I'd have to get my notes to give you what the bore clearance ended up being. IIRC, they would be about 1.5 thousandths loose for a normal piston, but mine have had their skirts coated with a moly-disulfide coating from Swain Tech in NY.

I'm still waiting (less and less patiently) for Total Seal to make me a set of gapless rings. They make some that are in the catalog, but didn't recommend them for my application, but they did offer to make me a custom set that would work. That was last August.

Break-in hasn't been an issue since the engine is still in pieces. I plan to break them in either a) the way I normally do, which is run it like I'm going to use it being careful not to run at a single rpm for any length of time for the first couple thousanc miles or b) howver Total Seal recommends I break in their rings, if that method is substantially different than what I nomrally use. I have everything I need except the rings. The heads are together with the CHRFab cams and springs. I did some mile clean-up and polish on them is all. When the rings get here, I'm ready to assemble.

John Stricker

Edited for the sleeve material. I saw that in the shop manual as well. All I can tell you is that if that's regular cast iron like a normal block, that's the hardest cast iron *I'VE* ever seen. A normal honing procedure hardly made a mark on it and in fact, acted almost like it was polishing it.

John Stricker

What was wrong with the catalog rings for your/our application? Not durable for high RPM?

Here's a link to the Swain Pricelist. They coat darn near anything. http://www.swaintech.com/price.html

John Stricker

Sounds great - can't wait to see the outcome. So you do have true duals. Do you think they help balance/HP/or???? Any cats? I really want to go true duals; what size pipe did you go?

How much were you quoted for your custom rings?
I'm getting ideas...
If I read the Swain price list correctly, I'd be down $18 a piece if I had my skirts coated with the high end PC-9 stuff (where do they describe the different coatings, anyway?), and $42 each if I have the skirts coated with PC-9 and the tops coated with GC, which is actually more cost effective than skirt or dome coatings by themselves.

Rods: $450
Pistons: $600??
Rings: ??
Coatings: $350
Block machining: $300+ (Wcapman spent about $300, but didn't have the head bolt holes thread-serted)

Looking like it'll be close to $2000 by the time everything's put together, but that will be one built shortblock.

The fortunate aspect of this is that I don't have to do this quickly, as I'm still 5 months out from being 100% after knee surgery.

The rings were ballpark quoted me at $350 minimum to $450 maximum. I'm betting it's going to be at the higher end of the scale, what do you want to bet?? Which pistons are you using? Mine are the early pistons with the thick lands. The later, thin land pistons use different rings (I know, you already knew that, but some other readers may not have).

Swain's web site doesn't explain the differences very well at all. I had to call them and talk to them about them. On the dome coatings, the Gold Coat (GC) is a better, more durable coating. All but one of the Indy cars last year used Swain Tech GC on their pistons. The downside of it is that the GC needs to be installed and run in the engine within 30 days of them coating it to final cure the coating. I wasn't going to be able to do that, so I went with the Thermal Barrier (TB) coating on mine which is about 90% as effective as the GC, according to them. For the skirts, The PC-9 is more durable than Poly Moly (PM) but their "slipperiness" is about the same. Because of it's durability, they can also coat the piston thicker with PC-9 and control it very well to make an even coat across the skirts. I had mine done with the TBC top and PC-9 skirts. Yes, I know it's expensive. In fact, it's about half the cost of a new set of forged pistons. Frankly, unless I get into some severe detonation that breaks the lands out, I think the durability should be as good or better than forged, but that remains to be seen.

Even if I had gone forged pistons, I would have at least done the TBC on the tops. In the two engines I've had ceramic coatings done on the domes, I saw about a 30° drop in oil temperature because it keeps the heat out of the piston, which is transferred through the rods and rings to the rest of the engine components. I think it's worth it, but a lot of people don't so the usual caveats apply, of course.

Give Swain a call. Tell them how you're going to use your engine and they'll help recommend the coating that will help you the best. They won't try to oversell you with something that won't help. I was very happy with them. In shop turnaround for them was about 7 days. That goes to 14 days at certain times of the year when they're doing a lot of racing engines that HAVE to be done on time.

John Stricker