Intrusion crown pistons

[johnymd]

As my mind has started drifting back to L-series engines and I've now picked up the engines from Steve Adams, I'm looking at the spare engine he started building with intrusion crown pistons. I understand the priciple of how they effectively reduce the volume of the chamber and so increase compression ration. Is it still something thats used today or is there an alternative method of doing the same job?

Basically, the reason I'm asking is: should I continue to build this engine with the parts he has supplied or throw them away and do it differently?

 

[datsun dave]

Why not finish whats been started as that going to save you a few quid if your not happy with the finished product you can build another engine.

 

[SKiddell]

Intrusion crown pistons are very current tech.......

But pointless in a "cooking" engine as they rely on optimising squish, are designed to create conditions for big compression ratios (12/13/14:1) and optimise mixture swirl.

(this is where we might get into airbox territory as this sort of engine build will require getting everything right) I.E if your not prepared to do that then you may as well use flat tops.

do you know what the make is

I would be very interested to know any info plus pictures etc

 

[johnymd]

They are venolia, the same as Matt ran in is race car. Here's a pic. This is just for the spare engine as I will get it back on the road with his proper engine.

 

[SKiddell]

Venolia....nice
Very well respected, more common in high end setups nowadays as JE etc have stolen a lot of their budget type work

If I recall Venolia pistons are mentioned in either of the "how to build" or "how to modify" books and had a specific pattern for the L series.
But I might be wrong, no doubt someone will tell me (funny that theres nearly always more people telling you when your wrong than when your right any way I digress)

Whats also important is the shape of the combustion chamber, the idea is for the two to work together to create a good swirl pattern and large quench area (anti det) with the intention of running high compression

This assumes that Steve had begun modifying the chambers etc......any pictures of the chambers

 

[johnymd]

I'll get the spike head from the lockup and take a pic as I may need a fair bit of advice on this. I'm leaning that I know less than I need to.

I love starting a new project. The wife will be too as it means I wont be looking at moving for a little while.

 

[Mr.F]

If I recall Venolia pistons are mentioned in either of the "how to build" or "how to modify" books

Page 28 "How to Modify...". Venolia the choice of Nissan Motorsport. Custom fit to cylinder head rather than grind too much out of combustion chambers says Frank Honsowetz.

 

[Albrecht]

Venolia the choice of Nissan Motorsport.

In this instance, as local suppliers to Datsun Competition USA and Nissan Motorsport USA.

Nissan Japan had their own domestic piston suppliers for Sports Option parts, Nissan factory race option parts, Nissan Sports parts and their various Works and semi-Works competition activities.