Are Piston Oil squirters essential ?

[red-beard]

The Factory moved to Piston oil squirters. Wayne's book says they are essential to Nikasil cylinders. What's the scoop? What are the advantages and disadvantages?

Are they essential, a very good idea, a reasonable idea to add life, something the factory did, etc.?

I'm getting conflicting information from various sources. This is a street engine and will not be seeing a tremendous amount of use per year. One source, who makes Nikasil cylinders, says they are not needed. Again, Waynes says you have to have them for Nikasil.

James

[911pcars]

I think the cylinder walls get enough lube from normally spinning parts. I believe the underside of the pistons benefit from the additional heat transfer from oil sprayed directly in this area. They added piston squirters when the engine got up to around 2.7 liters. Up to then, combustion chamber heat on the pistons was tolerable.

This image isn't directly related - piston died from detonation, but I thought it'd be interesting to see:


Sherwood Lee
http://members.rennlist.org/911pcars

[red-beard]

Hmmmm. I'm not too worried about detenation since the CR will only be 8.5:1

It's funny, my Case has the spots to drill and install oil squirters.....even though it's only a 914/6 case.

James

[Tim Walsh]

My personal impression would be that they're essential. THey cool the pistons themselves an amazing amount (over 50c). I don't think I would be comfortable running a biral or T cylinder over 180 HP without them and I certianly wouldn't run nikasil cylidners without them. The tolerances between the nikasil cylinders and their pistons are just too close to allow the higher running temperatures that resuolt from the lack of the squirters.

[andrew15]

Oil squiters were actually introduced on the '71 2.2L - relatively early on in development of the flat 6. This was before the nikasil plating that appeared on the 2.7 P&C's. Reducing oil temps seems like a pretty good idea in itself, but is particularily attactive when the tighter tolerances of nikasil are taken into account.

Regards,
Andrew M

[Wayne 962]

The piston squirters help to lower piston temperatures. This is essential when you are running the close tolerances that are facilitated by the Nikasil cylinders. The piston squirters keep these temps low, and give you a much larger margin in case anything else goes wrong. I recommend adding them to all engines based upon the research I did...

-Wayne

[red-beard]

Well, I'm steering my rebuilder that direction. I'm just getting back up information while he checks his sources.

I am planning on going to 2.7RS P&Cs with S Cams.

I wanted E cams, but...rebuilding the T's into E's were more money than brand spanking new in the box German RS "S" cams.

James

Wayne - I thought you were on vacation....But thanks!

[red-beard]

Well, having some "discussions" about the piston squirters with my rebuilder.

Does anyone have any factory information as to why the piston squirters were added? They were added before Nikisil was used. Were they added to cool the crown and prevent detonation in the high compression E&S engines?

[Tim Walsh]

Yes but they put them in T's as well. I'd expect for economic reasons (two assembly lines make things expensive)

I'm rebuilding my motor currently and I refuse to run my engine without piston squirters

[dtw]

Not sure why a rebuilder would put up a fight on this. They reduce crown temperatures and enhance longevity. 50 degrees stands on its own merits and doesn't need a whole lot of additional support- that's absolutely huge. At this point I'd be calling the wrench and telling him "pencils down" while I went over to pick up my stuff and find another builder.

[69 911s]

When were the first piston squirters used? I know about production cars, but what about race cars? They usually tried things out in racing first, so did 906's use them or 910's or any others, anyone know?
Thanks, Holder

[Wayne 962]

Better cooling, hands down. I'm still on vacation right now

I would go with high compression pistons from JE and 2.7 cylinders over the lower compression RS pistons and cylinders...

-Wayne

[red-beard]

Wayne - Ollie's is installing the squirters tomorrow.

Oh, and I wish I had a spare $1000 for the J&E's....I'm already over budget...