Nikasil Coated Biral Cylinders

[rkshanahan]

I am helping a friend gather parts for his 2.4 S rebuild before he pulls the engine in order to reduce the downtime. He has a lined up a spare set of used, original 84 mm Biral cylinders, I am just wondering if there is any new data on Nikasil coating these as opposed to just boring/honing them? Either way, the plan is to have CP make new pistons for them. I have two specific questions:

1) Is Nikasil coating of the Biral cylinders considered to be worth it? The car is used for occasional sporty, street driving, not daily driver or track use.

2) Is it safe to bore the Biral cylinders out from 84 mm to 86 mm, which seems to be pretty common?

I found some good discussion about this back in 2015, but I wanted to see if people have changed their thinking since then.

Rob

[Neven911]

For what it is worth I wouldn't bother a nikasil coating on cast iron (even if it can be done which I doubt). The nikasil/alusil coatings were developed to create a hard coating for aluminum.
Re how far you can bore birals (I have bored mine to 85mm) every mm you go you remove 0.5mm from the head to cylinder contact ring before the CE ring so increase the risk of blowing head gaskets imo - I've seen some go ridiculously close and the engines didn't last. I'm sure others with give better guidance.

[Zuffenwerker]

I would not plate the steel cylinder walls. It would be best to just oversize the liner as little as possible and not plate. Or better yet just buy new biral liners for 84 or 86 for around $700 that don’t need any machining…if he’s planning on spending $1,000 or more to recondition (plate) the old cylinders why not just buy new ones.
I’ve used the cheap cylinders plenty…a few 2.0 and 2.4 rebuilds. As long as they measure out they are a great option.