Time for a bit of an engine rebuild thread. So, my 2.0 CJ has 86k on the clock and as far as I know has only ever had light tinkering - I don’t think the heads have been off before. It runs perfectly well, with good compression, but has a little knock on start up and is prone to blowing oil smoke on warm start up. I know the cam is past its best and if I replace the bearings now I might avoid a regrind and line-bore later. Also an refreshed engine will give peace of mind when racking up those summer miles. So here goes.. Engine out (with help from @Chrisd)… Strip down started.. Heads off.. I wasn’t expecting to find sodium filled valves, even less so on the inlets - but on a bit of research I think this was the norm on a CJ - could anyone confirm? The lifters are a bit convex rather than concave, and that oily No 4 is helping to justify the strip down. Now in the scrubbing clean stage; will update on findings when I get to measuring up. In the mean time, what’s the best way of pulling out the valve guides? The YT video on cutting an internal thread, putting in a bit of tube and then a bolt with a nut to wind it out seams the best way, but also have access to a nice press. Which would you choose?
A press with the correct shouldered tool will be civilised. Having sodium filled valves makes that nice and original. ( I like the original VW disposal instructions.. snap and put in a bucket of water.)
Can't think why you'd need sodium-filled valves on the inlets. They don't get hot Do you really need to change the valve guides?
The knock on start-up could be a worn cam thrust bearing and it’s worth using a double thrust when you rebuild the engine. A type 4 is unlikely to require a line bore, especially at only 86k miles. AFAIK only some 1800 heads had sodium filled exhaust valves (with 0.2mm/0.008” clearance). No engine had sodium inlet valves – no need, the fuel/air cools the valve. Lifters should be convex; they wear flat and eventually concave when they are completely knacked. Valve guilds are one of the few things I would leave to those that have the equipment to not only remove , replace and ream the guilds but also to 3-angle cut the valve seats – and replace the seats if necessary.
Yes, I’m thinking press. I can knock up a dowel tool thing to drive them out with. Well not sure yet tbh. I’ll have a good measure of wobble with some new valves as per the book(s) and see, but I think from an initial hand wobble with the old ones there’s a bit too much play particularly on the exhausts. I’ll keep you informed! Thanks for that. Indeed, not expecting to go a for line bore. Don’t know why it should have the sodium inlets - perhaps a low-stock day of SS back in June 1978? Lifters are definitely flat or convex - so will get replaced with the cam. Thanks for the honest assessment of the valve guides replacement job. Stupid question, but does it really need 3-angle cutting, or would just 30-degrees do?
I did my type 4 valve guides via the YouTube method, and although it felt all kinds of butchery, especially putting them back in with a air hammer, it did work, and they haven’t fallen out yet! If I had had access to a press at the time, I would have used that I am sure.. much more civilised!
It doesn’t need three angles but if your replacing the guides and having the seats cut anyway it’s well worth doing at the time for the increase in performance You will be surprised what can be gained with head work on a Vw air cooled engine
VW never fitted sodium inlet valves to any engine – they are at least four times the price of standard valves and the bean counters would never have allowed something to be fitted when it is totally unnecessarily. New lifters will be convex, flat are worn out. What cam are you going for? No such thing as a stupid question, although you might get some stupid answers. Three angle seats are not essential but they make the engine more efficient and develop a bit more power. And if you’re having the seats reground the extra cost is minimal.
The sodium inlets will remain a mystery then - all four are sodium. I’ve got the full (I think) maintenance history for the last 2o+ years dating back to about 45k miles, and there’s no mention of heads-off work. I meant concave lifters, not convex! I have to stop and think which is which and I got it wrong way round anyway. Cam wise it will be stock, just as the VW gods intended. Going to have a think about how the valves get done once I’ve weighed up how worn they are, the availability of tools (and practical help and advice) and where I could get them done. Will report back.
Best way to get guides out is to thread them , put a bolt in and effectively hit the bolt out .. from the bottom . So your effectively stretching it not compressing guide . How do you know they are sodium valves ?
I see what you mean. Perhaps the best way then is to thread them, put the bolt in and use the press on the bolt head to push them out. Well, I’m taking the ‘S’ stamped on their faces to mean they are sodium, as with the 914, but am now waiting for someone to me tell me I’m wrong!
I thought sodium valves had a dimple in the head . But hence my question I don’t know . you press the bolt out stretching guide .
I doubt if those inlets are sodium filled, tap the stem, do they sound hollow and do they seem light for the valve size? if they are sodium and you don’t know how old they are I suggest you replace them, they can and do fail and the results are catastrophic to the engine – you wouldn’t be concerned about an align bore.
