jamesmartin
Well-Known Member
that would show in excessive sideways movement in the guide its the seat faces
jamesmartin
Well-Known Member
try lapping valves in you should see if its contacting 360 degrees
dag019
Well-Known Member
Not that i could see but it didn't meaningfully run with leaking valves because the timing belt had snapped
dag019
Well-Known Member
Having got hold of a proper micrometwer (all be it imperial) all of my valves seem to be under tolerance by about 0.02-0.03mm as long as the Haynes measurement are correct. Is this enough that they will need to be replaced or should I still try lapping them in to see if I get a seal as you suggest above?
jamesmartin
Well-Known Member
all old valves will have wear as will guides what play is there when fitted is there a clear contact mark 360, to cause blow by valve would have had to been bent during piston contact
mick 1986
Well-Known Member
Personally, if they are out of spec, then they are scrap. The specs are for a reason and I would replace. I don’t know if it’s the cause of your problem, but it can’t be helping.
dag019
Well-Known Member
There is a clear contact mark currently, but obviously that is the old one. I am still awaiting my valve grinding kit which should have been delivered today and did not arrive, so will have to wait before I can lap them in. I will then see if there still is a clear contact mark all the way around.
I need to remeasure them after checking the micrometer is zeroed correctly as have just been told it probably hasn't been used for 30 years! So will check if it properly zeroed and adjust the readings if not before deciding if they are truly out of tolerance.
jamesmartin
Well-Known Member
bung your valves back in and fill ports with diesel
dag019
Well-Known Member
Refit valves fully, head upside down, fill with diesel and see which ones still have diesel in tomorrow morning? That will narrow down the cylinders which are a problem correct?
dag019
Well-Known Member
Micrometer was 10thou out so the measurements are right at the bottom end of tolerance.
Have filled valves with diesel. And will see what it looks like tomorrow.
jamesmartin
Well-Known Member
ports up valves on the side, if any leak it will **** out
dag019
Well-Known Member
Will try that tomorrow. Don’t have enough diesel to do that now. And don’t fancy symphoning out of the tank!
dag019
Well-Known Member
Well this is 24hour later. One still has fuel in but not the full amount, one is wet the others are completely empty:
Does that mean I need new valves or does that mean I just need to lap them in again to get a good seal?
jamesmartin
Well-Known Member
its a new test to me and one ive never done or heard of, if you think how fast the valve opens and shuts there has to be a bad match between valve and seat to cause an issue ie bent or burnt through, try it on its side if it pours out as you fill it then theres an issue, seeping out not so but obviously id lap them in
dag019
Well-Known Member
Will do. Will get some more fuel to try the other way.
dag019
Well-Known Member
Have now carried out this test. None of them showed signs of pouring out straight away. A few of them trickled very slowly. I then lapped in all the valves and re tested and it had improved but a couple still show a trickle.
Am I expecting a perfect seal or just not pouring out?
jamesmartin
Well-Known Member
it doesnt sound like they were such an issue,whilst its off you may aswell lap them in well
dag019
Well-Known Member
Great. Thanks for that. I will give them a good lapping in and then refit the head and hope it will run.
Is there anything to be aware of when when refitting (other than torquing sequence) or is it as straightforward as it seems?
dag019
Well-Known Member
Well last night I finally got got the time to put everything back together and get the engine running again. A quick test drive yesterday and a drive into work this morning and everything seems to be fine.
I am still unconvinced the timing belt is running completely true on the tensioner, but could not see any issues with the casing or the tensioner. I will check it in about 1k miles and see if there are any problems and investigate further if there are.
I would like to say a huge thank you to @jamesmartin and @Flossie, as well as everybody else who has contributed to this thread and helped me get the engine back up and running.
I am still unconvinced the timing belt is running completely true on the tensioner, but could not see any issues with the casing or the tensioner. I will check it in about 1k miles and see if there are any problems and investigate further if there are.
I would like to say a huge thank you to @jamesmartin and @Flossie, as well as everybody else who has contributed to this thread and helped me get the engine back up and running.
