Project Dollywobbler's Invacar - Ongoing

[dollywobbler]

Can you try in really early one morning when it isn't too hot?  We were really struggling at the mower racing with the belts getting too hot and either slipping or coming off the pulleys.

 

It hasn't been that hot here. Plus, she's now wedged into the garage for the foreseeable. Not enough time!

 

Ian, does your manual have a diagram of the CVT system ?

 

The DAF system uses two variators (i.e. both pulleys change gear), but there are simpler versions of the CVT (i.e. the Mobylette Mobymatic) which use a single variator. Perhaps the Invacar system is like the latter ?

 

Regarding the slipping belt, aging rubber may be the reason. Even when stored correctly, a 40-year-old belt is bound to have hardened significantly.

 

The manual is shite. From what I can work out, only one pulley has a spring and therefore adjustment. I'm curious about what causes the ratio change on the first pulley. It clearly does change ratio and is alluded to in the manual.

[PhilA]

There are small gnomes in the pulley. They push and pull on it. Some may have fallen out on your long journey. You were hearing the screams of the remaining ones.

 

Phil

[SiC]

There are small Hubnut YouTube fans in the pulley. They push and pull on it. Some may have fallen out on your long journey. You were hearing the screams of the remaining ones.

 

Phil

FTFY.

[SiC]

I was renew my MGB Insurance today.

 

"How did you find about Hagerty?"

 

"Well this is going to be a rather random answer. I actually found out about you on a YouTube video about an Invacar."

 

"Oh yes, Ian Seabrook. We do like him here."

[captain_70s]

Cheeky Invicar content

[quicksilver]

It's all gone quiet in here now TWC is resting so have a thread bump. With nothing better to do tonight I tried to work out how many TWCs existed using the DVLA site. I reckon there was a batch of a hundred (TWC 701K to TWC 800K) as TWC 700K was an Austin of some sort. There's no record of TWC 801/2K but TWC 803K onwards were all Fords. 19 of them are still listed, their typical lifespan seems to have been around 11-15 years and 725 is the only survivor of the batch.

 

TWC706K 01/06/1987

TWC718K 01/06/1983

TWC725K 01/03/2019

TWC727K 07/10/1983

TWC731K 01/12/1986

TWC735K 01/06/1987

TWC741K 05/08/1987

TWC744K 01/10/1983

TWC754K 01/01/1985

TWC759K 28/10/1986

TWC766K 01/12/1987

TWC769K 01/06/1983

TWC784K 01/11/1989

TWC785K 09/04/1984

TWC786K 17/01/1984

TWC787K 01/06/1986

TWC792K 06/01/1993

TWC794K 01/06/1983

TWC796K 20/08/1984

[dollywobbler]

Thanks for that. Very enjoyable, if a little sad to see how many TWCs were scrapped some decades ago.

 

Anyway, one TWC is very much alive!

 

I sprayed some belt dressing all over the drive belt, thinking this would have as much use as smearing chocolate on a frog, but by heck is she improved! No squeal, CVT now working properly so no longer bogging on hills. 65mph achieved! Wow.

[dozeydustman]

I've been a passenger in a Rialto at motorway speeds, which given the imbalance of a skinny driver and a fat lump in the passenger seat made for an interesting journey.

 

I can imagine 65 in TWC being quite scary.

[LightBulbFun]

Woo!

 

glad to see you got the belt issues sorted

 

I hope there will be a video on TWCs newly unlocked performance

 

any plans to do a 0-60 going backwards? 

[dollywobbler]

I've been a passenger in a Rialto at motorway speeds, which given the imbalance of a skinny driver and a fat lump in the passenger seat made for an interesting journey.

 

I can imagine 65 in TWC being quite scary.

 

It is absolutely terrifying. The automotive equivalent of those birdman suits.

 

Woo!

 

glad to see you got the belt issues sorted

 

I hope there will be a video on TWCs newly unlocked performance

 

any plans to do a 0-60 going backwards? 

 

A new video will be made. I want to test her on the most severe hill I know first. No plans for a reverse test. It's scary enough going forwards...

[PhilA]

I imagine it going backwards, hit the brakes then fly off, end over end into the distance, rather like the red car at the end of Blues Brothers.

 

Phil

[Noel Tidybeard]

A new video will be made. I want to test her on the most severe hill I know first. No plans for a reverse test. It's scary enough going forwards

 

 

chicken!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Cardinal Wolseley]

While wasting time on YouTube I stumbled over the TWC project and naturally instantly subscribed, and have wasted many many hours subsequently working my way through the whole archive of wonderful assorted projects and road tests I have to say seeing Mr Hubnut roaring through those splendid Welsh lanes is possibly the most terrifying thing I've ever witnessed. I freely admit that there is no way I could be brave enough to get behind the wheel of an Invacar, but I love watching those that do. Almost as splendid are all those wonderful fettling and repair vids, Autoshites answer to Edd China  

[dollywobbler]

More video! Will she be good enough for Cholmondeleyeyeyeye?

[Tadhg Tiogar]

I was renew my MGB Insurance today.

 

"How did you find about Hagerty?"

 

"Well this is going to be a rather random answer. I actually found out about you on a YouTube video about an Invacar."

 

"Oh yes, Ian Seabrook. We do like him here."

His reputation goes before him.

[Steve79]

More video! Will she be good enough for Cholmondeleyeyeyeye?

https://www.youtube.com/watch?v=GHBc9vJezxc&lc=UgwjNOrGFyBHWrueJR94AaABAg

Like the way you clear just enough of the screen to peer through

 

Made me laugh as it reminded me of this scene in blues brothers when the monaco throws a rod!

[plasticvandan]

Have you not tried fitting the indicator stalk to the left bar on the handlebars so you can use your left hand to operate them?

Be interesting to see what long term effect the belt dressing has,unless it can sort of impregnate (soften?) The rubber then one would imagine it would just get washed/burnt off?

[Cavcraft]

More video! Will she be good enough for Cholmondeleyeyeyeye?

 

Ian, soz if I've asked before, but where is the petrol station in that picture, please? Looks like one I stopped at many moons ago during an horrific motorbike ride to somewhere near Newton mid Wales.

[dollywobbler]

Have you not tried fitting the indicator stalk to the left bar on the handlebars so you can use your left hand to operate them?

Be interesting to see what long term effect the belt dressing has,unless it can sort of impregnate (soften?) The rubber then one would imagine it would just get washed/burnt off?

 

The stalk seems very happy where it is. It's oxidises to the bar. As you say, will be interesting to see how it goes. It has covered about 30 miles so far, and hasn't gone back to squeaking horribly. Next weekend will be the test!

 

Ian, soz if I've asked before, but where is the petrol station in that picture, please? Looks like one I stopped at many moons ago during an horrific motorbike ride to somewhere near Newton mid Wales.

 

Pontrhydygroes. The first Shitefest Cymru included a scenic drive past it.

[Cardinal Wolseley]

Good grief the descents are the stuff of nightmares, especially in that monsoon. Lovely to see TWC out and about again.

[PhilA]

I've used something similar on my belts to stop them from squealing so badly with the air conditioner on. Mine is caused by a commination of oil ingress and the harmonic dampener rubber getting rather soft and as such the pulley gets all wobbly.

 

Left for a while it seems to soak into the rubber a bit, not feeling like a surface tacky but actually like it's altered the characteristics of the belt itself.

 

Long term effects? Unknown. Short term effects are well worth it though.

 

Phil

[Noel Tidybeard]

one can't help wondering if Twk wasn't originaly set up with a left handed throttle as all the other controls look biased for the right (possibly weaker) hand and the altered for someone else at a later time?

[LightBulbFun]

More video! Will she be good enough for Cholmondeleyeyeyeye?

 

Woo! more invacar goodness!

 

glad to see the belt slippage is solved it would be fun to do a top speed run, I wonder if theres anything left in the engine to tune?

 

imagine what other motorists thought when they saw an invacar pottering about in torrential rain...   (the scene where you turned her around made me chuckle )

 

 

one can't help wondering if Twk wasn't originaly set up with a left handed throttle as all the other controls look biased for the right (possibly weaker) hand and the altered for someone else at a later time?

 

I was wondering this my self, if at some point the handle bars of TWC where changed without changing the dash or even vice-versa.

[dollywobbler]

Just been out for another run, taking her to 900 miles covered in total. Problem is, the transmission still isn't 'shifting' on hills. It's making it a right sod to get up them! I think the transmission is locking into its 'top' ratio too soon, at about 25-30mph, when it should be more like 35-40. So, it's like trying to climb hills in top gear. With 20bhp... Not really sure what I can do about that. Does put me off making the trek to Cholmondeleleeyeye, because steep hills have me down to 20mph.

[SiC]

Are they supposed to shift down? Weren't they supposed to be driven at 30mph max? I.e. it was designed like it or it turned out like it and they didn't bother fixing it.

[wuvvum]

When I were a lad, to make CVT mopeds hold on to the revs longer, we used to replace the centrifugal weights in the drive pulley with lighter ones.

[Talbot]

When I were a lad, to make CVT mopeds hold on to the revs longer, we used to replace the centrifugal weights in the drive pulley with lighter ones.

#

 

This is exactly the issue. I suspect very much that the springs in the driven pulley are weak, which means the centrifugal weights are easily overcoming the springs, and hence the ratio is becoming too high too quickly.

 

Essentially, it's a balance between the force exerted by the centrifugal weights (related to speed) and the force exerted by the driven pulley springs (related to gear ratio). At a constant speed, they will balance out at a certain gear ratio.

 

Heavier weights makes that balance point at a higher ratio. Lighter weights means a lower ratio.

 

Conversley, Stronger springs mean a lower ratio, weaker springs mean a higher ratio.

 

However, the springs and centrifugal weights have to be strong enough to ensure there is sufficient belt tension too. If weak springs are balanced out by lighter weights, the belt tension will be too slack and it will slip... which sounds familiar!!

 

Next question... what type of springs are fitted to / act on the driven pulley, and how easy are they to change?

[Talbot]

one can't help wondering if Twk wasn't originaly set up with a left handed throttle as all the other controls look biased for the right (possibly weaker) hand and the altered for someone else at a later time?

Given that absolutely everything is set up for the right, I wonder if the owner only had (or had use of) one arm?

[dollywobbler]

Are they supposed to shift down? Weren't they supposed to be driven at 30mph max? I.e. it was designed like it or it turned out like it and they didn't bother fixing it.

 

Not as designed. It's actually fine above 40. The problem comes when the gradient becomes steeper. As Talbot says, probably a weight issue.

[dollywobbler]

However, the springs and centrifugal weights have to be strong enough to ensure there is sufficient belt tension too. If weak springs are balanced out by lighter weights, the belt tension will be too slack and it will slip... which sounds familiar!!

 

Next question... what type of springs are fitted to / act on the driven pulley, and how easy are they to change?

 

I wish I knew. The service manual doesn't go into much detail. In fact, it says don't even attempt repairs.