Topic: Piston Head Combination, is this going to explode?

[captain rats]

I am trying to wrap up the rebuild on my K1 engine. It has been a pain in the ass. The guy sold me a rebuilt engine that really was not. It had no rubber seals in the oil return passages and I decided to replace the top end and rebore the cylinders. First thing I did was get Hondamans book, great resource and due to his advice put heavy duty studs from APE in it. I also got a webcam 41a the milder one for it.

I rebored the cylinders and got a 811 wiseco kit from Chewie (good bloke). I have a standard K1 head, I cleaned it up a little, doesn't  leak from the seals and it is straight.

I had a question regarding the compatability of the standard head on the 811 wiseco kit. Is this going to work or is the compression ratio going to be too high?

Here is a photo of the head before I cleaned the carbon off it.


Here is a link to the project.
http://forums.sohc4.net/index.php?topic=120803.0

[Powderman]

While the increased bore size will also increase compression ratio I doubt that it would be enough to be concerned about durability of the engine.

[bjbuchanan]

No, the wiseco is usually around 10.5:1 without other mods, unless your pistons have the very obvious super high domes that the 12:1 have. Unless the head has really been milled down, like really milled not just cleaned up, it should be fine.

If you want to be really safe go get some playdoh and do a mockup and see if you have interference. Little extra work but better than crashing stuff.

[Vinhead1957]

Looks like it was running pretty good though

[captain rats]

Here is a photo of the piston tops, Just so there is some reference to the shape and whether the opinion is that they are too domed or not.

[Black 750K8]

A side shot would be more helpful.

[PeWe]

The pistons look like 10 something to 1.

This is what I should do:
Make a test without head gasket. Do not torque the head too much just put it together, mount cam towers and cam, time it as it should and turn the engine slowly around. If it will turn around without hitting anything it must be safe when the head gasket will add more in height and clearance.  Check valve clearance at max lift position by tighten the adjuster screw until it hits the piston. If you can tighten down another 1 mm, it must be OK when the head gasket will add more in clearance.

Remove head and add gasket o-rings and put it together properly torqued this time, time cam again as before.