Pistons QSC 2,7
 

Hi There,

while normaly i am involved in high performance applications, actually (strangely) i have a LOW performance application on a 2,7 CIS 165 HP.

Just crusing, short distance among usage, daily, even if in Germany almost no High speed highway need, just reliable daily usage. Is this (strange solution) an option on approx 8K miles/year?:

Porsche 911 92 mm Cast Iron Cylinder & Piston Kit | eBay

Anyone experience?

REAL experience appreciated.

Thanks and Greets,

Robert.

Andrew (Lapkritis) recently rebuilt a 2.7 with these cylinders, seems to have great results. Prepare for reading, this will take a while: http://forums.pelicanparts.com/911-engine-rebuilding-forum/738419-specific-question-arp-head-studs-2-7-magnesium-case-insane.html

:)

We caution against using substandard (read low quality) parts when building Porsche air cooled engines.
Our experience with QSC may be as comprehensive as any.
When we evaluated QSC cylinders we found that with Nikasil cylinders, we had to mix and match 3 different sets to find 2 usable sets.
With the cast cylinders, our biggest concern with quality was a very low Rockwell (hardness) reading. (real numbers not conjecture)
When fitting, the cylinder fins needed to be trimmed to before installation.
The most important issue is cooling. Cast iron offers inferior heat transfer which leads to cooling issue.
The Ps&Cs you are questioning come with cast pistons which are generally considered inferior when compared to forged pistons.

Could they work in a limited performance application? sure
Will they last as long or cool as well as Nikasil cylinders? absolutely not

Absolutely clear and true.

As mentioned on 911 engines i do usually work on high performance applications for which i would never consider these for.

Here i am talking about a LOW performance application which can probably come up to working temperature much quicker, as the car will mainly be used for short distances. Environmental teperatures are moderate not higher than 30°C. So here i am looking for LESS cooling.

Sounds strange but its so.

Although I understand your position on cooling there is also the question of quality.
Fit and finish as well as low hardness numbers make these a poor choice if you want it to last even moderately well.
If you elect to use these cylinders, fit them before assembly and I would recommend Nikasil plating. This will ensure low friction numbers and extended ring and cylinder life.
Cheers

Good point, Henry i will check that.
Usually when making engines the focus is the impossible between high performance, extreme long lasting and good fuel economics with good results.
This particular application will have the same criteria but more all weather short distance than performance, which is also a challenge kinda houswife's SUV.
So we are thinking more of condensate, daily use, mild summer but winter as well and cold periodes where the engine probably never meets its proper working temperature plus longer standstill times. WPC (Worst possible conditions). But longevity to be a must.
I absolutely do not trust the QSCs so anyone here with high mileage experience including winter use?
Unfortunately (and i mean only THIS particular application) these seem the only ones to feature steel barrels and we have a lot of high performance stuff in germany but not such.
BTW: i would plan to run them at some 9..9,5 CR for 98 pump gas.
Engine is a 165HP US non California Sportomatic and left mildly improved but standard and all old steel headbolts, no cams, just SSI's.


Thanks,
Robert

Hello Robert,

I do have a few miles on these but with JE pistons to accommodate a higher lift cam. The pistons you will receive are CIS-E replica with snap ring cir-clips and not the symmetrical example you see in their catalog photos.

They are very well packaged; as my experience shared above shows along with many pictures, the width of the cooling fins was too great to allow installation. The fins likely have to be trimmed before fitting which is about an hour of time. I did send notice to the retailer of the defect in design but I expect that may or may not have reached the production floor.

Cooling - I added heat sinks to billet valve covers with milspec hard black anodize and also ceramic thermal barrier coatings on piston tops, combustion chamber of the cylinder head/exhuast port/valve and into the exhaust header pipe to assist with shedding heat that Henry was sure would be present. The only issue I found was getting enough heat into the engine when the temperature was below 45F. The warm-up time to 180F oil temperature was over 20mins and never exceeded 200F in cooler weather. The highest maximum temperature observed during the hot summer months was 215F in New England region climate which is similar to Germany. The vehicle is equipped with a fender mount oil cooler. I have now stored the vehicle for the winter but if I were to continue operation during the cold weather I would fit regular turbo lower valve covers to keep heat in the engine.

Henry has a bit of a personal quest against QSC which is apparent when he shares adjectives to dissuade any potential purchaser. The QSC iron have superior characteristics of thermal expansion more suited to an air cooled engine relative to the inferior aluminum that destroys the delicate engine cases with poor inherent design. If you tune fuel mixture properly and use a quality motor oil then you should expect service life from the cylinder which is the same as millions of regular vehicles with iron combustion chamber surface... which is to say quite a long time.

Hi Andrew,
thank you, i have seen your thread. Interesting.
I understand you were wanting to compensate the mediocre cooling properties of the cast iron barrels.
I have been working on lots of T engines as well and i always have been astonished about the good wear and out-of-round readings of the old cast barrels even in completely worn out engines.
However, honestly i have to say on any engine i increased performances in significant values i have changed barrels to nicasils or birals and i will continue to do so.
The application i will be working on is completely different. Here i need the quickest possible temperature rise to operation temperature and it will almost never see full-throttle für longer than 10secs. It will unlikely ever see more than 150 Km/h (what a pity in germany :-) ).
But a good and stable all-day application with a majority of short distance, standstill over days, winter, and mostly inner city rides, one weekly longer ride on country roads at crusing speeds of some 120Km/h.
So i am thinking about cast iron barrels (i also like the idea of a slight increase of cc), 5 blade fan and a reduced oil filling.
Completely different from what i am doing usually.
I did not really catch what you were saying about the pistons which come with it. They deliver different ones than the ones displayed? Can you post a picture of the actual pistons, please?
I have noted the dissonances you had with Henry and i have to admit i understand his position: Since i am also doing engines since decades sometimes my lectures to others seem to sound quite arrogant. I try to keep an open mind though..
Also i understand your position, you do not like the stop-thinking-attitude which i like.
Henry has posted a lot of helpful input to this forum as you are doing also.
Different opinions on a hobby... ;-)

If looking for steel barrels/liners instead, you could look into the JB Racing cylinders

JB Racing - Porsche Engine Components

I realize you said you're looking for longevity and not looking to have max cooling, given the working environment. I mentioned the JB Racing cylinders only because you spoke of steel liners.

Thank you, i know these but i am really looking for all steel barrels incl. the fins.
As far as i know the QSCs are the only ones on the market?
That they do them all-steel i assume is for budget reasons.
So i ask myself: How bad are they really? ;-)
Anrews experiences sound promising, Henrys input sounds prohibitive.
Any further experiences with these?

Here are photos of the 92mm QSC:


http://i458.photobucket.com/albums/q...ps599ce9ab.jpg

http://i458.photobucket.com/albums/q...psfe14c2ba.jpg

http://i458.photobucket.com/albums/q...pscf125090.jpg

Mahle RS and qsc side by side:
http://i458.photobucket.com/albums/q...psb7a621f2.jpg

Qsc 92mm 9.5:1 911 piston:
http://i458.photobucket.com/albums/q...psb3f06553.jpg

http://i458.photobucket.com/albums/q...psa72d94be.jpg

I’m not sure why but these threads quite often turn into personalities over substance.

I don’t have a personal stake in any of these products other than my head studs.
The information I post is based on observation not supposition.

The reason I don’t like some of the QSC products is the specifications of the products not the name.

When I say that the Rockwell is low, it’s because we measured it.

Mahle Biral or cast 84mm 96B 911
QSC cast............. 86mm 76B 356
QSC cast .............. 90mm 76B 911
AA cast .............. 86mm 82B 356
AA cast.............. 86 mm 86B Heat treated 356 (we heat treated them to try and improve the product, we also tried Cryo)
AA Biral ............. 86mm 92B 911
We like this product but feel the Rockwell is still too low so we Nikasil the cylinder reduce ring wear (friction) and increase cylinder life.

Another product we wanted to use but don’t is their aluminum oil filter housing w/steel screen filter.
It looks like a nice product but the filter element is rated at 45+ microns and I prefer 25 but no more than 35 microns.

Like many of their product, it’s not a horrible product it just doesn’t suit my specifications.

Good info on hardness (pretty soft, the stuff) and thank you for the Photos! :-)

What do you think about their CE - gasket delete?

"There is no Rockwell scale for tests on cast iron, nor is there one for steel sheets thinner than 0.15mm. In order to close this gap, there are devices that work with the Rockwell procedure (with pre- and total test loads), but with much larger (or smaller) and thus non-standardised test loads."

"Cast iron: always use HBW x | 3000. Due to the smaller homogeneity, it is recommended to use the highest total test load of 29,420 N."

"The steel ball penetrator is used for softer materials. The softer the material, the larger should be the diameter of the ball and / or the smaller should be the total test load. For instance, the materials that can be tested with the HRB scale (ball 1/16" – total test load 980.7N) are harder than the materials tested with the HRL scale (ball 1/4 "- total test load 588.4N). "

If you're on testing using Rockwell on the b scale you did this wrong.

Guidelines to hardness testing

Check my reply. Soft without comparison to a control... and experiment claims contradictory to correct methods. Bzzzz, try again Henry.

Mechanical Properties of Gray Iron - Hardness

Hardness is the most commonly determined property of metal because it is a simple test and many of the useful properties of metal are directly related to its hardness. Within a class or type of gray iron, hardness is a good indicator of its engineering properties, but this relation is not useful between types of gray iron because differences in graphite structure have more of an effect on tensile properties than on hardness. Specifying the hardness at a designated place on each casting is an excellent method of establishing consistency of castings in production quantities where the type of iron being used has been established as satisfactory for the application. Compression strength does correlate very well with hardness for all types of iron because hardness is essentially a compression test. Hardness usually gives a good indication of tool life in machining, however, the presence of free carbides in the microstructure will reduce the machinability much more than it increases the hardness.

The Brinell hardness test is used for all irons because the Brinell test impression is large enough to average the hardness of the constituents in the microstructure. Rockwell hardness B or C scale tests can be used satisfactorily on machined surfaces where the supporting surface is also machined. Several Rockwell tests should be made and averaged, but extreme values should be discarded because of inordinate influence by a graphite flake or a hard constituent.

Quick question for you Andrew: how did you test your cylinders?

The Application of Hardness Tester for Metal Casting

Rockwell hardness tester

Rockwell hardness tester is also commonly used in the inspection to cast iron. All the parts with smaller grains, if there is not enough space for the Brinell hardness test, can be tested by Rockwell hardness tester. For pearlitic malleable iron, chilled cast iron and steel castings, HRB or HRC scale can be used, and if the material is heterogeneous, several readings should be measured to get the average value.

Rockwell hardness test is quick, convenient and has small indentation, which can be used to directly test the finished piece. It is suitable for testing mass production of finished or semi-finished parts piece by piece.

The Brinell hardness test is not a Rockwell test; they're very different. Not sure what you were doing or what setup you had rigged but the experiment description is already changing. First you said it was Rockwell test... now Brinell test? Which is it? It can't be both tests. If it is Brinell then we will discuss the integrity of the result.


Fuel, fire, miles and smiles. Thanks for asking. :)

LMAO, you're reading me the catalog of a tool. Do you recall which machine, tool head and measurement method you used? I want to help you out here to understand what you did. Too funny.

C'mon guys, I got the point.

Lets say QSCs are softer.

They do do not meet Henry's specs but Andrew's.

I would not use them on high performance applications but may be well off using them for a houswife's SUV application.

As to Henry i am concerned about tolerances, Andrew, whats your experience?

Any comments on CE-ring delete?
Any further experience concerning mileage?

Thank you.

I chose to use copper aerosol sealant (Permatex) for the joint between the head and cylinder in lieu of the CE ring. I used the same sealant between the heads and cam housings. No leaks to report.

No noticeable or detectable wear on the cylinders. I do not have plans to disassemble the engine at this time (famous last words).

When Henry says he experienced wear with similar but not identical cylinders he also states the engine ran too hot indicating improper or insufficient cooling. As many of us know, if you run an engine too hot it will tighten up and wear incredibly fast. I expect normal wear with sufficient cooling, proper fuel ratio tuning and modern oil formula lubrication.

Hmm.. is that really a solution?
I was thinking about (if i really take them) putting them onto a lathe to produce a proper CE- ring notch...
How do you see no noticeable wear? Have you been disassembliing the engine before?
Great you took the callenge to test them!
Did you also measure to check piston to liner clearance? What has been the tolerance and what has been the tolerance field?
As to Henry they are not very consistent...

Hello,

Yes, the cylinders were fully inspected by an ASE certified machinist with decades of experience. They are suitable without adjustment. The QSC pistons were not inspected as I used JE instead.

I haven't disassembled the engine since rebuild. Indicators of wear such as oil consumption, loss of power output, noise from slapping pistons nor smoke at any time from the exhaust are not present. Power output is good, engine consumes no oil and there is no smoke.

I wouldn't recommend retrofitting the CE gasket on an iron cylinder. The CE gasket won't give the same benefit on a cylinder with lower thermal expansion rate. The copper aerosol ensures seal and better thermal transfer without changing the geometry of measurement.

If selecting JE pistons then you should have the piston sized by manufacturer to the cylinder as it is more economical than honing the cylinder to size which is more labor intensive.

Thank you,

since the engine will basically stay original i will keep the pistons, i want also to keep the "bowl" for the CIS so the clearance values of the original kit would be interesting.

Once again Andrew is confused about the information I have posted.
He continues to believe that all the information I post are observations from a singular engine project.
Unlike Andrew, we have observed data in 100+ cast iron Porsche engines. Including 356, 912 and 911 engine equipped with cast iron cylinders. We exchange data with other shops about aftermarket cylinder manufacturers and they have observed similar results in other air cooled application.
When comparing cast iron cylinder wear, we include all manufactures that we've had the opportunity to observed. Malhe, Empi, NPR, AA and QSC
Wear predictions on cylinders with softer cast iron are based on observation of multiple engines built by a plethora of builders.

It doesn't matter if the hardness test of the cylinders is performed with a rock and a chisel of an outside firm specializing in non-destructive critical analysis (which is who we used) if all you're concerned with is a side by side comparison.


Quick note to Andrew: you ask questions with the sole intent to flame any answer, so why would I bother to answer. You asked my professional opinion when you started your project and then set out to prove you knew better. Interesting twist

Zero confusion here. I understand the differences between the two test methods you've claimed from one set of results. I know exactly what you're trying to do here and it's popularly referred to as "befuddling with BS".

If you're taking creative liberties with claims of scientific testing and then claiming empirical evidence after being found out then... understandably I'm going to take everything you say with a grain of salt. Opinions are fine but don't prop them up with BS.

I bump up the thread once again.
Any further experiences meanwhile?
Any further comments on the CE- ring delete?
Thanks,
Robert

Hi Robert,

I have no particular experience with QSC products - but IF you're going to use these cast iron cylinders, I would think it's a very good idea to machine CE-ring groves into them with a lathe as you suggested above.

Opposed to Andrews recommendation not to do it, it is my understanding that what you are building is essentially the same as a 2.4 T, a rather low performance engine just with a little more displacement (2.7).
Since you are in Germany, you probably won't be building a US-spec early thermal reactor engine either and as a 'housewifes' daily driver this engine will not see too much heat.

As you know, Porsche used the CE-ring on these (2.4 T) engines with cast iron barrels successfully without any known problems - this fact stands in strong opposition to Andrews pure speculation that it wouldn't work properly on cast iron cylinders.

If I was you, I would rely on what is known by experience (I know you have :-) combined with a portion of 'Gesunder Menschenverstand' - but certainly won't go into experiments with modern gasket alternatives like aerosol copper where there is no need to, especially if recommendations for these are based on theory and experience is limited to a single build which not even has been in long term use or disassembled once...

Just my $.02,
Arndt

Arndt,

You've misquoted me here. Please re-read my post. I never stated it wouldn't work properly.

Best Regards

QSC "quality specialty components" must be good they have "quality" in their name?

Andrew - how should we read this then?

I was trying to answer Robert's question RE fitting CE rings to these cylinders.
I recommended it to him, while you wouldn't (see quote above).

But please excuse me if I got it wrong - English is a foreign language to me.

So according to you, it wouldn't give the same benefit...
as what? ..as used on an Alusil cylinder? ..as aerosol copper?
(One thing's for sure: one cannot properly criticize an unsharp argument. mea culpa.)

However - I'd say it would give the same benefit on these QSCs as on earlier cast iron cylinders. I won't go any further into it, it was just my answer to Roberts question, who asked for further comments on CE ring delete.

Regards,
Arndt

Yes, the benefit would not be as great as a CE style gasket used on an aluminum cylinder with dilavar head studs...this combination of materials has the greatest thermal expansion and contraction.

For this specific inquiry for a grocery fetching, normally aspirated low HP car, I believe it would be a fools errand to bother dimensioning the iron cylinder for a proper channel and ring when the benefit is arguable. With that level of commitment to additional machine time, why not go for a full job and o-ring the head as well with a staggered diameter and a more modern designed, hand-fitted ring and a solid copper medium between head and cylinder? This level of machine work is more in line with a maximum competition level engine.

Steel fastener, cast iron cylinder and an adhesive sealant is a thoughtful design. I did work the numbers on thermal expansion previously and they were favorable to reduced relaxation.

The CE gaskets are prone to fatigue and flattening over time which may contribute to leaks... unlike an adhesive sealant that remains tacky.


A few notes on CE gaskets:

The purpose of a gasket would be to create a better seal and stop leaks. A couple factors come into play that challenge the integrity of the joint between the cylinder head and cylinder beyond the thermal expansion of the fastener relative to the cylinder. The mass of material between the cylinder wall and the wall of the CE channel is critical due to the temperature extremes the material is under. This is where the combustion occurs - the pressure and temperatures are highest in this area. With an overbore, you can compromise the integrity of the wall especially on aluminum.

The CE should be installed with the gap to the top of the engine; the lack of attention to this small detail is likely the cause of more slow oil leaks than we would believe.

Hi there, and thank you Arndt (kennen wir uns aus dem Elferteam?) for giving the CE - gasket a closer consideration.
In fact i do believe that Andrews version might work (as long as everything is perfectly level) but since the application i am planning is a very very conservative one i tend to using the CE - rings as a no-brainer.
But Andrew: Good point, i will give the portion you mentioned a closer look, not in terms of potential heat transfer but simply for stability as it will lack another 1 mm of wall thickness assuming the usage of the std 2.7 CE ring. If that proves to be too narrow i'd rather machine a more usefull groove for a copper ring...
Machining is no stunt for me, fortunately i have got all facilities inhouse using them regularly as a compensation for my regular occupation. ;-)

So you're saying that they are simply not needed in this config? theoretically?

I guess for that theory to work, with aerosol copper as a sealant or some other sticky stuff for that matter, would require the heads to have a perfect surface?
So he's got to crank up the lathe anyways since we're talking about an old 2.7 beater?

Probably he's done with machining the cylinders before she's back with the groceries - remember, she's got to walk...
Besides, there might be reasons why someone wouldn't want to machine the heads too much.
But this also is plain theory and speculation - I don't know the engine and it's condition.

I think we both made our points - maybe someone else has an opinion on CE ring delete on an early 2.7 rebuild?

edit: oops... too late, Robert's already at it ;-) Ja Robert - man muss ja auch mal woanders lesen :)

Yep, no use throwing crooked heads on anything regardless of the presence of a CE ring/NI resist ring or not. By the way, a CE ring won't save you from leaks with a warped head surface.

If fitting CE, ensure the gap is at the 12 o'clock position so oil isn't leaking out.

Andrew, why 1200 and oil leaking?
What do you mean?
Thanks,
Robert

With the gap in the CE ring at 6 o'clock (oil return tube side, visible from the bottom of the engine when installed) you will have a potential path out due to gravity. If you ensure the gap in the CE ring is at 12 o'clock (top of engine, under the fan shroud with engine installed) then the gap won't be in the path of puddling oil in the combustion chamber that may seep out.

I'm not sure I understand the recommendation above.
The CE ring is a solid ring with no gap.

The issue with installing a CE ring on a 92mm cylinder is that only Porsche CE ring available for this application is the 2.7 (90mm) CE ring. The inside diameter of that CE ring is 94.5mm. (IMSM) By using this ring you compromise the inner sealing area of the cylinder.
Some 92mm RSR cylinders were made this way with poor longevity.
The other option is the manufacture a ring. We've done this with 98mm cylinders when an additional seal was desired.
CE rings are designed to control weeping and minor weeping has a very small effect on the overall enjoyment of the 6 six engine.

http://forums.pelicanparts.com/uploa...1391218232.jpg
http://forums.pelicanparts.com/uploa...1391218249.jpg
http://forums.pelicanparts.com/uploa...1391218268.jpg

Pretty straight forward concept. If you put in a ring to seal then make sure any gap is to the top. Porsche, aftermarket wire as I suggest or even piston rings. Mind your gaps orientation. Simple. Questions?

http://i458.photobucket.com/albums/q...psff868a71.jpg

With the 2.7, I wouldn't expect warped heads - but heads with a pitted & worn surface...

BUT:

What I totally missed in this discussion was that we're talking about 92mm replacement cylinders, not 90mm... as Robert mentioned above he wanted to keep his original pistons...? (mea culpa again)