8 replies to this topic

[da2428]

Hi, I'm new to posting on the forum but have used it a lot!

With regards to my timing issue, I'll remove vaccume, block it off, set timing to 6 degrees using a timing light and I'll get pinking without putting the car under much load, increased my fuel and retarded my ignition to 3 degrees which means barely any pinking but now I have a lack of power, any ideas as to what could be the potential cause? Standard 998 Austin mini 1989 with hs4 carb

Cheers da2428

[KernowCooper]

A 1988 Mini 998cc the manual lists the timing with the vacuum off and blocked at  10º + 0º -2º BTDC at 1500 rpm

 

Try that setting and then report back, it could be that you have weak springs on the  mechanical advance in your distributor, or you have carbon build up causing hot spots, or a very weak mixture.

 

I would carry out a full engine tune and have a look at the base plate where the points are and see if it swings back and forth under spring pressure of the vacuum advance unit, or if its become detatched altogether?

 

If all the above works out ok were back to possible over advance due to worn springs on the mechanical advance unit

[da2428]

Thanks for the quick reply, I'll have a look as soon as possible and report back

Cheers

[da2428]

A 1988 Mini 998cc the manual lists the timing with the vacuum off and blocked at  10º + 0º -2º BTDC at 1500 rpm

 

Try that setting and then report back, it could be that you have weak springs on the  mechanical advance in your distributor, or you have carbon build up causing hot spots, or a very weak mixture.

 

I would carry out a full engine tune and have a look at the base plate where the points are and see if it swings back and forth under spring pressure of the vacuum advance unit, or if its become detatched altogether?

 

If all the above works out ok were back to possible over advance due to worn springs on the mechanical advance unit

quick update, wont have much time to do too much with the car until saturday, but i've found the the plate with the points on wont rotate, and the vacuum advance doesn't seem to function either, i think the advance is leaking due to the spring seizing and damaging the vacuum advance unit? also found a wire which had split, but was going from the coil up to the steering column and joining with the main power feed for the head lights, so they were powering up from the coil steeling voltage when connected, not sure why someone would have wired that up but ill be removing that completely, but i've ordered a new coil and distributor from minispares so i think ill just fit them and start again, just to rule it out i increased my fuel mixture until i almost stalled and then leaned it off slightly so definitely not lean and i was still getting pinking anything over 3 degress.  a friend has a spare hs4 carb so if this doesn't fix it then i might bung that on and give it a go

 

cheers d

[lewBlew]

You can buy a new vacuum advance unit from Mini Spares. Put the pipe in your mouth (make sure it's clean) and give it a good suck and the plate in the dizzy should rotate a little. Then again, when I took my car to a rolling road they disconnected and plugged up the vacuum advance... It runs great.

 

Can't really help with the other stuff but I would say that the rev counter is fed from the coil so could the wire you mention be that? Also I would only replace the carb as an absolute last resort as they are not usually the problem.

 

[da2428]

The wire wasn't anything to do with the tacho haha, just seemed like a bit of a weird system, but I've removed that, and now fitted a new distributor as it wasn't much more expensive than a new vacuum advance unit, and the car is running nicely, just need to fiddle with my fuel mixture, also bought a luminition blue coil which needs a ballast resistor fitting so I'm gonna put that in seeing as I have it, but it seems to be running okay for now, maybe if it's not broken I shouldn't fix it 🙈

[dklawson]

also bought a luminition blue coil which needs a ballast resistor fitting so I'm gonna put that in seeing as I have it, but it seems to be running okay for now, maybe if it's not broken I shouldn't fix it

 

If you have a ballast coil and run it without a ballast resistor or the pink resistor wire, excess current will flow through the ignition system causing the ignition components to fail prematurely.  Failure to fit the resistor will eventually leave you stranded by the side of the road.

[da2428]

Haha yeah I know that 🙈 cheers anyway though

[red81]

I'd like to open this one again but if i should post this else ware could you let me know please.

 

I'm struggling to tune Red1. (1981 engine pre A+ 99H791PZ - 456483) I started with the Carb, removing air leaks and sticking needles and can now get her to idle at 850 RPM. There was still a lot of induction noise and hesitancy when accelerating in 3rd & 4th, so next step Dizzy. I discovered that if I altered the timing from 8 degree TDC and did it by ear to about 16 degree TDC I had a lot more power but knew that this will damage the engine. I pulled the dizzy which turned out to be a 1989 59D4. which belongs to a different mini (1989)  I had mistakenly mixed it up, but the dizzy that came out of RED1 was a 1986 59D4 which I still don't know if it's suitable for my 1981 car. I have since discovered that the degree advance  on the 1989 59D4 is about 50% less that the 1986 59D4 which would explain the lack of power at higher rev's.

 

What I can't find is how to check that a 1986 59D4 41765B dizzy is compatible with the 1981 pre A+ engine. to ensure she has the correct advance. 

Also my Haynes 69-84 manual only lists up to the  45D4 dizzy so I need to know the dwell angle and Stroboscopic settings for the 59D4, can anyone point me in the right direction here please.