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alanmoor
Alan Moor
Winchester, VA
(57 posts)

Registered:
10/18/2014 08:58PM

Main British Car:
'73 MGB GT Ford 5.0

authors avatar
215 Oil Pressure Loss
Posted by: alanmoor
Date: May 31, 2015 10:08AM

This is not a cry for help. It's just a little story that may help somebody in the future with the same issue.

I live about 150 miles from my Dad (Richard Moor) and my brother Mike (Mike Moor, long time board member). Yesterday I was on my way to Dad's to swap the mechanical choke out for an electric one. I had driven about 148 of those miles when the motor "hiccupped". Sort of like if you quickly lift on the gas and go right back to the previous position. It was still running fine, responded okay with more gas, etc. I dismissed it as a random leg twitch. Maybe I moved my foot or something and don't remember. About a mile later, I noticed a pounding on acceleration, like a spun rod bearing. Looked down, no oil pressure. I immediately shut it down and coasted into a parking lot.
ParkingLot.PNG

Oil was full and clean on the dip stick. After a quick call for help, we towed it to Dad's Garage. The first thought was that something tragic had happened to the distro/oil pump. Pulled it apart and it looked fine. Dad has a cool drill attachment that fits over the oil pump drive. We put that on, spun up the oil pump, and it showed 20lbs of pressure. Odd thing was, there was a lot of gurgling when you stopped the drill, as the oil flowed down into the block. More than there should be.

Removed the left valve cover to take a look:
BrokenShaft.JPG

I took the picture after removing the #1 intake rocker arm and the last inch of the rocker arm shaft, which were lying next to the #1 intake valve.

Fortunately for me, Mike just happened to have a couple rocker arm shafts lying around. We transferred the bits and pieces from the old to the new shaft, and bolted it in place. There was a bit of an issue with the lifter. It had come out of place. After some cursing, a bit of bailing wire and a worm cam for light, Mike was able to work it back into place.
NewShaft.JPG

Note that by "we", I mean mostly Dad and Mike. I watched, asked questions, and occasionally held the light. :)

Once it was buttoned back up, it started and ran fine. Drove it home the 150 miles without incident.

The broken shaft:
ShaftCloseup.JPG

In summary:
1 - Always break down within a mile of your favorite mechanic. It's always fun and educational watching Mike and Dad do their thing. They're the best.
2 - Still don't know what that banging was. Wondering if I did some damage that will manifest itself later, and possibly provide that excuse for a horsepower upgrade ;)


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6468 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 215 Oil Pressure Loss
Posted by: BlownMGB-V8
Date: May 31, 2015 11:05AM

Alan, check thoroughly for possible coil bind on the valve springs. Every time I've seen that problem it's been caused by interference, usually not showing up until the engine is thoroughly warmed up and the lifters are pumped up as far as they are going to. Just because you can stuff some pasteboard between the coils when at rest doesn't mean you have enough clearance. Check retainer to valve guide clearance as well.

Jim


alanmoor
Alan Moor
Winchester, VA
(57 posts)

Registered:
10/18/2014 08:58PM

Main British Car:
'73 MGB GT Ford 5.0

authors avatar
Re: 215 Oil Pressure Loss
Posted by: alanmoor
Date: May 31, 2015 12:17PM

Jim,

Would that also cause the excessive valve train noise? I've been told by a couple guys it's normal for a 215, but it seems excessive to me. I'm still learning, definitely a rookie with these engines.

Edit: Disregard that. If it were binding, it would be too tight, and would presumably make less noise. I don't think it's coil binding. What I failed to mention was that the valve train has at least 20,000 miles on it. I think, through metal fatigue, or maybe at some point in the part's 40+ year history somebody torqued it too tight and created a small crack that eventually caused the failure. Since that end is cantilevered, there's probably some flex of the metal involved. Over time it will eventually fail. I'm just glad it picked 1 mile from my Dad's house to break.

Al



Edited 1 time(s). Last edit at 05/31/2015 12:55PM by alanmoor.


psmg
Paul Schils
Fredonia, WI
(89 posts)

Registered:
12/13/2007 10:27AM

Main British Car:
1973 MGB-GT, Buick 215 1971 MGB RD, SBF 302

authors avatar
Re: 215 Oil Pressure Loss
Posted by: psmg
Date: May 31, 2015 01:01PM

Al,
I am sorry to see your having a problem with the GT. Those rocker assemblies were replaced when the engine was rebuilt and were purchased from D&D. There aren't many miles on them.
That being said, I really feel bad that this happened.
Paul


mgb260
Jim Nichols
Sequim,WA
(2461 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 215 Oil Pressure Loss
Posted by: mgb260
Date: May 31, 2015 05:27PM

There is a known problem with those shafts being too small and unsupported on ends. D&D sell support blocks and I wonder if the newer replacement shafts are inferior/offshore steel. The aftermarket should step up with a thicker wall, chromemoly or tool steel replacement piece.



Edited 1 time(s). Last edit at 05/31/2015 05:30PM by mgb260.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6468 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 215 Oil Pressure Loss
Posted by: BlownMGB-V8
Date: May 31, 2015 07:03PM

Looking at the photo of the shaft, the first thing I noticed was that the surface finish is noticeably rougher than the OEM shafts. I could not tell if there was any plastic deformation at the break line but if there is or if the break line itself is grainy that would indicate an inferior grade of steel as well. The OEM shafts were really very good parts and despite the cantilivered design did not often fail.

On Harry Johnston's Olds engine which popped off about three of them before we sorted it out, a piece of pasteboard would easily slip between the coils at full lift, yet when we provided more clearance the problem went away. Bear in mind, you are checking clearance with the engine stopped and leakdown can be a factor. With the engine running, where the lifters pump up, lift goes to maximum and coil bind can occur despite your measurements. Where in the range of your lifters' travel your pushrod length sets it and your running oil pressure also has an effect. As for the lifter noise, the best cure for that is to have the lifters in the middle of their travel and then to have good oil pressure at idle and above. Many engine builders set their lifter preload at about .020" but IIRC the lifter plunger travel is in excess of 1/8" so you could run 1/16" of lifter preload without worry. If you do your lifters most likely will never tap. And that Olds engine of Harry's? It ended up serving as my spare engine for quite a few years before going under my Jetfire turbo back in my pre- roots blower days.

Jim


alanmoor
Alan Moor
Winchester, VA
(57 posts)

Registered:
10/18/2014 08:58PM

Main British Car:
'73 MGB GT Ford 5.0

authors avatar
Re: 215 Oil Pressure Loss
Posted by: alanmoor
Date: May 31, 2015 11:36PM

@Paul

No worries. Parts fail,, things break. I LOVE the car and am having a great time learning how everything works.

Really looking forward to seeing you in Indy,
Al



roverman
Art Gertz
Winchester, CA.
(3188 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: 215 Oil Pressure Loss
Posted by: roverman
Date: June 03, 2015 06:46PM

FWIW, The hole at brake point, appears to have no chamfer/radius ? This means stress riser. The shafts are likey rebuilt oem shafts, by someone like "Rocker Arm Rebuilders". Their usual method is to centerless grind the shafts back to unworn bare steel, rechrome and finish grind to correct size. This means base material is thinner/weaker than original and chrome is thicker than oem.,(hydrogen embritlement) is increased. The strongest oem style rocker assemblies are steel, adjustable Volvo B18 ? (see archives). Good Luck, roverman.


MGBV8
Carl Floyd
Kingsport, TN
(4511 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: 215 Oil Pressure Loss
Posted by: MGBV8
Date: June 03, 2015 07:41PM

Art, I once considered Volvo rockers, since I couldn't wrap my head around a non-adjustable valvetrain. Volvo rocker ratio is less than the Buick/Rover & must be offset drilled to get them close to the 1.6 ratio. Otherwise, I would have used them.

Don't lose any sleep worrying about Al. I'm pretty sure Mike has a spare Buick 300 tucked away in his garage. ;)


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