sixtwoeight Posted May 7, 2018 Share Posted May 7, 2018 I'm looking at changing my valve stem seals on my 2.25 petrol. I would rather not take the head off, so how much will the valve drop once ive removed the collets and springs - obviously with piston at tdc. Thanks Quote Link to comment Share on other sites More sharing options...
rtbarton Posted May 7, 2018 Share Posted May 7, 2018 One method is to pressurise the cylinder with compressed air, via an adapter made from an old spark plug. The piston needs to be at BDC and the pressure stops the valve dropping. Quote Link to comment Share on other sites More sharing options...
sixtwoeight Posted May 7, 2018 Author Share Posted May 7, 2018 Ah ok, thanks, so I'm guessing from that, that at tdc the valve would drop too much then? Quote Link to comment Share on other sites More sharing options...
rtbarton Posted May 7, 2018 Share Posted May 7, 2018 Haven't dared risk it Quote Link to comment Share on other sites More sharing options...
Peaklander Posted May 7, 2018 Share Posted May 7, 2018 (edited) When I did mine on my 300TDi I knew that they don’t fall far. Even so to start with I fastened a little bit of cord on them (clove hitch tied by forming one loop behind the other). This was a silly fail safe. You could do this just to see how far you could let them drop. Or simply use the cord to hold the stem whilst you get your fingers sorted to pull the seal up and the other back on. Edited May 7, 2018 by Peaklander Quote Link to comment Share on other sites More sharing options...
AV8R Posted May 8, 2018 Share Posted May 8, 2018 Another way of keeping the valves in place. In case you don't have compressed air. Remove sparking plugs. Rotate crankshaft so the piston of the cylinder you are working on is in a low position. Take a length of cord, about 6 to 8 mm diameter. Push the cord throught the sparking plug opening into the cylinder, leaving some outside to retract the rope afterwards. A knot in the end will keep the cord from entering completely. Now rotate the crankshaft until you feel resistance. The "compressed" cord will keep the valve in situ for you to do your thing with the seal. Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted May 8, 2018 Share Posted May 8, 2018 Could you find a small bar magnet and stick it to the valve stem to stop it dropping? Quote Link to comment Share on other sites More sharing options...
rtbarton Posted May 8, 2018 Share Posted May 8, 2018 ^^ It would have to be in place while you removed the springs & collets, bit risky IMHO. Quote Link to comment Share on other sites More sharing options...
sixtwoeight Posted May 8, 2018 Author Share Posted May 8, 2018 Interesting ideas, if the seals arrive tomorrow il be giving it a go - I was going to do what peaklander suggested with tieing some cord around the valves but the rope method that AV8R mentioned sounds good. Il see what takes my fancy tomorrow. Cheers chaps. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted May 8, 2018 Share Posted May 8, 2018 How are you going to compress the springs? There’s a write up for how to do this for the 300TDi in the technical archive. Quote Link to comment Share on other sites More sharing options...
sixtwoeight Posted May 9, 2018 Author Share Posted May 9, 2018 I had a read of your thread and have made a similar tool, seals didn't come in until late so only got as far as rockers off. (sounds like you had bit of a nightmare) Quote Link to comment Share on other sites More sharing options...
lo-fi Posted May 9, 2018 Share Posted May 9, 2018 Just to throw a curve ball in... Are you sure it's just the seals need doing, and not worn guides too? If the valve stems are a "proverbial in a bucket" fit, new seals won't do much for very long. Liking the ideas for keeping the valves from dropping, though. Quote Link to comment Share on other sites More sharing options...
sixtwoeight Posted May 9, 2018 Author Share Posted May 9, 2018 (edited) 52 minutes ago, lo-fi said: Just to throw a curve ball in... Are you sure it's just the seals need doing, and not worn guides too? If the valve stems are a "proverbial in a bucket" fit, new seals won't do much for very long. Liking the ideas for keeping the valves from dropping, though. No I'm not sure at all, just hoping I suppose. My theory is that it wasn't used for probably 20 years so hoping the seals have gone bad and now its been run, it is not sealing. So once the springs are out the valves should have little/no sideways movement??, just so I know whether I'm wasting my time with the seals. Edited May 9, 2018 by sixtwoeight Quote Link to comment Share on other sites More sharing options...
lo-fi Posted May 9, 2018 Share Posted May 9, 2018 53 minutes ago, sixtwoeight said: So once the springs are out the valves should have little/no sideways movement??, Sadly, the workshop manual doesn't give a spec, just a rather glib "replace if excessive". 2 thousandth of an inch would probably be OK for that size of valve. Very much more and you're probably best off looking at getting the head to a machine shop and getting the guides done. They'll fit new seals, and you might as well get it cleaned and the valves inspected and lapped while you're there. Sounds like a lot of work, but it's not major money and you'll know its spot on when you're done. But fingers crossed your theory is correct and the seal rubber is just old, perished and not doing the job any more. Do please take some pics either way Quote Link to comment Share on other sites More sharing options...
rtbarton Posted May 9, 2018 Share Posted May 9, 2018 Maybe get unleaded seats fitted at the same time? Quote Link to comment Share on other sites More sharing options...
AV8R Posted May 9, 2018 Share Posted May 9, 2018 1 hour ago, sixtwoeight said: My theory is that it wasn't used for probably 20 years so hoping the seals have gone bad and now its been run, it is not sealing. Unless there's a copper head gasket, after 20 years of neglect a regular steel head gasket may be on the edge of giving up. Like a lot things steel, time takes it's toll. I know my V6 had a blown head gasket within 500 Km after it's revival, having not run for 20+ years. Not trying to scare you off, just to keep an eye on it. Quote Link to comment Share on other sites More sharing options...
sixtwoeight Posted May 10, 2018 Author Share Posted May 10, 2018 Tried the above methods (not air) and none worked, the valve opened and spring compressed so couldnt remove the collets. I wasted an hour trying this so probably quicker to take the head off so... I noticed when I took the rocker cover off there seemed to be water in the top but I assumed it was condensation? Anyway, I've taken the head off to get the valves out and have noticed a few little potential issues...including more water, il stick some photos up when I get home for your expert knowledge... It had a copper head gasket and the pistons and bores look good and clean to me. I thought about getting the seats changed and guides replaced but phoned for a quote and it is more than I can afford so if the guides need doing il see if I can do them? Pics to follow. Quote Link to comment Share on other sites More sharing options...
sixtwoeight Posted May 10, 2018 Author Share Posted May 10, 2018 (edited) So, Gasket had water on it (appreciate water will have come from head as I took it off but...) and there is a stain by number 1 cyl - is that water getting by? where I'm pointing these are raised on both the block and the head - the gasket has obviously compressed more in these areas by wonder if that means the rest of the gasket wont seal as intended if the raised areas bottom out on each other? How do I get the areas flat - without getting the block decked and head skimmed? Edited May 10, 2018 by sixtwoeight Quote Link to comment Share on other sites More sharing options...
sixtwoeight Posted May 10, 2018 Author Share Posted May 10, 2018 (edited) The oval (ish) shapes between the pushrod holes on the gasket a couple have just very small pin holes and the others are more oval but have slightly torn the gasket - bad photo. Is that correct? Also 2 of the exhaust valves are a different colour? Edited May 10, 2018 by sixtwoeight Quote Link to comment Share on other sites More sharing options...
lo-fi Posted May 10, 2018 Share Posted May 10, 2018 2 hours ago, sixtwoeight said: How do I get the areas flat - without getting the block decked and head skimmed You can't, I'm afraid, or certainly not really acceptably. Flat deck and head are pretty much not negotiable. It looks like water has been sat trapped against the gasket rotting the iron as AV8R suggested above, which may explain the raised areas - rust is several times the volume of iron. The brown exhaust valves are pretty much "it wasn't running right". Possibly lack of compression, water in the cylinder, poor valve setting, even a cracked head.... So it looks like its wasn't happy when it was laid up, poor old thing. What's the history? Quote Link to comment Share on other sites More sharing options...
sixtwoeight Posted May 10, 2018 Author Share Posted May 10, 2018 10 minutes ago, lo-fi said: You can't, I'm afraid, or certainly not really acceptably. Flat deck and head are pretty much not negotiable. It looks like water has been sat trapped against the gasket rotting the iron as AV8R suggested above, which may explain the raised areas - rust is several times the volume of iron. The brown exhaust valves are pretty much "it wasn't running right". Possibly lack of compression, water in the cylinder, poor valve setting, even a cracked head.... So it looks like its wasn't happy when it was laid up, poor old thing. What's the history? Mmmm, not happy. Ive spent far too much time and far too much money on this now, its starting to get me down. Anyway... It has been sat for a good 20years, rear chassis was rotten, ive replaced that along with many brake and suspension parts, rebuilt the gearbox and probably other bits I forgetting. I guess it was parked up for a reason?? I did a compression test and posted the results on here on another thread, and they seemed acceptable. I have to get this done now for next to no money. Quote Link to comment Share on other sites More sharing options...
lo-fi Posted May 10, 2018 Share Posted May 10, 2018 Believe me, I feel your pain... The head, as it's now portable, you might as well get inspected, skimmed and whatever else sorted. The block is a bit more of a challenge, but maybe not insurmountable. First up, get in clean. Everyone seems to have their own methods - wire brush, gasket scraper, sanding block - I've seen it all. Once you've got the carp off, have a good look at those high spots and get a decent straight edge to it. If the rest is flat, you've got a chance of tackling those high spots. You might well find that a gasket scraper will blast the corrosion off and you'll be able to see what you're left with. Big divets are a different problem, but a few high spots can possibly be fixed with some DIY bush engineering if you don't want to pull the block and have it all apart. A deck skim isn't much more than a head, but it is a lot of work to get it to that state. Anyway, find a large, thick piece of glass (with nicely bevelled ground edges!) you can wrap some wet and dry (start at 80 or even 40 grit) around and get to work with plenty of WD40. Take it easy, keep it flat, keep it lubricated and keep checking with the straight edge. You'll soon see the high spots and can adjust where you're working and applying pressure to compensate. It's not ideal, it's not really the suggested way, and it's certainly not right, but hey, it's an old Land Rover. Might just get you out of trouble if you're happy to put some hours and elbow grease in in lieu of spending pennies. Setting the crank so the pistons are mid way up the bores and carefully cutting some cardboard circles to pop on top and sealing with a bead of silicone will save the grinding paste going into the bores. Protecting the rest is much more tricky. Filling with rag is maybe about all you'll be able to do, but necessity is the mother of all invention! Shout if you want some more hare-brained ideas thrown at you Keep us posted! Ian Quote Link to comment Share on other sites More sharing options...
sixtwoeight Posted May 11, 2018 Author Share Posted May 11, 2018 (edited) 7 hours ago, lo-fi said: Believe me, I feel your pain... The head, as it's now portable, you might as well get inspected, skimmed and whatever else sorted. The block is a bit more of a challenge, but maybe not insurmountable. First up, get in clean. Everyone seems to have their own methods - wire brush, gasket scraper, sanding block - I've seen it all. Once you've got the carp off, have a good look at those high spots and get a decent straight edge to it. If the rest is flat, you've got a chance of tackling those high spots. You might well find that a gasket scraper will blast the corrosion off and you'll be able to see what you're left with. Big divets are a different problem, but a few high spots can possibly be fixed with some DIY bush engineering if you don't want to pull the block and have it all apart. A deck skim isn't much more than a head, but it is a lot of work to get it to that state. Anyway, find a large, thick piece of glass (with nicely bevelled ground edges!) you can wrap some wet and dry (start at 80 or even 40 grit) around and get to work with plenty of WD40. Take it easy, keep it flat, keep it lubricated and keep checking with the straight edge. You'll soon see the high spots and can adjust where you're working and applying pressure to compensate. It's not ideal, it's not really the suggested way, and it's certainly not right, but hey, it's an old Land Rover. Might just get you out of trouble if you're happy to put some hours and elbow grease in in lieu of spending pennies. Setting the crank so the pistons are mid way up the bores and carefully cutting some cardboard circles to pop on top and sealing with a bead of silicone will save the grinding paste going into the bores. Protecting the rest is much more tricky. Filling with rag is maybe about all you'll be able to do, but necessity is the mother of all invention! Shout if you want some more hare-brained ideas thrown at you Keep us posted! Ian Ian, Thank you for your ideas and it's nice to hear that you can understand my situation and suggesting ways that are not correct but may work for me. Il have a think about it today and decide which way to go, but will probably do exactly as you've suggested. I can't be the first to be doing it the "wrong way" and knowing it's wrong. Thankyou. Edited May 11, 2018 by sixtwoeight Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted May 11, 2018 Share Posted May 11, 2018 Can you get composite gaskets for the 4 pots as you can for the V8? Might be slightly more forgiving of slight surface variations once you’ve given the block a clean although I’ve seen worse than what’s in your photos before. These old engines are quite resilient. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted May 11, 2018 Share Posted May 11, 2018 As its an iron head and block, hit it with a wire brush in a drill (or grinder if careful), that will remove most skunge very quickly. Rust is 50 times greater in volume than the iron that forms it, so I reckon you have a good chance of seeing that good enough to work again. A head skim it not pricey BTW, 30-40 quid would do it. Quote Link to comment Share on other sites More sharing options...
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