Rockers/Pedestals (pillars) Etc

[philthehill]

Stephen
That may be so but I have yet to find an original tap and die so the nearest size, TPI and profile is BSCY.
The tap and die that I have was supplied by Tracy Tools Ltd and listed in their catalogue section - BSCY, UNS & Whitform (specials). It was the nearest to the original specification and does what is required in that they clean the threads without removing any metal or altering the profile.
Phil

[svenedin]

These absolutely disgusting rockers are small-bore pressed steel type. The reason they are small-bore type is the round valve stem contact pad.

Why you may ask am I fiddling with such nasty looking rockers? Well I found the rocker assembly amongst other things that were given to me many decades ago. I noticed that there is very little wear on the pads. So little in fact that I cannot feel any wear with my finger nail. The bushes look good too and there is no slop on the rocker shaft. The rocker shaft itself is worn and is scrap. The pedestals are good (steel) but I had a tremendous fight with the rocker shaft lock screw. In the end I cut a slot with a Dremel cutting disc and got it out with a big screwdriver and lots of penetrating oil after a go with a blowtorch.

Stephen

Small-bore, round pad, pressed steel rocker arm. According to Calver ratio 1.23:1 (standard)

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[svenedin]

Stephen
That may be so but I have yet to find an original tap and die so the nearest size, TPI and profile is BSCY.
The tap and die that I have was supplied by Tracy Tools Ltd and listed in their catalogue section - BSCY, UNS & Whitform (specials). It was the nearest to the original specification and does what is required in that they clean the threads without removing any metal or altering the profile.
Phil

Fair enough and as you can see from the photo above, I will be needing that tap!

How many TPI is the 7/16" BSC tap? I can see one listed by Tracy Tools at 20 tpi and another at 26 tpi

UNS 7/16" tap is 19 tpi so it looks like I am mistaken.

Stephen

[philthehill]

The BSCY tap and die I use for cleaning up the nuts and threads of the adjuster is 9/32" x 26 TPI.

[les]

Thanks Phil, thanks for your reply, however I was enquiring about the rear main bearing cap pipe, I might have to check mine as I think I still have a slight leak from the rear sump seal.

[svenedin]

Thank you Phil that's very helpful.

I have a lot of pressed steel rockers in a box. All of them used, perhaps 40 of them but I haven't counted. I need to assess their condition and clean up if worthwhile. I want to make up a set of 8 excellent condition ones if I have them. Criteria for re-use is good bearing bush and unworn contact pad.

Incidentally, the rocker tips are case hardened and that hardened layer is thin. Case hardening is typically as thin as 0.4mm but can be thicker depending on the process used. So if the contact pad is badly pitted from contact with the valve stem there is little point in trying to stone or grind the pad smooth to the correct profile. If the hardened layer is worn through or ground through the soft metal underneath will wear rapidly.

Stephen

[svenedin]

I spoke to Tracy Tools and ordered the 9/32" British Standard Cycle tap and die. The helpful chap on the phone said BSCY is a 60 degree thread angle and perhaps the actual thread for the pressed steel rocker adjusting screws is 9/32" BSF which has 55 degree thread angle. In any case they don't sell such a BSF tap and he said (as Phil says) that for the purposes of cleaning threads the BSCY tap and die are perfectly satisfactory.

The above applies to the pressed steel rockers ONLY.

Stephen

[les]

I have some new old stock pressed steel rockers, unfortunately there are only 7 !

[philthehill]

Les
The pipe from the rear main bearing cap was/is an actual pipe and was very effective. Unfortunately it cannot be retro fitted to the later engine rear main bearing caps because of the way the later oil drainage drillings/galleries are arranged.
NOS pressed steel rockers do come up for sale on 'e' bay on a regular basis so you may be able to make the number to 8.
I am fortunate that I have a set of near new pressed steel rockers fitted to a new thick wall shaft, steel moulded pillars and non waisted adjusting screws.
I also have a near new set of forged steel rockers again fitted to a thick wall shaft and steel moulded pillars.
Plus a near new set of CNC machined 1.5 ratio steel rockers fitted to a thick wall shaft with spacers and shims between the rockers and mounted on steel pillars.
The rockers fitted to my 1380cc engine are 1.5 ratio full roller rockers with steel pillars.
The early rocker shafts had a removable screwed plug in one end so that the inside of the rocker shaft could be cleaned. Sadly the screwed plugs have been replaced by steel plugs. The plugs can be drilled out so as to enable the inside of the rocker shaft to be cleaned. If a new shaft is fitted it is most important that the centre of the shaft is cleaned. I have drilled out the steel plug on one end of the rocker shaft on several occasions and used a short length of suitable steel rod to close up the end of the rocker shaft after cleaning the inside of the shaft.
Phil

[les]

Thanks Phil, I suspect my cap is minus this pipe. As you hinted it appears to be a backward step to discard it.

[svenedin]

Very lightly used complete rocker assemblies turn up on eBay quite often. The bush in the pressed steel type is usually fine but the rocker shaft is worn. The reason is that bronze tends to pick up tiny particles of grit and that makes a grinding paste against the steel rocker shaft. The rocker shafts are noticeably more worn on the underside than the top. Engines died for other reasons and they were scrapped for parts so NOS (though brilliant to find if you can) is not necessary. Sometimes rocker assemblies are quite ridiculously cheap and the postage is more than the cost of the parts. People can't be bothered to clean the parts up. Some Hyperclean (or paraffin or white spirit) and a wire brush can work wonders as can an ultrasonic tank (with aqueous fluids of course; explosion risk with petrochemicals). The ultrasonic I bought years ago for clock and watch parts is incredible for cleaning up small parts. it has a heater and can do ultrasound and heat at the same time. It is not necessary to clean threads with a tap and die when the ultrasonic shakes out the muck and anyway, with ancient clock and watch parts nobody knows what the thread actually is! In those days, there were no interchangeable parts. A screw fitted in one place and one place only. This was long before any kind of standards with threads. I remember my grandfather boiling cyanide for some kind of gold extraction (I was too young to remember) on the kitchen stove (he was a watchmaker). My grandmother's gold wedding ring was used in this process and got thinner and thinner. It's a wonder I was ever born!

Anyway Les. I'll look through my somewhat vast collection of pressed steel rockers and maybe the least worn one can make your set up to the full 8.

French clocks of the 19th century are renowned for having absolutely dead hard steel. They basically never wear their arbours at all but the brass the arbours turn in does wear. Rockers are the opposite. The shaft wears badly but the bushes don't much wear. The brass of those days is also hardened but being a different material it is hardened by work hardening and not heat. I have seen case hardening in steel where there is a defect (a pinhole) in the case that allows corrosion to set in underneath and the hardened skin peels off. it is not much thicker than taking some aluminium kitchen foil and folding it 4 times. Really thin. Old clocks have the steel hardened all the way through generally and this makes that hardened steel very brittle.

Sorry for being such a nerd tonight! I went to a brilliant prom at the Royal Albert Hall. My 16th this season. Saint-Saëns organ symphony on what was once the greatest pipe organ in the word "The Voice of Jupiter". Now the second largest in the UK, second only in the UK now to the Gilbert Scott masterpiece, Liverpool Anglican Cathedral. Bells are my thing really!


Stephen

[les]

Thanks Stephen for your kind thought re 8th rocker, I’m not in need of using my rockers as yet but a complete set is, of course desirable.

[Bill_qaz]

Decided to try my recently purchased spqr tool.
These are the rocker I found on my engine.
Are they sintered type? the lock nuts are 1/2 af so I'm assuming non wasted screws?

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[philthehill]

Bill
The rockers shown above are the sintered steel type.
The adjustment screws are not waisted.

[Bill_qaz]

Thanks Phil, I know from paper work that it had a lead free head fitted in 2011, so good news on the valve gear

[svenedin]

As Phil mentioned, here is an early rocker pedestal locking plate. It prevents the rocker shaft securing screw from working loose. It is a silly design because it goes under BOTH the rocker pedestal stud and the cylinder head stud so you have to remove a cylinder head nut to change the rocker shaft. As Phil says, you can shorten the plate so that only the rocker pedestal stud nut has to be touched to change the rocker shaft. OR part 2A259 which is retained only by the pedestal stud and nut and not the cylinder head stud.

Stephen

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[Bill_qaz]

Bill
The rockers shown above are the sintered steel type.
The adjustment screws are not waisted.

Phil, is the TPI of the solid screw with 1/2 " nuts the same?

Just thinking about the spqr tool says 8 clicks for 12thou but 7/16 nut.

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Just may of found answer to my own question, another chart list A series with 1/2" nuts as 7 clicks

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[svenedin]

Bill
The rockers shown above are the sintered steel type.
The adjustment screws are not waisted.

Phil, is the TPI of the solid screw with 1/2 " nuts the same?

Just thinking about the spqr tool says 8 clicks for 12thou but 7/16 nut.
20250809_132501_1.jpg

Just may of found answer to my own question, another chart list A series with 1/2" nuts as 7 clicks
20250809_132501_1.jpg

The modern tool does not come with a list of clicks for different engines. It just has instructions to determine the number of clicks required by using a feeler gauge the first time. Once you have done this initial calibration you just count clicks subsequently. I would read the table that you have but check with a feeler gauge as well. You might also choose to set the gap at a setting larger than 12 thou in which case you would need to use a feeler gauge the first time anyway.

Stephen

[Bill_qaz]

Bill
The rockers shown above are the sintered steel type.
The adjustment screws are not waisted.

Phil, is the TPI of the solid screw with 1/2 " nuts the same?

Just thinking about the spqr tool says 8 clicks for 12thou but 7/16 nut.
20250809_132501_1.jpg

Just may of found answer to my own question, another chart list A series with 1/2" nuts as 7 clicks
20250809_132501_1.jpg

The modern tool does not come with a list of clicks for different engines. It just has instructions to determine the number of clicks required by using a feeler gauge the first time. Once you have done this initial calibration you just count clicks subsequently. I would read the table that you have but check with a feeler gauge as well. You might also choose to set the gap at a setting larger than 12 thou in which case you would need to use a feeler gauge the first time anyway.

Stephen

You need to make sure if you use feeler for initial check it would have to be a rocker with no wear, or you're bridgeing, exactly what the tool negates.
This is only required for an unlisted engine, no feeler gauge required if listed.
My tool comes with several charts for a wide range of vehicles.
If you want a larger gap than standard setting, you can easily work it out.
Example 8 clicks 12thou so 1 click = 1.5 thou.
If you want 15 thou it's 10 clicks etc.
I only queried as I hadn't fully read the chart and it gives different setting clicks for 7/16 nuts(pressed steel rocker) and 1/2 nuts (sintered rockers) but both 12thou gap, so tpi of screws must be different if rocker ratio is the same.

8 clicks used on my sintered rockers has set the gap to 13.7 thou.
If I find it too noisy when warm then I will re-adjust to 7 clicks 12 thou.

[svenedin]

Phil, is the TPI of the solid screw with 1/2 " nuts the same?

Just thinking about the spqr tool says 8 clicks for 12thou but 7/16 nut.
20250809_132501_1.jpg

Just may of found answer to my own question, another chart list A series with 1/2" nuts as 7 clicks
20250809_132501_1.jpg

The modern tool does not come with a list of clicks for different engines. It just has instructions to determine the number of clicks required by using a feeler gauge the first time. Once you have done this initial calibration you just count clicks subsequently. I would read the table that you have but check with a feeler gauge as well. You might also choose to set the gap at a setting larger than 12 thou in which case you would need to use a feeler gauge the first time anyway.

Stephen

You need to make sure if you use feeler for initial check it would have to be a rocker with no wear, or you're bridgeing, exactly what the tool negates.
This is only required for an unlisted engine, no feeler gauge required if listed.
My tool comes with several charts for a wide range of vehicles.
If you want a larger gap than standard setting, you can easily work it out.
Example 8 clicks 12thou so 1 click = 1.5 thou.
If you want 15 thou it's 10 clicks etc.
I only queried as I hadn't fully read the chart and it gives different setting clicks for 7/16 nuts(pressed steel rocker) and 1/2 nuts (sintered rockers) but both 12thou gap, so tpi of screws must be different if rocker ratio is the same.

8 clicks used on my sintered rockers has set the gap to 13.7 thou.
If I find it too noisy when warm then I will re-adjust to 7 clicks 12 thou.

Yes about the wear but the instructions (which I can't find at the moment) say to use a suitable feeler gauge AND a feeler gauge of 12 thou (for instance). You put your base feeler gauge in the gap and tighten the tool down until it makes the loud clunk. You then work out how many clicks backing off are needed to produce a gap of 12 thou with the other feeler gauge still in place. The first feeler gauge is just to provide a level surface to measure from in case there is wear. Once you know how many clicks equates to 12 thou difference you of course have to set the gap again for that particular valve.

Stephen