Questions: Arrow on piston, Milling cylinder head, stock washers

[mikedabomb]

Opened my 66cc and the arrow on the piston is pointing towards the intake? Also, how far to mill the head? I'm guessing I have to mill it until it has a consistent surface, and no more.

On my mounting hardware and the head nuts I have split washers and I do not know what the order is for the nuts, flat washers, and split washers.

 

[crassius]

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I have never, in close to 1000 motors, had to mill a head. Never look at arrow (or lack thereof) for direction of piston - only important thing is that the ring locating pins are on the intake side. Several flat washers, split washer, nut. Add enough flat washers to keep stud from binding inside the acorn nut (just one washer if you use a normal open nut).

 

[HeadSmess]

ditto that. have never milled a head, but do remove the stock gasket and use teflon tape instead, works so much better.

the spring/split washer should be in contact with the nut.

use as many or few flat, plain washers as required.

ignore the arrow, locate the piston by the pins in the ring grooves. place them towards the intake.

 

[mikedabomb]

Thanks for the responses. You guys saved hours of time that I used to seal up the wiring hole

I came across something weird...when I put the head back on, I noticed that I had 10 flat washers instead of the 8 which I expected. This concerns me, I don't know if my organization is wrong and they came from a different part sitting nearby or if the manufacturer is sloppy and put a few extra on...I'll use 2 on each stud to stay consistent

How do you make a Teflon tape gasket?

What do y'all think of packing snow on the cylinder to keep it cool during break in, where I can't resist WOT?

Thanks, Mike

 

[butre]

take some teflon tape, twist it up, and coil it around the mating surface and don't overlap anywhere. it'll compress to a hair under 1 thou. teflon gaskets aren't reusable so they'll need to be replaced if you ever disassemble the engine, but they cost all of a quarter to make so no biggie.

putting snow on the cylinder is a good way to crack it. think of what happens when you try to boil water in a drinking glass, or put cheap dollar store glassware into a sink of hot water. same mechanism, just less extreme.

WOT is good for break in, just don't hold it at top speed. that's how you glaze rings. as long as the loads are kept high (ie. accelerate only, no cruising) you'll have the best possible break in. that whole "baby it for break in" thing you get with new cars and bikes and such is just lawyers talking, not the engine builders. hard break in gets you the most power and the longest engine life.

 

[KenM]

Hi Mr. Butre. You have me interested it your Teflon tape gasket now too. This is a head gasket you are talking about?
I can see it working for the side covers. But I thought their would be to much compression at the head for it to work there . Thanks for the tip!
Keep looking up! Ken.

 

[mikedabomb]

take some teflon tape, twist it up, and coil it around the mating surface and don't overlap anywhere.

I'm struggling with "twist it up," "coil it" and "don't overlap anywhere". When I think twist it up and coil, I think of the structure of a rope.

I think I get what you mean by coil, lay each piece next to each other in progressing circles, but "twist it up"...like the end of a joint?

Thanks ahead of time

 

[sbest]

Opened my 66cc and the arrow on the piston is pointing towards the intake? Also, how far to mill the head? I'm guessing I have to mill it until it has a consistent surface, and no more.

On my mounting hardware and the head nuts I have split washers and I do not know what the order is for the nuts, flat washers, and split washers.

As mentioned, ring ends go toward the intake. How does this match up with the arrow now?

The head as it comes is probably fine.
Mine did warp, but as a result of heat and detonation.
New sheet of 150-250grit sandpaper on a flat surface and rub.You will see when it is good.

I am not a fan of the Acorn nuts or stacks of washers. Buy good nuts and use one flat washer is my choice.

Steve

 

[crassius]

the assembler at the factory will usually try to get the right amount of washers needed (they do sometimes fail tho) - having two extra washers tells me that you have two studs that are a bit taller than the other two (or one stud way taller than the other three) and that's where the extra washers are needed - you could measure how tall they are, but I usually just sight across them to spot the high ones

 

[butre]

I'm struggling with "twist it up," "coil it" and "don't overlap anywhere". When I think twist it up and coil, I think of the structure of a rope.

I think I get what you mean by coil, lay each piece next to each other in progressing circles, but "twist it up"...like the end of a joint?

Thanks ahead of time

you got it.