Club 80-90 Forums

Recently, a loud ticking noise from cylinder no. 1 has been geting worse (2.1 DJ engine) i wrongly thought that it was due to a sticking hydraulic lifter, so tried some flushing oil at fast idle for 15 mins, as stated on the can, changed oil and filter in an attempt to see if that would cure the lifter noise, well it didn't but i noticed a worrying amount of bronze coloured particles in the drained oil. after getting the cover and rocker assembly off, it became obvious that the problem is not lifter related but the exhaust valve on no. 1 cyl.
the end of the valve stem is 'mushroomed' over and shorter than it should be, also there is noticable play, if you try to move the valve side to side that is not present in the other valves.
i'm certain the bronze colour particles are from a very worn exh. valve stem guide.
a bit of the engines history... i rebuilt it 4 years/25K Miles ago, and it had new inlet and exh. valves and guides as part of the rebuild. also new valve adjuster screws. no problems at all up untill this recent tapping noise, all the other exh. valve stem ends have slight pitting, and very slight mushrooming as well, so they look to be heading for the same fate.
obviously the heads need to come off and at least the exh. valves and guides need replacing, and i would imagine the seats would need re-cutting, but does anyone else have any experience of this problem? maybe it's down to inferior quality non original (sourced from GSF) valves which weren't hard enough on the stem ends, there is no real wear on the adjuster screw ends, which were changed at the same time, or would guide wear have caused the problem? the plug on cyl. 1 is blackened slightly as well which must be due to oil getting past the guide. any thoughts on this would be good to hear.
Is 25K the sort of mileage where this kind of problem would be appearing? i make sure the oil and filter changes are never left for more than 6000miles. I'm really not looking forward to getting the heads off again after i thought all would be well for a good few more years yet, they're even still watertight!

Dear Sir, at least you know what the problem is and you can sort it without having to rely on others to do the job for you.

I supose you have been through all the possible reasons as to why this has happened so soon after a recent re build and would like to prevent it re occurring.
Personally I'd be having a close look at the rocker shaft and rockers for signs of wear which may be linked to the wear on the valve and guide.

Don't forget to check that the valves are seated properly (once they have been replaced) as it is possible to put the valve guides in on the p iss.


Regards,


Fritz,,,,,,,,,,,,

Worse than i thought..... engine is out and heads off, the exh. valve guide of the noisy valve is unbelievably worn, almost thru to the alum. of the head in one spot and the seat is well battered, to the extent that some of the actual head material around the seat has been worn away, that valve head must have really been moving about a lot! I dont know if a replacement seat would work, as the alum. of the head around it could do with building back up by welding, then machining back to shape, def looks beyond just recutting the valve seat, I'm wondering if the cheap, GSF guides and valves not being of the right type of metal/hardness has caused this, i got some good quality german made TRW/Kolbensmitt valves from brickwerks and will put phosphor bronze exh guides in the 'good' head, which is nowhere near as bad, but does slightly have burred over pitted stem ends and some wear in the guides, new heads would be nice, but they really cost!
a localish breaker wants 150 quid for a 2nd hand head,
Fritz, thanks for the reply, had a look at the rocker shaft assemblies and all look to be fine, no loose rattly fits on anything, the jk rocker adj. screws which i fitted at the time of rebuild are still fine and only lightly scuffed, all seems to point to the premature wear of the ex. guides being to blame, i know they get really hot and have a harder time of it than the barely worn inlet valves and guides, which get cooled by the incoming mixture constantly,
2nd hand head and quality valves and guides seems the best option. all in all, a right effing p1sser!