Rocker Arm wear

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A Collaud
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Location: France

Rocker Arm wear

#1 Post by A Collaud » Sat Feb 08, 2020 2:58 pm

Hi,
Here some photo of my Rocker arms on my 1600S (616/12). Wear is quite visible, but is it too much ?
what is your opinion ?
Do you who / where I can may be resurface them ?
thank you

IMG_5547.JPG
IMG_5547.JPG (739.83 KiB) Viewed 468 times
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IMG_5552.JPG (336.79 KiB) Viewed 468 times
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IMG_5553.JPG (338.62 KiB) Viewed 468 times
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IMG_5557.JPG (282.47 KiB) Viewed 468 times
IMG_5559.JPG
IMG_5559.JPG (195.72 KiB) Viewed 468 times
IMG_5565.JPG
IMG_5565.JPG (285.39 KiB) Viewed 468 times
IMG_5566.JPG
IMG_5566.JPG (351.34 KiB) Viewed 468 times
IMG_5570.JPG
IMG_5570.JPG (153.42 KiB) Viewed 468 times

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Don Gale
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Re: Rocker Arm wear

#2 Post by Don Gale » Sat Feb 08, 2020 3:53 pm

I see you're in France? There are numerous shops in the States that do them. I'll follow up with names if you're willing to ship them. There's one in the UK:

https://www.hthoward.co.uk/engine-machi ... nufacture/

The tips have a cam-like profile, so verify that whoever grinds them, has the proper 356 specific curves coded into their machine. You may get by simply dressing the worst ones by hand on a honing stone, but by the looks of yours, better to have them professionally ground. You'll have a smoother running engine with better valve rotation imparted, and more accurate lash setting.
1958 356A 1600 Super Sunroof Coupe
former 1966 Euro 912 Sunroof
former 1978 Intermeccanica Speedster w/'68 912

Martin Benade
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Re: Rocker Arm wear

#3 Post by Martin Benade » Sat Feb 08, 2020 4:16 pm

Each arm doesn’t just have a single radius?
I was debating yesterday if I could make belt sander jigs to clean mine up.

Dick Weiss
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Re: Rocker Arm wear

#4 Post by Dick Weiss » Sat Feb 08, 2020 5:23 pm

WOW--these are the worst ones I've seen during my 60+ years of rebuilding engines!
Some would need a little hard-welding which have "smeared tips" being a little off-center
due to excessive wear in the shaft-bores (ovaled) and shaft wear exceeding 0,05mm/.002" clearance
between them. Refinishing some tips may not be reusable if there's not enough radius left and
interference between the valve spring's retainer during valve depression occurs--I've seen several
of those caused by not much of the tip left!!!
There's many rocker arms (used or new) available in swap meets around the world, but the critical
situation is the scored shafts and bores; I've checked and done many as other shops.

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Al Zim
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Re: Rocker Arm wear

#5 Post by Al Zim » Sun Feb 09, 2020 1:32 pm

Normal and early super rocker arms should be easily available since most people were searching for horsepower and wanted the extra lift of the valves they used the aluminum rocker stand rocker arms. Replace all of them with the earlier style I doubt if you will notice the difference. Usually they will not have to be redone. al zim
Last edited by Al Zim on Tue Feb 11, 2020 3:29 pm, edited 1 time in total.
 

Tim Berardelli
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Re: Rocker Arm wear

#6 Post by Tim Berardelli » Tue Feb 11, 2020 10:55 am

Were the rocker arms dipped in sand prior to taking the pictures?

A Collaud
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Location: France

Re: Rocker Arm wear

#7 Post by A Collaud » Tue Feb 11, 2020 5:21 pm

Hi,
thank you for your comments.
I've contacted several machine shop in France but nobody seems able to resurface them
I contacted hthoward and I will send them the rocker so thet will confirm the feasablity (price is around 12/15USD per rocker to be remachined)
Tim : no, I've just cleaned them in a ultrasonic machine so far
Al : not easy to find parts (in france) and I fear that they won't be better than mine ...

jay darlington
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Re: Rocker Arm wear

#8 Post by jay darlington » Tue Feb 11, 2020 8:59 pm

Those are really rough especially the ones all chewed up on the ends. have you checked out eBay or the samba both have several complete and individual rockers for sale. GR AND SONS has boxes full of them on the samba
Jay D.
jay darlington

Robert Vaughan
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Re: Rocker Arm wear

#9 Post by Robert Vaughan » Wed Feb 12, 2020 4:54 pm

IMG_5559.jpg above shows the worn area that contacts the valve stem top, and the unworn area (to the right) that does not contact the valve stem top. Several months ago Ron LaDow posted the image of a narrow feeler gage that will enable the correct measurement of the rocker arm tip clearance. A wide feeler gage used beneath a rocker arm tip with this characteristic wear pattern will likely span both the unworn area and the worn area leading to an incorrect rocker arm tip clearance measurement and setting. (The person setting the clearance thinks the gap is to spec, but actually the gap is larger, and noisier.)

jay darlington
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Re: Rocker Arm wear

#10 Post by jay darlington » Thu Feb 13, 2020 12:17 am

that's just a temporary fix. they should be ground but some of the O/Ps are to far gone.
Jay D.
jay darlington

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Harlan Halsey
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Re: Rocker Arm wear

#11 Post by Harlan Halsey » Thu Feb 13, 2020 5:16 am

The rocker arm tips are part of the valve lift geometry. As is the rocker arm angle. If you want to return the engine to like new performance, The tip profile, along with the rest of the dimensions needs to be right. While I have known of several shops, over the years which "reconditioned" rocker arms, they all just ground the tips by hand to something smooth. However, the tips can be welded up with hard rod, and jig ground to the original profile. Dean Lyon, just north of Santa Rosa, CA is a retired machinist who has a jig and has been doing this job for many years now. When I rebuild a 356 engine, one of the routine tasks is to send the rockers to Dean. I recommend you do the same.

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