I intend to fabricate an engine test stand for a Mk2 Polo engine I'm working on.

 

It'll have a gearbox fitted, because the starter motor needs a shaft bearing.

(though @Yeti suggested a Fabia AEE adaptor plate could work, if anyone has one lying around LOL).

 

And obviously it'll need engine electrics, gauges, and engine cooling.

For fuel, I'll use gravity feed to a carburettor, so there's only a small amount of petrol involved.

 

I've got a wheeled metal trolley as the base, and several lengths of 3mm thick

rectangular steel section and 2mm plate steel.

 

Here's a first rough sketch

 

Wondering what to use for throttle control, to pull a Boden cable.

Lawnmower lever?

Motor bike twist grip?

 

It'll be in neutral for most of the setup, so don't need a gear lever.

Been suggested a big water pump as a cheap brake load/dyno.

 

Suggestions welecome.

 

 

looks a bit top heavy...can it be lower with wider legs?

Good point. Would not want it to topple over.

I'll do some measurements of the wheel spacing on the trolley base.

 

Centre of gravity needs to be low, but the engine needs to be high enough for exhaust below sump have clear passage.

And not burn the operator.

Not thought about a silencer either.

Maybe a motorbike can.

 

 

 

 

Not sure I understand when you say it needs a gearbox "because the starter motor needs a shaft bearing". I thought the starter doesn't need the gearbox for cranking the engine.

Far end of the starter motor axle shaft is held by a  bush/bearing in the gearbox casing. So the bendix flies out along the shaft and engages with teeth in flywheel, then retracts, once engine fires.

 

Modern starters have continually engaged cog. Maybe one could fit with right cog teeth size...

 

I tried testing a Mk2 starter motor off the engine and the axle shaft end gets very wobbly when it spins.

Edited 29 July, 20224 yr by dvderlm

Oh, clutch pedal/hand lever. Can I just pull the release bearing lever at the gearbox, or do I need to be superman?

Just noticed the words on the newspaper I was resting on

Went to look at the trolley wheels, which are substantial but forgot to take a tape measure. 

 

I estimate 60cm wide, while a 3 wheeler Clarke stand for up to 340kg engine is 80cm wide but much higher.

https://www.machinemart.co.uk/p/clarke-ces340-340kg-engine-stand/

 

Can't imagine Polo engine and gearbox and all auxiliaries exceeds 250kg.

 

50 at the most. I used to be able to lift one before I became fat and middle aged. 

13 hours ago, dvderlm said:

Far end of the starter motor axle shaft is held by a  bush/bearing in the gearbox casing.

 

Indeed. Reminds me I should think twice because I forgot how it was mounted. I've looked at pics of all parts I've removed from my car and find out the starter had 3 bolts on the gearbox. Unfortunately it would be hard to crank the engine without the gearbox. Would be easier if it wasn't the case...

I lost the starter motor 160mm M8 bolt on a very bumpy road in south Wales.

Made an awful rattle for 10 minutes before going anvil clang, silence.

 

I walked back up the road and couldn't find anything. Thought it might be inlet manifold support bar, but that was still attached. Assumed I'd picked up a broken tree branch or something. Took until a year later to realise that bolt was missing while working on the exhaust flexi.

 

15 hours ago, dvderlm said:

Can't imagine Polo engine and gearbox and all auxiliaries exceeds 250kg.

 

I've weigh the engine (MH) and gearbox (085) few month ago (after I stripped them out of the car).

- The engine head was about 15 kgs (without : oil/coolant)

- The engine block was about 65 kgs (without : oil/coolant, engine head, water pump, starter, alternator - with: crankshaft, pistons, clutch, flywheel)

- The gearbox was about 33kgs (with : gearbox oil)

 

We are definetyly under 250kgs 👍

Edited 30 July, 20224 yr by cedreex

14 hours ago, Yeti said:

50 at the most. I used to be able to lift one before I became fat and middle aged. 

Good, then I've over dimensioned the beams about 5 times, ready for when I fit

a helicopter engine.

I remember a gearbox being just a bit too heavy to post, despite draining the oil, but I can't remember how heavy the limit was. Felt like 30Kg last time I humped one around, not using a skateboard.

 

I reckon the car is about 700Kg.

 

Polotreff.de

Polo 1,3T writes

"Ein Getriebe ohne öl wiegt ca. 30 Kg, ein Motorblock ohne Kopf 50Kg, also wirds sich wohl so bei ca. 100Kg einpendeln"

 

A gearbox without oil weighs about 30kg, a motorblock without cylinder head 50Kg, so it'll probably narrow down to around 100kg.

https://www.polotreff.de/forum/t/123017?op=1

what is the intended use for the stand...just to prove the engine runs or prolonged revving etc ?

1)Get an engine to run on a simple carb no more than 2000rpm, perhaps 20 minutes run time per session.
2)Change cylinder head / cam, repeat.

3)Change to turbo carb(s), and boost plumbing, repeat.

 

Might be able to put it in the car after 1, 2 or 3.

 

Got a big fan.

 

Looking at old farm water pump (shaft or belt drive) to provide some load like 5 to 20hp lifting water from a tank that flows back to a reservoir.

Wondering what the diff will do with only one gearbox flange driving a pump.

 

 

cant imagine the gearbox would like driving one flange only...although what do i know

 

so what measurments are you going take from each run ?

4 hours ago, dvderlm said:

.

Wondering what the diff will do with only one gearbox flange driving a pump.

 

 

It won't drive the pump unless you weld the diff 

kinda sounds like an accident waiting to happen...im sure a home made frame will cope with a running engine , if you want to load test it then things need to be stronger 

6 hours ago, steveo3002 said:

so what measurments are you going take from each run ?

AFR versus RPM logging.

How long to consume fixed quantity of fuel at x RPM.

If i manage the Heath Robinson pump; seconds to pump 100 liters of water or liters pumped per second through narrower pipe.

 

I found getting the ignition and jetting right while driving in the 1000 to 2500rpm range took a frustratingly long time, because I had to drive, analyse, adjust. Did a lot of measurements during commutes to work, until I could take a roundabout in 3rd gear with just a fraction of pressure on the gas pedal (seat of the pants feel) and the average fuel consumption was tending over 47mpg.

 

A local hill and dash cam with GPS speed (Roadhawk) worked to review acceleration time over 3000 to 7000rpm range.

An old G-Tech Pro unit just confirmed peak power and 0to60mph times were plausible for the car's weight. 

 

3 hours ago, steveo3002 said:

kinda sounds like an accident waiting to happen...im sure a home made frame will cope with a running engine , if you want to load test it then things need to be stronger 

I would ratchet strap stand and bolt the pump to pegs set in concrete.

 

But the diff is an issue. Suppose I could start it with a crank handle, or find a starter motor that does not need the gearbox.

Could you make up a bracket that picked up on the starter mounting bolts and then cleared the ring gear and had a hole for the end of the starter gear shaft to spin in ? that way you wouldn't need the gearbox 

dont see how its worth the effort without a proper load like a dyno ...like me sitting in the car revving it up and saying its tuned , but it wont be when it has to pull 900kg up a hill

 

think id do a few hrs overtime and pay for a dyno 

1 hour ago, nige8021 said:

Could you make up a bracket that picked up on the starter mounting bolts and then cleared the ring gear and had a hole for the end of the starter gear shaft to spin in ? that way you wouldn't need the gearbox 

Worth thinking about, thanks.

This scheme and resultant testing require YouTube videos. Fact. 👍

Aha,

I could drive the water pump with a belt off the crank pulley. Use a double V pulley for a G40; can probably transfer 20hp through a single V belt, connect to a centrifugal clutch on the pump shaft.

 

That means the engine controls and battery should be moved to the other side like a left hand drive car, in case the belt snaps, though it's more likely to slip.

 

https://mechanicalland.com/complete-guide-to-design-v-belt-drive-systems-with-calculators/

 

I might have the maths wrong, but I think a totally lossless, friction free 13hp pump system can lift 100 liters of water 10 meters in 1 second.

 

https://www.engineeringtoolbox.com/pumping-water-horsepower-d_753.html