Rocker Arm Bushings whats the best material to use?

twr · Sep 17, 2017

Hi i need some help picking material for bushings and who better to ask than guys on PM!!! So here goes the bushing .930 long about .055 wall thickness it is for the cast rocker arms on a boss 429 its for a very good bud. It has a lot of spring pressure and a big roller cam the stock ford bushing don't last. Fords are 6060 or something bronze then he tried aluminum bronze which was better but only about 500 miles and they are junk. Shafts that bushings ride on is 56 rockwell and are oil feed he wants me to make some out of magnesium bronze do you think that is a good choice or is their something better?
Thanks Tracy

strokersix · Sep 17, 2017

With apologies below is not a direct answer to your question because I don't know:

Are the bushings simply overloaded and pounding out or is it more an excessive wear condition?

If it's overload maybe run a shaft that is .110 bigger and no bushing at all? Probably an invitation to wear and galling but something to think about. Some sort of coating on the rocker bore?

You said the rockers are cast. Guessing that must be investment cast steel. Cast iron running against hardened steel is often a decent wear couple. Steel on steel not so good.

yardbird · Sep 17, 2017

oilite is what I use when making bushings mainly because I have access to a bunch of it. I have no clue if it would hold better in this application or not? Maybe someone else can chime in with a better choice of material. Good luck Tracy....

Brent

Guest · Sep 17, 2017

I think I would go with whatever the Nascar guys use. Go to the track, get a pit pass and ask.

twr · Sep 17, 2017

My guess is they are investment cast steel, the bushings can't handle the spring pressure combinded with the 1960s rocker geometry doesn't help either. He doesn't want to mod the shafts or the inside of the rocker. He just wants to make a bushing the same as the ford ones but made with a material that lasts longer.

Milland · Sep 17, 2017

It's probably manganese, not magnesium bronze your friend's talking about. Here's a reference for selection of bearing bronzes, note that Al bronze wants a regular supply of filtered oil, it may be that during startup the oil flow is too low and causes damage to the bearing surface.

Applications: Industrial - Selecting Bronze Bearing Materials

twr · Sep 17, 2017

Dualkit said:
I think I would go with whatever the Nascar guys use. Go to the track, get a pit pass and ask.

Nascar rockers will likely use needle bearings.

twr · Sep 17, 2017

Milland said:
It's probably manganese, not magnesium bronze your friend's talking about. Here's a reference for selection of bearing bronzes, note that Al bronze wants a regular supply of filtered oil, it may be that during startup the oil flow is too low and causes damage to the bearing surface.

Applications: Industrial - Selecting Bronze Bearing Materials

Yes you are right, i don't deal with bronze my mistake. Also the rockers have oil pressure feed their is 2 oil holes inside that feed the rockers from the rocker shafts. Also found out 220 pounds spring pressure closed and 660 open.

HuFlungDung · Sep 17, 2017

Do the stock bushings have any kind of oil gallery groove inside? You might try adding such a feature in a troublesome situation to see if it helps. The failure as I see it, is not in the bushing material but in the oil film. Make the grooves of such a design that they do not exit the ends of the bushing, which would allow all the oil to dump out the ends, rather than encircling the shaft.

omcgee · Sep 17, 2017

twr said:
Hi i need some help picking material for bushings and who better to ask than guys on PM!!! So here goes the bushing .930 long about .055 wall thickness it is for the cast rocker arms on a boss 429 its for a very good bud. It has a lot of spring pressure and a big roller cam the stock ford bushing don't last. Fords are 6060 or something bronze then he tried aluminum bronze which was better but only about 500 miles and they are junk. Shafts that bushings ride on is 56 rockwell and are oil feed he wants me to make some out of magnesium bronze do you think that is a good choice or is their something better?
Thanks Tracy

The Oil, Gas drilling people use Beryllium Copper silver plated for their deep hole Tri-Cone journal Bushings.They have a tremendous amount of pressure on the bushings.I would use that before using any other type of Bronze .

twr · Sep 17, 2017

HuFlungDung said:
Do the stock bushings have any kind of oil gallery groove inside? You might try adding such a feature in a troublesome situation to see if it helps. The failure as I see it, is not in the bushing material but in the oil film. Make the grooves of such a design that they do not exit the ends of the bushing, which would allow all the oil to dump out the ends, rather than encircling the shaft.

Yes they have 2 oil holes in the bushing and small groove between the 2 oil holes. The oil from the shaft goes through groove to the holes one hole pionts toward the push rod the other pionts to the valve.

twr · Sep 17, 2017

Milland, i sent him your link and let him read through it to decide. Thanks

twr · Sep 17, 2017

omcgee said:
The Oil, Gas drilling people use Beryllium Copper silver plated for their deep hole Tri-Cone journal Bushings.They have a tremendous amount of pressure on the bushings.I would use that before using any other type of Bronze .

I know this would work but here their is all kinds of safety shit to machine that stuff.

omcgee · Sep 17, 2017

twr said:
I know this would work but here their is all kinds of safety shit to machine that stuff.

I machined it for years you just don't want to breathe fumes or dust.

moonlight machine · Sep 17, 2017

Dualkit said:
I think I would go with whatever the Nascar guys use. Go to the track, get a pit pass and ask.

Only been about 45 years since the last one raced in NASCAR, do you think any of the engine builders are still alive? I would convert it to rollers.

twr · Sep 17, 2017

moonlight machine said:
Only been about 45 years since the last one raced in NASCAR, do you think any of the engine builders are still alive? I would convert it to rollers.

Rollers are around $5000 and one of the guys that made them doesn't make them anymore, i don't know if anyone even makes them now. Anyway he wants to make bushings that last not by rockers.

Rigor · Sep 17, 2017

You can buy new Boss 9 engines at Kaase racing. They use roller rockers. He lists 4 rocker arm manufacturers. Probably a grand for a set. But may be worth it.
BTW their rockers are made of aluminum.

Rigor · Sep 17, 2017

Oops double post.

Limy Sami · Sep 17, 2017

My first move would be to check the rocker shafts are getting enough oil, .......having rebuilt a good few engines - of many flavours in my time, ....I have see a lot of knackered rockers and shafts, many if not most of them down to blocked oil feeds and / low oil pressure.

Overheating an engine for long periods will cause the oil to ''coke up'' - especially if it hasn't been changed regularly, ......using flushing oil is another cause, .....bit's of crap dislodge and block small oil ways.

As for hard bronzes, here's the Ampco overview sheet, .......I'd be looking at Ampco 22 - 26 AMPCO(R) Alloys Overview | AMPCO METAL

Application guide https://www.ampcometal.com/documents/APPLICATION_GUIDE.pdf

trevj · Sep 17, 2017

twr said:
I know this would work but here their is all kinds of safety shit to machine that stuff.

You should actually read the MSDS sheet on the stuff. Don't make smoke, don't make dust, wash your hands. Easy!

Read the MSDS all the way to the end, instead of doing what my boss did, which was to stop reading at the word "Beryllium".

And if the MSDS for Be-Cu scares you, go find the one for Water. Do you know how little of that stuff you are able to breathe in before it can kill you?

Rocker Arm Bushings whats the best material to use?

Hot Rolled

Hot Rolled

Titanium

Guest

Guest

Hot Rolled

Diamond

Hot Rolled

Hot Rolled

Diamond

Plastic

Hot Rolled

Hot Rolled

Hot Rolled

Plastic

Diamond

Hot Rolled

Banned

Banned

Diamond

Titanium

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