Project Dollywobbler's Invacar - Ongoing

[LightBulbFun]

while talking to a friend not of this parish about invacars

 

it got me thinking about the fact since the new pulley setup, TWC holds 3500RPM till 55Mph now instead of the normal 45Mph, what would TWCs theoretical top speed speed be, assuming a red line of 6300RPM

 

now a stock invacar has a reported top speed of 82Mph, at which the engine would be doing 6300RPM (if the engine is doing 3500RPM at 45Mph, which is final/max ratio,  so we can divide 3500 by 45 gets you the magic number of 77 (im not sure what this number would actually be called) so 82*77 gets me 6300RPM roughly)

 

 

now on TWC she holds 3500RPM until 55Mph so in this case we divide 3500 by 55 gets you a "magic number" of 63, so now if we do 6300RPM divided by 63,

 

we get a theoretical top speed of 100Mph LOL!

 

I have a feeling the engine would run out of puff before you got there (we only have 20 horse power on the best of days, and I dont think a Model 70 is exactly what you would call aerodynamic), but its hilarious to to think about a 100Mph Invacar 

[MorrisItalSLX]

Does the speedo on an Invacar even go to 100mph?

[LightBulbFun]

Does the speedo on an Invacar even go to 100mph?

 

Nope   (on goes up to 80, so even at 82Mph you would be off the scale just )

 

 

 

 

it would be hilarious in court

 

a bit like the stories of people getting cought doing nearly 100Mph in a Bus/coach and it getting thrown out because the judge genuinely did not belive a Bus could do 98Mph or something

[somewhatfoolish]

Prosaically it does not have enough power to get much beyond 70 mph, it may even have a lower absolute top speed than the standard gearing as the higher gearing may not let the engine rev out.

[LightBulbFun]

Prosaically it does not have enough power to get much beyond 70 mph, it may even have a lower absolute top speed that the standard gearing as the higher gearing may not let the engine rev out.

 

aye yeah, im not even 100% sure on the 82Mph claim, its a top speed iv seen thrown around a lot (but i have heard of at least 2 reports of Model 70s going even faster one doing 85, and another doing 90!) however I have not had anything actually verified first hand etc

 

and as evidently proven on the various invacar threads on this forum, what little information there is out there on these lean mean blue machines, can often not actually be the case or be skewed in someway or another

 

its one of the reasons im eager to see someone try a top speed run in a Model 70

 

 

it would be much fun to throw some 650cc engine parts at a Model 70 

 

(apparently one was built with a 650cc steyr puch engine to test the drive belt to destruction I bet whoever had to rag that round a test track to do so must of had some fun )

[dollywobbler]

Prosaically it does not have enough power to get much beyond 70 mph, it may even have a lower absolute top speed that the standard gearing as the higher gearing may not let the engine rev out.

 

That's certainly have it feels. She's no faster, just more relaxing - an overdrive will generally provide a lower top speed than the gear without, and some cars are fastest in fourth gear than fifth. If I could improve the aerodynamics, or slip stream a Merc Sprinter, then maybe more than 65 is possible. As it is, I don't think so.

 

Sadly, no servicing video. There simply wasn't time. Filming stuff makes it take about three times as long, and time is not something I have much of. Haven't touched the Fox for days!

[Zelandeth]

One thing I'm curious about is whether closing off the area under the front service hatch would help both the overall aerodynamics and reduce the tendency for front end lift. It's something I've half a mind to investigate at some point, would quite like to have a small compartment up front I can stick a basic toolkit in and/or possibly stick the battery there to get a bit of weight there.

 

Hopefully I'll be able to confirm or deny TP's ability to do 70 before too much longer! Realistically though, 50 feels like where she's going to be happiest.

[LightBulbFun]

On 4/10/2019 at 10:09 AM, dollywobbler said:

 If I could improve the aerodynamics, or slip stream a Merc Sprinter, then maybe more than 65 is possible. As it is, I don't think so.

 

what something like this? 

 

 

https://www.flickr.com/photos/28083135@N06/8558460260/

[Peter C]

[LightBulbFun]

F13261F3-1ECE-402A-BE35-03C0C5307C4F.jpeg

 

hah yeah iv seen that a few times,

 

heres a higher rez version with fewer compression artefacts

 

 

(id love to know where this thing originated from exactly and if any other such brochures etc exist for the Model 70)

[dollywobbler]

The day dawned bright, so the Invacar was readied for a trip out.

 

Aberaeron was visited, purely because it is pretty.

 

The Internal Fire Museum of Power was visited, because it is awesome. The new steam room is immense. TWC the Invacar met some posh friends.

 

Then I went back to Aberaeron for ice cream and some interesting encounters.

 

Heading home.

 

80 miles covered today. She went well, though she still really does not like hills. Maybe Invacars just don't like hills. 

[LightBulbFun]

Very cool stuff

 

I do wonder about the hills issue

 

TPA (with KPLs engine) seems pretty competent but I dont know exactly how many hills she has conquered so far

 

theres not a rolling road/dyno you can stick TWC on and see how many horses she still has?

 

I do wonder if the engine is a bit poorly for some reason, but im not sure how one would go about checking for that?

 

I mean what would cause an engine to be down on power? I know timing can, but IIRC that checked out fine plus the Dizzy is sized  (is she still on electronic ignition? could that be causing issues? I find it funny how TWC is on a mechanical fuel pump and electronic ignition where as TPA is on normal ignition and an electric fuel pump   )

 

if all else fails you could always drop in a 650cc engine 

[dollywobbler]

I'd like to know what sort of compression reading I should get but haven't been able to find out yet. That's a key check. Could be I've still got a slightly cruddy valve seat, or even rings that are past their best. TPA had only clocked up about 11,000 miles, but the condition suggests that she was standing for quite a while before being moved to the field, whereas I suspect TWC was in service right up until the end.

[LightBulbFun]

I'd like to know what sort of compression reading I should get but haven't been able to find out yet. That's a key check. Could be I've still got a slightly cruddy valve seat, or even rings that are past their best. TPA had only clocked up about 11,000 miles, but the condition suggests that she was standing for quite a while before being moved to the field, whereas I suspect TWC was in service right up until the end.

 

 

ah good points there does the same kit you used on the Fox work for TWCs engine? (IIRC it just screws into the spark plug hole right?)

 

also being air cooled there would be less symptoms for detecting a HGF if there was one although reading Le workshop manual they dont have head gaskets so im not sure what you would do exactly if there was a leak there

 

as for compression the numbers are as follows 

 

compression ratio is 6.7:1

 

and compression should be 92-113 PSI with a wear limit of 72 PSI if im reading things correctly

[plasticvandan]

They weren't known as rolling road blocks for nothing! Pity about the siezed dizzy,sounds like it could use some advance.if still on points you can open the gap a bit to advance it a tad

[dollywobbler]

I should at least check it again shouldn't I? 

 

Thanks for the psi info. Very handy.

[somewhatfoolish]

I'd be more interested in the two cylinders being relatively close than in the actual pressure reading.

[LightBulbFun]

 

thoroughly enjoyed the video on TWCs day out

 

also loved the the little click and bang phone exchange they had setup  (and the MAR)

[dollywobbler]

Getting a bit fed up with this. The new pulleys seemed to be far better at first, but the above trip really drove home the point that she's no different at all. Hills are still horrific, squealing occurs very much at speeds below 30mph (so that's fun around town) and as mentioned in the News thread, it can feel very chuggy when slowing down. Clearly, something is not at all right, but I don't know what. It can't be sticky pulleys, because they're brand new. The belt is brand new too, very slightly longer than the original, but I've compensated for this by moving the pulleys apart. Last week, I even tried going further with that, to see if more tension would stop the squealing. No. I cleaned the faces of the pulleys with brake cleaner. No difference.

Starting to get a bit urgent now, as in a week's time, I'm meant to be setting out on the next big roadtrip - Essex and Sussex and the Retro Rides Weekender. It'll be over 800 miles I suspect. In this state, it'll be utterly horrific. Now, it does occur to me that a certain Rover does have a tow bar on it. Perhaps a slightly more sensible approach is the right way to go. Maybe I can get me a little trailer. Seems like wussing out, but given the mileage involved, it just won't be fun at all.

[Floatylight]

5 minutes ago, dollywobbler said:

Getting a bit fed up with this. The new pulleys seemed to be far better at first, but the above trip really drove home the point that she's no different at all. Hills are still horrific, squealing occurs very much at speeds below 30mph (so that's fun around town) and as mentioned in the News thread, it can feel very chuggy when slowing down. Clearly, something is not at all right, but I don't know what. It can't be sticky pulleys, because they're brand new. The belt is brand new too, very slightly longer than the original, but I've compensated for this by moving the pulleys apart. Last week, I even tried going further with that, to see if more tension would stop the squealing. No. I cleaned the faces of the pulleys with brake cleaner. No difference.

Starting to get a bit urgent now, as in a week's time, I'm meant to be setting out on the next big roadtrip - Essex and Sussex and the Retro Rides Weekender. It'll be over 800 miles I suspect. In this state, it'll be utterly horrific. Now, it does occur to me that a certain Rover does have a tow bar on it. Perhaps a slightly more sensible approach is the right way to go. Maybe I can get me a little trailer. Seems like wussing out, but given the mileage involved, it just won't be fun at all.

No shame in trailering it there Ian, 800 miles is a hell of a long way and could be quite horrendous if you avoid the motorways..

[Floatylight]

5 minutes ago, dollywobbler said:

Getting a bit fed up with this. The new pulleys seemed to be far better at first, but the above trip really drove home the point that she's no different at all. Hills are still horrific, squealing occurs very much at speeds below 30mph (so that's fun around town) and as mentioned in the News thread, it can feel very chuggy when slowing down. Clearly, something is not at all right, but I don't know what. It can't be sticky pulleys, because they're brand new. The belt is brand new too, very slightly longer than the original, but I've compensated for this by moving the pulleys apart. Last week, I even tried going further with that, to see if more tension would stop the squealing. No. I cleaned the faces of the pulleys with brake cleaner. No difference.

Starting to get a bit urgent now, as in a week's time, I'm meant to be setting out on the next big roadtrip - Essex and Sussex and the Retro Rides Weekender. It'll be over 800 miles I suspect. In this state, it'll be utterly horrific. Now, it does occur to me that a certain Rover does have a tow bar on it. Perhaps a slightly more sensible approach is the right way to go. Maybe I can get me a little trailer. Seems like wussing out, but given the mileage involved, it just won't be fun at all.

No shame in trailering it there Ian, 800 miles is a hell of a long way and could be quite horrendous if you avoid the motorways..

[EssDeeWon]

Watched the video's on this..  I never ever knew these came from Thundersley, that is 5 minutes from me!  I can't imagine where in Thundersley as its 99% residential.  Be interested to know where.

[dollywobbler]

Apparently the old factory is a sofa factory or something today.

[LightBulbFun]

sorry to hear of continued woes (are all the gearbox fluids topped up and in check?)

have you thought about dropping in the spare gearbox from TPA maybe ?

(also worth checking the brakes again maybe?)

[dollywobbler]

Yeah, fluids check out - though it's an odd system on these, so may double-check everything at the weekend. Brakes are fine - any dragging would have been picked up at the MOT.

Spare gearbox has a seized selector at the moment, which shows no sign of wanting to free off...

[LightBulbFun]

28 minutes ago, dollywobbler said:

Yeah, fluids check out - though it's an odd system on these, so may double-check everything at the weekend. Brakes are fine - any dragging would have been picked up at the MOT.

Spare gearbox has a seized selector at the moment, which shows no sign of wanting to free off...

maybe strap a camera to the inside of the transmission cover and record what the belt and pulleys are doing on a test drive around the block? might provide some useful info

anyway it sounds like if you keep your speed above 30Mph avoid hills and dont slow down, everything will be fine  (like the Invacar version of speed, but hopefully with less explosions!)

[Dick Cheeseburger]

^ And no Bullocks... ?

[tommytwo]

Could the belts be squealing because they are dry? I had this problem once on a CX2400. Solved by spraying the belts with WD40 and the belts did not slip afterwards.

[wuvvum]

9 minutes ago, tommytwo said:

Solved by spraying the belts with WD40 and the belts did not slip afterwards.

That's kinda counter-intuitive...

[brownnova]

I’ll be honest, the trailer option seems rather more sensible... and whilst sensible is not what Hubnut is all about you do have to draw the line somewhere!