Zel's Fleet Blog...Rover, Renault, Peugeot, Trabant, Invacar & Sinclair C5

[Zelandeth]

Looks like the gauge is at least reasonably accurate. Highest temperature I saw measured on the top of the radiator end tank immediately adjacent to the inlet was in the low-mid 90s after the car had been warmed up and then idling for about 20 minutes. If my math is right the boundary between the green/red sections of the gauge is near as makes no odds 100C, and we were sitting a little below there. The sender is in the water jacket in the inlet manifold right next to the front coolant passage from the driver's side head, which I imagine would be slightly warmer.

While I had the IR thermometer out I did a check on each branch of the exhaust manifold. They were all within 15C of each other, which suggests to me that we've got pretty even contribution being made by all cylinders. Kind of wish I'd done that before doing all the work on the heads now as it would have been interesting to compare. At least it's showing me what I want to see now at least!

One reason I wanted to do these tests, aside from confirming the engine was running in a safe zone temperature wise was so that I've got a baseline to compare to when I get the radiator re-cored.

While I think about it, am I right in thinking that there was no lower fan shroud fitted on these cars? I know I don't have one, but I don't believe it's missing.

Did run into an issue when I subsequently took the car out to cool it off a bit before shutting down in that after two or three minutes driving it started to cut out under load. Felt like fuel starvation. Engine would idle fine, but fall flat on its face if you gave it any sort of throttle. Idling for a minute or two got me another minute or so of normal driving before it would happen again. Which makes me think fuel delivery even more as during a period of low demand the float bowls were being able to refill. Of course as soon as we got into our neighborhood where I had somewhere safe to stop the problem immediately disappeared. Go figure.

Rebuilding the fuel pump has always been high on the to do list, so that's now been moved to the top of the to do list as failure of that would result in exactly this sort of behaviour. I did check we didn't have a vacuum forming at the tank end and we didn't.

I just need to figure out a reliable way of stemming the high pressure jet of fuel that's going to want to escape as soon as I disconnect the inlet side of the pump. Going to investigate if I have any random fittings of the right type as just sticking a hose on there which extends above the height of the level in the tank would be the easy solution.

[suffolkpete]

I just need to figure out a reliable way of stemming the high pressure jet of fuel that's going to want to escape as soon as I disconnect the inlet side of the pump. Going to investigate if I have any random fittings of the right type as just sticking a hose on there which extends above the height of the level in the tank would be the easy solution.

It is claimed that setting the petrol reserve tap mid-way between main and reserve does the trick, though I've never tried it, I just clamp the hose.

[Zelandeth]

I just need to figure out a reliable way of stemming the high pressure jet of fuel that's going to want to escape as soon as I disconnect the inlet side of the pump. Going to investigate if I have any random fittings of the right type as just sticking a hose on there which extends above the height of the level in the tank would be the easy solution.

It is claimed that setting the petrol reserve tap mid-way between main and reserve does the trick, though I've never tried it, I just clamp the hose.

That definitely sounds worth a try. Haven't seen anything which would be clampable, all the pipework upstream of the pump I've laid eyes on so far has been copper or nylon.

[Zelandeth]

So we currently have an issue in that the engine is now falling on its face under load if you try to give it any more than about 1/8 throttle. It will rev to the moon cleanly off load and the throttle response is as snappy as it's ever been. Pulling the choke out will improve things a bit - and was instrumental in me actually managing to not get myself stuck halfway across a busy road yesterday afternoon. This is one of the things I hate most about Milton Keynes, it is a *violently* unfriendly place to have a breakdown if you're not in a residential estate. If you're outside one of those quiet 20mph areas you're on fast 60 or 70mph roads, often with no turn offs between the roundabouts spaced every mile, generally with no provision for pulling off aside from the occasional bus stop. This is why TPA had done something like 50 miles I think before she ever left our estate.

This to me seems like one of two things. Either fuel starvation or a weak spark. Which from the driver's seat are annoyingly hard to tell apart in terms of symptoms - remembering that a lean mixture takes a stronger spark to ignite than a rich one. Yes, I did fall down the rabbit hole of misinterpreting an apparent fuel starvation issue on a car before, and ended up rebuilding basically the entire injection system to eventually find the problem was that the Intermotor catalogue has the wrong rotor arm listed for the Saab 900. It worked perfectly for a week, then started dying on me once warm - behaving exactly like it was starving for fuel. It never totally lost spark...which is one reason I think it took me forever to figure it out. On the plus side, I did learn a heck of a lot about K-Jet, and maintain that it's an incredible bit of engineering and in its original incarnation before they started stuffing loads of electronics in, works really astonishingly well and is very reliable.

Given that I was already planning on rebuilding the fuel pump on here, that seemed a good place to start. I've generally found that when cars with mechanical pumps are dragged out of long term hibernation that the pumps do one of two things: Expire within about 50 miles, or continue working perfectly until the heat death of the universe. So if this one was going to die on me it would be pretty much right on cue.

First contact with the very oily enemy. Fact that it's leaking no small amount of oil tells us that it was in need of attention anyway.



This had actually been cleaned a couple of days before as I wanted to confirm if it was actively leaking anything.

After a fair amount of consideration we went for the "have a piece of hose the right size and stuff it on the end of the hard line" approach. Of course I had to use a little lateral thinking there as the supply line is a fairly rigidly mounted copper line, so before I could do that I had to release the pump from the engine so I could move it enough to detach the line and to stuff a pipe on the end. Worked well actually, only lost about half a pint of fuel I reckon, all of which landed in the catch pan.



I couldn't of course remove the line on the outlet side of the pump before the inlet was capped off or that would have also started peeing fuel everywhere. Having an active head of fuel on the system at all times really does make working on it a faff. Clamping a supply line off isn't an option either as all the lines on the car save for the tail between the fuel pump and carbs (which is non-original) are either copper or nylon.

The possibility was raised above that there is an (unintentional) "off" position on the fuel reserve tap in between the main and reserve settings. This far I've been unable to test this theory as that control is thoroughly seized on this car. Great given I don't have a working fuel gauge either!

With the inlet now detached, the inlet can be removed, allowing us to extract one rather slimey fuel pump.



The line on the discharge side of the pump running to the fuel filter originally would also have been a rigid line - goodness only knows how they intended you to do this when that was still here - guessing with an empty tank and a lot of patience was probably the answer.

Fair to say that the innards were generally well past their best.



Mmm...crispy.



That definitely wasn't far from leaving me standing at the side of the road. The pushrod oil seal had also turned into plastic.

Despite the obvious degradation of things due to old age and likely modern fuel (though I've no idea what's actually in the tank, it doesn't smell old though - unlike what was in the oil originally which *reeked* of ancient fuel), the pump was actually really clean inside and just needed a quick rinse out.

Everything was reassembled with the new parts and refitted. Unlike the previous repairer, not using copious amounts of silicone sealant on the block gasket.



I'm quite thankful to whoever cut those slots in the bolt heads, it made spinning them in most of the way far quicker using a stubby screwdriver, as getting a good swing on a ratchet down there is a bit awkward. The engine was run up to temperature and it was confirmed that we had no apparent issues with leaks.

Unfortunately during reassembly I managed to drop the pump and get it wedged between the block and inner wing while trying to thread the union in. I only caused a *minor* ecological disaster due to the amount of fuel spilled.



I knew things had gone far too smoothly when I removed it!

The fuel decided to hit the side of the dropped pump and spray a lovely fan over pretty much everything except the catch pan I had in place under the car. Especially up my right sleeve.

While I was working in that area I took the opportunity to secure the coil to distributor wiring to the engine steady. This previously was absolutely determined to wobble around about 1" away from the exhaust manifold which just seemed like A Bad Idea (TM) to me.



I'll look at getting some more period looking fasteners in due course, for now I just wanted to get the wiring secured out of harm's way.

Pretty much as soon as the thermostat opens and the radiator starts rejecting heat, we start getting bubbles in the filter still, which is fuel boiling off in the line between the pump and filter I'm pretty sure. It's right in the air path from the fan so does get plenty toasty (as in uncomfortable to hold levels of warm). I'm going to lag it with some reflective foil tape to see if that helps. I may look at rotating the discharge side fitting on the pump to see about tweaking the routing a bit as well. The fuel must be pretty warm by the time it gets to the pump anyway...given that it arrives in the engine bay on the driver's side, travels up to the reserve changeover valve which is tucked in behind the engine on that side, not all that far from the exhaust manifold, then travels all the way around the engine, over the top of the bell housing just behind the heads, then to the pump along the side of the block. You couldn't have done all that much better a job of preheating it if you had tried.

While that is an issue, I don't think it is *the* issue here as I'd observed that well before we started having problems. Sadly our problem remained despite the pump having been rebuilt.

My next thought was to rule out ignition issues. I hadn't even looked at the points as far as I could remember...think I pulled the distributor cap off briefly when pondering the miss when the car first arrived and noted that everything looked serviceable, that was about it. So that seemed a good place to start...get everything cleaned and set up as per the book and we at least know where we're starting from.

Oh.



So I guess I'm not checking the points then!

Someone has fitted a Breakdown in an Box at some point in the past. Wonderful.

I get it. When it works electronic ignition is superior, and it's lower maintenance. However my experience with aftermarket systems has been extremely poor, with literally every car I'd bought with such systems fitted leaving me stuck at the side of the road when some component involved decided to fail completely out of the blue.

Personally I don't really find checking and if necessary adjusting a set of points a couple of times a year to be that much of a chore. Especially if you do away with the frankly useless current production wax/paper condensers and just fit a good quality polypropylene film cap in its place - that probably eliminates 95% of the likely issues in one shot. At least if something does play up, you can fault find with a bit of logic and nothing more sophisticated than a test lamp. Whereas if an electronic setup decides to throw it's toys out the pram you're basically stuck.

This appears to be a Pertronix Igniter system, so not a cheap eBay job (assuming it's not a knock-off anyway), but it does make testing things a little more difficult. I don't actually have a dwell meter handy at the moment*, but that is something I'd like to check. Especially as it's not something I can adjust.

* I do have one...it's one of the things the parameters that the 200kg or so of engine analyser sitting in my conservatory can measure, it's just rather...well not in the garage still.

Guess my testing there is going to be a bit more back to basics and start with making sure I've got a nice hot spark. Then start going over everything with a microscope. This behaviour came on like someone flicking a switch, so *something* has changed.

Check spark, check timing hasn't moved, check fuel delivery is actually decent, though I did test the pump by hand before fitting, then I guess we're into pulling and inspecting carbs...as I don't really know what else it can be! This isn't a massively sophisticated setup, there's only so much that can go awry. Just annoying that it's a really difficult fault to provoke when the car isn't actually being driven, especially working on my own.

The fuel reserve valve is something I will need to do battle with at some point as it is weeping slightly.



No actual drips, but it is damp with fuel. This is a pretty simple matter to resolve. Undo one grub screw, extract the core of the valve, remove old O-ring, fit new one, reverse process. Having a helper on hand to stick a finger over the hole in the body when you remove the core to stem the flow of fuel is helpful. However as the core is thoroughly seized in place on mine that's obviously going to be a bit more of a faff. Especially as I can't just remove it to work on the bench as it has positive pressure on it at all times... remember what I said about putting the pickup in the bottom of the tank being annoying? The tank is mounted quite high up in the frame too which doesn't help either. That's a job for another day though.

[Dick]

Would running the fuel tank until empty and lifting the front of the car on ramps help avoid fuel spills.. my jcb has a sediment bowl under the tank that needed cleaning a couple of times. Diesel bath every time.. I ought to fit an inline tap... its only 20 years I've been meaning to do it

[Zelandeth]

Would running the fuel tank until empty and lifting the front of the car on ramps help avoid fuel spills.. my jcb has a sediment bowl under the tank that needed cleaning a couple of times. Diesel bath every time.. I ought to fit an inline tap... its only 20 years I've been meaning to do it

Probably, but the tank is mounted pretty high up so it would need to be properly empty.

-- -- --

Who thought this was a smart place to put a fuel changeover valve?



Right pig to get to.

As this is the highest point in the system aside from the carbs and is on the suction side of the pump, a leak here could well be drawing air in. Especially as I could see that it was weeping - turns out looking at it closely this morning there was a drop ready to drip from the arm. So it has been leaking more, just evaporating before I could see the evidence. The sticky residue around it suggests it's been doing so for A Long Time.

I'd picked up an O-ring yesterday that was, according to the internet, the right size. More on that later.

I did eventually manage to get it unseized, at which point a solid dribble of fuel emerged from around the valve core. Pretty much as expected. This did mean that I could at least remove the core to replace the O-ring. Or at least it would have if someone hadn't previously completely rounded the head of the bolt used to retain the cable off so I could detach that (needed to get enough clearance).

After wrestling with that for (and I'm not kidding) nearly an hour I just ran out of patience and cut the cable. The end was already kinked so it probably wouldn't have worked properly anyway - I'm just filing that under acceptable losses and will replace the cable core. Sometimes you just have to know when to call it quits. I think I may well actually have a suitable one floating around somewhere - it does need to be a solid rather than stranded core though as it needs to be able to push as well as pull.

With that out of the way I was able to wiggle the core of the valve out, at which point an absolute torrent of fuel appeared, which initially was the colour of black tea, I'm guessing the gunk from the reserve line that's probably been in there for the last couple of decades. My original plan to cap it off failed as I'd not accounted for the vacant grub screw hole. Eventually I resorted to a bolt with a rubber glove wrapped around it which stemmed the torrent to a mere dribble.

That O-ring, 9mm ID and 2mm thickness, that the internet had said was the necessary size? Way too big, no way it was ever going to go into the body.

After a rather panicked scramble around, I found one which did the job. It's not properly fuel rated so isn't a long term fix but it's got the system fuel-tight again so I can order one that is definitely the right size. At which point I will measure it and confirm the exact dimensions for future reference.

This is all that was left of the old one.



For now though I'm confident that we're not drawing air in there. Unsurprisingly this has had precisely zero impact on our issue, though it did take a little longer to manifest today, when I just drove out and we warmed the car up while driving, whereas yesterday we were pretty much up to temperature before I pulled out the driveway as I'd been keeping an eye out for leaks. Again my eyes are drawn to that spark module.

I did check and we *seemed* to still have a reasonable spark when I tested it hot, but I don't actually have a proper tester with an adjustable gap so it's hard to quantify how much it's changed. Wouldn't have said it was the strongest spark in the world (hello P4), but it seemed reasonable. I may borrow a coil from somewhere to test that by substitution as that's an easy one to eliminate at least.

I'd usually do exactly that with points/condenser at this point as that would pretty much prove/disprove the ignition system as a cause. Unfortunately the spark module currently fitted is a roughly £100 part, so just grabbing one to test by substitution isn't ideal. Though I do admit I'd breathe easier knowing I had a spare in the car anyway given my prior history with aftermarket electronic ignition systems...so maybe I should just buy one.

One more simple thing I'll check tomorrow is that we haven't ended up with water in one or both of the float bowls. I really, really doubt it, but we did have some pretty torrential rain on a couple of days last week and the fuel cap is on the top of the rear wing, and it's reasonably easy to discount.

I did wonder if the ignition timing had shifted, but it's still exactly where I set it, and I have definitely secured the clamp on the distributor.

Spotted a likely source of where some of the engine noise in the cabin is creeping in. It's always sounded a bit louder in there than I'd expected.



That's where the throttle linkage passes through the bulkhead. There should be a rubber boot sealing that hole. Obviously it will need to be replaced. For now I've zip tied it more or less back into place.



Better than it was anyway.

Further tinkering to follow.

[Zelandeth]

Well this would definitely explain our issues.



That's not going to keep up with a 3.5 litre V8! That's the flow we have irrespective of engine speed, and there's absolutely no pressure behind it.

This puzzled me. For one, the whole reason we went through the fuel pump was the belief it was failing (and it plainly was), but it definitely pumped when manually actuated before I fitted it. Though I guess that might have been right at the extreme of the stroke or something?

On checking I could pull fuel through it, but not back so at least one of the valves was working.

Time to pull the pump again. This also allowed me to confirm that under gravity we do have ample flow from the tank, so our issue pretty much for certain isn't on that side.

At this point I became even more confused, as again when actuated the pump worked well. It seems that something is amiss with the drive.

I didn't get a good photo of it, but there doesn't seem to be any excessive wear on the rocker arm, a shiny spot where it's run on the cam, but nothing excessive. Not really sure what I should be looking for in here - the curse of working on an engine I don't know well!



Found myself pondering if I was missing a spacer block or something between the block and pump as that would change where on the arm the cam would run...I don't see any sign of one on the diagrams I can see though.

I did test flow when I refitted it...but I only checked it at the pump outlet, not up at carb level...oops.

I faffed about with this for a while and have cobbled together an electric setup borrowing the little Hardi pump from TPA to do some testing with tomorrow.



Obviously this need to be secured etc, but I just wanted to see how much fuel it delivered - several times more in 10-20 seconds than the mechanical one had in several minutes was the answer. I know these pumps generally do a lot better when pushing than pulling, though I reckon it will be happy enough here given that we already have a gravity feed from the tank, so long as I don't mount the pump too high up.

I then had a thought. This engine core we have established originates from an SD1, we worked that out from the engine number. As far as I can recall, the V8 SD1 never in any form used a mechanical fuel pump. To which end I find myself wondering if they bothered to actually machine the eccentric on the camshaft to drive the non-existent fuel pump on an SD1 camshaft (assuming it's the camshaft itself which would drive the pump - this manual I have is useless, it has barely any diagrams of anything, I really need to order a better one). Being well into the era where BMC were involved by then, I find myself thinking that if the bean counters had figured out a machining step that could have been skipped that they would have indeed skipped it.

Which definitely would explain our issues, if the eccentric the pump is meant to run on simply isn't there! Though it does raise the question of how the car was running absolutely fine for a while? Given that we know the tank was brimmed when it arrived, my theory there is that it's actually just been running on a gravity feed, and we've started having these issues now that the fuel level has started to level up with the carbs. The tank on this is mounted in an upright position behind the rear seats, so the fuel level when it's full is definitely above the carbs. The float bowls on these carbs seem to be a decent size too, it will run at idle for several minutes just on what's in there, much to my surprise.

Thinking back to when I first got the engine running and we had the carbs overflow - they continued to do so for quite some time after the engine stopped, only stopping when I whacked the side of the float chamber with a screwdriver. When I saw that happening it was also the first time I had parked the car facing towards the garage - with the rear end facing up hill. When I got the car too, there was more petrol in the sump than oil I reckon.

I'm going to see if I can borrow a helper tomorrow at some point, pull the pump back off and observe what's going on through the opening in the block. Hopefully then I can see if there is actually an eccentric in there for the pump drive to run on, and if there is if it looks like there's any damage to it. As I really don't see what else our issue can be. The pump tests fine in isolation - it just isn't pumping when on the engine. So there's either something wrong with the drive to the pump, or...well I don't really see anything else it can be to be honest. It's not a particularly complex system. An eccentric makes a lever wiggle up and down which in turn moves a diaphragm up and down against spring tension. Not much to it.

Watch this space for another exciting installment tomorrow. After which point hopefully I can put stinking of petrol behind me for a while!

I've always found myself wondering if there was a reason that this car got parked up, and I find myself wondering if this might be it. It's the sort of slightly odd fault which could have you running around in circles and tearing your hair out if you don't have the patience for it. Yes there were issues with the valvegear, but that wasn't particularly hard to find, and could well have happened after the car was parked up originally. We will never really know though.

[Luxobarge]

That's a really interesting problem, that you've explained logically and well. I'd agree with your hypothesis, looks and sounds to me like there's no eccentric on the cam.

For me, it's a no-brainer to go straight to an electric fuel pump set up, yes there's an initial cost of course, but thereafter you'll know where you are, with better starting, less fuel wastage and more consistent pressure. Should be plenty of suitable pumps on the market, go for one that is solid-state of course.

You might well find that the mixture will need leaning off a little on the carb settings when it's sorted, but that'll be a nice problem to have.....

Enjoying this as always, keep up the good work.

[Zelandeth]

Tentatively calling this one resolved. You won't believe what was wrong...well you probably will, but hopefully it gives someone a bit of a laugh.

Had a look earlier on today and there was definitely an eccentric on the cam, and it looked to be intact from what I could see.

The arm on the pump looks to be fine.





Bit of wear to it as you would expect but nothing I'd expect to cause issues functionally. No plastic end piece or anything on here on any of the new pumps I saw on sale so I don't think anything is missing. I do wonder about a spacer on the block as it really would help with heat management, but looking at how the rigid fuel line lines up it doesn't look like there was ever one there. Plus I can't see one in any of the diagrams I have.

A bit of experimentation continued, and I discovered something. The pump would expel fluid through the outlet with great enthusiasm when run from a gravity feed - however what it wouldn't do was suck anything in through the intake. Pointing at a leaky valve.

Said valves were changed when the pump was rebuilt - that was a pig of a job without a vice to hold the pump body in as removing the old ones eventually required quite a bit of violence. Wasn't much left of them!





I did peen the edges over a bit further after that photo was taken by the way.

So the pump came back apart again. Any guesses what I found? Valve not seated properly? One come adrift because I hadn't peened the metal over enough?

Nope. Stuck neatly straight through the middle of the suction side valve was a single strand of dog hair.

I blame the "helper" who was assisting me during the rebuild process.



Thanks for that, you fluffy, endlessly shedding idiot...

With said hair removed, the pump reassembled (again), and refitted (again) I'm glad to report that we had a much more convincing looking flow.



I then set about removing yesterday's bodgery, returning the engine bay to a relatively tidy state. Though I do need to so something about those HT leads. Or at the very least figure out which ones are meant to go where so they sit more neatly.



Excuse the "soft focus" effect, my poor phone was covered in oil yet again by that point.

After playing car Tetris to extract the P6, I went out for about half an hour of driving around in circles without any incidents. Right up to the point where the car which had been running flawlessly cut out without any warning - halfway around a dual carriageway roundabout - about 60 seconds after I'd left my "safe zone."

Mercifully I was pointing downhill at the time so was able - amid much honking of horns, wound down windows, hurling of profanities and rude gestures at me from other drivers - to slowly roll out of harm's way.

And people ask why I want to move. You know, a car moving very slowly with their hazards on probably is having an issue. How about you just have some patience for the seven seconds it takes them to get out your way, already...is that really too much to ask?

Positive wire to the coil had come off. The connector was quite a loose fit so gave it a nip up with the pliers and it now stays in place properly. I will probably replace all the connections to the coil in due course as a couple aren't pretty.

The coil etc needs some attention anyway. Now I know I've got the Pertronix Ignitor setup in the distributor, that changes a couple of things.



For a start it's designed for a coil with a 1.5 ohm primary resistance (which this one isn't), and shouldn't be run via a ballast circuit (which is still in place on here). So I'll need to look at sourcing an appropriate coil and removing the ballast from the circuit. That may well go a good ways to explaining why the spark isn't quite as lively as I'd expect from a system like this. Also need to gap the pickup properly as it's currently far too close to the magnet. Just realised I'd meant to do that this afternoon but totally forgot.

Despite that minor hiccup with the coil supply, the car seems to be running fairly well again. I've tweaked the kickdown cable a bit so it now will actually drop into 3rd when just bumbling around on idle in residential areas rather than being totally absent until over 40, but still changes at sensible seeming points when actually under load.

Getting there bit by bit.

Given the time of year, next up on "broken stuff I really need to sort" is likely to be the heater blower, as being able to demist the windscreen on demand would be nice. Hopefully that's not just a solid block of rust.

Also hopefully I don't need to dismantle the entire car to get to it...

Regarding the cleanliness of the fuel system, in 70-ish miles of driving and probably an hour or so total of running otherwise when testing things, prior to me fuelling up again this afternoon, this is the total amount of sediment which has turned up in the fuel filter.



So I've no real worries about the overall condition of the fuel system. Need to get that washer in the reserve valve changed when it turns up changed and replace those two bits of rubber line between the pump and carb inlet, but other than that hopefully the fuel system is fine. Well...except for the non-working fuel gauge anyway.

[suffolkpete]

For the blower fault look at the fuse box first. The connectors can get hot and "relax", especially if 30mm fuses have been used instead of the correct 32mm. Otherwise the whole heater has to come out, which is a bit of a faff.