Marmaduke
Well-Known Member
No, belt off and only turn the crank 360 degrees leaving the camshaft and injection pump lined up
ivancrx
Well-Known Member
Well what can I say, spot on, slipped the belt off spun crank 360 degrees belt back on and hey presto it all turns over nicely. just need to wait for the new gaskets to arrive and hopefully that will be the end of that little chapter.
Thank you for all of your help Marmaduke and everyone else who has had input, you are all what makes this place so good.
David_Cooper
Active Member
Ummm.. if you turn the crankshaft 360degs, it'll be in exactly the same position as it was before...
Marmaduke
Well-Known Member
No two rotations of the crank to one of the camshaft and injection pump sprockets
David_Cooper
Active Member
Correct.. but how would that change anything? When the piston/ crank is moving upwards, it doesn't know whether both valves are shut (compression stroke) or the exhaust valve is open (exhaust stroke). Turning the crank 360degrees won't change anything- if the engine is correctly timed up, ie dots aligning, FIP pin in place, arrows pointing to arrows- it's correctly synchronised.
jamesmartin
Well-Known Member
wouldnt make any difference at all
Marmaduke
Well-Known Member
Why did it then?
David_Cooper
Active Member
I would say something else isn't quite right, eg a sticking valve or the timing originally was a tooth or so out and loosening and refitting the belt 'moved' something. Personally, I wouldn't ever turn the crank with the cam shaft static though..
jamesmartin
Well-Known Member
it cant off done, as long as key on crank is at 12 oclock before belt fitted nothing else matters, if you remove the belt and turn the crank 360 then refit it its still the same,you only worry about turning engine twice once the belts fitted
ivancrx
Well-Known Member
The bottom end has been stripped so there was always going to be the potential for things not going back together as it was originally. It is all turning over as it should now so I am happy at the moment. I dare say next weekend with throw more problems at me though.
The only other thing I can think of is if a push rod hadn't seated correctly?
David_Cooper
Active Member
That's possible. Personally, if it's turning over ok now, I'd whip the rocker cover off and very carefully check your gaps and ensure the small caps are correctly seated on the top of the valve stem. If all checks out ok, and you're confident the bottom end is correct, you should be good to go.
ivancrx
Well-Known Member
They are all fitted and still there, I will be checking and triple checking before I fit it and try starting it.
David_Cooper
Active Member
Good, all you need now are brave pills for when you first turn the key!
Marmaduke
Well-Known Member
Just give it a few rotations by hand to check the timing is spot on then put faith in your methodicalness and you'll be fine. I think I've rebuilt three 300's recently and they've always started first time
cornish rattler
Well-Known Member
But the head is still off as he has ordered a new H.G. still not convinced
I would like to say to all see post number 12
yes its correct 2 turns crank is one turn cam/fip, BUT this only matters when belt is on (as James said above) so one turn of crank cam/fip will be 180 degs out and another turn they all line up again, or to put it another way for the advice given by others to make any sense the op would have had to turn the crank 180 deg then refit the belt.
Turning the crank 360 will logically put it back exactly where it was before Im not sure how anyone can fail to see that?
I think people over think cam/fip/crank alignment.
Back to the op I reckon it might be a good idea to get some plastigauge and see what your piston to valve head clearance is with head torqued up.
yes its correct 2 turns crank is one turn cam/fip, BUT this only matters when belt is on (as James said above) so one turn of crank cam/fip will be 180 degs out and another turn they all line up again, or to put it another way for the advice given by others to make any sense the op would have had to turn the crank 180 deg then refit the belt.Turning the crank 360 will logically put it back exactly where it was before Im not sure how anyone can fail to see that?
I think people over think cam/fip/crank alignment.
Back to the op I reckon it might be a good idea to get some plastigauge and see what your piston to valve head clearance is with head torqued up.
