Recommendations, boring, ballancing

[Nessism]

Then the GS1100 guys go way overbore like you are they bore the cases to accept the larger sleeves.

 

[GregT]

Then the GS1100 guys go way overbore like you are they bore the cases to accept the larger sleeves.

Correct - this is the correct way to do it but if you've got nothing else, filing will work with patience....I wouldn't reduce the sleeve diameter as it would be easy to create a stress raiser where it changes.
You're looking for some clearance - .006 - .010 inch area but it's not critical. The sleeves don't locate the barrel - the dowels do.
As it's a plain bearing motor cleanliness is paramount after enlarging the case bores.....

 

[Guest]

As it's a plain bearing motor cleanliness is paramount after enlarging the case bores.....

I hear ya, the last time I had it apart was to powder-coat it. That took a long time to get perfectly clean!

I wash several times, clean and rinse, run air and cleaning brushes through everything,

As a side note: A co-worker said to me one day, why not just put it in the dishwasher?
I never thought of it the whole time I rebuilt it the first time


Anyways its settled, I'll pull the base apart and file just the case top to accept the block the way it is.

I'm looking at 0.040" in the front and back on both sides and half of that for the left to right on each side but there is lots of meat there.

 

[Graham]

A pen grinder could save some time over a file on the case bores.

Something to help with your compression ratio. It's VW but it works the same.
http://www.msgulfcoastvwclub.org/TechPages/Tech10.html
http://www.vdubn.com/sandrailing/engine/deck_height.htm

 

[rustybronco]

Can you find a metal hole saw in the proper diameter? you could chuck it up in a drill press and center the case half under it.

 

[Guest]

Sorry its been a while since I've had the chance to get back to this project.

I'm involved in Oval track racing in the thunder devision and they call me "The Doc" for these cars (88-91 civics).
http://www.scotiaspeedworld.ca/weeklyracing.html

Its been taking up all of my free time.

But when I had the chance I've been making base shims and cutting out paper gaskets.

I've finally found the right piece of aluminum I want to make the head gasket out of and its just a mater of getting time to cut it out with a friends scroll saw.

Something to help with your compression ratio. It's VW but it works the same.
http://www.msgulfcoastvwclub.org/TechPages/Tech10.html

Graham I was looking at that site again and it finally made more sense.

I took the stock measurements

67 bore
56.6 stroke
deck height .5 (piston is .5mm below top of deck with stock base gasket.
combustion chamber 19cc's ( this is the head and the head gasket that makes the combustion chamber)
comp ratio 10.5


new using calculator

78mm bore
56.6 stroke
combustion chamber 21cc's
comp ratio 12.5
deck height 0.5mm

 

[Guest]

Still busy racing or have you had a chance to do some more? Curious to see how this turns out...

 

[Guest]

I'm done with the racing thing for a while Pete. Now its just a matter of getting motivated to get out in the cold and strip the bike down.

I spent 4 hours tonight taking the engine out of the frame and getting it ready for disassembly.

To do:
1 split the case
2 remove the studs
3 enlarge the case to fit the cylinders.
4 reassemble
5 shim for cp ratio
6 check piston to valve clearance and adjust valve relief
7 order proper base gasket
8 slot cam sprocket's slightly
9 determine best cam timing.
10 assemble engine
11 install, start, cross fingers ray:


I have a scrap case that I tried to mill by hand to fit the cylinder block but I think its better to just take the case to a machine shop and have it bored precisely to match the cylinders. $30 why not, no guess work.


I'll use washers for the base shim until I get the proper height and then either make one or order one that would be the right thickness.




I'm going to try and add pictures as things progress, but I get carried away sometimes and do 10 steps and then take one picture

 

[Guest]

Sounds like you got it all planned out! Nice

For $30 I'd get it done professionally too...

Pic's are always good, but I understand on the 10 steps/1 pic thing

 

[platinum2]

hey i have some pop up pistons that will make it scream if your going 67mm 4valve piston buy the kit wayy cheaper than wiseco, then sell the other 2 ,would make a crazy fast bobber or cafe ect...

 

[Guest]

Thanks platinum2 but my stock pistons are 67mm and all the sleeves i have are worn. I would like the increased compression keeping stock piston size but i need to bore to at least 68mm to clean up the cylinders.

 

[Guest]

Cylinders bored, Head decked, and shortened sleeves.

Here is where my pictures will be:

http://www.flickr.com/photos/61692938@N08/page5/

 

[Nessism]

Looking forward to seeing this engine going back together.

A bevel on the bottom of those cylinders would assist getting the pistons installed.

 

[Guest]

thanks Nessism

That's something I'm going to ask for when I have the case machined to the block.

 

[Guest]

Nice to see you back into it! And having put my cylinders back on using my fancy ring compressors (my fingers), a bevel is a damn good idea... I would've been screwed if there wasn't one there from the factory...

Definitely looking forward to seeing this go back together also

 

[GregT]

For those with ambitions of the ultimate twin. I 'd point out that Toyota 4AGE from '85 to '87 used an 18mm gudgeon pin....81mm bore.

Wiseco do forged pistons for them too....

You'd have to sort sleeves and bore the block to the max to fit them, but a quick measure up says it's possible.

 

[Guest]

My block with the GR650 sleeves is as big as I would go with this cylinder block. It gets really thin in the middle of the sleeve.

81mm is possible and it leaves 2mm left.

 

[platinum2]

Cylinders bored, Head decked, and shortened sleeves.

Here is where my pictures will be:
/www.flickr.com/photos/61692938@N08/page5/

they cut the sleeves but didnt taper the lips?, pain in the arse putting pistons in with out it

 

[Guest]

Actually I cut them myself by hand.

I had the block bored, then I baked and set the sleeves. After that I cut the sleeves to length and had a shop bore to 78mm and plane the head.

I'm going to ask them to add a taper to the cylinders when they bore the case to match the cylinder block.

 

[platinum2]

wow i searched a lil , found nothing , i dont know what your going to do for good caamshafts, send them in to web or somewhere i guess, thats going to kill the build with out good cams