Breather pressure

Hi
How
Much smoke
And pressure would be normal
From breather pipe after an engine rebuild while running in ?????
Thanks in advance
John

What engine ?

sierrafery said:

What engine ?

Click to expand...

Hi
Sorry forgot the info. Its a TD5. I have changed
head
one piston
all pistons rings
all bearing shells
had bore honed
changed all engine wiring

Starts great but seems to be choking a bit and when i take off the breather there is smoke and pressure. Do i need to run engine in a bit before everything will calm down or has something gone wrong as not sure a fuming head is what should be going on

Thanks

All i can tell is that it's not normal to be pressure or smoke at idle, here's how mine is:

Winter Rover said:

Hi
Sorry forgot the info. Its a TD5. I have changed
head
one piston
all pistons rings
all bearing shells
had bore honed
changed all engine wiring

Starts great but seems to be choking a bit and when i take off the breather there is smoke and pressure. Do i need to run engine in a bit before everything will calm down or has something gone wrong as not sure a fuming head is what should be going on

Thanks

Click to expand...

Were the valves ground in properly? And/or, is the camshaft properly timed in?
Could the exhaust be blocked in some way?

Stanleysteamer said:

Were the valves ground in properly? And/or, is the camshaft properly timed in?
Could the exhaust be blocked in some way?

Click to expand...

HI
Recon head and no exhaust is fine. Im running it in so the question is during run-in would the pressure be more while the rings are seating properly
thanks

sierrafery said:

All i can tell is that it's not normal to be pressure or smoke at idle, here's how mine is:

Click to expand...

HI
So I've just started running it in today. Could it be that I need to run the new rings and piston in for longer to get them seated properly as there seems a lot of smoke coming out and really don't want to have to start again !!!!!!!

Thanks

Winter Rover said:

HI
Recon head and no exhaust is fine. Im running it in so the question is during run-in would the pressure be more while the rings are seating properly
thanks

Click to expand...

Forgot to say timing i have just set at the far end of what i can turn the camshaft to. Should i try changing this to get it running smoother ? Ive messed about a bit but doesn't seem to do anything

Winter Rover said:

Forgot to say timing i have just set at the far end of what i can turn the camshaft to. Should i try changing this to get it running smoother ? Ive messed about a bit but doesn't seem to do anything

Click to expand...

As long as the timing chain and sprockets are properly aligned with the marks, then all you should need to worry about is that the tensioner is set properly

Stanleysteamer said:

As long as the timing chain and sprockets are properly aligned with the marks, then all you should need to worry about is that the tensioner is set properly

Click to expand...

Yep that’s all sorted.

Well pressure in the crankcase is usually due to blow by which, if you hadn't done all this work, would usually imply worn pistons and bores. You only changed one piston so I have to assume there was a good reason for not doing the others. You didn't mention a rebore so again I have to assume that there was no problem there. But there must have been wear or you wouldn't have changed the rings, unless you just thought you might as well do it while you were in there so to speak.
What was the reason for the rebuild in the first place? Cam chain snapped or summat?
It maybe that the pistons/rings/cylinders need to bed in a bit. Maybe you are getting a bit of blow by due to an imperfect seal, but usually after a rebuild things should be tight rather than not.
Can you do a compression test and/or a leak down test?
Might help narrow it down.
As for it "choking", what exactly do you mean by that?

Did you space the ring gaps?

Winter Rover said:

Hi
Sorry forgot the info. Its a TD5. I have changed
head
one piston
all pistons rings
all bearing shells
had bore honed
changed all engine wiring

Starts great but seems to be choking a bit and when i take off the breather there is smoke and pressure. Do i need to run engine in a bit before everything will calm down or has something gone wrong as not sure a fuming head is what should be going on

Thanks

Click to expand...

The piston rings will need bedding-in, so report back after 500 miles. replacing just the rings is only a short term solution as i'm sure u know, a proper job would be a rebore and 5 new pistons.