipped V8.... you have half. If both engines make 500hp each one of your pistons is taking twice the brunt of combustion.

 

maybe, but the c5R is the car they used at the 24hr of lemans, chances are it had a lot more R&D into every detail.

but that also could explain the tapered pin. it was designed as a race piston, not to live years of street driving

the c5r made something like 620hp on i want to say 7 liters of displacement with the inlet restrictors

 

Fu<k my life.......

Turns out my rods are too wide at the pin end to fit the pistons......

I tried both my Manley rods and Carrillo, Manleys measure .850" Carrillos are .860"


HELP

WTF do I do?

 

take them to a machine shop and have them cut

/thread

 

Thanks Spawne.... I'm looking for experienced opinions though, and they should fit out of the box.

I'm not sure which is better narrowing the rod or opening up the pistons.

Does anyone know the P.E. with of a stock GSR rod?

 

lol just calling it like i see it

 

call mahle, this is weird, they fit stock gsr rods fine BUT should fit what you have. i'd ask if you could send the pistons back to be cut to spec.

acually, pm gringoteg and ask him what he did in that build. he used mahle pistons and a believe eagle H beams

 

As far as i know they should fit right on with no issues....

They fit perfect on mine...

If worse comes to worse i think the best idea is to shave down the piston on the inside Not the rod...

Back when i lived in the Dominican republic my amazingly bad mechanic (when i was 16) shaved down B16 rods to fit in PCT(CTR pistons) pistons... They were all even except #1 looked like / / when you looked at it from the top.. ironicly enough that rod starting knocking not too long after the motor was put together.. Now im not 100% sure if that was the cause of it or not.. I like to think it was tho

 

Measured some stock pistons.

P72 0.705"
PR3 0.710"
PR4 0.785"

Seems my problem lies in the rods...

 

So the question begs, narrow the rod or open the piston.

 

If your only .010 too wide I would just mod the rod, I would think doing that to a piston would be more difficult. Personally I wouldnt do it but you didnt give an option for getting a set of rods that fit right out of the box.