Bottom end rebuild blues

After breaking my crankshaft, I finally got a new one and what is supposed to be the correct piston for it.

I got my whole engine back together, but before I could even install it, I noticed that the piston was hitting the head. I wasn't too worried about this because I could always add some extra head gaskets(that kinda stinks though), but then I noticed that the piston always covers the intake!

For those of you who haven't seen any of my other threads, I have a RAW motor with a broken crankshaft. RAW doesn't make their own motors anymore, and they don't sell the original crankshaft with the ZAF 60 connecting rod. Because of this, I had to settle for a crankshaft from Kings with a Z-L rod and I had to buy a piston with a lower wrist pin hole.

I really don't understand this.



I thought I got the right thing, but how the heck can the piston never clear the intake? It's not like there was a significant length difference between the old connecting rod and the new one. I expected maybe a little overlap but this is just ridiculous! I don't even have an obscure jug or anything like that, as far as I know.

Do I need to just buy a whole new motor to be able to finally ride again? I'm tired of buying parts to rebuild, only to discover that nothing works like it used to.

So let me propose this...

Does this mean that IF I get the right piston for the crank I have, and if I get a jug that should work with both the crank and piston, I should be alright then? I don't see how much else could be different, since I doubt the crank would be placed any higher or lower in different engines. Then again, I'm probably wrong.

wayne z said:

[QUOTE



Are you saying that the top, or the bottom of the piston never clears the intake?
The top of the piston never clears the intake, but the bottom does, on these piston ported engines.

Click to expand...

Oh my god.

I am a world class idiot. I should have remembered that the intake goes under the piston, not above.

The bottom of the piston clears the intake except for a tiny bit. This frankenengine of mine may work just yet! Thank you for pointing that out, sir.

But it's still hitting the head. I am assuming that this can be remedied with an extra head gasket or two? Also, is there such a thing as 'too much' compression? What if the piston clears the head but only by a tiny bit? Can this create enough compression to cause damage?

I thought I heard about extra compression causing the connecting rod to bend, if memory serves me right.