Rebuilt & Improved Dauntless Rocker Arm Assemblies

Hey Roy ! I haven't done a forum in years. Whats happening ?

@vintage_Jeeper

 

After studying the valve train oiling system for the 225 and the 231 some during the past several days, and a further discussion with Sal, I realized that my understanding about the rocker arms on the 225 being different from those on the 231 was incorrect. Those who are more knowledgeable than I am about these motors probably already know that the rocker arms on both the 225 and 231 (at least the earlier 231's) actually have the same design.

What's interesting to me is that the same oil passages inside the rocker arms, in between the rocker arm shaft and the pushrod cups, were fed from one direction in the 225, and from the opposite direction in the 231.

In the 225, oil is fed from the cylinder heads up through the shaft to the rocker arms, then through the passages in the rocker arms out to the pushrod cups:



On the 231, the oil lubricating the rocker arm assemblies is fed from bleed valves in the hydraulic lifters up through hollow pushrods to the pushrod cups in the rocker arms, and through the passages in the rockers to the shaft (this diagram shows a V8, but it's the same in the 231 V6):



In both engines, the oiling of the ends of the rocker arms where they meet the valves is via the "splash system".

During the rebuild of my engine a few years ago, new TA Performance lifters with bleed holes were installed. So, using hollow pushrods on my 225 should augment the oil flow to the rocker arms and the shafts, as the shafts will then be lubricated from the cylinder head ports as well as through the rocker arms. My rebuilt 225 also has a TA Performance timing cover and adjustable oil pump, so the oil pressure can be adjusted as necessary to accommodate the additional oiling ports.

 

I 2nd Pat's book.

 

There was a reason that GM changed the lubrication path to the rockers, with the later (improved) versions supplying oil via the pushrods.
An old retired machinist I knew in the Keys actually was on the design team creating the small Buick engines in the late ‘50s which became the 198/225 V6 and the 215/300/340 V8s . The main engineering went into the alloy block 215 V8, and the V6 was an off-shoot of the V8. GM had many problems with the casting process that led to large quantities of defective alloy engine blocks. My friend managed to “acquire” all the leftover 215 development project parts when GM pulled the plug after ‘63. He had a ‘37(?) Plymouth Coupe that he drag raced in the Detroit area through the ‘60s to early ‘70s that used all the R&D 215 V8 engines. He ran those over 9000 rpm, until his supply was finally depleted.
He knew Rover bought the 215 from GM, but made engineering changes, including oiling through the pushrods. He adopted some of those changes, helping his high rpm engines hold together longer. Many of Rover’s improvements were adopted when GM bought back the rights for the 225 V6 from Kaiser Jeep to produce the 231 V6s in the mid-70s.
The rocker arms, pushrods, rockers stands, and associated parts from the Rover V8 engines up through the early 2000’s bolt onto the 225 and are an improvement in design.
-Donny

 

I installed the rebuilt rocker arms this past weekend. It turned out that during the engine rebuild in 2015, my engine builder had already installed pushrods with holes in them - so I didn't have to upgrade those, and the oil pressure is already set correctly for this setup.

I went with Sal's suggestion and used Lucas Assembly Lube on the rocker arm assemblies prior to installation. After letting the engine idle for half an hour or so, I'm happy to say that as expected, the rebuilt rocker arm sets are much quieter than the worn originals were.

The only thing left to deal with now is that one of the new cork valve cover gaskets has a small leak. User error for sure . I'll have to try again, but the leak is slow and minor enough that it can wait a little while. I'll probably end up going back to rubber gaskets though.

 

Its great to hear that the rebuilt rockers met your expectations. I was in the same boat with my Dauntless rebuild , everything was done but the rockers. Having thrown on the same set , she run so much quieter.

 

I made the following video to demonstrate my engine’s sound at idle before the replacement of the original (80k+ mile) rocker arms, vs. after installing the rebuilt assemblies.

Unfortunately, my phone didn't perfectly capture the sound of the motor - but hopefully you can distinguish the difference in the valve train noise, as this upgrade significantly reduced it.

(I re-did this video after realizing that my talking during the first version interfered too much with being able to hear the engine running and the associated valve train noise. Fortunately, I'd made a "before" segment without my big mouth running too.)

 

Thanks for sharing! Its amazing how quiet a set of rebuilt rocker arm assembles will do on a Dauntless. I had the dreaded hit pitched ticking from a set of push rod cups that had worked loose. We wheeled 8hrs straight this past weekend and purred the whole why.

 

I had a 56 Buick with the "Nailhead" V8 back in high school. Didn't know much about what I had at the time, and don't know if it was the aluminum or iron block engine, but that old gal would really run. Wish I still had it.

 

That was the original nailhead, close to 700lbs of iron! The alloy “baby nailhead” was the 215 from ‘61-‘63.
-Donny

 

Oddfire 231 heads will work on 225. There are some differences. You would need to use a late model valve cover as one corner is not rounded off or Offenhauser valve covers. There is a passage in the head...something to
do with hot gas through the intake. This will need to be plugged if using Felpro gaskets. High-temp JB Weld works. Not sure if a 231 oddfire cast intake would work as I used an aluminum intake or if a metal valley pan gasket
would work the cast iron manifold. The metal gasket is not recommended for the aluminum intake. They do have the correct oil holes. The combustion chamber may cc out slightly larger. I am curious if the block is the same and how far a 225 can be
over-bored. Things that make you wonder.

Edit to note that the valves are different between the 225 and 231 oddfire. Just gets more convoluted. Confused my machinist when I had hardened seats installed. I have 1-1968 head and 1-1975 cylinder head. Not a race motor, so no big deal. I did use adjustable push rods.