MFG / Reseller Experience QSC

[burndog]

Does anyone have any experience / opinions on using the QSC brand forged aluminum pistons? Good, bad or indifferent?

[stephers]

This topic has come up on Pelican porsche forum sites a few times, the general consensus is that they are not well made.  One engine builder had to go thru 3 sets to find six good pistons      Have a look at the site and see what everyone had to say

[oldguy]

I just bought a set off the guy on ebay.  Curious what I'll get in the mail.  The factory mahle pistons are no rocket science pistons and the pelican forum is talking about cylinder jugs not pistons.  He accepted my "offer" of $125..  for 4 pistons that's not bad, unless they're junk...

[TobyB]

Quote

The factory mahle pistons are no rocket science pistons

Totally agreed.  I've got a tractor that has a fancier set in it.

 

However, the Mahle quality control is very good, so you tend to get 4

exactly identical 50- year- old designs....

 

Let us know what comes in the box!

 

t

 

[oldguy]

Got em here...   um..   so here's what came in the mail....A nicely cast and machined piston.  On just checking it with a dial caliper, there are some good things and bad things. 

 

Good Things,

 

It uses a 02 ring package.  

Top ring thickness = 1.75mm 

2nd ring thickness = 2mm 

oil ring thickness = 4mm

 

Are these 9.5:1 euro TII pistons?   Ehhh  Yeah kinda

Ok per the old pat allen reference sheet.  it should be a 6.8mm dome.  These QSC pistons are 7.2mm domes.  So I'm not really crying at that stat.  Lil Extra dome.  lil Extra CR. Not much but you can always remove dome, never get it back.  

 

 

 

The Meh things

 

Pin to deck height.  

 

 

If you use the "A" value in the scanned book drawing then you should be at 1.240" for TI cars.  These pistons are 1.251" pin to deck.  So again.  more CR, will the protrusion be a problem?  Not sure.  I think if everything isn't surfaced a lot, then these will be great but if your block and head are decked you might end up with protrusion problems.  I checked small bathtub and flat top and those are around 1.231".  

 

 

The bad things

 

The castings look great on most of them.  Some of the casting lines are not deburred.  There is plenty of evidence that a little china man had a hand whizz wheel and cleaned these up.  There is a buildup of extra aluminum on one wrist pin boss that I'll need to clean up with a file.  Ugly yes. Structural, No.  There still needs to be deburred and cleaned up.  I think you could spend 10 mins on each piston, you could run them.  I'll run them.  I did get atleast 3-4 small flakes of aluminum casting flash / metal splinter type things off the pistons.  

 

 

I'll put up a video comparing them to mahle's side by side

 

[1974_Verona]

Im digging this old thread up to add detail. I bought these, and can agree they are OK, not great, just OK. They will suffice for a street build on a budget. BUT...the data the seller gives you about his own product is very, very wrong. 

 

The pistons are sold as "90.00mm" - which they most certainly are NOT. They are 89.47mm.

 

The crown reads "0.25". Again, this is NOT correct as a 89.47mm piston is a 2nd over bore, which would be +0.50mm

 

These are sold WITHOUT rings. The dipshit who is the tech help when you call QSC was more than happy to give me the "correct hastings part number for the pistons." He then gave me a hastings number for a SIX CYLINDER engine of STD bore (89.00mm). BZZZZT- incorrect again sir. I asked him who on earth told him those were right and he told me "John at DCRA solutions, surely if you have been working on BMW for as long as you say you have, you know him." Umm, yeah, thats Select Classics in Dallas, from whom I wouldn't by a pencil, much less trust their opinion about anything BMW. 

 

So- long story short here is that these Cali folks are selling Chinese parts, made in a passible manner, and have dangerously inadequate mechanical knowledge in general.

 

Techboy further went on to tell me DCRA Solutions has been using that hastings number for years and "they work fine"- (With a ring gap measured in the hundredths, not thousandths? Hard to imagine.). Buyer beware of any motor those guys have built, you could probably run air tools off the blow by on a "rebuilt" engine. 

Edited August 17, 2017 by 1974_Verona

[442stang]

To 1974_Verona

 

Just saw your post

 

Yes the QSC guy called us asking how he could find piston rings as we ordered one set of pistons for a customer who did his own thing with them... I think he found some OEM piston rings.    As a favor to the QSC guy I had  my machinist a mechanical engineer who teaches automotive engineering builds BMW engines for us research the size rings required.   He looked up the gap, ring size, etc. on piston rings and the BMW I believe M20 6 cyl piston rings are the exact same piston ring on the 4cyl engine.  We do not use these QSC pistons and thus have not used these rings but according to Hastings specs they should work ? 

 

We generally use Goetz piston rings in stock engines and order custom forged pistons with custom rings for our high performance engines 

 

Will put the box of pencils I had reserved for you back in inventory

[TobyB]

Quote

M20 6 cyl piston rings are the exact same piston ring on the 4cyl engine.

 

Only if you're building a 1600.

 

The M20's an 84mm bore.  The 2L M10's an 89mm bore.

 

t

 

 

 

[wegweiser]

I would only buy these pistons if they had massive amounts of oversprayed paint on them, and if the sides were nice and wavy.