Avenger 85 help

[Wyvern]

This is the Avenger, Phantom and MS380 pistons. All are 51.8mm diameter, avenger is 40.5mm height while phantom and ms380 are 39.3 height.

I'd wager the Avenger piston is lighter weight.

What is interesting is the other two have sipes for oil on the wrist pin where the Avenger does not.

I wonder how much compression the Avenger loses/blow by vs. a standard 2 ring design.

Also with less ring, less heat from the piston is going into the cylinder wall, but it's also less friction, so it may be a wash.

I'd love to get a phantom to compare, I do not believe the Avenger is an entire HP shy of a Phantom, but I also know, even with more surface area, this engine still generates gobs of heat and is still a "problem ”

 

[NeedSpeed]

This is the Avenger, Phantom and MS380 pistons. All are 51.8mm diameter, avenger is 40.5mm height while phantom and ms380 are 39.3 height.

Bravo! Thank you for that information. Can you measure the distance between the wrist pins to the top of the pistons, please?

 

[mony0_3]

Avenger=18mm, Phantom=15.8mm, and MS380=16.2mm

 

[Whitewill1412]

Avenger=18mm, Phantom=15.8mm, and MS380=16.2mm

Those are substantial differences. How can they all be interchangeable?

 

[mony0_3]

By adding a base gasket or shaving the cylinder.

 

[NeedSpeed]

Avenger=18mm, Phantom=15.8mm, and MS380=16.2mm

Thank you, Mony!

 

[ImpulseRocket]

Looks like they have similar crown heights from the wrist pin center too, at least close. Nice. I wasn't the biggest fan of the single ring design the avenger comes with.

 

[NeedSpeed]

Finally, they have arrived!

 

[NeedSpeed]

Update. After replacing seals, bearings, gaskets/polishing all mating surfaces, swapping heads, coils etc, the A85 still doesn't run. It continues to be too lean. I guess I'll smoke test it. Here we go again. At least I like how it looks.

 

[mony0_3]

Your exhaust will be blue like mine after the test!