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Long-time lurker, first-time poster.

Hi, my name is Ross and this is my childhood dream car.

1990 S13 Silvia K's

https://imgur.com/Pm55Dma

I've had this S13 tucked away for 7 years now, I feel that I'm now in a place where I can start to work on it.

The car has always had some engine trouble, low compression on cylinder 3, excessive blow-by, overheating issues, and eventually having a catastrophic failure on the freeway.

Ever since then, it's been put on the back burner... until now!

Last weekend I had pulled the engine out with the intention to strip it down and rebuild it.

https://imgur.com/PxvyUiF

This is my first time building a car engine, I've had some experience with motorbikes before though, so any tips you have would be greatly appreciated!

I was expecting to see a head gasket failure or a warped head, but to my surprise the head was flat and the head gasket looked fine.

Pulling the pistons out showed where the failure occurred.

https://imgur.com/l8GNTzw

Piston 3 had a failure of the ring lands, luckily the engine was immediately cut off when the failure occurred! this is evident by looking at all the bearings, which show no damage.

The crankshaft is in great condition, all journals are within spec with no damage, and the crank is not warped.

The bores all measure within spec. All bores are round and not oval.

I have a question for you all.

Cylinder 3 has a faint scratch corresponding with where the piston failed.

my options for forged pistons are +.5mm or +1mm, Speaking with my machinist he has recommended that we go with +1mm pistons. My only concern is if the bores are machines out +1mm and the engine needs to be rebuilt again, my only option would be to use the same bore or have it sleeved if there was any bore damage. whereas if I go for +.5mm it gives me some headroom for future machining to take place.

What would you do?

Attached Files

Assuming it's on a stock bore, I'd have the machinist take out out to ~0.4mm (or where it would be before final hone to size) over on that cylinder and check if the scratch shows - if it doesn't I'd use the 0.5mm over option, if it does I'd go to the 1.0mm.

That said, if I was expecting to put a lot of load on the engine as I upgraded other parts, I'd check to see what sort of power/torque/boost the stock cylinders will accept and if I was going to be pushing that I'd consider sleeving it now IF the budget was there. If not, just give it the lower over-bore that cleans it up and start looking for a short block you can build up with sleeves/pistons/rods, etc. for when you are ready to really lean on it - if that's your intention.

Personally, they're a lovely little car and I'd be looking at keeping it nice to drive rather than making it a horse-power monster that's a pain in normal driving.

Cheers Gord,

That's a great idea! I'll have a chat with the machinist, hopefully, he is ok with that.

If money wasn't a consideration I would go for sleeves, but unfortunately, I'm not in that position right now.

minimizing the amount of material being removed is only a concern as I do intend on keeping it for a very long time. So having the ability to bore it out again will be useful.

I agree with keeping it nice and tame, huge power isn't what I'm chasing.

First of all, sweet looking ride! I miss owning a Silvia, lowkey wish I had buy one instead of my R32.

And yeah, I would try to go with the smallest oversize possible. Give you headroom in case of failures as you said. Gord has a good solution that I haven't even think about!

I think the Nissan OEM piston choices for the CA18DET are +0.5 and +1mm, maybe they're still available (I don't think they are but who knows) and could be a cheaper option, but I would personally go for forged piston anyway.

Frank

Cheers, Frank

I think forged pistons are a great choice for the money. leaves me with some headroom for a little more power without being concerned about a piston failing.