Rocker Assembly and Oil Distribution!

Evening all.

In the final stages of a complete motor rebuild, and the last challenge is the amount of oil being distributed through the rocker assembly.

I've got a 67 B with the 1800GB, the rocker assembly installed with the car when I purchased it last December was in dire need of TLC with scarring and grooves on the shaft. Bought a 67 B complete assembly off of eBay, bought a "tuff rided" shaft and bushings through our own Chris Roop, and sent it to an outfit in Northern CA for a rebuild.

Well, all's good to go right? Drove the car home from the shop about two weeks ago, and after 10 miles or so it started missing. Turns out it galled the #2 exhaust valve, and when we dug into it the rocker assembly isn't distributing any real oil; the holes in the rocker arms get a little, but it just dribbles and clearly doesn't "shoot" out onto the valves and the springs, even with 65+ PSI oil pressure. There is plenty of oil on the rods, but little to none on the springs or valves and they were actually turning blue from heat.

The majority of the oil is dribbling out of the back of the rocker shaft, and as the oil warms the 20w-50 just pours out in a pretty continuous line; either through the back of the shaft or between the two rear rocker arms and the rear tower. Looks like plenty of oil on the top of the head, but little to none being thrown around when you run the car with the valve cover off.

Now, the question I have - the car, since purchased, has never produced more than 40 PSI oil pressure, and 10 PSI at operating temp, so I don't have experience with a car with essentially a new motor (new cam, new pistons .20 over, fully machined block, machine crank, new gaskets, oil pump, the works) and plenty of oil pressure. How much oil should be distributed through the shaft and through the holes in the rocker arms? Did the outfit I sent the rocker assembly to in Northern CA botch the rebuild and not seal the rear of the shaft properly?

Kind of stuck, and looking for a little guidance.

I was going to wait until I had some pics of the full rebuild, but I did want to give a shout out to Chris Roop - he's been awesome to work with, especially when trying to decipher the Moss Motors catalog with the various parts, SKU's, pricing, etc. He's been fantastic in working with me and the mechanic I've coerced into doing the work (I keep waiting to see the MG parked out by the street as he's gotten frustrated), so thanks Chris. For anyone looking to do a rebuild, I would certainly shoot Chris an email and see what he can do to assist.

Thoughts?

Thanks Scott, but I'm confused; do you have 10 psi warm or 65 psi? Or is the 10 what it used to have?

If oil is pouring out the rear of the shaft you have a missing plug. It normally sits just inboard of the cotter pin, one at each end.

The oil pressure when warm at 2000 rpm should be in the neighborhood of 70psi; at idle 50 would be expected.

The rocker shaft does get lots of oil and with the rocker cover off it will soon be all over the garage.

The oil feeds (IIRC, I'm sure someone will correct me if I'm not right) into the shaft at the rear pillar and then thru the shaft. There are holes in each rocker arm bushing (or there SHOULD BE...that would be #1 to check that, eh?) that feed a small amount to that busing while not bleeding off too much that the next bushings down the line don't get theirs.

You should see oil coming out from each side of each rocker. If you don't, I think I'd want to pull and disassemble the shaft and look in the bushing for each rocker.

oil coming up the pushrod lubricates the ball and socket, not the shaft.

Kapish?

Hey Chris - just to clarify, pre-rebuild I was getting 10 PSI at operating temp, and now I'm getting in the 70 start up/50 operating temp.

As for the rocker arms - the arms that were original to the car (so far as I know) had a hole on the valve side of the arm, but not on the rod side; the set I bought off of eBay had a hole on both sides, as did the mid 70's rocker assembly Chris dropped off with my mechanic for reference.

My mechanic has pulled all three assemblies apart, and all three are different - different positioning of the bushings (i.e. the groove on the bottom between 4 and 8, the groove between 2 and 4, etc.), different oil holes on the rocker arms (i.e. holes on the valve side, holes on both sides)...makes it hard to try and see what the issue is or determine what that car should have had when original.

We have holes drilled through the bushings to distribute the oil through the bushing into the rocker arm, but again it just sort of "drools" out versus actually shooting out. Given that we have plenty of oil pressure, just not sure if we're getting enough oil to the rocker assembly itself (it appears we are, but you never know), if we are loosing too much oil out the rear of the shaft, or ???

Should ANY oil be dribbling out the back of the rocker shaft? Or should the plug completely seal the rear of the shaft and seal it completely?

I'll double check to see if the plug has been correctly installed behind the cotter pin on the rear of the shaft, but another question - given that the rocker arms on the car originally had a single hole in the arm on the valve side, should I swap them out for the arms that have holes on both sides (the valve and the rod sides)?

So close! I have a friend who is rebuilding a '64 Datsun Fairlady roadster, and he's determined to get his on the road before me! Can't let the Japanese beat the Brits...

I just got off the phone with John. My bet is that it is all fixed, but we will pull the valve cover off of my 73 on Saturday and compare the oil spray compared to your engine Scott. I want to see the oil coming out of the back of your shaft also.
Meanwhiles, all of you who know stuff should still keep talking.

Thanks Chris - I'll stop back in tomorrow to see John, I know he was feeling pretty frustrated with the car so I thought I'd see what the folks on the forum thought...

Good plan. It is going to cost him though as I want him to replace the 3rd member seal in the blue b; I do not do pumpkins. And he owes me for some carb setting work. :)

There should be no oil coming out of the rear of the rocker shaft. The plug's purpose is to seal it off. Once you obtain the proper rate of oil flow, it doesn't matter which design rocker that you use. RAY

Scott, there has been a few of us who has had issues with oil feed to the rockers over the last year or so due to mismatch of parts and/or incorrect assembly of parts. - me being one of them. Do a search on a few key words and have a read of a few posts to give you an idea of those issues.

They include an incorrect rear pedestal which can block the oil feed and, as in my case the whole assembly being put on backwards and no oil going into the rocker shaft.

Look at some photos of motor assemblies with the cover off and compare with yours.

This link will take you to an entry in my journal which in turn will take you to ALL the relevant posts regarding the whole sorry story of my rocker stuff-up.
Caution, it's a bit long winded.

http://www.mgexperience.net/journal/sweep/2703

Chris

Today we pulled the valve cover off of the 73 and watched the oil flow from the rockers, then compared that to Scott's rockers. The flow seems to be the same. I haven't ever done that before, always trusting that what was supposed to happen did, and was happening inside of the sterile covering. John has threaded and replugged the rocker shaft, an improvement. Mine was threaded, but some of the shafts we looked at were just compression plugged. It is amazing that so much variation can occur in one part.