Perkins 4236 engine rebuild rocker shaft

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Whitlock 505
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Perkins 4236 engine rebuild rocker shaft

Post #1 by Whitlock 505 » Tue Apr 24, 2018 4:40 pm

Hi Guys

After some information on what size a perkins 4236 rocker shaft should be unworn? Ordered a left hand and a right hand rocker arm from malpas online and reassembled rocker shaft without checking parts assuming they were right :dizzy: ,when it came to do the valve clearances the left hand rocker shaft was right but the right hand new rocker shaft is to big on the valve top and doesn't allow me to get the valve clearance and the adjusting screw is barely sitting in the push rod seat, contacted malpas online and they contacted their supplier who are saying it is not a manufacturing issue and they will supply a new right hand one if we tell them what size we want? I looked in the perkins 4236 manual and all it gives is wear an tolerances, another valuable lesson learned as i threw away the packets they came in so can't prove that we've been supplied with a wrong part :doh: any body got any ideas? Could I grind the rocker shaft to fit?


Jeremy Rowland
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Re: Perkins 4236 engine rebuild rocker shaft

Post #2 by Jeremy Rowland » Wed Apr 25, 2018 7:42 am

Ian I am trying to picture in my mind where you want to grind this shaft? I would say that you probably could grind it but some pictures of the issue would help. :thumbup:

Jeremy


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Re: Perkins 4236 engine rebuild rocker shaft

Post #3 by essexpete » Wed Apr 25, 2018 9:39 am

Are talking about grinding the tappet surface?

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Re: Perkins 4236 engine rebuild rocker shaft

Post #4 by FOWLER MAN » Wed Apr 25, 2018 10:41 am

Hi Ian,
Like Jeremy and Pete I'm not sure what your looking for either. :?
Some 4-236 rockers were bushed and others were not. If its the shaft and rocker bore size your looking for I have them here. :thumbup:
If as Pete suggests you're thinking of grinding the tappet, (valve), end of the rocker the dimension wouldn't be critical, (as long as it works), but you will be grinding off the hard face which may lead to other problems. :think:
I think a replacement is probably the answer.
Good luck.
Fred


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Whitlock 505
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Re: Perkins 4236 engine rebuild rocker shaft

Post #5 by Whitlock 505 » Thu Apr 26, 2018 2:30 pm

Thanks for the replies guys, its the small block that sits on top of the valve stem, after much toing and froing with emails and after the manufacturer firstly denying there was a manufacture problem they have now admitted there is a production problem, they are saying it will be weeks before it is resolved and offered a full refund including postage, will try to source elsewhere rather than grinding down, they were about 6-7mm to big to achieve the valve clearance.


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Re: Perkins 4236 engine rebuild rocker shaft

Post #6 by essexpete » Thu Apr 26, 2018 9:28 pm

I think that is not completely unusual. I had a Sparex spring for the clutch pedal on my ford tractor. The spring was slight wrong in every aspect and guess what? The NH part was similar price. That is not to say that all non OM parts are crap because they are not but it helps to know if someone else has recently used those parts.


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Re: Perkins 4236 engine rebuild rocker shaft

Post #7 by Jeremy Rowland » Fri Apr 27, 2018 7:12 am

Hi Ian I can see in my mind what you were thinking but my advice would be not to grind parts down which may have been case hardened and would become 'soft' when you ground through the hardness; there are other options, firstly try and get a good second hand part while easier said than done it may be quicker than waiting for the manufacturer to sort, secondly if you know a good engineering company and the part in question is not to complex get them to quote on making you a new part to sample. :thumbup:

Jeremy


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