Loosing power uphill or under load any ideas?

[Worby876]

Well...seeing the end of the World didnt happen  ...I thought I'd spend some more time tinkering on the beddie. 

Drove down to Supercheap, and scored a new fuel filter and a can of carby cleaner..and some new diff Oil
as the guy at Midas told me it needed changing a month ago when I got him to do my road worthy for rego.

When I got home I changed the in line fuel filter over and set about cleaning the ouside of the Carby and throttle
assembly as per the instructions...waited a minutes and did it again.

Then started the engine on petrol and took the air filter tube off and while running at high revs (1,000) I squirted
the cleaner in the throat of the carby around the butterfly and the little boy etc...stopped the motor waited a few minutes and
as per instructions did it again...put it all back together and then started the engine and adjusted the idle to about 550 RPM
and then with the aid of the timing light set the static tuning to 6 deg BTD, with the vacuum off, and then put the vacuum
tube back on the dizzy and observed the mark advance a few more degrees.

This gave the best vacuum level on the vacuum gauge too...a smidgen over 20 Hg and the motor was idling smooth as with just
a little bit of roll every now and again...

When I tried to run her on LPG she was rough as guts  and wouldn't idle unless I pumped the accelerator...

So I re attached the lever mechanism dad had rigged up and pushed the dissy round for max advance and it idled better but not great
seemed like it needed more advance but it was hard over as far as it could go.

So I went back to running it on Petrol and got is sound pretty sweet.
Then I noticed and every so little flick down of the needle ever now and again in concert with the little roll or peculation of the motor...
H'mmm is this a possible tell, that one of the valves could be sticking

Or possibly the spark plug gaps need adjusting see scenario 11 on this useful online demo on diagnosing engine problems using
your vacuum gauge  http://www.secondchancegarage.com/public/186.cfm its pretty cool 

[Worby876]

Well...seeing the end of the World didnt happen  ...I thought I'd spend some more time tinkering on the beddie. 

Drove down to Supercheap, and scored a new fuel filter and a can of carby cleaner..and some new diff Oil
as the guy at Midas told me it needed changing a month ago when I got him to do my road worthy for rego.

When I got home I changed the in line fuel filter over and set about cleaning the ouside of the Carby and throttle
assembly as per the instructions...waited a minutes and did it again.

Then started the engine on petrol and took the air filter tube off and while running at high revs (1,000) I squirted
the cleaner in the throat of the carby around the butterfly and the little boy etc...stopped the motor waited a few minutes and
as per instructions did it again...put it all back together and then started the engine and adjusted the idle to about 550 RPM
and then with the aid of the timing light set the static tuning to 6 deg BTD, with the vacuum off, and then put the vacuum
tube back on the dizzy and observed the mark advance a few more degrees.

This gave the best vacuum level on the vacuum gauge too...a smidgen over 20 Hg and the motor was idling smooth as with just
a little bit of roll every now and again...

When I tried to run her on LPG she was rough as guts  and wouldn't idle unless I pumped the accelerator...

So I re attached the lever mechanism dad had rigged up and pushed the dissy round for max advance and it idled better but not great
seemed like it needed more advance but it was hard over as far as it could go.

So I went back to running it on Petrol and got it sounding pretty sweet.
Then I noticed and every so little flick down of the needle ever now and again in concert with the little roll or peculation of the motor...
H'mmm is this a possible tell, that one of the valves could be sticking

Or possibly the spark plug gaps need adjusting see scenario 11 on this useful online demo on diagnosing engine problems using
your vacuum gauge  http://www.secondchancegarage.com/public/186.cfm its pretty cool 

[Mr Whippy]

I read through  all your posts Worby and I reckon I have an idea of what it could be due to my own past experience.I had an old hq that would do exactly the same thing. it would idle sweet but as soon as you tried to put any load on  it, it  would break down and stumble just like yours is doing. It turned out  that the problem was the positive wire going to the coil was worn half through and not flowing enough current to the coil.
 So I suggest checking the power to the coil, firstly check to make sure your getting full battery voltage to the positive terminal on the coil.  you should be getting atleast 13 volts there when the motor is running. The other thing is changing the coil out for another if you have a spare as these can wear out too.

good luck.

cheers,

roy

[Worby876]

Gday Roy,

Yeah Im getting pretty desperate..tried just about everything else  ..i've been thinking if maybe I should look
at the electrics...so tomorrow I will test the voltage to the coil and check the wiring..maybe even replace
any thing that look dodgy I have seen the new Bosh Coils in Supercheap around $60-$80 is there a particular
size or out put I should be looking for to match the HEI Bosh Dizzy?

The Other thing Im toying with..is to look at changing the head over to a High compression head eg 173
that has been set up for LPG with the hardened Valve guides etc and see if that not only helps my current
woes but also give me a little extra poke  (I will be talking to Rothu about this option)

Cheers

Ian

[Mr Whippy]

yeah ian definately check out everything with your ignition electrics and repair any suspect looking wiring, it could be as simple as a dodgy crimp terminal somewhere in the coil relay setup.
I am using the bosch HEC 716 transistor coil with my HEi dizzy and it works perfectly.

If you put a higher comp head on and your problem is ignition related it will make it worse, as the higher compression will put more load on your ignition system.

Not to say dont do it as i reckon the 173 head you are talking about is a great idea. but you need to  fix your problem first.

[Jeff]

I agree with Mr Whippy. As stated, sparks can break down under load, and this often manifests as the high tension taking a short cut.
If you haven't already, check all the plastic bits, and plugs for cracks, dirt, or signs of tracking. Under the distributor cap is a common one.
Often I have found a problem by watching the motor at night; any leakage will show up as blue sparks...quite clearly.
Another possibility is the leads could be cross firing between themselves. This would be apparent with the night test, but make sure they are not touching each other.
Another one that had me fooled for ages was a  faulty ignition switch that came and went. You could try shorting that out.

Your problems  definitely sound electrical to me.
Good luck!

[Worby876]

Thanks fellas...I will have a look at it today...after I mow the Lawn as the missus is complaining about
the jungle out the back 

I just dont understand how come everything was work 100% until the motor blew the gasket and started
over heating and lossing coolant out the exhaust...no water in the oil..no milky tell tale...so after I replaced
the head gasket everything decided to go pear shaped !!! Its really strange.

Thinking about it some more I did have an embarrassing incident before I did the gasket change over.
The battery was flat so I did a swap from my other vehicle and silly stupid me i reversed the polarity and in 3 seconds
cooked the wiring from the alternator through to the starter solenoid...what a mess!!!

I carefully unwound the electrical tape around the harness and replaced the entire wires good as new...perhaps
I may have done some more damage to the coil side of things..its seems ok and normal looking at it but I will
get a new multimeter from Supercheap and check the voltage.

Cheers

Ian

[Mr Whippy]

I just dont understand how come everything was work 100% until the motor blew the gasket and started
over heating and lossing coolant out the exhaust...no water in the oil..no milky tell tale...so after I replaced
the head gasket everything decided to go pear shaped !!! Its really strange.

Thinking about it some more I did have an embarrassing incident before I did the gasket change over.
The battery was flat so I did a swap from my other vehicle and silly stupid me i reversed the polarity and in 3 seconds
cooked the wiring from the alternator through to the starter solenoid...what a mess!!!

I think you might have answered your own question here, GL on finding the issue Ian, I think your on the right track now.

[Bas / NZ]

Yes this information, puts a whole new light on the matter... anything else we should know about... I agree with MW I think it might pay you to investagate in this direction.........

[cords]

the easy fix would be chev it