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Post by lollygagger on Jul 12, 2020 18:10:19 GMT
I doubt that the Chinese would be making pattern parts for a 76 year old design engine! If you can't find a screw, an allen cap head machine screw, 5/16" UNF with the end ground to a ball will do, they are hardened throughout. Sam. But they are! Or someone is. The problem of soft adjuster screws plagues the classic (old) car world.
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Post by Isambard Kingdom Brunel on Jul 12, 2020 18:19:29 GMT
I doubt that the Chinese would be making pattern parts for a 76 year old design engine! If you can't find a screw, an allen cap head machine screw, 5/16" UNF with the end ground to a ball will do, they are hardened throughout. Sam. But they are! Or someone is. The problem of soft adjuster screws plagues the classic (old) car world. Really? Is nothing sacred from the yellow peril industries? Ooooops, racist, Warning sirens. What have the Chinese ever done for us? Besides cheap electronics, clever mobile phones and Covid 19? Soft screws? Sounds a bit perverse. When you look at the industries just in Kowloon never mind mainland, its incredible. Easy to temper them with a torch and a can of oil, heat to straw colour and quench.
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Post by lollygagger on Jul 12, 2020 18:52:21 GMT
But they are! Or someone is. The problem of soft adjuster screws plagues the classic (old) car world. Really? Is nothing sacred from the yellow peril industries? Ooooops, racist, Warning sirens. What have the Chinese ever done for us? Besides cheap electronics, clever mobile phones and Covid 19? Soft screws? Sounds a bit perverse. When you look at the industries just in Kowloon never mind mainland, its incredible. Easy to temper them with a torch and a can of oil, heat to straw colour and quench. They wouldn't be making them without someone over here asking them to. Left to their own devices they make some high quality well priced parts in my experience.
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Post by Isambard Kingdom Brunel on Jul 12, 2020 18:55:48 GMT
Really? Is nothing sacred from the yellow peril industries? Ooooops, racist, Warning sirens. What have the Chinese ever done for us? Besides cheap electronics, clever mobile phones and Covid 19? Soft screws? Sounds a bit perverse. When you look at the industries just in Kowloon never mind mainland, its incredible. Easy to temper them with a torch and a can of oil, heat to straw colour and quench. They wouldn't be making them without someone over here asking them to. Is there that much demand for tappet screws? I can't remember ever having to replace any.
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Post by lollygagger on Jul 13, 2020 9:40:10 GMT
They wouldn't be making them without someone over here asking them to. Is there that much demand for tappet screws? I can't remember ever having to replace any. In my funny world of self destructing air cooled VW engines there is demand. An M8 or M10 adjuster will fit any and every single one of those engines and no doubt other makes too. Millions are still in service around the world despite all being over 40 years old. Same for imperial versions? Hence MM ending up with a "fits all" incorrect length one I imagine.
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Post by Deleted on Jul 13, 2020 9:55:36 GMT
Yes.
The end rocker has been replaced as the nuts on the filter mount have been disturbed. I expect what happened is they got a new rocker which had the short screw but I don't get why you wouldn't just get it out and put the original one in...
Strange really. I suppose not everyone would notice it.
I suppose there is a slight chance that the valve was gummed up causing the long rocker screw to hit the cover. Haven't checked that out, this could theoretically prompt someone to choose a shorter screw which becomes inadequate as the valve decokes itself in use.
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Post by TonyDunkley on Jul 13, 2020 10:00:39 GMT
I've ordered one for a mini which I believe is the same item. 5/16 unf so the thread is right at least. If the Mini (BMC "A" Series engine) adjusting screw doesn't do the job try Calcutt Boats. I think they're still re-conditioning BMC 1.5's, so they might have a scrap head or two that would provide what you need. Failing that, I believe the MG owner's club has a very comprehensive parts network. The BMC "B" Series 1500cc and 1800cc petrol engines were in both the MGA and the later MGB models, and some parts, such as valve gear, will probably be interchangeable.
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Post by Deleted on Jul 13, 2020 10:04:55 GMT
I certainly intend to find an original at some stage as slightly concerned that the new one I have ordered may indeed be made of "I can't believe it's not butter" as discussed above by lollygagger. It's such a basic thing yet they do make inadequately hardened ones...
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Post by lollygagger on Jul 13, 2020 10:06:05 GMT
Yes. The end rocker has been replaced as the nuts on the filter mount have been disturbed. I expect what happened is they got a new rocker which had the short screw but I don't get why you wouldn't just get it out and put the original one in... Strange really. I suppose not everyone would notice it. I suppose there is a slight chance that the valve was gummed up causing the long rocker screw to hit the cover. Haven't checked that out, this could theoretically prompt someone to choose a shorter screw which becomes inadequate as the valve decokes itself in use. Maybe the rocker came with the adjuster fitted and looked good. Sorry to go on about the rocker but the damage to the adjuster kind of looks like it has been slipping off the valve stem. Are you absolutely sure the rocker has the correct geometry? EG if there was more or less adjuster through the rocker on the valve side or the sideways throw of the rocker is different. Are there witness marks on the spring retainer, collets or valve stem?
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Post by Deleted on Jul 13, 2020 10:09:44 GMT
I see what you mean. I had a look at those and the rocker is in good condition at the valve end as is the top of the valve stem. Does not appear to be slipping. Pretty certain no problems and it does seem to be the correct rocker.
It's just a short screw at the end of the day.
I didn't realise there was sideways throw though so will recheck this particular feature.
I assumed the odd shape of the ball end of the screw was simply due to incorrect hardening perhaps part of it was done but other side softer.
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Post by Deleted on Jul 13, 2020 10:20:44 GMT
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Post by Jim on Jul 13, 2020 10:21:30 GMT
Here's a thought, can you put the locknut underneath the rocker arm, instead of on top. It would work then. Maybe there ls no room to get a spanner in etc.
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Post by Deleted on Jul 13, 2020 10:26:51 GMT
Here's a thought, can you put the locknut underneath the rocker arm, instead of on top. It would work then. Maybe there ls no room to get a spanner in etc. No space. Anyway I think the fact the new screw has around 29 threads and the one I have removed has 21 makes sense because it seemed to be about, by eye, 3/8 inch too short compared with the others. 24 tpi so 8 is 1/3 of that so 1/3 inch length difference. That's about 8mm which is not far off 3/8 (9.5mm) So I reckon the initial diagnosis is correct.
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Post by Deleted on Jul 13, 2020 10:29:30 GMT
Looking at the top of that valve I am now wondering if the guide is nackered as it looks a bit like soot on top of the collets. Despite the end of the rocker looking dodgy it is actually smooth not damaged it's just shiny and I guess the movement is related to the dodgy screw and/or possibly valve guide problem. Might do a full top end overhaul on this unit next winter.
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Post by Andyberg on Jul 13, 2020 10:37:57 GMT
Sounds like a Jerry-built old knacker to me! 🙄 Scrap it! Told you👍
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