Question For Wisco Piston Kit Users

[79XS11F]

I am about to check ring end gaps so I can move forward with the work on my hop up engine. Wisco instructions say end gap should be .004 per inch of bore.
The instructions say that additional gap may be necessary depending on engine mods. There is however NO guidance. I will on this engine have:
accel high performance coils
Exhaust side of head ported and somewhat polished.
4 into one performance exhaust.
pod filters.

Should I be thinking about a larger end gap for the rings? If so by how much?
The bike will not be raced.


Rob

[79XS11F]

OK .. I have 2 and 9/10 inches of bore on #4 cylinder. If I understand this correctly that means I need 2.9 X .004 of end gap for that cylinder?
That = .0116 of end clearance.
Does that make sense?
Rob

[pggg]

Rob if the machinist rebores the sleeves properly there won't be any hassles with ring gaps, about the only thing to do is make sure the 4 ring gaps on each piston are apart - not in line. Some mechanics spread the gaps 120 deg apart on all 16 rings(includes the oil rings)

[webbcraft2150]

"This bike will not be raced"

Yeah right!!!

[DiverRay]

Rob,
Your figure should be good. Round it up to .012, and keep them all the same. As the rings wear in, the gap will open a little bit, so when you run it "hot", they should not bind and break.
As pggg said, spread the gap around the bore, then follow the break in restrictions so the rings and cams all "wear in" properly. Once done, you should be able to get over 100K miles on the engine with no problems.
Ray

[79XS11F]

The machine shop that did the boring did not have the rings. Just the pistons and the block. Now I checked the top and second rings on #4 and if I go by the numbers the top rings gap was too small and the second rings gap was too big. There's nothing i can do about any gaps being too big but should I not correct the gaps that are too Small?
I do know to set up the gaps 120 degrees apart.
Rob

[79XS11F]

Originally posted by webbcraft2150
"This bike will not be raced"

Yeah right!!!

Well not in the "real" sense but there is no doubt that the throttle will be twisted from time to time.

Rob

[79XS11F]

another question about this hop up. Should I start running higher octane gas in this engine when the rebuild is complete?
Someone told me I will have to!!
Rob

[John]

With the increase in compression, premium gas is a must, unless you like the sound of detonation.

[DiverRay]

Rob,
You do want to have the ring gap at least to the minimum. If the gap is too small, then file a little off the end of the ring to adjust it. The big gap, you'll just have to live with. It should not make much difference, the bike will still be FAST when your right wrist wants it to go.
Ray

[79XS11F]

Originally posted by John
With the increase in compression, premium gas is a must, unless you like the sound of detonation.

Thanks John. I wanted confirmation on that one. At current gas prices I am glad it's a small tank compared to a car. What about the ethanol fuel. It is supposed to be cleaner but i am not sure about the octane rating.

Rob

[79XS11F]

Originally posted by DiverRay
Rob,
You do want to have the ring gap at least to the minimum. If the gap is too small, then file a little off the end of the ring to adjust it. The big gap, you'll just have to live with. It should not make much difference, the bike will still be FAST when your right wrist wants it to go.
Ray

So it's a fiddle fart sort of job then eh.. file a little tiny bit and measure and file a little tiny bit and measure ..........
Rob

[pggg]

Just being difficult here, but my bike's got wiseco pistons and all the other drama - and there's no noticible difference between regular or high octane. The high stuff burns slower so's less chance of knocking but My ignition timing is even 5 degrees advanced and regular is still fine. 11:1 isn't that high. Run BP7's or 8's tho.

[mro]

file a little tiny bit and measure and file a little tiny bit and measure ..........

When you get em where you want em,
put a very slight bevel top/bottom of ends.


mro

[79XS11F]

Re: file a little tiny bit and measure and file a little tiny bit and measure ..........

Originally posted by mro
When you get em where you want em,
put a very slight bevel top/bottom of ends.


mro

Will do. I guess that's what they mean by taking a stone to the files ends eh?

As for compression i have been led to believe that the final compression ratio will be 10.1 to 1 which is up from stock 9.1 to 1.
Is that spec in the paper work that cames with the pistons?
Rob