Project 1974 MGB GT - The Mustard (Mit) Mobility Scooter - 6yrs ownership & the end is potentially nigh!

[Rusty_Rocket]

Don't let it get to you! The SU will give many thousands of trouble free miles with next to no maintenance, you've just copped them at rebuild stage! The needles are ok if they're straight and unworn. They should have no scuffed/ polished sides. The jet normally 'ovals' before the needle wears. There's a baseline setting for the jet position, I'll look it up when I have the books in front of me!

[SiC]

The SU will give many thousands of trouble free miles with next to no maintenance, you've just copped them at rebuild stage!

It feels like everything has needed rebuilding on this car so far! My mojo isn't helped by a little 2dr Triumph Toledo I've fallen in love with on eBay. Unfortunately additional storage is proving difficult to find and there isn't really enough room in the inn for both cars. No idea what I'll do if I win that Toledo!

 

As I've spent so much time (and money) on this, I feel inclined that I need to use it - especially before I sell it. Oh and the wife keeps taking the piss out of me and it on how little it gets driven...

[Rusty_Rocket]

You're so close with it now, this summer will be worth it I'm sure!

[SiC]

I have the old fashioned principle that "if it's not broken, don't fix it".

Problem is, everything seems broken or about to be broken! So I've got to the point where I'm just trying to make it work even just a little bit more reliably.

 

I'm glad the compression turned out reasonable. Part of the reason I did it was that I didn't want to continue putting so much effort in for the engine to then die. If the lump does shit itself, I think it'll be up on eBay pretty quick as spares & repairs...

[SiC]

Carb stripped down and scrubbed (well I've put the jet bearing back in already...). I just hope I remember where all the bits go now!

 

[Guest Hooli]

I miss simple cars like that.

[SiC]

A ten quid oops is a very good sign that I need to pack up and go to bed. I blame the carb cleaner and petrol fumes...

 

I'm just glad I didn't strip the thread in the body of the carb. It's that horrible sinking feeling when you tighten something and then feel the thread let go.

[Guest Hooli]

Silly bugger.

[SiC]

Two carbs cleanes, serviced, baselined and ready to go. Went back to the original floats as I didn't want to have 2 different floats. The new posh float might float different height than the other one or something.

 

 

A great tip I found on a MGB forum to set the float heights on the HIFs is to get a paper clip and bend a tip into a short right angle section. The diameter is pretty much 1mm and makes a perfect feeler gauge to set the level.

 

To baseline the carbs, I followed the Haynes procedure. Move the jet body up as high as it goes. Then turn the other way until it just starts moving. Once at this point, turn the adjustment 2 full turns. I guess this is done like this because the temperature compensator means you can't just level the jet at the bridge of the carb.

[Sigmund Fraud]

Great work ! Now prepare yourself for hours of entertainment* with a screwdriver and synchrometer...

[Guest Hooli]

Pfft. Bit of hose to your ear & hold it near the carbs, takes 10mins tops to balance them.

[SiC]

Plan is to get it the best as I can and then throw it at my local garage to tune it properly and fit the fuel tank. The older guy at the garage said he does it all by ear. I suspect his ear is far more experienced and better tuned than mine for tuning carbs. I've also splashed out on a Synchrometer so I have to use it to justify its purchase to myself.

 

I assume the engine will run with the carbs set at baseline? Also you're supposed to warm up the engine fully before tuning?

[tooSavvy]

"..I assume the engine will run with the carbs set at baseline? Also you're supposed to warm up the engine fully before tuning? .."

 

Engine tuning flowchart:-

 

START ENGINE*

 

*[yes] Proceed to Tuning section..

*[no] Investigate Non-Starting..

 

B.O.L. m8 

 

 

TS

[Sigmund Fraud]

I assume the engine will run with the carbs set at baseline?

 

 

 

Edit : Joking apart, you may get lucky, but it could well require a bit of mixture tinkering before you can get her to fire up and idle.

[Guest Hooli]

 

I assume the engine will run with the carbs set at baseline? Also you're supposed to warm up the engine fully before tuning?

 

Mine always did, if the carbs aren't worn (& they shouldn't be after what you've done) then I doubt you'll have an issue.

[SiC]

Got the carbs back on, done an oil change and tuned the carbs. I say tuned the carbs but it mostly consisted of turning it half a turn to get it rich enough. Now when you raise the piston it raises the revs around 400rpm. Idle is between 800 and 850 rpm.

 

I'll try and get them closer another day, but for now I don't want to piss the neighbours off anymore with it running and reving it! Plan anyway is to get it running well enough to then take it into the garage to get them to use their expertise to tune anyway.

 

One thing I can't explain is that when cold the oil pressure was 50psi at around 1500rpm. Well it was actually 45psi to start and then tapped the gauge a couple of times to get 50psi. This would be right at the bottom of the acceptable scale. When warm though, the pressure is around 35-40psi at 800rpm idle. I'm thinking the gauge is just a bit crap?

 

Oh and after I did an oil change, I cranked the engine over and the pressure didn't rise at all. Checked all underneath for leaks and the dipstick for oil - all ok. Then tried cranking again and the oil pressure rose pretty much immediately (1 to 2 seconds) from 0psi to 50psi. Again, I guess it's because the gauge is a bit knackered?

[Guest Hooli]

Does it have a capillary or electric gauge?

 

I've known people have to blow the pipe out of capillary gauges as it bit of gunk has got stuck in there. With electric gauges I've seen the hole in the end of the sensor get partly blocked with gunk & cause issues.

[SiC]

It has a pipe going to the gauge yes. Not electrical.

[Mally]

I've changed a few oil gauge pipes.

I've changed a few bearing shells as well.

[Sigmund Fraud]

One thing I can't explain is that when cold the oil pressure was 50psi at around 1500rpm. Well it was actually 45psi to start and then tapped the gauge a couple of times to get 50psi. This would be right at the bottom of the acceptable scale. When warm though, the pressure is around 35-40psi at 800rpm idle. I'm thinking the gauge is just a bit crap?

 

Yes, because 1970s Smiths. If you're worried about it, ask your garage to check with a properly calibrated gauge (provided they have one).

 

Oh and after I did an oil change, I cranked the engine over and the pressure didn't rise at all. Checked all underneath for leaks and the dipstick for oil - all ok. Then tried cranking again and the oil pressure rose pretty much immediately (1 to 2 seconds) from 0psi to 50psi. Again, I guess it's because the gauge is a bit knackered?

 

It does take some time for the filter to fill with oil and pressure to rise, this was probably not the gauge's fault.

[SiC]

I was expecting it to take a while to fill the filter but I was cranking for a good 20 seconds and the battery was fully charged. The needle didn't even flicker. When I tried the second time it pretty much started to move instantly which confused me. I assume oil pumps don't suffer from air locks or anything similar?

 

Good idea about getting the garage to test. I'm sure they must have a gauge. Pretty certain I've seen it read much higher previously and before the oil change.

 

If the engine is kippered, I think that'll be the end of my tenure with it. Don't fancy forking out £1.5k for a rebuilt unit. Plus then having to fit.

[Mally]

It will run for ages like that.

Worry when it won't go above 20psi.

[busmansholiday]

Stop worrying, it's a product of BL, so it will not always work like you expect from a piece of modern shite. As it's a capillary oil gauge there's a chance you've got a small air lock in it. As long as it moves off zero when you start it then it'll be perfectly OK. Just have a few beers tonight, get up tomorrow and go for a run in it. If the oil pressure stays steady, no matter what it is above 20 like Mally says "Don't panic!"..

[SiC]

 

 

Just have a few beers tonight, get up tomorrow and go for a run in it. If the oil pressure stays steady, no matter what it is above 20 like Mally says "Don't panic!"..

I would take it out tomorrow ... except I've found something else to take out and fiddle with.

 

In truth, I'm replacing the points that came with this cheapy replacement distributor with a set of genuine quality* Intermotor points I got from Moss the other day. Also going to put in this expensive condenser in too, so I don't have the exact same problem again.

 

My fear with the oil pressure was mostly if the main bearings were on their way out!

[twosmoke300]

1500 to rebuild an a series ? Are the parts unobtainium now or something ?

[SiC]

1500 to rebuild an a series ? Are the parts unobtainium now or something ?

That's for a ready rebuild engine that can be dropped straight in.

 

http://www.msc.parts/contents/en-uk/p8092_01b._48G733LFE_-_ENGINE_-_18V_-_CHROME_BUMPER_(IVOR_SEARLE_ENGINE).html

 

Moss is a little bit more expensive, but I can drive down and pick it straight up:

https://www.moss-europe.co.uk/engine-assembly-complete-1800cc-18v-standard-lead-free-reconditioned-48g733e.html?assoc=110144

[PhilA]

Psh

 

My old man's Sprite (1275) with 147,000 miles on the engine is real sensitive to the oil that's in it. Anything less than about 40 weight and it takes about 5 seconds after it's started for the oil pressure to come off zero and at idle it'll flicker between 40-60 psi cold.

 

Fresh 20W/50 and it'll start to come off zero on the starter and hold 72psi on the relief until it's hot when it'll keep about 20-25psi at 850rpm.

 

It's a boat anchor. When the needle doesn't go up when you rev it, worry. If it's building pressure well then you'll be fine.

 

Phil

[SiC]

I was expecting a much higher pressure, especially after changing that pressure relief valve. The old spring was a fair bit shorter too. Really can't be bothered to take the carbs all off again to put a shim on it. The gauge probably needs testing first.

 

Anyhow this is the original points that came with the distributor. The condenser is crimped as one piece onto the flylead.

 

New points with supplied condenser. I was going to crimp a connection on as that means I can swap out points but keep the condenser. However there really isn't enough room to fit a crimp piece - even the smallest red size.

 

So decided to desolder the flylead off the super-duper one, chop the condenser off the new points and solder the super-duper one onto the new points.

 

Refitted it all and set the points.

 

Then realised I had put the points together wrong. This black lead is very close to the metal plate and likely to short on advance. Something that can easily screw you over and take forever to find.

 

So I had to remove the points again and turn the connector around. There is a dimple on one side and it feels like it's the wrong way around like this. Checking the old points it appears to supposed to be like this though.

 

Put the points in and reset the point gap once again!

 

Not sure how well these points will last. The rocker arm is plastic and feels a rather soft one at that. Unfortunately there doesn't seem to be any "high quality" versions of the points - unlike there is for the 25D.

 

The original 25D off the car looks pretty much knackered. Needs a new housing (cracked around the mounting ring) and new vac advance unit. Both together are twice what this unit cost.

[SiC]

This is mostly a note to myself to remind me of this.

 

Laying in bed and suddenly realised why the rear carb was being a pain to set the idle on and needed quite a bit more rich mix. I forgot to reattach the vacuum advance line on the bottom! So it's effectively got quite a bit of an air leak.

 

Oops. They will need retuning again then.

[richardthestag]

good work on carbs and dizzy.

 

re compression, hold the throttle open when checking compression. 3 to 4 cycles should see the compression reading. 12 seems a lot. neighbours curtains twitching etc.

 

I have kind of always looked at anything over 120 is ok and if all the cylinders are within 10% then there is not a lot to worry about except that the engine is wearing.

 

if readings are low, squirt a dap of engine oil into the bores and try again, if the reading goes up the piston rings are tired. if it doesnt then you could have valve issues or a head gasket issue. valve issues can be checked by making sure rocker clearances are good. 

 

Dont look at an engine rebuild if the readings are NOT perfect text book, guessing a b series should have iro 150psi if yours are all within 10% of 135 then I would be drinking to the engines good health

 

for oil pressure a long one here, hope some of this helps

 

Firstly oil flow is way more important than oil pressure. tbh your oil pressure seems ok. 

 

IIRC MGB have mechanical gauges. the behaviour of the gauge is more important than the actual reading unless it is 10 psi or summut like that.

 

it is normal as the oil warms for the reading to drop at specific engine speeds. make sure that the reading goes up though as you rev.

 

The spring length is not as important as the force to compress it. if the spring is designed to compress at 45psi then you are unlikely to ever get oil pressure higher than that as the relief valve has opened.

 

I dont have the design stats for a B series to hand but can relay my experiences from a Stag V8 perspective.

 

For a Triumph v8 Oil pressure should not exceed 55psi, hydraulic chain tensioners will over tension and accelerate wear to the chains and sprockets. also too high oil pressure on a stag will see oil seep past the puny big end bearings (a series are wider) and straight back to the sump, thus limiting the flow elsewhere in the engine.

 

this is where I am coming from with flow being more important than pressure.

 

so the relief valve on a stag pump will open at about 50psi or thereabouts.

 

on a recently rebuilt engine at cold idle I get 50psi, at warm idle I get 35psi. this is very good

 

As soon as I touch the throttle the oil pressure rises - this is important, doesnt really matter how much it rises by so long as it is within the operating tolerances of the manufactures.

 

When the revs rise above 2000rpm the oil pressure at hot will be between 45 and 50psi depending on age of the oil and how hot shit is. i.e. at the maximum operating oil pressure. it will not get any better at 5000rpm though my smile will

 

The staaag doesnt have an engine oil cooler so the oil does get hot, at motorway speeds I will get 45psi which is more than enough. this is down to the engine design and oil quality. though more to do with design.

 

However - old engines and worn old engines especially will see the oil contaminated with petrol very very quickly. quality oil is used, stag uses 20/50. Range Rover prefers a 15/40 (Hafords blue can)

 

I always use a full mineral quality oil (not halfords classic in the green metal can with the stag on the front) , the range rover gets oil changes every 6k miles because it is largely using LPG i.e. no pez contamination. with fresh oil the oil light goes out within a second from a cold start. at 6k miles on the oil that can take 4 seconds on a cold start.

 

The stag oil pours like water after 2k miles - even on a beautifully rebuilt engine - the service schedule is 3k, my stag gets fresh mineral oil every 2k. oil is cheaper than engine rebuilds.

 

next oil filters. use a quality filter, the oil light on my rr takes 9 seconds to go out on a cold start with a pattern filter and 1 second with a land rover filter. they are the same price!!!! The stag has a cartridge filter, some come with the sealing ring glued to the top. these are only good for the bin. again quality filters cost a lot less than an engine rebuild. Also if you have a cartridge setup. make sure you have all the bits. when I first bought my staaag about 1000000 years ago the filter was flopping about in the bottom of the canister because the spring was missing. = unfiltered oil. might as well have not bothered fitting a filter at all.

 

ok so all this has been about good oil pressure behaviours. what about when doom is looming

 

rover v8 behaviour first. after changing oil, getting pressure back up is notorious. can take 20 seconds of engine running at idle. nowt to panic about so long as it isnt every time. 

 

oil light on my RR flickered at idle, ouch I am thinking, but I had just fitted a new oil pressure switch after swapping out the steering box and breaking the original. fitted a gauge temporarily and the oil pressure light had no right to flicker. a new sender fixed the issue. just because the part is new it doesnt mean that it works!!!!!!

 

stag, I had some big issues with stag oil pressure when I first bought it. and this is kind of why I now think that behaviour is more important than the reading itself.

 

for instance on the stag - it always without fail reads 50psi at cold start. if one day it doesnt it will need investigation.

at 2k rpm is always reads 45psi, if it doesnt then I will see that and need to investigate. 

 

however if I am on a motorway and ease off the throttle at speed I expect the gauge to drop a couple of psi and then go back to 45 psi as i load the throttle again.

 

what happened with my worn engine when I first got the car was that the hot pressure just got lower and lower and lower. I tried to fix / bodge it by resetting the bypass valve such that it was 85psi on cold start but still only 30psi at motorway and 10psi hot idle. I should have read the symptoms, the behaviour changing over a short period of time.

 

The nail in the coffin for that engine came when the oil pressure dropped slightly as I applied throttle but then rose as I eased off. what was actually happening was oil was pissing past worn bearings and back to the sump under load. I ignored that hoping for the best and then one morning on a cold start I could hear the big ends , sorry feel the big ends knocking. fuckedy fuck.