AAZ Ring gap?

[RunninWild]

Hey guys, getting ready to put my aaz back together and I cant find any info on ring gap for my new pistons. They are KS # 91 429 620 .50mm oversize, box says 80.010mm
Pistons say:
79.980
Sp0.03
A23K
91429

I tried emailing ks but never got a response from them. Anyone happen to have the info on hand? I'll be running a holset turbo around 25psi if it makes any difference. I'm also interested in the clocking info...

I just checked 1 set of rings and they are .305mm for the top ring and .330mm for the middle ring

[RunninWild]

I just did some math following this guide http://www.aa1car.com/library/ringendgap_wiseco.pdf
The piston reading 79.980mm = 3.1488189 inches
3.1488189 x .0050 = 0.0157440945 inches = 0.3999mm 1st ring
3.1488189 x .0055 = 0.43989000033 inches = 0.4399mm 2nd ring

is this correct? I'm thinking I need to know the exact size the cylinder was bored to?

[libbydiesel]

You do NOT figure ring end gap by any sort of math.  You insert the ring into the cylinder, true it with an inverted piston to push it down a little so it is eve, then use feeler gauges. 

I don't have the Mk3 Bentley here, but have the Haynes.

Piston ring end gap specs:
Top compression ring:
     Spec for new ring: 0.0079-0.0157
     Wear limit: 0.0472

2nd compression ring:
     Spec for new ring: 0.0079-0.0157
     Wear limit: 0.0236

Oil scraper ring:
     Spec for new ring: 0.0098-0.0197
     Wear limit: 0.0472

I don't tend to trust the Haynes specs so hopefully someone who has the Mk3 Bentley in front of them can confirm. 

[RunninWild]

ahh thanks, I just found a copy of the bentley online.

looks like your specs are right .20mm-.40mm for the first and 2nd rings, and .25mm-.50mm for the oil ring.

Looks like my rings, on the piston I checked anyways are right in the middle of spec. Good to know I dont need to file them.

Here is the engine loosely piled together. I'm happy with how the paint turned out. Por15 ford corporate blue on the block, vht metallic black on the head, duplicolour metalcast blue on the valve cover/injectors and vht wrinkle paint black on the G60 intake.

[RunninWild]

I just got the crank installed and measured the gap on all the rings. They are kind of all over the place and 2 rings are right at the edge of spec.
Piston 1:
.381mm
.305mm
.457mm
Piston 2:
.330mm
.356mm
.406mm
Piston 3:
.356mm
.305mm
.381mm
Piston 4:
.356mm
Between .381mm-.406mm
Just under .508mm

Basically the last 2 rings on piston #4 are just on the edge of spec. I guess my question is, is it worth hand filing all the rings so each cylinder has a close to equal gap, or should I just install them as is? I'm not going to spend $100 on a special ring filer, so is it worth the risk of messing up the square edge to have an equal gap? Is there much of a performance or reliability difference in doing so? I don't really care about getting every last hp out of this thing, I'm more interested in having optimal compression and minimal oil consumption.

[ORCoaster]

Are you wondering if you should change the gap on cylinders 1-3 to match the gap that is nearly at the acceptable point of wear?  I would go with what you have, know that as the piston ring wears on #4 it will be out of spec and could become an oil consumer. 

These dilemmas where one of the cylinders is so bad you want to bore and just jump up a size of piston are head scratchers.  If you don't upsize all cylinders at the same time you are in a bad way.  If you just button it up as is you are in a bad way.  But the cost to do the right thing may be more involved both mechanically and financially.  So I would say start saving those shekels now for the proper repair later.  You are on a limited clock but won't see a real problem until the top ring wears bad enough to allow the oil to burn.

If it wasn't for bad luck we wouldn't have any at all right?
 

[RunninWild]

The thing is the block was already bored and I'm installing new pistons and rings. I was wondering if I should try and even them out a bit closer but I just went ahead and installed it all as is. I doubt the machine shop would re-bore it and pay for new pistons for me for the next size just because I'm on the edge of spec so it is what it is. These rings came with the pistons (ks) and pre-installed on them already. If oil consumption is an issue in the future I'll get some file to fit ones and gap them better. The wear limit according to the bentley is 1.0mm and 1.2mm so they should still have plenty of life in them and hopefully oil consumption wont be an issue for a long time. This is "my baby" so it will have regular oil changes and be very well maintained. Its going in my samurai which I don't plan on daily driving for very long so I'm hoping for 20+ years out of this engine. Assuming I can make the truck live that long anyways haha.

[ORCoaster]

You will have the Samurai on its head long before the engine wears out then.  Happy Wheeling, be safe and not sorry.