Rocker Arm Shaft Replacement

[WHT]

Hi,

I need to buy a new rocker arm shaft since the one in our car has a groove worn into it by one of the positioning springs. Rocker Arms Unlimited advised me to source a new rocker arm shaft and send it to them before they rebuild the assembly. They usually only reclaim/hard chrome good condition OEM shafts which may not be available used; and they have no information on new shafts.

BTW, our oil pressure is 60 PSI at idle, 50 psi above 2000 rpm when hot and 25 psi at idle when hot (using 20-50 oil). So, we are only having the assembly rebuilt due to the groove being worn into the shaft.

I have not replaced a Healey rocker arm shaft before and I am not familiar with the quality of new replacement shafts. Is it better to (i) buy a new (not chrome plated) hardened shaft, (ii) find a new rocker shaft that IS hard chrome plated or (iii) try to find a used OEM shaft that Rocker Arms Unlimited can reclaim and hard chrome.

Thanks for any thoughts and recommendations.

Regards, Bill

 

[Bob_Spidell]

How much money and time are you willing to spend? If I had spare jack I'd be tempted to go with a roller rocker conversion though, to my knowledge rocker/valve wear isn't a big issue for a street car.

New/upgraded complete shafts are available:

Austin Healey Rocker Shaft Assembly | New | | BN4 to BJ8

Austin-Healey Rocker Shaft Assembly, made from new components with improved oil pressure and increased oil feed. Machined and polished for reliable performance.

www.ahspares.co.uk

By the time you source a new shaft or a used one--check with BCS--have it hardened and the rockers ground and installed it might be a wash. The OEM shaft in my BJ8 lasted well over 100K miles before being worn enough to warrant rebuild--by RAU, I don't recall chroming even being an option--so I don't see that hard chrome is really necessary (just my IMO).

 

[gonzo]

I went with the AH Spares Rocker Shaft Assembly option rather than a rebuild; it was a simple plug and play. There was no change in engine oil pressure which, by the way, matches your description.

 

[WHT]

Bob and Gonzo,

Thank you for the replies.

Bob, I was considering the roller rockers as you suggest, but found out they require clearancing of the pushrod holes. And, I was hoping to avoid removing the head. I also thought about the new shaft assembly as per your link. But, not sure I want the holes in the top of the rocker arm sealed. Like everything in life, lots of decisions and consequences to consider. I think that you are correct that most shafts are not hard chromed, which is a RAU service.

Gonzo, do you remember how the rocker arm holes were sealed? Have to admit this still bothers me a little. There are many comments pro and con on the AH forums regarding sealing these holes on a street engine running at 4000 RPM and below and I have no experience with this.

Our Austin-Healey rocker assemblies are of the highest quality, in keeping with the high standards for which we at A.H. Spares are world renowned. Constructed from all new components with machined and polished rocker arms, then assembled with our aluminium competition pedestals, rocker spacers and ARP nuts.

The oil hole at the top of the rocker is sealed for improved oil pressure, in addition to increasing the oil feed to the areas that need it most. The rocker arms are reamed and honed to the correct size then carefully assembled by a time-served Chief Engine Builder.

Regards, Bill

 

[gonzo]

The rocker arms weep hole appear to be brazed but oiling of the rocker arm / valve doesn't seem to be a problem, they're still getting a good misting of oil on the rocker arms. I emphasize "misting" as opposed to a "coating" of oil with the original rocker arm assembly. I have about 1000 miles on the sealed rockers with no change in engine performance or tone.

 

[WHT]

Thanks, Gonzo

I will call AHSpares and speak with them!

Regards, Bill

 

[Patrick67BJ8]

Hi,

I need to buy a new rocker arm shaft since the one in our car has a groove worn into it by one of the positioning springs. Rocker Arms Unlimited advised me to source a new rocker arm shaft and send it to them before they rebuild the assembly. They usually only reclaim/hard chrome good condition OEM shafts which may not be available used; and they have no information on new shafts.

BTW, our oil pressure is 60 PSI at idle, 50 psi above 2000 rpm when hot and 25 psi at idle when hot (using 20-50 oil). So, we are only having the assembly rebuilt due to the groove being worn into the shaft.

I have not replaced a Healey rocker arm shaft before and I am not familiar with the quality of new replacement shafts. Is it better to (i) buy a new (not chrome plated) hardened shaft, (ii) find a new rocker shaft that IS hard chrome plated or (iii) try to find a used OEM shaft that Rocker Arms Unlimited can reclaim and hard chrome.

Thanks for any thoughts and recommendations.

Regards, Bill

I purchased my Rocker Shaft from Auto Farm in Canada. It was done on an exchange with them sending me a Rocker Shaft fully assembled with a core charge and my core charge refunded when they received mine. Their shafts are slightly larger diameter. Call them to discuss and they will explain the technical stuff about their shafts

 

[WHT]

Thanks Patrick,

I will call AutoFarm tomorrow, and believe they are a Denis Welch dealer (?).

After going through both Forums for several days and discussing parts with Denis Welch and AHSpares, I am 90% ready to go for the Denis Welch Tuftrided rocker arm shaft along with their steel pedestals and rocker shaft spacers. And, then have all of the surfaces (shaft, spacers and rocker arms) polymer coated by Techline Coatings after Rocker Arms Unlimited rebuilds the rocker arms and sizes them to the new shaft.

Over build, but this will get rid of the springs that started wearing a groove in the old shaft. The person who setup the current rocker assembly apparently did not notice one of the locating springs had a sharp end wire. The new rocker assembly will hopefully be more reliable and last a long time.

I thought I would try Techline's Dry Film Lubricant coating which supposedly reduces friction and gives "high-pressure lubrication to metal surfaces subject to sliding, rotating, or oscillating motion"; and "helps retain oil on the surfaces of moving parts". Randy Forbes recommends the coating and there is a Techline shop nearby.

We should be ready to start taking longer trips (200 to 500 miles).

Regards, Bill

 

[gonzo]

Hi Bill,
Looking like an excellent plan for rebuilding the rocker assembly. The one I purchased also has the aluminum spacers in place of springs. Good design, but the spacer nearest the oil feed pipe needed to be recessed further for clearance. Test fit first, then when you're ready for final installation, thread both ends of the oil feed pipe by hand to avoid any cross-threading. Although this may not be a problem with the steel spacers you specified.

Were you satisfied with their reasons for sealed rocker arm holes? Thanks for sharing.

 

[Patrick67BJ8]

Thanks Patrick,

I will call AutoFarm tomorrow, and believe they are a Denis Welch dealer (?).

After going through both Forums for several days and discussing parts with Denis Welch and AHSpares, I am 90% ready to go for the Denis Welch Tuftrided rocker arm shaft along with their steel pedestals and rocker shaft spacers. And, then have all of the surfaces (shaft, spacers and rocker arms) polymer coated by Techline Coatings after Rocker Arms Unlimited rebuilds the rocker arms and sizes them to the new shaft.

Over build, but this will get rid of the springs that started wearing a groove in the old shaft. The person who setup the current rocker assembly apparently did not notice one of the locating springs had a sharp end wire. The new rocker assembly will hopefully be more reliable and last a long time.

I thought I would try Techline's Dry Film Lubricant coating which supposedly reduces friction and gives "high-pressure lubrication to metal surfaces subject to sliding, rotating, or oscillating motion"; and "helps retain oil on the surfaces of moving parts". Randy Forbes recommends the coating and there is a Techline shop nearby.

We should be ready to start taking longer trips (200 to 500 miles).

Regards, Bill

Thanks Patrick,

I will call AutoFarm tomorrow, and believe they are a Denis Welch dealer (?).

After going through both Forums for several days and discussing parts with Denis Welch and AHSpares, I am 90% ready to go for the Denis Welch Tuftrided rocker arm shaft along with their steel pedestals and rocker shaft spacers. And, then have all of the surfaces (shaft, spacers and rocker arms) polymer coated by Techline Coatings after Rocker Arms Unlimited rebuilds the rocker arms and sizes them to the new shaft.

Over build, but this will get rid of the springs that started wearing a groove in the old shaft. The person who setup the current rocker assembly apparently did not notice one of the locating springs had a sharp end wire. The new rocker assembly will hopefully be more reliable and last a long time.

I thought I would try Techline's Dry Film Lubricant coating which supposedly reduces friction and gives "high-pressure lubrication to metal surfaces subject to sliding, rotating, or oscillating motion"; and "helps retain oil on the surfaces of moving parts". Randy Forbes recommends the coating and there is a Techline shop nearby.

We should be ready to start taking longer trips (200 to 500 miles).

Regards, Bill

Hi Bill,

I believe Autofarm is a distributor of “A-Head 4 Healeys” parts. Excellent service and no problems with the parts I have purchased. “Bob” is the guy I talked to about rockershafts. I sent Bob a video of the rockershaft so he could see it leaking with the engine running. Bob had explained the problems they were having with the bushings from India and why they rebuild the shafts the way they do now.

Cheers,
Patrick

 

[BoyRacer]

Here's my two cents about pluging or brazing the hole at the top of the rocker arms. Don't do it. A good spray of oil up there serves to cool the valve springs. That's why there are holes in the top of the rockers.

 

[WHT]

Thanks Richard, for your comments.

Not sure it is a major factor, but a friend who builds high performance engines (not Austin-Healey) says controlled oil flow through the holes also helps remove some of the wear particles in stock OEM assemblies that would otherwise be embedded in the rocker arm bushings. They don't build engines with rocker arm locating springs.

Regards, Bill

 

[WHT]

Thanks Gonzo,

I am going to take as long as needed to fit the assembly, and appreciate the information on the oil feed installation and the need to position and center the shaft correctly first.

Regarding the closed top oil holes, I think it makes sense given how they setup their rocker assembly. They adjust the rocker bushing clearances so oil is released (or misted as you say) at the edges of the rockers directly onto the shaft and springs. Both methods, although different, should be fine when setup correctly.

Regards, Bill

 

[Randy Forbes]

WHT, why don't you repair your original rockershaft? If it just has a groove from a spring (visualizing this without a visual aid...) the groove can be welded, turned smooth and then sent out to be hard-chromed.

Bob, I can remember collecting and dropping off 10-12 rockershafts at a time at Ward Hard Chrome in Fremont (or Hayward?) when I worked at Austin Healey West in SF back in the 70s. Occasionally there might be a void in the chrome, usually where it didn't throw around an oil hole, but never caused an issue.

As far as brazed holes go, I'm in Richard's Camp; take a look at these from a Longbridge (2-port) engine (in all fairness, rumor has it that Healey spent time in a New Mexico HS Shop Class, so economy being paramount__or students not wanting oil stains on their shirts for next period, they were brazed shut)...

Reconditioned tips, bushes reamed to size and new shaft and lifters: > IMG 4300 | spcarsplus.com photo gallery <

 

[WHT]

Hi Patrick,

Thanks for the additional information. AutoFarm allows you to upgrade to a hardened Tuftrided shaft for $73 (US) more (neither shaft is hard chromed). And, as you said, they are an Ahead4Healeys dealer.

Their current charge is $439 and $512 (US) respectively for a rebuilt assembly; plus you have to send them your old rocker assembly/parts at your cost. I can have my rocker arms rebuilt, upgraded with a Tuftrided shaft with spacers and have everything Techline coated for not much additional cost.

I decided to go with the Denis Welch parts because I wanted to do both the initial and final measurements/assembly myself. I have a small lathe and will assemble the parts and adjust the rocker arm pad/valve stem positions and rocker arm/spacer clearances if needed to match our head casting, before sending all the parts to Techline. The DW parts arrived in 48 hours! Faster than Moss or most US based suppliers.

Many MGers have replaced their aluminum rocker shaft pedestals with later factory steel pedestals for increased stability (some added aftermarket spacers). And, several US companies have produced OEM engines with rocker arm spacers instead of springs (including the Hemi in my Jeep) with 150,000 mile reliability when setup correctly. This is about improved fit and reliability; and not HP.

I have discussed this with Rocker Arms Unlimited, who are going to rebuild the rocker arms for me and clearance them to the shaft. They use good quality bushings and they are going to check the rocker arms to ensure their edges are absolutely perpendicular to the shaft bore and keep the bushing clearances close to the factory 0.0005" minimum; adjusted for the burnished coating thickness.

Workshop specified clearances between the inside diameter of rockers and outer diameter of rocker shaft are 0.0025" to 0.0005"; (0.063 mm to 0.012 mm).

Regards, Bill

Edited for AutoFarm information.

 

[WHT]

Hi Randy,

I discussed repairing the current rocker arm shaft with Rocker Arms Unlimited and they recommended sourcing a new shaft. They didn't want to weld the shaft. I think (hope) the Tuftrided and coated shaft will last longer than I last ( good news - bad news).

They rebuilt a MG TD rocker assembly for me several years ago and it came out great.

I am not closing the top rocker arm holes. However, when I was a kid and working on my first car, brazing the rocker arm top holes closed was a common modification made by engine builders in the Mid-West.

Regards, Bill

 

[WHT]

The DW parts arrived and they look to be well designed and executed; and they are machined by DW to require minimal fitting.

The two pictures show the (i) parts and (ii) a diagram I made showing the sequence of spacer installation.

Now waiting for the rocker arms to be rebuilt by RAU and fitted to the tuftrided shaft.

The parts were coated with Boeshield T-9 while waiting.

Regards, Bill

 

[Bob_Spidell]

Excellent diagram! Just out of curiosity, what is the advantage of solid spacers vs. springs? Do the rockers float that badly?

 

[WHT]

Hi Bob,

Most people will say there is no advantage unless you are (i) operating your engine at high RPM or (ii) have roller tip rocker arms that need to be accurately located on the valve stems. Probably correct, but a lot of people have never run spacers and are just repeating what they have been told. More than a few OEM engines have used spacers very successfully over the years.

In my case, I was adjusting the valves and saw that one of the rocker arm springs was cutting a groove into the rocker shaft; and the shaft needed to be replaced. I also looked at the rocker arms carefully and saw most of their valve stem pads were not consistently located on the valve stems when the engine was running. Springs do loose tension with age and the quality of new replacement springs is said to be inferior. And, many times all of the "rubbing" surfaces on the pedestals and rocker arms are not machined absolutely parallel in production engines.

All of this can be examined and addressed when setting up spacers.

Several engines I play with use rocker arm spacers and they have proven to be long lasting and reliable when setup correctly (which IS a lot more work than sliding-on locating springs). But, there is little side loading on the rocker arms when running steady-state (side loading increases with changing RPM and shock loading) and wear is not a problem when using good materials. Neither is cooling or filling the rocker shaft with sludge.

I worked at a research center that ran test engines to study lubrication and wear, and watched one engine run (for a time ) without rocker arm springs or spacers; the rocker arms were held in place (with fluctuations) by the pushrods and valve spring pressure.

Anyway, having nothing else better to do, I decided to install the DW steel pedestals and spacers. They have less friction, produce less heat when running, accurately locate the rocker arm pads and the pedestals have similar thermal expansion with respect to the head and other rocker assembly parts. Being retired, I have time to optimize the Healey engine as I see fit.

There have been warnings that using rocker arm spacers on a street Healey will increase sun spot activity and may ultimately cause all gravitational forces within the solar system to end. If so, I apologize to everyone on the Forum in advance.

Regards, Bill

 

[Patrick67BJ8]

Hi Bob,

Most people will say there is no advantage unless you are (i) operating your engine at high RPM or (ii) have roller tip rocker arms that need to be accurately located on the valve stems. Probably correct, but a lot of people have never run spacers and are just repeating what they have been told. More than a few OEM engines have used spacers very successfully over the years.

In my case, I was adjusting the valves and saw that one of the rocker arm springs was cutting a groove into the rocker shaft; and the shaft needed to be replaced. I also looked at the rocker arms carefully and saw most of their valve stem pads were not consistently located on the valve stems when the engine was running. Springs do loose tension with age and the quality of new replacement springs is said to be inferior. And, many times all of the "rubbing" surfaces on the pedestals and rocker arms are not machined absolutely parallel in production engines.

All of this can be examined and addressed when setting up spacers.

Several engines I play with use rocker arm spacers and they have proven to be long lasting and reliable when setup correctly (which IS a lot more work than sliding-on locating springs). But, there is little side loading on the rocker arms when running steady-state (side loading increases with changing RPM and shock loading) and wear is not a problem when using good materials. Neither is cooling or filling the rocker shaft with sludge.

I worked at a research center that ran test engines to study lubrication and wear, and watched one engine run (for a time ) without rocker arm springs or spacers; the rocker arms were held in place (with fluctuations) by the pushrods and valve spring pressure.

Anyway, having nothing else better to do, I decided to install the DW steel pedestals and spacers. They have less friction, produce less heat when running, accurately locate the rocker arm pads and the pedestals have similar thermal expansion with respect to the head and other rocker assembly parts. Being retired, I have time to optimize the Healey engine as I see fit.

There have been warnings that using rocker arm spacers on a street Healey will increase sun spot activity and may ultimately cause all gravitational forces within the solar system to end. If so, I apologize to everyone on the Forum in advance.

Regards, Bill

Is this the reason for that near perfect eclipse? (Asking for a friend).