Betsy Posted November 12, 2007 Share Posted November 12, 2007 My 2.25 was fitted with hardened valve seats a few years ago, and the engine bottom end rebuilt 3 yrs ago. It has been running perfectly on unleaded until now. I just did a 3500 mile trip to Morocco and back, a lot of it was spent on motorways at 55mph. The car seemed to cope easily. Towards the end of the trip, I was aware of more fumes than normal from the engine, especially when the engine was on over-run. She also seemed to be idling on 3 cylinders, but once up to speed drove pretty well, but down on power slightly. I did a compression test, and 1, 3 and 4 were 145 psi, 2 was 60 psi. So yesterday I lifted the head off. The composite gasket showed no signs of leakage, the exhaust flange gasket had a slight leak on 1 and 4 cylinders. I turned the head upside down, and filled the combustion chambers with petrol. 1, 3 and 4 were perfect and held the petrol with no leakage. Number 2 just peed out through the exhaust port. The exhaust valve was obviously not round and is 100% sure to be the cause of the rough idle. However, what can cause this to happen? do hardened seats have a detrimental affect on the valves themselves? why only 1 cylinder? the others are perfect with no pitting at all. Its an easy fix, but I am just wondering if there are any other experiences of prolonged use at motorway speeds with unleaded fuel in an engine with hardened seats fitted, and is there something I am missing that could have caused this. It may of course just be old age. Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted November 12, 2007 Share Posted November 12, 2007 Or one duff valve. Quote Link to comment Share on other sites More sharing options...
tacr2man Posted November 13, 2007 Share Posted November 13, 2007 insufficient valve clearance( rocker gap) to start, ? Insert not cut quite true ? there are many possibilities. rebuilkd paying particular attention to anthing connected to valves probably never happen again.IMHO Quote Link to comment Share on other sites More sharing options...
Ras Thabiso Posted January 1, 2020 Share Posted January 1, 2020 Guys, all my three engines 2.25 engines, gasket, cylinder head and engine block, get knocked. Tired of 2.25 series engine. Somebody blames the unleaded petrol and advised me to install hardened valve seats. Does this work? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 2, 2020 Share Posted January 2, 2020 Yes. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.