QSC Cast Pistons & Iron Cylinders

[Roger 911]

Does anyone have any experience with the QSC cast pistons and Iron cylinders?

These are selling for under $500 new, with rings and clips. I've done some searches and found a lot of references to the QSC aluminum cylinders being used with JE pistons (Supertec), but I never found anyone talking about the QSC cast pistons and the iron cylinders.

As the long time (about ten years) owner of a 72T, I have a fair amount of respect for the combo of cast pistons and iron cylinders. My motor has been bulletproof. I installed E cams and Webers a few years back for more top end on long tracks like Road America, also added an external oil cooler. I have been doing DEs for the last 8 yrs. My long block has never been apart with well over 100K. It doesn't smoke or use oil.

I'm not ready for a rebuild, but it sure would be tempting to use a set of these P&Cs if I were. For example...a set of these 92mm P & Cs (which appear to be 8.5:1 CIS pistons), 964 cams, heads ported to 36mm (S size), Webers, headers and a pair of M&K sport mufflers (I love the way these sound!). I would think that this 2.8 would come darn close to the 2.7 E cam Weber motor described in Bruce Anderson's book (for those not familiar with this, supposedly, this motor came close to the power of a 2.7RS).

I understand the disadvantages of iron cylinders, i.e., more heat. But I think this would be controllable, given that this motor would only see revs in the low 6K range and there is an external cooler. On the other hand, I also understand that iron cylinders may actually be the least prone to head stud failures as well.

So, "in closing" I'd be curious to hear from anyone who has used/bought this QSC combo. It looks very interesting.

Roger

[kenikh]

I dare say that "cast" and "Mahle" together mean a lot more than "cast" and "chinese". The materials may be the same, but I don't trust chinses castings as far as I can throw them.

[911 tweaks]

henry @ supertech offers these and he inspects ALL shipments i.e. cyl for roundness... and I would go to him to get your q's answered as to what you want to do.

henry wont steer you wrong and knows his stuff inside out and backwards!
Bob

[kenikh]

Henry's inspected cylinder are good; he and I have talked at length about them. I am not sure he uses their pistons, though. The bottom line is that you are shooting yourself in the foot with QSC, IMO, if you aren't getting a trained eye on them first or good refund policy on QSCs.

[mb911]

Originally Posted by kenikh

Henry's inspected cylinder are good; he and I have talked at length about them. I am not sure he uses their pistons, though. The bottom line is that you are shooting yourself in the foot with QSC, IMO, if you aren't getting a trained eye on them first or good refund policy on QSCs.

Henry uses the QSC cylinders only and rejects a good amount of them at that. those go back to QSC and they end up making it to ebay.. he does not use QSC pistons as of last time we spoke = 4 weeks ago he only uses JE or mahle

I have the QSC and JE combo on my car it it runs perfect with very little oil usage to this point-1000 miles.. lets hope that continues

[Jeff Alton]

Originally Posted by mb911

Henry uses the QSC cylinders only and rejects a good amount of them at that. those go back to QSC and they end up making it to ebay..

Careful, Henry also sells them on Ebay. I would assume these are checked too.

Cheers

[Roger 911]

Yes, I would be interested to hear Henry's thoughts on both the cast pistons and the iron cylinders. I would think if QSC is capable of producing an acceptable cylinder, they should be able to produce an acceptable piston, no? I'm not ready to write them off just because they're Chinese.

[mb911]

Originally Posted by Jeff Alton

Careful, Henry also sells them on Ebay. I would assume these are checked too.

Cheers

Yes he does but anyone else on ebay would be selling his rejects.. I beleive this has to do with some sort of agreement? Anyhow he does not sell or use the QSC pistons at this point

[nilknarf]

I'd be interested in Henry's take on this as well- I may be in the market soon too!

Curt

[Henry Schmidt]

I have no direct experience with the QSC P&C set referred to above.
I will say that some of the QSC pistons I have seen are replicas of Mahle pistons. The problem is they used forged piston design to produce a cast piston. This will produce a piston expansion that can/will be unpredictable.
Cast pistons generally have steel cast into them to control expansion or they have a full circle skirt.
Forged pistons generally have a limited amount of skirt width and reduced amounts of material inside the skirt.
The inherent strength of forged material allows for these thin skirts.
Cast aluminum is weaker and will crack if casting is too thin where the skirt is subjected load.
Conclusion: They are nice castings but they are engineered incorrectly. Could they work? Maybe, but I wouldn't bet on it.

[Henry Schmidt]

Originally Posted by Jeff Alton

Careful, Henry also sells them on Ebay. I would assume these are checked too.

Cheers

It is correct to say that Supertec sells products on Ebay but we won't sell anything that we haven't tested and can guaranty with complete confidence.

We were involved in the design, testing and production of most of the products we sell on Ebay.

2.4 911 P&Cs made by QSC are not among those products.

[Jeff Alton]

My point was that folks should not discount all the QSC stuff on ebay, because if they did then they would be righting the stuff off that you have checked out as being good.

Cheers

[Roger 911]

Originally Posted by Henry Schmidt

I have no direct experience with the QSC P&C set referred to above.
I will say that some of the QSC pistons I have seen are replicas of Mahle pistons. The problem is they used forged piston design to produce a cast piston. This will produce a piston expansion that can/will be unpredictable.
Cast pistons generally have steel cast into them to control expansion or they have a full circle skirt.
Forged pistons generally have a limited amount of skirt width and reduced amounts of material inside the skirt.
The inherent strength of forged material allows for these thin skirts.
Cast aluminum is weaker and will crack if casting is too thin where the skirt is subjected load.
Conclusion: They are nice castings but they are engineered incorrectly. Could they work? Maybe, but I wouldn't bet on it.

Thanks Henry. This is the kind of insight I was looking for.

Also FWIW, I e-mailed QSC directly with some questions. I got conflicting reponses on some of my questions. As others have noted, I suspect you would really be on your own buying their products directly from them.

On the other hand, if there are some "gamblers" ot there, maybe they could buy this stuff and let us know if they get lucky!

[sp_cs]

Originally Posted by Henry Schmidt

I have no direct experience with the QSC P&C set referred to above.
I will say that some of the QSC pistons I have seen are replicas of Mahle pistons. The problem is they used forged piston design to produce a cast piston. This will produce a piston expansion that can/will be unpredictable.
Cast pistons generally have steel cast into them to control expansion or they have a full circle skirt.
Forged pistons generally have a limited amount of skirt width and reduced amounts of material inside the skirt.
The inherent strength of forged material allows for these thin skirts.
Cast aluminum is weaker and will crack if casting is too thin where the skirt is subjected load.
Conclusion: They are nice castings but they are engineered incorrectly. Could they work? Maybe, but I wouldn't bet on it.

Henry, have emailed you previously on the topic of QSC/JE - what are your thoughts on longevity? There appears to be some doubt as whether suitable for high street mileage or not? Or whether more suited to engines that get re-built frequently?

Cheers

[Tom C.]

While we are on the subject I've got a set of Henry's QSC/Mahle 90mm combo with RS spec pistons, wrist pins, clips for sale.

Make me an offer . . .

And I'm sure Henry would be glad to talk to you about this setup since I pulled them out of a motor he built with zero miles.

No reasonable offer will be refused.

Cheers,

Tom
(805) 630-5573

[nabilious]

Has anyone actually weighed the mahle/JE/QSC pistons?
Just curious.
Thanks,
Nabil