Project Dollywobbler's Invacar - Ongoing

[Talbot]

What diameter is the venturi on these? This pattern of fault matches carburettor icing. If the venturi is quite small (which I would expect it to be.. 20hp doesn't need much) then just a very small amount of ice would be enough for it to give up on you, but then clear quite easily with the engine idling.

 

Temporary vacuum gauge on the Inlet Manifold will reveal.

[dollywobbler]

No idea, but I doubt that it's icing. I've had carb icing on the 2CV (before I remembered to fit the grille muff) and it's a very different sensation.

[Zelandeth]

Pretty sure it's not icing, simply because it does it right from startup (assuming the behaviour is exactly the same).

 

My money is on the float level being the main issue though, as that's critical on this sort of carb. It's the only thing I've not really checked on mine.

 

Does keeping the choke closed a bit help it behave more normally (at least at parking speeds)? I've found that helps massively with mine, hence my assumption that an overly lean mixture is at least partly to blame.

[dollywobbler]

No, applying choke makes no difference at all. Hopefully next week, I'll get a chance to have the carb off and have a proper explore.

[richardthestag]

wonder if running issue is because the carb is flooding because the float valve / float level is wrong.

 

Too much fuel may cause a surge of neat fuel into the inlet manifold which could then cause the bogging down. giving it a rev could cause a backfire through the carb of the unburnt excess fuel in the inlet manifold and normal service is again resumed.

 

Flat valve is #60 on Red5s helpful piccy above. test is easy if the carb top is in your hand, blow into the fuel inlet pipe on top of carb and you shouldnt be able to with the valve closed. i.e. upside down with force of gravity holding it closed. wouldnt be surprised if it had a bit of crap in it

 

here is a carb popping vid that was becuase the ignition timing was hoplessly out. dont think this is your issue, but might sound similar

 

https://youtu.be/O2Oon2qcXiQ?t=33s

[dollywobbler]

If it was flooding, I wouldn't expect applications of accelerator pump to keep it going. They'd just make it worse. I'll know more once I get a chance to have a play with it.

[plasticvandan]

more throttle also means more air though doesnt it?

[PhilA]

Does have the nasal BNUUUUUUU of fuel starvation. Is the float chamber able to fill up fast enough? Looks like the design may have the throttle pump drawing from the very bottom of the float chamber so that should always have fuel.

 

Valve 60 might have an old O-ring in it that's now swollen up with modern fuel, allowing enough fuel through to keep the level correct for low to medium draw but not for prolonged high speed running.

 

Phil

[Squire_Dawson]

I think the only solution is a strip down and replacement of any defective parts. The trouble with any machinery left standing for years is that things dry out and perish, causing trouble when pressed back into service.

[Squire_Dawson]

Regarding gaskets (in the video), I make my own from sheets of gasket paper or cork; this is better than any gasket goo as there's a risk of the goo oozing from the joint inside and blocking an oilway. Gaskets of lesser importance can be cut from cereal packets etc.

[mat_the_cat]

Quick check is to cut the engine precisely at the point of rough running. Pull out a spark plug and check the colour - that will give you a snapshot of the mixture at that point. Bear in mind (doubtful in this case) that an ignition misfire can give the same symptoms as a rich mixture when the now rich unignited mixture fires.

[madrat]

Regarding gaskets (in the video), I make my own from sheets of gasket paper or cork; this is better than any gasket goo as there's a risk of the goo oozing from the joint inside and blocking an oilway. Gaskets of lesser importance can be cut from cereal packets etc.

never been a fan of instant gasket

[dollywobbler]

Not had chance to do any work, due to being away, but my £1.86 oil filters did actually turn up. Carparts4less if anyone else is feeling brave, and doesn't mind being bombarded by emails telling you to complete your order - the one you've completed and for which you have an order confirmation. Don't expect any response from customer services when you ask what's bloody going on.

 

At least they are entire oil filters...

 

EDIT - don't get excited. Someone just sent me the DAF manuals. I have no plans to buy one.

[PhilA]

EDIT - don't get excited. Someone just sent me the DAF manuals. I have no plans to buy one.

Yet

[Aston Martin]

I had a nap and now I can’t sleep, so I’ve just watched all the parts that are on YouTube.

 

You’re a maniac.

[dollywobbler]

Thanks! Sadly, oil is very much not sorted. 

 

So much for instant gasket. I've given up and ordered a proper gasket for the strainer in the bottom of the sump, and the oil filler where it fits into the block. 

 

I also need to find out where the brake fluid is going. I've cleaned up the master cylinder and left some towel underneath it to see if the leak is there. 

[dollywobbler]

Right. New sump-strainer gasket and oil filler gaskets fitted. Still some oil leakage, but barely a dribble now. Will try it on another hillclimb at some point, as that tends to get the oil nice and warm.

 

Horrendous test drive, full of splutters and misfires, and even a refusal to leave the driveway at one point! Loose connector on the coil. The crimp connectors that came with the ignition module are bloody hopeless, and I should replace them with ones made out of actual metal. They just open up! Useless.

 

However, that drive was only to warm the oil and get it circulating. Though I was amused to find myself stuck behind a girl dithering about in an MX-5! Come on! Get a move on!

 

So, next plan is inlet manifold off, them remove the carburettor from it and see how stripped I can get it.

[dollywobbler]

I entirely forgot to update today's photo. Here is TWC with some rocks.

[Tadhg Tiogar]

I entirely forgot to update today's photo. Here is TWC with some rocks.

 

Surely a candidate installation for the next Turner Prize.

[dollywobbler]

You're right. I shall call it "Disabled transport choices in the 1970s. Between a rock and a hard place" and shall be inundated with praise by people with large glasses and strange sweaters. Oh, hold on. That's me...

[Zelandeth]

Given that the inlet manifolds are reported to be quite fragile and getting it off involves disturbing exhaust connections would it make more sense to just pull the carb off on its own? Or are you hoping to get a look at how much crud is present around the inlet valves and to replace the gaskets to prevent and possibility of air leaks causing issues?

 

I just remember the fact that virtually every time I've had to disturb exhaust manifold connections it's resulted in significant levels of pain and suffering...

[dollywobbler]

You can't get at the carb retaining nuts in-situ. I seem to recall they're not great to get at even when you've got the manifold off. Remember, this manifold has been on and off the old engine, was fitted to this engine in the old car, then removed and refitted when the engine was in TWC. It's been around a bit. I do have a spare inlet manifold with the half-carb on it.

[Zelandeth]

That's a good reason! Also if it's been off recently you should be fine anyways...

 

Didn't realise the carb retaining nuts were inaccessible...guess I have that fun to await me as well then.

[dollywobbler]

Yup. It's not that much of a challenge to get off really, though accessing the exhaust bolts is a bit fiddly. Like most things!

 

What worries me more is that I can't find rebuild kits for the Solex 40PID carburettor. Were they really only fitted to Steyr-Puch engines?! Seems it later changed to a Weber 34 something or other, which was common to the Fiat 500. I think.

[Zelandeth]

Weber 32ICS on mine...Seriously, no two of these cars are the same...

 

 

Figure it makes sense to at least know all the carbs used, that way you've some chance of finding one that works!

[dollywobbler]

I think that's normal. At some point, fairly early on I'd guess, they changed from Solex to Weber. Not that I can find much for the Weber either! If the bolt pattern wasn't different, I'd consider chucking a twin-choke 2CV carb on...

[Zelandeth]

I think that's normal. At some point, fairly early on I'd guess, they changed from Solex to Weber. Not that I can find much for the Weber either! If the bolt pattern wasn't different, I'd consider chucking a twin-choke 2CV carb on...

 

Know anyone in a machine shop?

 

Wouldn't be too hard I imagine to machine up an adaptor plate.  Just a flat bit of metal with a few holes in...

 

I'd originally planned to do exactly that to fit the injection throttle body onto the Lada, until I discovered that the entire inlet manifold from the 1.7i engine just bolted on...

[PhilA]

I think that's normal. At some point, fairly early on I'd guess, they changed from Solex to Weber. Not that I can find much for the Weber either! If the bolt pattern wasn't different, I'd consider chucking a twin-choke 2CV carb on...

I should imagine that would liberate a few horses, particularly if the weights in the dizzy are set up right.

[dollywobbler]

Tonight, I pulled the carb off, which took barely any time at all, then took it off the inlet manifold altogether so I could see what's what. First of all, I'm an idiot. It's only a sodding Weber! I mean, there are subtle clues, like Weber being written in two places, and a big W somewhere else. Duh! That means no diaphragms. Phew.

 

Removed jets, blasted a lot of crap out of various areas. Also cleared a lot of soot from the main venturi. That's not ideal...

 

Put it all back together again. Took about an hour and ten minutes all-in-all, but what a difference it has made! Sure, she still goes 'TOOK!' every now and then, but those in the know say they were always like this. The main difference is you can manoeuvre far more easily, and come off the throttle, go back on and actually accelerate! I'm over the moon. So I went for a drive.

 

Annoyingly,  I've still got an oil leak, so I think that filler neck will have to come off yet again. I'll try some blue Hylomar on it now I have some. I'm still losing brake fluid as well, but I can't see where from. It's definitely damp around the master cylinder, but I cannot see a source of the leak. Very frustrating. 

 

So, a major step forward, but it certainly isn't all plain sailing just yet. That's ok. Festival of the Unexceptional is still three months away! 

[Cavboy80]

Congratulations on getting it running well, this makes all the difference. Still a while before the FOTU to iron out the other issues. Seeing as how long this had stood idle it's not going too bad really.