1.8 T Burn exhaust valves, head back on. - Page 2

Ratdogfink · 18th November 2009, 17:04

All the exhaust valves were pitted so I changed them all.

Telferstr · 18th November 2009, 18:52

Hi,
A number of years ago I know of a case where the valve stem oil seal failed due to what looked like the bad fitting of the seal at the top of the stem. This in turn allowed excessive oil to travel down the valve stem with the result that it burn-out the exhaust valve face. Or at any rate it was thought to be the cause.
Just a thought that this could be a possibility in your case.
Regards,
Telfer.

Gary · 18th November 2009, 19:25

Quote:

Originally Posted by Telferstr

Hi,
A number of years ago I know of a case where the valve stem oil seal failed due to what looked like the bad fitting of the seal at the top of the stem. This in turn allowed excessive oil to travel down the valve stem with the result that it burn-out the exhaust valve face. Or at any rate it was thought to be the cause.
Just a thought that this could be a possibility in your case.
Regards,
Telfer.

I agree with the above…..Pitting is often caused by the stem seals leaking and oil running down the valve, then burning and "sticking" to the exhaust valve.

Ratdogfink · 18th November 2009, 22:25

I do like that idea. Certainly both burnt exhaust valves are black around the valve seat and the plug came out wet with oil. The piston crown was reasonably clean but wet looking, the others dry.
The other cylinders seemed to be burning lean and I put this down to correction by ECU from the lambda sensor being flooded with un burnt fuel at the wrong time.
I can't seem to find a real reason why it did it so the valve seal idea seems pretty good. No smoke out of exhaust but then it's only one cylinder.

Thanks for the help on this one. I'm up to 85 miles since the head went back on and the plugs come out for a check tomorrow.

Phil · 18th November 2009, 22:29

How much oil did it use prior to the repair?

Ratdogfink · 18th November 2009, 23:03

A bit, not that much. Half a dip stick every few months. Didn't really worry as it just seemed normal.

Telferstr · 19th November 2009, 11:58

Quote:

Originally Posted by Ratdogfink

I do like that idea. Certainly both burnt exhaust valves are black around the valve seat and the plug came out wet with oil. The piston crown was reasonably clean but wet looking, the others dry.
The other cylinders seemed to be burning lean and I put this down to correction by ECU from the lambda sensor being flooded with un burnt fuel at the wrong time.
I can't seem to find a real reason why it did it so the valve seal idea seems pretty good. No smoke out of exhaust but then it's only one cylinder.

Thanks for the help on this one. I'm up to 85 miles since the head went back on and the plugs come out for a check tomorrow.

Hi,
The case I mentioned was on a colleagues 1.8 75. He thought it had suffered a head gasket failure but it turned out to be burnt out exhaust valves on one cylinder. Unfortunately I did not see the valves or the extent of the damage to them. As far as I know he had no further problems with the engine following the repair.
Hope all goes well from now on with your engine repair, keeping fingers crossed.
Regards,
Telfer.
Regards,
Telfer.

18th November 2009, 22:29	#15
Phil This is my second home Rover 75 CDT Connoisseur SE Join Date: Nov 2006 Location: Wales Posts: 12,227 Thanks: 469 Thanked 523 Times in 241 Posts	How much oil did it use prior to the repair? __________________

18th November 2009, 17:04	#11
Ratdogfink Loves to post 1 Join Date: Jan 2007 Location: 1 Posts: 336 Thanks: 0 Thanked 0 Times in 0 Posts	All the exhaust valves were pitted so I changed them all.

18th November 2009, 18:52	#12
Telferstr Posted a thing or two Mitsubishi Eclipse Cross 3. 1.5 Petrol 6 Speed Manual Gearbox. Great fan of the Mk1 75 which I had 3 Join Date: Feb 2007 Location: Inverkip, Scotland. Posts: 1,223 Thanks: 23 Thanked 68 Times in 44 Posts	Hi, A number of years ago I know of a case where the valve stem oil seal failed due to what looked like the bad fitting of the seal at the top of the stem. This in turn allowed excessive oil to travel down the valve stem with the result that it burn-out the exhaust valve face. Or at any rate it was thought to be the cause. Just a thought that this could be a possibility in your case. Regards, Telfer.

18th November 2009, 22:25	#14
Ratdogfink Loves to post 1 Join Date: Jan 2007 Location: 1 Posts: 336 Thanks: 0 Thanked 0 Times in 0 Posts	I do like that idea. Certainly both burnt exhaust valves are black around the valve seat and the plug came out wet with oil. The piston crown was reasonably clean but wet looking, the others dry. The other cylinders seemed to be burning lean and I put this down to correction by ECU from the lambda sensor being flooded with un burnt fuel at the wrong time. I can't seem to find a real reason why it did it so the valve seal idea seems pretty good. No smoke out of exhaust but then it's only one cylinder. Thanks for the help on this one. I'm up to 85 miles since the head went back on and the plugs come out for a check tomorrow.

18th November 2009, 23:03	#16
Ratdogfink Loves to post 1 Join Date: Jan 2007 Location: 1 Posts: 336 Thanks: 0 Thanked 0 Times in 0 Posts	A bit, not that much. Half a dip stick every few months. Didn't really worry as it just seemed normal.