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Post by vkh307h on Jun 24, 2018 17:22:45 GMT
Cranked over my bug today after a good clean out of the engine and new oil and it’s smokes terribly, it’s very choking!! Not sure if this is oil or fuel or both. Should I be looking at diving into the engine more deeply or is this because the engine hasn’t ran for so long this is normal? I’ve read lots of forums and people are saying valve stem seals, is this a straight forward task for a moderate engineer like myself or am I diving into the unknown and may total what bit if an engine I have left. When I turn it over from cold it’s not to bad to start with then as the engine gets warmer boom smokey smokey and it’s chokey chokey, any ideas and help would be much appreciated guys.
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Post by UncleFester on Jun 24, 2018 18:51:00 GMT
Hi, My Bug was in a museum for 20+ yrs. I did a total strip clean and re build on mine as don't want any probs when body goes back on. Mines a long way from being finished so bolted my engine to an upside down pallet I turn the crank from time to time and start it now and again anything mechanical left stood can be a problem. If no knocks and horrible noises then I would almost certainly consider changing the head gasket at least then you will be able to see the condition of the bores and delve into the condition of the valves, guides and seals. Took me two days of gentle tapping and rocking with a wooden mallet to get mine off, better to do now mate while its easy to access.
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Post by vkh307h on Jun 24, 2018 19:09:01 GMT
Hi!! Thanks for the reply, yes I did the head gasket valves etc they were coated in black residue which has all been cleaned. I think I will tackle the valve stem seals...
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Post by ayrbugger on Jun 24, 2018 19:57:03 GMT
vkh 307h.
When you take an engine head off the kit of parts usually includes the valve stem seals.
If you did not fit them you may be doing a second head off, on some engines it is possible to use a cranked tool to hold the valve in position when you take the collets and springs off, but the Bond Bug is very compact and tight for space.
regards Bill
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Post by vkh307h on Jun 24, 2018 20:09:13 GMT
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Post by cdb15 on Jun 24, 2018 22:43:46 GMT
Hi!! Thanks for the reply, yes I did the head gasket valves etc they were coated in black residue which has all been cleaned. I think I will tackle the valve stem seals... Reading your posts I am left wondering - and please don't be insulted by this - did you actually remove the valves completely from the head, or did you just clean up the areas you could get to? If you didn't replace the seals then either you removed the valves but refitted them with the original seals still in place, or you didn't remove them at all. Either way I would suggest you need to remove the valves from the head completely, so that not only can you change the stem seals, you can also check the valve seats are in good condition (re-grind them if not, it's an easy job if they're not badly pitted) and you can check for wear in the valve guides - poor lubrication in the past can lead to excessive wear in the guide bores, meaning the valve stems flop about in the guides to the point where even new seals aren't big enough to stop oil blow-by, resulting in oily exhaust. As the engine gets hotter, so the valve guide bore increases, and any gap increases, allowing more oil to get into the combustion chamber. Replacing valve guides isn't a huge deal, though you may want to place the work with an engineering firm if you're wary of doing it yourself. Personally I've never needed to do it on any engine, but doubtless others on here can advise how realistic it is as a DIY operation. I am really impressed by Fifers home made tool, though I have to question the effort involved - it seems to me just as easy to lift the head as to go to all that effort of the special tool, especially as there is always the risk of something tiny being dropped into the cylinder even if the cable stops a valve dropping. For the cost of another head gasket, and certainly while the engine is out and accessible, it will be a sound investment to life the head again. |
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Post by vkh307h on Jun 25, 2018 5:21:04 GMT
Hi cdb15 yes I didn’t remove the valves just cleaned up what I could see, looks like head off again.
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Post by cdb15 on Jun 25, 2018 11:13:16 GMT
Hi cdb15 yes I didn’t remove the valves just cleaned up what I could see, looks like head off again. Look on the bright side - the job will be *much* easier second time around, cos you know what to expect, which tool to use that *just* fits perfectly etc, plus you know you've narrowed down the search for your smoke problem to the valves.
As you take the head off, check each cylinder carefully - it could be you have general wear all over, in which case all cylinders should look about the same, or you may have one specific failure, such as a crack in a guide or a broken stem seal on just one valve - if it's a clearly localised problem like that, then you can choose whether to fix just that one problem, or completely strip the head and renew everything. There are arguments both ways - if it ain't broke, don't fix it. OTOH if it's all apart anyway, why not go the whole hog? Depends how you are for time and cash.
There is a strong argument that says if one of the four/eight components has failed, the others can't be far behind. The strength of this argument depends on how old your engine is, and how much you know about its history. If the whole thing is unknown, then personally I would go for the 'replace the lot' view, then at least you know you have a good baseline for the future.
If it's any consolation, I am facing exactly the same dilemma with my entire braking system. Ho hum, the joys of old classics  |
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Post by bondbug750 on Jun 25, 2018 15:17:15 GMT
I was told the this later top hat type with a little spring around are better than this earlier simple cap type:   Anyone confirm this please? |
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Post by vkh307h on Jun 25, 2018 19:10:30 GMT
Hi, the ones in my pack have a small spring around they look quite rigid and robust tbh.
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Post by ayrbugger on Jun 26, 2018 22:11:08 GMT
Hi,
Reading the post and replies...Take the head off and do a full deck and valve grind, fitting the new seals on rebuild.
Fixing one cylinder is in my opinion a waste of time...you'll end up doing the rest anyway.
Any gasket set comes with a FULL set of seals and gaskets, why leave some on the shelf for tomorrow, DO the Job Right
Bill
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Post by tod on Jun 27, 2018 3:25:55 GMT
When you took the head off did you clean the carbon from the top of the pistons ? If so it could be the cause of your problem . The carbon that builds up around the edge of the piston acts as a seal and if you scrape it off the engine will smoke more . The centre of the piston should only be cleaned leaving a ridge of carbon around the edge . Worn valve stem seals cause smoke on start up and smoke when shutting off the throttle as the vacuum sucks oil down the guides .
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Post by vkh307h on Jun 27, 2018 5:23:29 GMT
Hiya Tod, yes your spot on I did clean all the pistons as they were heavily carbon soaked. Does this mean I could just leave it and a new seal will eventually be created, I’m a great believer in not messing if not needed as this engine is so old opening up again I’m worried will just open up more problems.
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