when piston 4 is at tdc is it at the right height or the lower hieght? could simply be the crank is not perfectly plumb? not that thats a simply hey
hey guys, wanted to ask about this on here i think cause i just want someone to tell me this isnt the case, but i guess i would be neive to think its not.....
When me and my mate were pulling apart the ze to do the head gasket my mate pointed out to me when piston #1 is at TDC, piston #4 sits about 2mm lower.
My mate is telling me that it could be a couple of things.. different height piston, bent rod, bent crank... or some gay'd up bearings.
Regardless of what it is, its not good and it pretty much needs to be a rebuilt...
If i have to pull this thing apart again im going to be shattered and i cant see my motor going in anytime soon...
so can someone give me some hope? lol
when piston 4 is at tdc is it at the right height or the lower hieght? could simply be the crank is not perfectly plumb? not that thats a simply hey
RIP Carly - a smile to light the world.
06/07/2011
when i spun a bearing in my smallport, i pulled the head off, and i quickly saw this very thing. to make sure, you can turn the motor over, just past tdc, then stick a long screwdriver down piston number 4 spark plug hole, and try and push the piston down, if you feel it 'clunk', like it moved down a few mm, you probably have stuffed bearings.
stuffed bearings would be my first though,
doesnt sound to good there grant...
i assume you have it on an engine stand? if so spin it around and rip that sump off. and the bearing caps, you will quickly see if you got stuffed bearings. pluss if you get that far you might as well spend a bit on rebuilding it anyway.
not much nicer than a freshly built engine...but it does suck when you find out it NEEDS it...rather than you WANTING to rebuild it...good luck mate
That isn't the case.
I really have no idea, but you said you wanted to hear it. By the sounds of it, it dosn't look to good?
Nah doesnt sound too special, had a chat to 4a guru old man Josh and he reckons bearings. Gona take the sump off one night and he's gona come check it out for me, sucks either way but fingers crossed its just the bearings and nothing else too major.
If you have the head off.
Turn the engine so the pistons are half way down the bore then rotate then crank back and forth.
You should be able the feel the lack of bearing which has no don't been shreaded to oblivion..
It'll make a nice clunk feeling when you change direction and turn the crank in the opposite way...
Other than a totally stuffed bearing (most likely) is tha you have a nicely bent rod...
Which would you rather..??
If its a rod then you just gotta get a rod..
It is a bearing there's a good chance you'll need a rod or at least get all your rods resized. And its almost enevitable that you'll will have to get a crank grind.. Possibly even a new crank depending how bad it is...
That sounds terminal Grant, sorry to say. If it was bearings then 4 would presumably be the same height or 2mm higher at bottom dead centre. If thats not the case Id say it's likely a rod thats been hydraulic locked and bent.
Last edited by Anthony; 10th March 2009 at 12:10 AM. Reason: clarification
yeah can't be much better than either a slipped bearing or a screwed rod, in my auto class we had this happen, but was cyl number 2 and it actually stuck out like 2 mm over the top every few rotations. we decided to put it back together how it was and blow it up, good fun