Project Dollywobbler's Invacar - Ongoing

[plasticvandan]

Yup,change the sender,it's 45 years old and been set in a field for 15 of them.crap or thin oil can cause it to come on when hot,common reliant problem was the pressure relief valve sticking.don't know if these have one.can't see it being the pump,it would have seized by now.

[dollywobbler]

Yup,change the sender,it's 45 years old and been set in a field for 15 of them.crap or thin oil can cause it to come on when hot,common reliant problem was the pressure relief valve sticking.don't know if these have one.can't see it being the pump,it would have seized by now.

 

Yes, they do have a pressure relief valve apparently. Both times it has come on has been in the aftermath of a long hill climb with revs, so I guess the relief valve would be open at that point. Oil is 20w50, so should be up to spec.

[dollywobbler]

Oh, I did another fill today, and the calculation has come out at 33mpg. Now, I'm pretty sure I didn't fill the tank completely first time, so I'll need another one to prove it, but that still seems pretty poor. Probably because of the losses through the belt drive. This car is still frustratingly hard to even push.

[richardthestag]

mechanical oil pressure gauge. find out what is actually happening.

 

I had a rover v8 which had the oil light on at anything under 1500rpm. new pressure switch fixed that

 

BUT you need to know what the baseline is for your type of engine for instance

 

the staaaaags first engine suffered from failed main bearings. oil pressure dipped on acceleration then rose briefly on letting go of the accelerator and was about 5psi at idle.

 

rover v8 at idle 10psi seems to be ok and running at 30psi doesnt seem to cause problems

 

I do have a gauge you can borrow for diagnosis. pretty sure I have the pipe also but need to know what thread your pressure sensor is

[dollywobbler]

Thanks. No idea on the thread, but I do have figures for what the pressure should be in the manual. Not in anything as helpful as psi you understand. Kilogram metres I think.

[PhilA]

Seconded on the pressure light.

 

Might be after a lengthy high speed run the oil pressure relief might not be seating itself properly? Might have worn a notch or something that makes it fail to sit correctly in the seat, causing the hot oil to pass by and reduce pressure?

 

Also, does it only do it when it's firing on one? Plus, the idle might be too low?

 

(Optimism mode on)

 

Phil

[dollywobbler]

I did some experimentation yesterday, and the revs at which the light goes out seem slightly too high for the clutch to disengage. Which is annoying.

[Squire_Dawson]

People have covered all likely causes:

 

1. Wrong grade oil.

2. Faulty oil pressure switch.

3. Faulty pressure relief valve.

4. Worn oil pump/bearings.

 

You can rule out the first as you put 20w50 in the sump, I doubt it's the switch as these either work or don't, but its rating would be good to know (no harm in having a switch that operates above the danger parameter). Relief valve and spring could be checked. If it's the last point I would ignore it as long as the light only comes on when idling, otherwise I agree its engine rebuild time, so you might as well just drive it until then anyway.

What does it actually say in the handbook about the warning lamp?

[dollywobbler]

There is nothing in the manual about the oil pressure light. It merely says the oil pressure at idle should be 1.5 to 3.0 kg/metre squared, rising to a maximum of 4.5-5.5. If oil pressure is too low at lower speeds, it suggests that the 'mushroom type valve seating is leaking' on the pressure relief valve. The remedy is to remove the mushroom type valve, clean oil pump cover, hammer in valve prior to fitting. It hammering does not help, recondition valve seating [which is an utter ballache requiring special tools."

 

That all sounds a bit beyond me to be honest. I'm dangerous when it comes to hammers.

[dollywobbler]

Ah-ha. Went and started her up today. Oil pressure light off even before she'd fired up, which is nice. Didn't quite give her enough choke, so she spluttered to a halt after a short time. The oil pressure light didn't come back on. Not for a good few seconds. I therefore am going to hope the switch is duff, or certainly heading that way. Will pinch the one off the spare engine and will see how it compares. 

[PhilA]

Definitely a good sign that it's holding pressure like that. That's an interesting remedy though- did the old oil show signs of sludge? It may pay to pull the pump and clean the passages and make sure the relief valve isn't fractured or something obtuse.

 

Does the manual have a picture showing how much ballache that would be?

 

Phil

[dollywobbler]

No, the manual is bloody hopeless. The dismantling guide is basically a list of steps to take, with no explanation! It says "Dismantle oil pump cover and take out oil pump gears." Well, cheers for that. That's after a whole host of steps, including removing the clutch and pistons, so you don't even know which steps you need to take first. It's Step 19. I can't even see where the bloody oil pump is.

[dollywobbler]

Changed the switch. If anything, it now takes even longer for it to come back on after engine turn-off. Like ten seconds. Hmmmm. Now wondering what's normal behaviour.

 

May have run out of tinkering time today though. I need to head away for work stuff.

[PhilA]

Maybe the switch was bad. 10 seconds is about right on cold, thick oil.

 

Excuse to go take it for a razz and get it nice and hot and see if the light comes on at idle.

[dollywobbler]

Zero time for tinkering really, but I used some of my lunchbreak to tweak up the idle a bit, then went for a test drive, hitting 28,500 miles as I did so.

 

That's now 150 miles covered on the road, which is still fewer than I need to cover on Friday 13th July on the way to Buckinghamshire...

 

Engine doesn't seem to be pulling that cleanly on full throttle at the moment. Picks up much better, but is struggling a bit at higher loads and throttle openings. Think I need to pull the plugs and see if they have any clues.

[madrat]

I could never get a carb engine set up properly without an exhaust gas analyser, and a timing light. But if you carb is still dirty you will never get it set properly.

 

My car rolled over to 144,000 at the weekend.

[dollywobbler]

I could never get a carb engine set up properly without an exhaust gas analyser, and a timing light. But if you carb is still dirty you will never get it set properly.

 

My car rolled over to 144,000 at the weekend.

 

By contrast, the 2CV has clocked up over 206,000 miles, and will be adding another 400-500 to it this weekend...

[dollywobbler]

This evening, I fiddled with the carb some more, and squirted some neat fuel treatment into the carb to see what that did. The result?

https://twitter.com/HubNutVids/status/986657748350898176

[lexi]

So who didn't clean that carb out proper?  Compressed air, Toluene and teeny weeny drills or very soft wire are the way to go. Get a set of micro drills from China. Will do the other stuff.  Find out the size of jet and pick a drill just under it. Honda supply a set of wires to dealers for small engine carb cleaning.

[PhilA]

Hopefully with cleaning and use it'll improve then. Certainly positive results now, you've done it a good job, certainly better than sitting in a field.

 

 

Phil

[dollywobbler]

So who didn't clean that carb out proper?  Compressed air, Toluene and teeny weeny drills or very soft wire are the way to go. Get a set of micro drills from China. Will do the other stuff.  Find out the size of jet and pick a drill just under it. Honda supply a set of wires to dealers for small engine carb cleaning.

 

If I kept buying all the stuff people keep telling me to buy, I'd be bankrupt. I've not even actually got any carb cleaner in stock at the moment (I was sure I had some somewhere). 

[madrat]

 

I was sure I had some somewhere

That's my stock phrase.

[Squire_Dawson]

From time to time the jets do need cleaning out as the orifices are comparatively small.

[Asimo]

No use worrying about oil pressure unless you are actually going to measure it with a pressure gauge.

An oil pressure warning switch confirms only that the pressure it sees has changed.

[Bobthebeard]

The wiper switch on the Invacar appears to be upside down...

Not that it matters in the least of course.

As you were.

[dollywobbler]

Oh shush! I get fed up with people telling me that. I didn't do it!

[madrat]

The wiper switch on the Invacar appears to be upside down...

Not that it matters in the least of course.

As you were.

Its in the wrong place, DW looks like a demented organ player when he's using it and trying to keep the throttle open.

[Dick Cheeseburger]

Its in the wrong place, DW looks like a demented organ player when he's using it and trying to keep the throttle open.

That really made me chuckle.

Driving this thing looks like an extreme sport, which only a select few would dare to attempt. I'd say it's up there with bungee jumping using the cheapest Chinese rope, or caving blindfolded after three months of solid rain.

[drum]

Re carb cleaning, I cut some strands off wire brush and poked the jets clean with those.

Saw it on YouTube.

[MorrisItalSLX]

This video just appeared in my youtube reccommended:

 

 

A word of warning, watching it did give me a headache.

 

Edit: Likewise, minus the headache