SLROC Forum

When I bought my 1972 SIII (with it's original engine and 140k miles) nearly 3years ago the guy said his next job was valve stem oil seal replacement.  Now it starts with a puff of blue smoke, but does not smoke once running, and some times it runs on in a lumpy way for a few seconds after being switched off and after it's worked hard (not very often!).  I think therefore it needs a decoke and the valve oil seals replacing.  So my stupid questions are: will "decoke in a can" work and can I replace the valve oil seals without taking the cylinder head off?  (There's a guy on You Tube who replaced vavle oil seals on a Suzuki Vitara, with the cylinder head still on by bringing the piston to TDC, and stuffing rope into the cylinder to stop the vavle dropping into the cylinder).  Or am I better to take the head off in case valves etc need more work. Any advice would be appreciated, cheers Clive.

Hi Clive
I've not done it on a landrover engine but have changes valve stem oil seals on other motors and I've always taken the head off - I wouldn't do it any other way cause you can do other things at the same time
Once the heads off you can clean the inlet and exhaust ports plus grind / lap the valves too - check the boars and see how much play is in each piston while your there, the oil scraper rings might be getting passed it which can show the same as you've discribed
It's not a big job and there loads of dark winter nights ahead - you'd be amazed at the difference once it's all done
Take your time, enjoy the work and be proud once it's all done and 'up n running'
Hope it all goes well, Ian

You need to take the head of it is impossible all-so dangerous  to replace the seals with head still on. You can then clean all carbon from the ports and head surface. You may at worst have to have to re-cut vale seats or at least re-grind the valves.

Thanks for the advice, it's in for an MOT on Wednesday, so assuming that goes okay, I'll go for taking the head off in the next couple of weeks.

It's not a big job and there loads of dark winter nights ahead - you'd be amazed at the difference once it's all done

Those dark winter nights don't have the same appeal, when I don't have a shed/garage big enough to put the car in.  The car is on the drive, but at least I can work on the head in my small workshop, so the more delicate elements will be inside!

Out of interest - why is it dangerous to do the oil seals with the head still on?

Cheers, Clive

The danger is in trying to remove the valve spring col lets without a spring compressor.

There are tools available to replace the stem seals without removing the head, Sealey VS1601 and VS160, first item is an adaptor to screw into the plug hole to use air pressure to keep valves closed,the other is a tool to compress the spring to remove the collets.I would try to replace the seals with the head on,if not a total success take the head off,the seals can still be used after a decoke. My way on Ford 2 Litre OHC Pinto engines was to put the piston halfway down,feed a length of string in the plug hole, bring the piston up till it jammed the string against the valve. This held the valve closed to allow the spring to be compressed with a pry bar under the cam allowing the collets to come out and then replace the seals.