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MG MGB Technical - An oil pressure odysseus

This is going to be bit long so be warned. At this point I know I have 2 choices - drive it which I am doing since its a daily driver - or have it pulled and redone, which is costly and I can't have the car down so I would have a short block rebuilt and just swap when budget allows. However, its all a big mystery as to where the oil pressure is going. Even the shop who will do the swap is mystified.

I had the engine rebuilt about 35K ago. Supposed to have been done perfectly. Everything save for the pistons was renewed, balanced, line bored, etc. VP-11 cam new billet. Rods and mains sized (supposedly). Head by Huffaker and touched up with larger valves eventually by Sean Brown. Supposed to have lasted over 100K.

Its a 1971 daily driver with over 500K on the odometer. I just restored it again around the time of the engine.

With the electric gauge I showed a steady OP of 70-75 lbs even in traffic and the heat of L.A.

Moved to Oregon which is much more MG friendly weather. A couple thousand miles ago I suddenly saw the oil pressure drop 25 lbs + Obviously, I was immediately concerned.

Went through everything I could prior to pulling the pan including buying a cheap sun pro mechanical gauge. That gauge showed the electrical gauge was WAY off. Changed the oil/filter but that wasn't it and only 4000 instead of 3500 interval. Even put in a larger oil filter.

Bought new tri-metal bearings and a new oil pump. Pulled the pan and the caps on the rods and 3 mains I could get to. Plasti-gauged a couple rod journals. One was .0018 and the other was a depressing .003 Top of one rod journal had a slight score. The fingernail test showed the other were fine but #3 main had micro grooved and a slight burr which I carefully sanded down with 600 solvent soaked sandpaper as per crank grinding sites. None of the rods had any crush to the bears which sucked. Also found a dingle berry from a hone in the oil pan. Otherwise no metal or metallic substances.

The uprated oil pump was fine but the part that goes into its housing was heavily scored. Photos attached. The rest was perfect. Put in a new oil pump one just in case.

The rod bearings looked like the came from a 100K+ engine and the backs clearly showed they had been moving within the caps. Naturally the tops were worse than the bottoms.

Followed the manic no dust policy using dust free wipes and carefully cleaned and dried the journals and caps/rod tops. Proper use of assembly lube.

Crank was polished and not turned. I had at one point put in a new crank and helping mechanic though it was better to polish than turn. STD beading but I think it should have been turned. Oh well.

Reassembled and let the car get oil pressure prior to firing. No change in oil pressure. Yesterday was a hot day here and was stuck in freeway traffic. The SunPro read at the worst 48 speed and 25 idle. Once it cooled down on the road it went up to 54/35.

Got a used mechanical Smiths oil pressure gauge and the associated line/junction. Cleaned and adjusted it. Reads same as the cheapie SunPro. Hot in traffic 48/25.

I'm at a complete loss why the oil pressure didn't get any better. Spoke to one person who insisted it was the cam bearing but the cam looked fine and I'm pretty sure I had them line bore it but with what I saw I think the Speed Shop in Burbank CA just charged me and didn't do much of anything they were paid to do or did it very badly. Head came off twice and I finally gave up and sent it to Sean Brown who said guides were in backwards and wrong like intake in the exhaust etc. Once fixed the car ran and still runs great.

The only reason why I didn't put in new pistons was because one previous mechanic's shop made a mistake and instead of skimming the block they decked it. Compression is high and I didn't want it any higher.

Hot compression is 190/187/204/192

I did the math on the compression table on the net but it shows about 9.1:1 which can't be with the compression. The head is 42.6cc. The piston dish is 6.5cc. The pistons are .015 below the deck. Payen head gasket. The shop calculated it around 10.5 :1

No rod knocking. Car runs great but oil pressure is a complete mystery. Being a daily driver I can't put it down for a month or more waiting on a machine shop. Plus I think the block is toast with almost zero deck. Oh, and no budget since I put so much into the car to make it new.

I also had a complete new pressure relief valve / spring/ packing etc put it. That raised the top OP to around 60 at speed but still drops to around 25/28 at idle.

Again, I know what needs to be done, but no one I spoke with can figure out what's happening. Its so odd that bearings didn't make any difference. Appreciate all the detectives here.

Max71

more photos: this next series is the bearings.

Max71

Back of rod bearings

Max71

Main Bearings front

Max71

Main bearings backs

Max71

removed oil pump end that goes into its housing. Rest was perfect and in spec.

Max71

Finally the present I found in the oil pan obviously left over from the questionable builder

Max71

You haven't mentioned the integrity of the seat the relief valve sits on, I would try a ball bearing with full length spring to see what happens.

Your relief valve in the first pic looks like a very poor quality version of the OE. We only use ball bearings. The OE ones which were steel then copper plated then chromed are NLA only seem to find steel versions.

Peter
Peter Burgess Tuning

X2 on the relief valve. Your relief valve and oil pump shaft look like a piece of threaded rod. I'm afraid, at the least, you're going to have to remove the crankshaft and have it cut undersize to regain the proper bearing clearance. I don't know who did the machining work on your engine, but they should be ashamed of themselves. RAY
rjm RAY

I'm no expert but I'm wondering if the bearings are oversized for the crank.

Other than that 70-75 is high for hot running, although I can't see why it didn't read even higher than that when cold if the electric gauge was reading high.

35 hot idle is fine, the book quotes 10 to 25. 54 running is a bit low, the book quotes 50 to 80. The reasonable idle with the low running does indicate relief valve problems to me as well.
Paul Hunt

Thanks for the replies. I would love to solve this mystery.

Peter - this is all we can get in America, as fas as I know. The valve came from Moss Motors as did the new assembly. I've never seen a description of a ball bearing so I wonder why this is the accepted valve. Again, its a MKII MGB - 1971. Since I had someone do the replacement there was no time to ask if they had a bore scope to take a shot. Unless the valve is of softer metal the mating surface could be scored.

A tidbit I did not mention is that the speed shop kept complaining that Moss was sending the wrong bearings and Moss sent them two more times and in each case they were STD bearing. In guessing I think the 'polish' might have put the journals in between STD and .010 and the shop didn't bother to mention there was any issue and maybe the crank should be turned. Then again, they were paid to resize the rods etc and with no 'crush' who knows. As mentioned they did the head wrong 2x so they just charged and got money for who knows what.

Paul - I've been studying a lot about this relief valve and all opinions so far pointed to it blowing off at top pressure but nothing about lower pressure. If the new one 'opens' at now 65 lbs then 'closes' is it possible that OP at idle could be lost as its not a tight seal?
Max71

Here's a screen shot of what Moss shows - its looks like the drawing is from the factory but Peter I know you will be the final judge

In this it shows the cone shaped valve.

Max71

And here's Moss' decryption of the valve...

Max71

The valve you have may not seat well, if it doesn't seat well you may get poor oil pressure. You should be able to get a ball bearing....from memory it is 0.625" but I will measure one tomorrow and get back to you.

Peter
Peter Burgess Tuning

Thanks Peter! I'm willing to try anything at this point. After watching them work on getting the new valve/packing/spring in for an hour -- any tips you may have for me doing it is very much appreciated.

I'll wait for your measurement.
Max71

Max,

Those bearings don't look that bad to me. They certainly don't look like what I usually see when I tear down an engine that needs a rebuild. And, the fact that replacing them made no difference to the pressure would seem to back me up, and indicate that they weren't the problem.

I agree with the others about the relief valve. That thing looks like it was made in someone's basement with a drill and a flat file. And, they didn't have any emery cloth.

I don't know how much pressure you can loose through the top end, but isn't there a plug in the end of the hollow rocker shaft? If that went missing I think you would loose some pressure in addition to starving the valve train for lube.

I certainly would not consider the block toast because of only 0.015 piston to deck height. If you want to bore it and put in oversize pistons without raising the comp ratio, you can either get pistons with greater dish or get a thicker head gasket. I would have to consult my specs (which are not here now) but I think I built my A-Series Sprite engine with zero piston to deck clearance or maybe only a few thou.

You said, "A couple thousand miles ago I suddenly saw the oil pressure drop 25 lbs +"
Since this happened suddenly, I don't think you are looking for something that wore out. I think you are looking for something that failed suddenly. Not that it relates to your initial problem, but when you put your new oil pump in did you use the right gasket for the 5-main bearing block?

What happens if a cam bearing spins a bit? Aren't they supposed to be lined up with an oil hole? Would that just starve the cam or could it effect oil pressure?

Are there any welch plugs that could blow out and cause a loss of oil pressure without causing an external leak?

Charley

C R Huff

Max,

I recall the ball bearing for a relief valve mentioned by Peter before. If you do an archive search you might find the size.

Charley
C R Huff

Max. If your oil pressure is wandering around the Mediterranean see seeking to return home, that might indicate the problem. As Charlie notes, a sudden problem indicates some form of sudden failure. A gradual drop of oil pressure, over a long period of time, is characteristic of worn bearings and other parts.

As to the size of the ball bearing to be used, measure the size of the current relief plunger and purchase a ball bearing of that, or slightly smaller, size. (One larger will not fit in the hole.) Be aware the the difference in construction between the factory plunger and the ball bearing--the plunger is of different shape and has a hole drilled partly through it where the spring and, sometimes, the 1/10th inch spacer go. The ball bearing will be solid and the thickness is whatever the diameter of the ball bearing is.

Lay your current system out on a flat surface and measure the overall length of the system. Then, measure the overall length of the spring and add the diameter of the ball bearing. The spring and ball bearing will need to be approximately the same overall length if the system is to work properly. Just dropping a ball bearing into the hole, followed by the spring and cap, would lead to an out of specification condition and may (have not measured it myself) lead to the spring binding and the relief valve system not working at all.

Les
Les Bengtson

Thank you all for your comments. I am concerned about getting the right ball bearing to provide the same size. Right now the new set up (you're looking at a photo of the one removed) has the 'packing' in it which gave me about +5 lbs on the top.

Don't know what to say about the removed OP valve. I bought it from Moss and usually they're very good.

I also agree that the change was sudden so something failed and I cannot find what part it is.

Here's a couple photos of my OP hot in traffic.

Max71

Here's the hot idle OP.

The shop who will do the swap thinks there's plenty of lubrication on the valve train. In their words, "Your valves are almost silent". Which does not mean they are too tight. When taking the car to an engine builder not familiar with MG's he thought they sounded too loose.

I have them set within .0005 of APT spec for the VP-11 cam.

Max71

Also should have mentioned - the present block deck height worries me because through 2 rebuilds its never been surfaced and I think surfacing would make it zero.

But the biggest issue is being my only car. So all the downtime wouldn't work. Too bad. I'll miss the original block - if that makes any sense….
Max71

Well, Max, until you lay a straight edge across it you don't know if it needs to be skimmed. And if you skim it and need more piston top to deck clearance, you could shave it off the top of the piston as long as you have pistons with thick enough crowns. And with a dished piston it is more likely (than with flat tops) that shaving will be fine.

Of course none of that solves your downtime issue. However, if you go through this again you may be in the same position. So, keep the old engine so you can rebuild it and save downtime next time.

Charley
C R Huff

The ball bearing is 0.562" 9/16" (not0.625!)

Peter
Peter Burgess Tuning

Thanks Peter!

Does it matter where I get one? Does it need to be a special composition?

Any tips on doing this in the car? The mechanic had a lift and it still took him over an hour.

I measured the old valve and the filled space at the end of the valve is 5.5mm. I assume I measure the old assembly and take into account the 'packing' and replicate that length with the ball bearing, right?
Max71

We do it from the top using a machined down 1" socket so it only just grips the head, this gives you just enough room to get in. If you are LHD does the steering rack cause problems? Getting the reatining nut/bolt? back in is a mano thing, I only get two goes then have to let my muscles recover to try again if I fail!

Nothing special about ball bearing, go to a bearing type supplier and ask, they will have good quality ones.

Peter
Peter Burgess Tuning

Thanks again Peter. Yes LHD, exhaust down pipe and steering rack are there. I'm thinking about making some kind of spreader. I'll figure out something.

Once done I'll let you know the results. Hopefully good ones. :-)
Max71

As I source the ball bearing I would like to fully understand the pressure relief valve system. Everything people state is that it only affects the top blow off pressure.

Once the new set was put in with packing I did get the expected 5 lbs increase at top OP. Idle OP unchanged.

Is it a correct assumption that if the new valve (which was smooth btw) is still leaking OP due to not sealing tight like say a valve in the head then there is continuous loss of pressure throughout the range?

I appreciate the lesson as this is clearly misunderstood if it affects pressure throughout the range.
Max71

Spot on assessment. The ball bearing sits better on a not perfect seat. We have seen little bits of debris stick on the seat the valve seats on which also holds the valve open. You could lap the bullet style relief valve but any grinding paste would be horrific if it gets into the engine. The ball bearing tends to work well, you may have some weird noises if it sings to you and odd fluctuations at diff revs but it works to perfection.

Peter
Peter Burgess Tuning

Thanks again Peter. It would be great if people really understood this mechanism and potential issues at all pressures.

What you say makes perfect sense to me. I'll follow up once done. Singing is ok. Just another feature of owning an MG. :)
Max71

"Everything people state is that it only affects the top blow off pressure.

"Once the new set was put in with packing I did get the expected 5 lbs increase at top OP. Idle OP unchanged."

That's my understanding, and to have idle pressure unchanged but upper pressure increased says to me that the sealing was fine, it was just lack of pressure on the valve onto its seat that was the problem.
Paul Hunt

Paul. Since I did get the expected improvement at the top, its a strong theory I've also debated. However Peter is a legend so I'll give it a go.

I tried to make a couple tools so it would be easier, but its still going to be very difficult. I measured the length of the spring/valve + new packing diameter (.11) Then of just the spring and ball bearing.

Length of Spring and ball bearing - 3.562

Length of present assembly with valve+packing (.11) - 3.348

Leaving an additional 0.214 or almost 2 more packings. This will put a lot more force on ball bearing than the valve had and will make the spring compression to close the cap nut even more difficult.

On a LHD car the steering column is indeed in the way so this all has to be done from underneath.

My crude math says with that extra force, and so far with +.11 giving me +5lbs of pressure this should result in an additional +10 lbs if its linear.

Its a shame this is so difficult to do with the engine in situ or it would be no big issue to change and change back if there is a problem.
Max71

I fit spring full length then shorten it to drop oil pressure if too high. Have had to shorten 1/8" when oil pressure around 100 psi!

Peter
Peter Burgess Tuning

Peter - did you shorten by cutting the actual spring?

Hmmm. Maybe I should use the old spring which is a bit tired and a touch under 3.00?

Since its a real pill to do this I've been trying to figured out a tool - a type of spreader with a worm screw. My first attempts didn't work out. Due to the nature of LHD steering column I have to work under the car with minimal clearance.

If I can perfect it I'll share it with the board here. I'm hopeful on something I found today and modifying it. The goal is to be able to play with it and check OP. Not have 'a once in its another nightmare to redo'.
Max71

I keep forgetting:

Only fiber washers seem available for the cap nut. I have a GK engine which calls for one but the new fiber washer is leaking. Should I use 2? Or try to find a copper washer?

What is target OP at speed/idle when hot? Some say 75 at speed and 70 at idle. Others say no more than 60 at top OP or the lump will leak.

Confused...
Max71

When we say the relief valve only affects the peak pressure is only correct on a valve that is working 100%. A leaky seat will lower the pressure from idle up. Oil pressure has little to do with oil leaks. I like a new engine 75-80 at revs and around 65 idle. It will vary as there are tolerances in the various components that affect the final result so the pressure also has an "acceptable" range. You "dont want more" than 80 lb for reliability reasons Denis
Denis4

For some reason in owning the car for 44 years those numbers are what I would shoot for in OP.

On another note, I wonder why its not a common practice to lap the OP relief valve on engine rebuilds. No one ever mentioned doing or needing this but with what I learned here it makes as much sense as doing the valves in the head.

Do all of you always have this done? When explained it makes so much sense.
Max71

Lapping is not common practice in case of paste left in awkward places.
I grind through the coils on bench/off hand grinder to reduce length.
As Denis says don't go over 80. 70 is fine and any more costs bhp. I would use a new spring to be honest and see how it settles. I know it is hard to do but if you use old spring and it is low you will have to put new spring in then maybe have to shorten new one...three goes. If new spring maybe only two goes?
All our conversion sets we buy in have copper washers for the relief valve.
Oil pressure figures are relative and I say to folk look for changes in the norm for idle and at high rpm not specific numbers. A rule of thumb for engine design is 10 psi per 1000 rpm. Some never seem to get near this at higher revs...MGCs...V8s
Hot pressure is heavily infuenced by oil quality. Long chain polymer oils tend to hold higher pressures when hot.
As I said earlier you may get some 'funny' fluctuations with the ball bearing BUT it is almost impossible to jam a ball bearing open which can be disastrous for oil pressure....a bullet valve can and does jam easily especially with the low quality new ones.

Peter
Peter Burgess Tuning

Thanks again Peter. I'll naturally do as you say. I'm determined to make a tool that makes it easier in case I need to grind the spring. Since grind the coils it makes no difference if one end is flattened like the new coil. I'll put the cut end if it comes to that at the cap side so the flat side is at the ball bearing.

What I meant about lapped would be when the whole block was being boiled out afterwards. If this doesn't work and I eventually go with a new rebuilt block I want to tell them what to do with the valve so its seating properly. Unless you think it should always be a ball bearing no matter what.

I'll report back and shoot for the figures you spoke about getting. You can see where its at now with new 20/50 VR1 Vavoline.
Max71

If you go to Paul Hunt's website, you'll see his method for fitting the oil pressure relief valve cap. He match marks the cap, where it just begins to thread into the block, without the spring fitted. This way, the cap can be lined up before putting pressure on it. It makes installation so much easier. RAY
rjm RAY

Hi Ray, I've seen that great tip from John Twist's video. That part I'm confident about - its just compressing the spring to get to that point. Especially now with a ball bearing.

Even when I perfect the tool I will definitely use that method. Thanks a lot for bringing it up.
Max71

Sweeeeet!

Just got the tool back from the welder and it looks like it should work perfectly. Have to get under the car, but did a test in a tight space between two 2x4s and it worked smoothly.

Here's some pic's. Last thing I have to source is a 1" combo wrench without paying a silly amount for a tool I'll use 2-3x.

Here's the tool.

Max71

Another view

Max71

Finally a view with the cap nut in the hole.



Max71

Last question for Peter - When you trim the spring and I suspect I will have to - are you trimming an entire coil at a time as an example in this photo?

IE each arrow represents where I would cut off an entire coil. Not sure how much spring translates to how much pressure...

Max71

That's about right for coil cutting, as I use the grinder I can put a slight flat on the coil to fit into the cap end better.
I always use ball bearings. I would never use grinding paste in block as you cannot guarantee getting it out of all the oil ways and nooks and crannies.

The springs are not perfect in terms of overall strength and effect of each coil. Cut to suit, couldn't be better.

I think sometimes we think we need absolute numbers for our classic cars, mostly these numbers are relative and subject to 'fifty shades of grey' and we have no really accurate ways of measuring the absolutes....just ball park figures:)

Peter
Peter Burgess Tuning

Thanks again Peter. Understood. Everything you say makes sense.

I have a small dremel tool and should be able to grind a flat as well. Hoping the tool makes it simple.
Max71

After several hours and two days including another trip to the tool store -- finally I got the bugger in. The photo is of cold start up.

I'm a little concerned the OP is now too high. I wanted to check with all of you before cutting a coil. What do you think? I haven't taken it for a test drive in case its too high right now - of course this is cold start, cold oil.

Max71

At what speed was that oil pressure reading taken? If at regular running speeds, it's just at the safe limit. If it was taken at idle, then it's too high and will need to be reduced. RAY
rjm RAY

This was taken at initial engine start up. I only let it run for a minute or two.
Max71

My GG sits on 60-65 on start-up and only shows variation once the oil has warmed up. Running pressure is around that again but swings between 45 and those figures underway and stop light idling.

I'd suggest trying a decent run and seeing what variations you get before the effort involved in removing/replacing the spring.

As Peter said, these things are relative and figures differ between individual cars.

Regards
Roger
R Taylor

So I won't hurt anything by doing a run? I'm just being ultra cautious….I've never seen the OP this high. :)
Max71

I tried an edit but Max71's post prevented it. I meant to add the bottom of my engine has 130,000 miles on it, so not rebuilt from new but is in good condition with 155-165 cylinder pressures. It runs and responds really well. Also, the running variation in oil pressure is consistent with engine load.

Roger
R Taylor

Sorry Taylor.

I just went to let it warm up with the idea of taking it for a run. As it warmed up holding at ~ 80 lbs I blipped the throttle and it went past 80 to to like 85+

Seems like too much. I best take out a coil. Its an incredible pain to do this - hours. I know its relative. Any chance you all feel one coil will be enough?
Max71

I guess practice does make one better. This time it only took 20 minutes to get the cap nut back on. I took around a coil off maybe a hair more. I'll post a pic for future reader. I think I finally found the magic combo. I'll post in a separate thread for reference.

This time at startup it was around 70-75. I blipped the throttle and it looked like it blew off at 75 which is much better.

After a long run OP is all over the place. Like crazy and many times opposite behavior. For example, cold the idle OP is 75 but as soon as I start driving it drops lower the higher the RPMs - 50 and minus. Then I stop and OP rockets back to 75 lbs.

Hot oil the idle drops to where it was before. But top OP is much lower. Around 50 lbs. But hot or cold the faster I go the lower the OP.

Stopped the car and let it sit for a while. Then fired it and drove some more. Same results. I'm very confident I did it right. I don't understand.
Max71

I told you the pressures will fluctuate. What you should have is better pressure at lower revs and at higher revs you will be safe. I did say quite a few times what to expect. Does it sing to you when you blip the throttle and listen carefully? I think the ball bearing can oscillate faster than the bullet style hence the ups and downs. Let it all settle in then think of longer spring for steady higher rpm pressure if necessary. Maybe you should have let it all settle longer before you shortened the spring, will takes a few hundred miles not one drive. You need time to let the oil bed in. Lower pressure after a while. On race engines we drop the oil pressure on the dyno so we keep oil pump losses to a minimum. Never lost an engine from oil pressure yet, road or race. Some of 'the opposition' run the pressure at 55-60 psi flat out.

"The ball bearing tends to work well, you may have some weird noises if it sings to you and odd fluctuations at diff revs but it works to perfection."

"As I said earlier you may get some 'funny' fluctuations with the ball bearing BUT it is almost impossible to jam a ball bearing open which can be disastrous for oil pressure....a bullet valve can and does jam easily especially with the low quality new ones."

Here is a youtube link to a race A series we built. Practice was in wet on slicks so the midgets and Bs at the back of the grid. We get through to first in class, then safety car comes out, then when race restarts debris comes up from track and takes out screen....ball bearing relief valve as ever.

http://www.youtube.com/watch?v=VJ_wtcQ7SaM

Peter
Peter Burgess Tuning

Hi Peter,

Yes, you did say it would fluctuate and it sure does. I was expecting that and prepared, it's just odd working in reverse for a while.

Unfortunately, at hot idle the OP is the same. I admit I did panic a little and knew the time change, but being a daily driver I need to use it so once I saw blipping it reached above 85 lbs I got nervous.

As you said, "As Denis says don't go over 80" so I read that to mean it was too high. Didn't hear any odd noise. I guess I was too focused on the OP gauge.

Do you want me to order a new stock spring and put that in? Or is the fact the idle OP being the same as before tell you something.

Max71

Run what you have and see how it settles then make a decision re length of spring, it takes time for the process, a couple of hundred miles(or a race!). The fact the pressure is still lowish at idle could imply poor seat but also lazy oil pump. No need to worry though as the pressures are safe. Keep an eye on it and look for change. We have had em 100 plus psi before we shorten the spring after first race. No problems with the pressure just uses bhp to run the pump!
The noise tends to occur when you blip the engine to say 3000ish rpm and let it come down to idle, makes the noise as it comes down to idle....not guaranteed though:)

Peter
Peter Burgess Tuning

Will do Peter. It has a brand new oil pump in it. The OP didn't change at all once I put in the new pump and bearings. I ordered a new spring to have handy just in case...
Max71

Enjoy the car and don't worry.

Peter
Peter Burgess Tuning

Max,

Twice you have said that the hot idle oil pressure is the same as before. There are about 60 posts on this thread. So, give us a break and don't make us shuffle through 60 posts trying to find out what it used to be (I didn't bother). Just tell us.

Charley
C R Huff

Don't you mean Odyssey rather than Odysseus?
sam christie

Hot oil pressure before was around 55 lbs at speed, Idle was around 25 lbs in traffic.

Now speed is about 50 lbs and sometimes idle is 75 lbs or 25 lbs as stated in the above about the oddities of the ball bearing which Peter had warned.

Yes I meant Odyssey. Wish I could change that.
Max71

I was wondering if the folks here thought it was worth me doing a new post devoted to getting the spring/cap nut back the spring valve. A far easier process than I've read or asked people.

I've got it down to 20 minutes or less under the car on the LHD. When I talked to folks months ago who did it they ended up taking the carbs off etc.

Peter's idea of the cut down socket is spot on and I ended up doing that when it was clear I couldn't get a tool in there to turn the head of the cap nut. In essence the cut down socket, a lock tie on the socket (to turn it) and that tool I had made. With all in place and a pair of bent needle nose the job is pretty painless.
Max71

Wouldn't be a bad idea, Max. It does seem to be a dreaded job. Did you go back to a full length spring?

Charley
C R Huff

I ordered a full length spring. I don't hold much hope this will fix the issue. I'll just watch the OP and hope it keeps me going until I can afford the proper fix.

Ok, I'll start a thread and post.
Max71

This thread was discussed between 10/06/2015 and 19/06/2015

MG MGB Technical index

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