89.47 mm 9.5:1 Pistons, what are people using?

[1974_Verona]

Ive decided to skip using the QSC pistons I bought. They are just funky in dimensions, and I don't trust them at this point. Im not up for rolling the dice to find out down the line that they really are junk etc. 

 

Soooo....

 

Ive got a block ready for 89.47 mm (2nd over) pistons. Using an E12 head that has a IW 292 cam. What are people using? TIA 

[2002Scoob]

QSC? 

 

You're doing almost the exact build i'm doing on my donor motor, it sounds (minus I have a Schrick 292), right down to the bore. 

 

The pistons that are going into mine are lightly used 89.47 Mahles. 

[1974_Verona]

QSC is a Chinese manufacturer that is selling $200 USD a set pistons on US ebay. They are, for all intents and purposes, very nice paper weights as they are made incorrectly in deck height and piano dome height. 

 

They seem to have pulled their listing after my 7 heated phone calls to them. 

 

I found some used Mahles on ebay, but the seller is asking $100 shy of having new ones made. 

 

Im using a IE 4:1 step header as well as a 38/38 Weber. Ive been watching your thread Scoob- great work you are doing there!

Edited August 18, 2017 by 1974_Verona

[1119]

You are exactly one week to late.

I sold my last set of MAHLE's to a shop in New England.

Sold 'em for $790.

 

Sorry.

 

1119

[kbmb02]

 

2 hours ago, 1974_Verona said:

Ive got a block ready for 89.47 mm (2nd over) pistons. Using an E12 head that has a IW 292 cam. What are people using? TIA 

 

Consider custom ... it allows you to compensate design / adjust compression ratio for head thickness, deck height, etc (I don't quite get how an off-the-shelf piston can be called a "9.5:1" piston without knowing the other variables (they matter)). With custom, you can get most bore sizes (sourcing ring sets for 89.47 are a little tricky, I've found).

 

If your block was with me, I'd have a set of custom forged pistons made of 4032 alloy (I don't sell them, except in the engines I build). -KB

 

 

[1974_Verona]

KB, Since you clearly have some experience here, what do you consider a safe deck clearance? .040"? .050"? 

 

I put my engine together with these odd ass pistons I have and I get .051" using a compressed 1.8mm HG. 

 

I ask because I see on the photos you attached that piston is relieved slightly.  

Edited August 18, 2017 by 1974_Verona

[D.martijn]

I bought a new (still sealed) set of 2nd oversize pistons form this guy in Germany (I live in Belgium and it was no problem to send them to me not sure about the US though)

I see that he still has a set for sale.

 

http://marktplatz.bmw-02-club.de/showad.php?adid=12311

 

(edit: I paid 510€ incl shipping)

Edited August 18, 2017 by D.martijn

[worzella]

I used TEP Top End Performance made to order forged ones and although a bit more pricey than other options they were great to work with and installed beautifully

 

I think they were $695 on sale a few months ago. Life blood of the car (besides that insanely overpriced oil pump!) so a good part to not skimp on

 

[worzella]

My second choice was some from Walloth Nesch

[1119]

D. Martijn:

 

Your friend in Germany sold you 8.3:1 c/r pistons. 

 

74_Verona is shoping for 9.5:1 c/r pistons.

[D.martijn]

10 hours ago, 1119 said:

D. Martijn:

 

Your friend in Germany sold you 8.3:1 c/r pistons. 

 

74_Verona is shoping for 9.5:1 c/r pistons.

 

Aah right! I forgot he was looking for ti/tii high compression pistons.

The pistons I bought are for a single carb 2002.

[jrhone]

I got a set of used but within spec 89.47 9.5:1 Mahle Pistons that were the high dome piano tops when Ken did my refresh. I hav seen them on eBay at times but I put a parts wanted as here on the FAQ and got a nice set here. 

[1974_Verona]

Ok, well no one seems to have any to offer so I will consider this case closed. I went ahead with the pistons I had, what is life without a little risk? 

 

 

[torquewrench80]

On 8/18/2017 at 0:24 PM, kbmb02 said:

 

Consider custom ... it allows you to compensate design / adjust compression ratio for head thickness, deck height, etc (I don't quite get how an off-the-shelf piston can be called a "9.5:1" piston without knowing the other variables (they matter)). With custom, you can get most bore sizes (sourcing ring sets for 89.47 are a little tricky, I've found).

 

If your block was with me, I'd have a set of custom forged pistons made of 4032 alloy (I don't sell them, except in the engines I build). -KB

 

JE Pistons  As used for my rebuilt tii engine and recommended by my machinist. 90mm, 10.5:1, custom. Not cheap! Rudy, the rebuilder, told me the best way is to make a mold of the combustion chamber with the valves installed and send that to the piston manufacturer so they know exactly what they are dealing with. It probably depends on high a c/r one wants as the whether or not a mold is necessary. With custom you get the latest and the greatest technology and materials. 

[pehlivanov_tii]

On 8/22/2017 at 3:37 PM, 1974_Verona said:

Ok, well no one seems to have any to offer so I will consider this case closed. I went ahead with the pistons I had, what is life without a little risk? 

 

 

 

Please share some feedback after you fire up the engine. I just ordered my set QSC pistons. I hope they should fit even after some little work on them. Sorry but the price for new OEM set is too overpriced for piston with 50-years old specs.