2.2S Change to from Biral to Nikasil Issues.

[bobmagyar]

I am rebuilding a 1970 2.2 S engine. As the Biral cylinders are no longer available I have a set of Nikasil to replace the originals. This raises questions about case squirters and Timeserts. I have a magnesium case without case squirters or Timeserts.

What I would like to determine is there any absolute reason to install squirters and timeserts? When Nikasil cylinders are discussed a 2.2L engine is not the engine being rebuilt.

2.2L Engines have less cooling issues, as the cooling fins on the cylinders are larger due to the smaller piston bores. The engine that I am rebuilding is an S engine so the cylinders already had Aluminum outer cylinders so the stresses on the head studs should be similar to the Nikasil cylinders. Could there is an issue with the expansion rates of the alloys that I am unaware of?

In summary these two common upgrades are done to manage thermal stresses within the engine. Thermal issues are not a common problem with the 2.2 engines so are the upgrades necessary?

My engine will not see much track time.

Any experiences or advice would be appreciated.

Thanks in advance.

[fryardds]

When I had my 2.2S case at the machine shop (Competition Engineering) last year I went with the suggestion from the owner, Walt, to do the case squirters, the oil by-pass modification and have case savers installed. He strongly urged using case savers over time certs.

[raspy2point2]

I to am looking at a 2.2S rebuild fairly soon and have begun research. I know the stock head studs which are steel are the best. But Nikasil is only avaible now I herd. I think you are asking for trouble if you have aluminum barrels and steel studs. One mechanic told me they use 993 studs with Nikasil barrels. I am hoping that the machanic I use says the same thing when I rebuild my 2.2S. I know the heat issue is not as important as 2.7 or bigger engines, but I am not taking any chances-- I want to rebuild this engine once. Chris 70S R-Gruppe #144 / Early S reg.

[Eric911S]

It seems to me that there is a lot of bull being tossed out there. Yes use the steel head studs they are great even with nikasil cylinders. I've raced and built many street engines using them.I would install the squirters for sure and the by-pass depending what you use the engine for.The 993 head studs are coated with a rust coating of some kind and look like a piece of threaded rod. I use time serts not case savers because I've seen the case savers come loose. Again if you are using the engine for racing use time serts, if a street engine and the threads in the case are ok than use as is.Thanks Eric

[Edwin Ek]

Did the '73 RS cars, the first to use Nikasil p & c's as far as I know, have squirters? When did they first show up in road cars or race cars?

[nick-moss]

Piston squirters were first fitted to the 1971 MY 2.2 motors

[Steve@Rennsport]

Hi:

I'd just chime in here and affirm the recommendation for installing case squirters.

The main reason Porsche used them was to control piston temperatures and expansion rates when hot. Nikasil P/C piston-to cylinder wall clearances are based on the use of squirters to prevent piston scuffing at high temps.

Porsche first used Nikasil cylinders in the 4.5 litre 1970 917 motors and began using them in the 2.7 RS (911/83) engines.

Steel studs are just fine for all of these small (90mm and smaller) engines. We've used Case Savers since 1976 instead of Time Serts in magnesium cases as the thread pitches are very different and Case Savers are far more stable. If one pulls out, thats due to an improper installation and no fault of the technology. If a Time Cert fails, you will need another case.

For high-HP big-bore, mag cased engines, we use the superb 993 TT Dilavar studs. The heads stay torqued (without cylinder head distortion) much better throughout a wider temperature range than steel, ARP or Raceware ones do.

The last thing I'd mention is the extensive detailed preparation and machine work that all these magnesium cases need anymore to be durable and reliable. This metal is not particularly stable at high temperatures and given all the heat cycles that these engine cases have undergone in the past 30-35 yearrs, its only prudent to pay close attention to all fasteners, oil galleys, blind holes, and all dimensions to ensure trouble-free operation.

I do hope this helps a little,...

[fryardds]

Thanks Steve,

Now that is cutting through the bull. Your information is exactly what Walt at Competition Eng. and Wayne D. says in his engine rebuilding book. Time certs for a Mg case is not recomended. My understanding is that if they fail it is a rebuild again.

[Chuck Miller]

I agree with all Steve has said,
Having gone through a recent mag case rebuild let me add ...

Our 30 year old mag cases come with their own set of 'issues' before they ever get to the machinist.

After first starting my rebuild we discovered a head stud leak... Out the motor came, back on the stand it went, and we were 'down to the studs' on that side in a day. Nothing was obvious at first but after 'oiling' and pressurizing the case we found the leak. It seems that the boring and taping for the savers had opened an anomaly (read-casting flaw) in the case and it left a pin hole in the roof of one of the case saver threads INTO the case... Once the case was under pressure - out came the oil.
The machinist and my mechanic concurred that epoxy in that one hole would seal it up (and it has) However... WHAT'A PAIN IN THE A$$ !!!!

Have the machinist 'triple-check' all case saver work before it leaves their shop... Our old mag cases seem to have a life and history of their own.

BTW - One thing that hasn't been mentioned is that the change to Nici cylinders will drop Bob's engine weight by 8 pounds.... right in the right place...