Project 1974 MGB GT - The Mustard (Mit) Mobility Scooter - After nearly 7yrs, The End (for me)

[Guest Hooli]

 

When setting the valves I have noticed that the feeler gauge catches on some bits more than others under a rocker. I.e. as if its worn unevenly on the face between the valve and rocker.

 

 

That'll be it then, wear there always makes them noisey as it becomes impossible to set the clearances properly for the full stroke of the rocker.

[SiC]

Saw this on an MG forum and made me chuckle.

Good old British engineering: choose a or b

a. Smooth and quiet and it will die an ugly death after while.

b. Runs good and clatters a little (probably drips a bit of oil, too...)

 

Tempted to reduce the clearance a bit and choose a).

 

Tbh if I went down from 0.015" to 0.013" (i.e. down from the cold to hot) when cold, I don't think it would be that bad. Some mention going further than that - like 8 intake and 10 exhaust. There will be 1 or 2 mils difference when tighten up anyway.

 

I mean worse case with it too tight, I just bugger up the valves and need the head rebuilt? The miles I do a year in it probably make it a long time. Some mention they have gone 250k with no problems on a tighter clearance. Anyway would be a perfect excuse for a performance head!

[busmansholiday]

Leave them alone and buy some ear plugs like DW needs for TWC. Far cheaper option.

[SiC]

Or maybe take a silencer out of the exhaust and mask over the clatter?

[dozeydustman]

I think dropping a thou or two won't harm the top end if it's that badly worn. Wouldn't set the gap under 10 thou. The wear pattern on your rocker pads looks quite even. You can see a little circular ridge on the arm's pad on that photo above, but it's still circular so any lateral wear along the rocker shaft must be barely noticeable for the moment.

 

I'd try with 13 thou to start with. Not enough to give you a tight clearance and would easily compensate for that wear in the pads. Wouldn't bother replacing the rocker arms until you need to do some major work on the head. I used to knock 0.03-0.05mm off the valve clearances when I had a Horizon and a Simca 1100, they ticked gently with no issues or mega rattles.

 

Alternatively, see if you can find an SPQR or Gunson clickadjust - it will compensate for that wear as each click is a predetermined number of thou or fractions of mm once you have calibrated it.

[Guest Hooli]

Alternatively, see if you can find an SPQR or Gunson clickadjust - it will compensate for that wear as each click is a predetermined number of thou or fractions of mm once you have calibrated it.

 

Or even cheaper google for the thread details & work out the turns. I've forgotten the figures now but on a lot of old Triumph bikes it's impossible to get a feeler gauge in, so people have worked out the correct clearance is '2 flats' from nipped up as an example.

[dozeydustman]

Assuming it's a 5/16" UNF @24 TPi (It's a half inch AF locking nut on the B-series rocker IIRC)

 

one thread would equate to 41.6 thou (1/24")

 

Therefore from just tight (i.e. no clearance but not opening the valve), a 1/3 of a turn of the adjuster screw to loosen would give 14 thou clearance. Approx 2 flat of the locking nut.

 

If my maths and interpreting Hooli's method is right.

[SiC]

Sounds about right. It only takes a smidgen (technical term ) to go from just about right to quite tight.

[Guest Hooli]

Sounds like you've understood my method, I'll trust you on the sums as never worked it out myself.

[SiC]

Tightened up the tappets to 13 thou and replaced the grommets.

 

Old Vs new grommets.

 

Not sure if they're a different design or when they're squidged they change shape. Old gasket on the bottom looked a bit too compressed but as I wanted to go for a drive and needed putting back together relatively quickly.

 

Restarted the engine and it sounds a bit less tappy. Still tappy but quieter. Don't think I'll get much better than it is to be honest.

 

Went out for a drive with the father-in-law. Didn't go as far as I planned to as I still don't fully trust it. At least we got a few more miles on the clock.

 

I drove half and I let the FiL have a go on the way back. One observation is the oil pressure gauge when in motion.

[Video]

 

Sorry for the crap quality of the video but hopefully you can see it. When cruising along the gauge fluctuates between 40 and 55psi suddenly. Not sure what that's about. I'm going to assume it's the gauge is a bit duff. Mostly because I don't know if I want to know the reality if it's not...

 

Idle went a bit lumpier by the time we got back. Still idled fine but lumpy. I think it's just the idle has dropped back a bit for some reason. Maybe just needs a retweak on the mixture or just idle.

 

Sounded tappier again warm. Not sure if it's in my mind or just the cheap oil isn't thick enough when hot.

 

Next step is to chuck it through an MOT and pray it doesn't need anything. Payday this week so I may book it in. But will give me reassurance that things are ok. I've noticed the steering feels a bit slack and my FiL has noticed too. Then I need to continue, slowly, getting more miles back on it.

[Squire_Dawson]

The B Series was a cooking engine based on American designs, as were all the engines in that family, just scaled up or down accordingly. As such, they usually never fail completely, just get louder and burn more oil. It was the 1622cc Farina engines that could throw a rod through the block at motorway speeds.

 

If yours has a moderate oil consumption, I would leave it well alone. They all make a 'ticking' sound at idle. Just the nature of an old pushrod lump.

[captain_70s]

Sounded tappier again warm. Not sure if it's in my mind or just the cheap oil isn't thick enough when hot.

 

Probably due to the fact the BMC B-series is a BL motor with tolerances set in yards. A tappy top end won't actually affect anything on a normal road car, my 1300's engine has been fitted with a second hand rocker set which will be differently worn to my pushrods and it made no difference to the way the car drove at all, that was over 10,000 miles ago and the engine shows no sign of exploding.

 

I reckon that gauge is a bit duff, I'd be surprised if fluctuations that fast would actually display clearly on the gauge if they were actually happening.

[SiC]

 

 

How many miles have you covered in this now? I don't think not driving it far is going to build confidence though - get out and razz it about. It'll either break down or it won't

Not enough! I don't even want to figure it out. To be honest, you could work it out from the previous MOT. The owner who got that MOT only did about ten miles or so after doing the MOT.

 

I'm just nervous that if it does breakdown I'll completely fall out with it. Also fearful of requiring major work if it does. As the 1100 is taking the drive up, it'd need to be fixed at a garage. Which is expensive. Expense that I don't want as we're considering moving again and that will consume a lot of funds...

[danthecapriman]

Tbh, taking a brave pill and going out for a long drive and kicking it’s ass a bit will probably do it some good.

You could always tell on my Capri when it’d been sat around but after an hour or two ‘in use’ it’d noticeably free up a bit and feel nicer.

I’m a massive hypocrite saying this but, they need to be used!

[captain_70s]

Am I correct in thinking that nearly all the car's reliability problems were doing to ignition related stuff?

[cort16]

At least you’ve got an oil pressure guage I noticed the oil pressure light doesn’t come on before I turn the key on the cortina meaning something had broken or has fallen off.

Sounds like you need to plan a decent length a and B road drive to build some confidence .

[SiC]

I can't even remember fully! One was SU fuel pump stopped pumping, second was I think condenser. First I changed the pump and all the fuel lines - including solid. Second I put a high quality condenser, new distributor (vac advance dead and casing cracked on original) and rebuilt carbs. So one of those things potentially fixed it. I think there was a third event but I can't remember? Would have to search back on the thread. Those events happened all before Christmas last year.

 

On the 25th July I'd have had this for a year. Possibly not the best purchase I've ever made. Probably should have kept my Smart Roadster.

[Noel Tidybeard]

on the landcrab oc they reccon 50-60 psi cold idle max 75 and 15-20 psi hot on idle & 45-55 hot running

 

they said on mgb forums there has been mention of high/fluctuating oli pres with wrong oil filter

[captain_70s]

A lot of that sounds like the sort of issues that occur when a car is laid up for a while and things just give up the ghost when pushed back into use.

 

Given there isn't actually a lot to go wrong with a B-Series and you car seems to be mechanically pretty good I'd be tempted to go for a drive with a set destination not terribly far from home but taking a convoluted route of A/B roads to get there, say 30 miles away? Perhaps enlist another local shiter to tail you or come along to lend a hand/push should it break down. (I'd follow you in the Doloshite but Glasgow to Bristol is a bit of a trek!)

 

Providing it doesn't completely shit itself I can't see it dying in a manner which can't be fixed/bodged at the roadside with a bit of logical thinking.

[Noel Tidybeard]

so lets get this right:

1. you have an Aldi with a DSG gearbag
2. you have an Sherpa coop

...and your worried about the mg breaking down? :roll:

[Eddie Honda]

I don't even want to figure it out.

It's ok.

 

 

 

 

 

 

 

I'll do it for you. (57440-57301)-10=129

[SiC]

so lets get this right:

• you have an Aldi with a DSG gearbag
• you have an Sherpa coop

...and your worried about the mg breaking down? :roll:

IKR. Been through this not trusting loop with the TT too, after it was problematic early on. However I still always trust the TT more as it has computers. Computers are predicable in their logic and engine ECUs, despite their bad reputation, will try to do everything they can to keep the engine running. They have to, it is part of safe software design to ensure whatever the fault is, it should choose the safest option for the occupants.

 

Mechanical based fuel-air mixing however has very little in the way of feedback systems. Likewise with a contact distributor ignition system. It doesn't know if it's running too rich or too lean, too retarded or too advanced. If the revs drop down, it can't open up the throttle body more to help counteract that. Thankfully it doesn't either, otherwise it would be a complex nightmare.

 

Maybe I should convert the MGB to fuel injection? Not as hard as you may think! Mega squirt, throttle body injection to replace the two SUs and a couple of sensors.

[Six-cylinder]

Standard MGB components are simple to understand unlike ECU that is beyond me! Why does the display screen on my Range Rover roll? Two Land Rover specialists can't work it out!

 

Tomorrows plan is to get my MGB GT out of storage.

[Six-cylinder]

Please drive it 130 miles in one day, to show it can be done

 

Tuesday 7th Aug I plan to do a 100 mile evening trip will that help?

[SiC]

Standard MGB components are simple to understand unlike ECU that is beyond me! Why does the display screen on my Range Rover roll? Two Land Rover specialists can't work it out!

 

Tomorrows plan is to get my MGB GT out of storage.

Probably the video line is getting interference and so loosing sync of the video signal. Either dodgy connection, electrical interference from something else or maybe a dodgy oscillator in the display unit itself.

 

Signal is made up of distinct lines. A line is a row of pixels on the screen. Each will have a special pulse to tell the display to move to the next line. If a sync pulse is lost or interference fools it to thinking it's one early, it'll move to the next row.

[Six-cylinder]

Probably the video line is getting interference. Either dodgy connection, electrical interference from something else or maybe a dodgy oscillator in the display unit itself.

 

All 5 components of the set up have been changed and a Land Rover reader finds nothing, vehicle electronics are a nightmare! 

[SiC]

All 5 components of the set up have been changed and a Land Rover reader finds nothing, vehicle electronics are a nightmare!

Wiring? Make sure the display signal cable is routed correctly, away from any other wiring and electrical noise sources. Also that the shielding is connected correctly. It could well be something else nearby is causing it. Maybe even wrap the display cable in copper tape and the back of the display unit.

 

Ideally get a oscilloscope on the display lines and making sure that they aren't too noisy. But you need to know what you are looking at to understand the signal structure and make a proper diagnosis on what's going on.

[SiC]

Oh and I should mention that I really ought to refurbish the passenger seat too. It doesn't offer much support from being rolled out of around corners and the back support poles in the seat dig in. Same problems as the drivers seat.

 

Maybe when winter comes I might do it. If I still have it.

[Guest Hooli]

8 & 18. Your cars just work after you sell them

[PhilA]

Question, re the oil pressure gauge:- at idle does it move much when hot? If not, try flicking it repeatedly with your finger, if it moves about with each flick then it's just a bit stiff inside and TADTS when they get old.

 

Once you've built up a bit of confidence in the thing let me know and I'll give you a real nice driving route to go take down through the Mendips. No really busy roads, places to stop if you need to and such.

 

The only reason I would want fuel injection and electronic ignition on a B-series would be the ability to add a knock sensor so it could adjust the timing accordingly and not need the pfaff with choke to make it run when cold. A moderately simple MAF/TPS/IAC/CTS/CPS system with oxygen sensor and knock feedback with two throttle body injectors on the original carbs (mostly gutted) retaining the distributor but losing the points would probably see that engine run well under most conditions.

 

Phil