846 replies to this topic

[timmy850]

Looks good. Always a treat to be able to work in a nice clean engine bay !

Thanks! It's slowly coming back together. As always it takes much longer to get it all reinstalled

 

Saturday afternoon I got a few jobs done:
Wiring loom rewrapped with cloth tape
Speedo pod cleaned & bolts installed
Speedo installed & wired
Wiper motor reinstalled
Bulkhead plates wire wheeled ready for paint


And a few more jobs this afternoon:
Bulkhead plates painted and installed
Earth cable added
Master cylinders installed
Choke cable and grommet installed
Engine steady installed with new bushes
I bought a new set of clevis pins, the lower clutch pin was still looking new, the top one plus master cylinder pins had some wear and will be replaced


Still quite a few jobs to go, but getting there

[timmy850]

I had the whole day off today, and I managed to get 99% of the jobs done. It's now all plumbed up and started up straight away.


Next up I'll need to do a brake & clutch bleed, and set the initial toe. The good news is the steering rack already feels firm and there's no play

[Steve220]

Great effort on the bulkhead!!!

[timmy850]

Great effort on the bulkhead!!!

Thanks Steve! 

 

There has been a little bit of progress the last few weeks, first up I noticed that the new white/clear oil pressure line needed a new adapter that suited the fibre washer - new one on the right

 

Next up I've started to bleed the brakes. I'm doing a full system flush through too, and it took a while to fully flush through the reservoir with new fluid. Not a particularly photo worthy or fun job to do, but it needs to be done 

[timmy850]

I'm a bit late for the update & I haven't been able to go for a test drive yet, but it's ready for a road test now. There were quite a few jobs to finish which took a bit of time and effort, plus just general life business and hot weather in the garage.

The wiper motor didn't work after being installed, so after an hour or so of mulitmeter probing & unplugging and replugging wires it started working again. With that working OK I was then happy to reinstall the dash panels, carpet, and get the interior sorted again


Next up I checked all the lights were working, and the RH headlight was very dim. It was the same on low and high beam, so I swapped the bulb with no change. After a bit more multimeter probing I found the earth wire bullet connection behind the grille had come out, so that was an easy fix.

There's still a few things I want to sort out, especially the fuel lines & vacuum lines, but for now it should work fine and I need to get the annual inspection done in the next week.

[timmy850]

The first test drive went ok, but one thing to fix was to rebleed the clutch. Once that was done it shifted smoothly again.

Last week I took it for a rego check and it passed with no problems for another year. I did a couple of hours driving that afternoon and it was nice and smooth on the highway, the steering wheel had very minimal vibration compared to before and it seemed to have less free play in the centre too. Overall it was a success!

[timmy850]

A little update for May - I managed to get to a car show (and didn't take any photos). While driving there and back the engine had been running decently, but it had been getting more noticeable that the carbs weren't in optimum condition. I'd previously bought a rebuild kit to refurb the pair, but I was supplied some defective spindles so I ended up assembling them with the old worn spindles. When driving now it's a decent mixture, but when coming back to idle it's super lean at 16-17:1 on the gauge. If I stop and let it idle it'll just keep getting richer and richer, which indicates one or both of the float bowls aren't maintaining the right fuel level. They had also still been a bit tricky to start, as only one carb has a choke and it was a regular occurrence to foul a plug on the choke side. Ideally if I keep the dual HS2 carbs they'll need a proper rebuild and another kit..


The following Wednesday I thought it'd be a good day to drive the mini to work. I made it a few blocks from home before I noticed the indicators weren't working. Knowing that the wipers (and brake lights) also came from the same fuse I checked the wipers and they also didn't work. I pulled over to check the fuse and it was certainly blown! I had a spare fuse in the boot, but when trying to replace it I was met with sparks - so I drove home with my tail between my legs.


I asked for some ideas and one suggestion was the clevis pin on the clutch arm may have contacted the brake light switch. This turned out to be the cause, and the clevis was touching the 12v feed to the switch. With the clevis pin bent to prevent it happening again I put in a new fuse and all good.



I had a few days at home and soon enough I needed a mini project to keep me going, so I stripped down and reassembled the HIF44 with a new seal set. It had arrived in June 2023 and it was in very good condition, and super clean inside too so I didn't expect it would need much work.



I found a nice spot in the sun and got stuck into it


The spindle seals appeared to be the wrong size as they didn't match the inner diameter of the carb body. The original throttle spindle was super solid and had absolutely no wiggle or play, so I decided to keep the factory spindle and throttle blade.


Choke seals were a bit old and cracked


Assembled & cleaned and ready to be fitted


Kev made me these stepped washers to make up the difference between the Maniflow exhaust manifold and the Metro intake manifold


They were a perfect fit and held everything in place tightly


It only took a few hours to remove the HS2 carbs and install the HIF. It was an easy bolt on swap and it started right up and idled smoothly. I managed a few laps around the block, once I get the AFR gauge re-installed I can dial it in a bit more as there is a bit of a dead spot off idle. I'm very happy so far with how easily it starts and how smooth it is at idle and under load. It's also nice to know there's only one carb and I don't need to worry about syncing multiple carbs or barrels on the Dellorto

[KTS]

..nice bit of work as usual; the single carb may be a lot more practical, but certainly doesn't have the visual impact of the twins 

 

have you noticed any changes in vacuum advance with the HIF ?

[timmy850]

..nice bit of work as usual; the single carb may be a lot more practical, but certainly doesn't have the visual impact of the twins

have you noticed any changes in vacuum advance with the HIF ?

Thanks! I guess it’s back to its roots really, as it had a single HS2 from the factory and for most of its life. I’ve started working on the twin H4 carbs too, but they are horrendously complicated in comparison and I hope I can learn some SU tuning tricks from the single carb first

As usual I struggle with the visual aspect vs performance vs reliability & simplicity. At the moment I’d like simplicity and reliability so I can drive and not work on it!

I lent my afr gauge and timing light to a friend so he could get his rebuilt engine started, so hopefully I’ll get it back by the weekend and I’ll double check the vac advance (among other things). I’d imagine this HIF should make similar vacuum to the HS2 as the vac port is in a similar position pre throttle blade, but we will see!

[Designer]

You may get some useful help here

 

Technical | SU Carburetters

[timmy850]

You may get some useful help here

 

Technical | SU Carburetters

Thanks for that, I've read that one and found the SU Tuning Manual too. 

 

"The SU carburettor high-performance manual" by Des Hammill has a lot of good info as well.

 

I've also watched AC Dodd's tuning video series a few times and I hope I can give it a decent shot

[timmy850]

I've managed a few drives this week to work and I've got stuck into getting the carb working properly. When I got the carb it came with a yellow spring and BBW needle. I got a few extra parts to try out as sometimes you just need a bit of trial and error, along with measuring with the AFR gauge
BBW - minispares says for a 1300 engine, stage one kit, KN air filter
BCE - minispares says for a 1300 engine, 266 degree cam, stage one kit, KN air filter
BDL - minispares says for a 1300 engine, 256 degree cam, stage one kit, KN air filter
BAS - this one was much leaner than the others, as I had no idea which one would suit
Yellow spring - 8oz - normally used on tuned 1275
Red spring - 4.5oz - this is normally used on mild 1275
The damper is an LZX1505
When I put in a new needle I set the idle mixture to approx 13.0 to 13.5:1

First drive around the block:
Penrite SU damper oil
BBW needle
Red Spring
Note: No AFR gauge - drove OK but a lean bog off idle or when changing gears

Change 1:
Penrite SU damper oil topped right up
BDL needle
Red Spring
Idle mix set 13.5:1
Notes: Severe lean bog under throttle (up to 22:1)
Needed a bit of choke to keep cruising AFR under control
Full throttle not great

Change 2:
Red spring changed to yellow
Notes: Much better throttle response and much less bogging. Still leans out to 16 or so off the line and at gear changes
Full throttle starting to lean out up top

Change 3:
BDL needle changed to BBW
Notes: Overall mixtures much better
Small bog off idle
Leaning out up top under full throttle. Also a bit lean when cruising

Change 4:
BBW needle changed to BCE
Driving through the gears it's a bit rich
Still a lean bog off the line but a little better
Driving at 4000rpm on the highway it's spot on

Change 5 (day 2):
BCE needle back to BBW
SU damper oil swapped for HPR30. The thicker oil should slow the rise of the piston under acceleration which should richen it up
Notes: bogging off idle much better. Driving off gently is fine, but still a small bog with sharp throttle
Still lean cruising at 4000rpm on the highway, choke is needed to get the mixtures in the 13.5 to 14.0 range

Change 6:
BBW needle swapped for BCE
Driving through the gears it's a bit rich
Still a lean bog off the line but a little better
Driving at 4000rpm on the highway it's spot on
Overall a bit better with the thicker oil

Next I think I want to try the BCE needle, HPR30 oil and the red spring to see the difference in just the spring now.

Overall it's been going very well. All the changes I have made so far have worked in the way I've expected which is nice. I haven't got the ideal needle yet, but with some more work I can get a bit closer. It's also quiet and smooth most of the time, and having the breathers hooked up to the carb mean I don't smell like oily blowby by the time I get to work!

[KTS]

if you haven't already found it, i highly recommend the needle comparison tool on the sucarb website; takes a little bit of getting used to but is really useful

 

https://sucarb.co.uk/needle-comparison

[timmy850]

if you haven't already found it, i highly recommend the needle comparison tool on the sucarb website; takes a little bit of getting used to but is really useful

https://sucarb.co.uk/needle-comparison

I’ve got the full spreadsheet version of that needle comparison database. It’s quite complex!

[timmy850]

In June I actually made it out to a Minis in the Gong drive in my own mini. I think this was the first (and only so far) of the year.


It was a nice drive through the National Park to Maianbar for lunch. It ended up pretty rainy and my wiper motor started having a weird grinding noise and the wiper arms stopped moving. On the way home after lunch they started working fine, so something I need to investigate. We ended up going straight back home as Audley weir was underwater


In July I started to do some checks over the engine in anticipation of going to Rylstone this year. I found the throttle cable was a bit loose and not allowing full throttle at the carb, so that was adjusted properly.


Next up I wanted to check the timing was correct and while checking my timing marks I noticed the crank pulley had a little wobble back and forth so I stripped the engine bay down to get access to that.


In the end after removing the radiator, engine mount, pulley, timing cover and timing gears I found the woodruff key had some wear and it was allowing the timing gears and pulley to rock on the nose of the crank. I had a similar issue with this in the last year due to the poor quality lock washers so this was probably where the initial wear started. The nose of the crank didn't have any wear, and the timing sprocket and pulley were a nice firm fit


This time I didn't use the lock washer, and used some loctite instead on the crank pulley bolt and the camshaft nut. The woodruff key had about 0.08mm of wear compared to the new key



While this was all apart it seemed like a good idea to replace the radiator hoses, the heater hoses and reinstall the fresh air heater. It's always nice to have some heat on the Rylstone trip, and the additional cooling is a bonus too.


When I added the new heater lines I also decided to plumb in the manifold heating port. It was a bit tricky, as the manifold takes a 5/8" hose and the rest of the stem is 1/2" so I got some adapters and added all the hoses in. I thought this would make the lines look a bit tidier, but it ended up having 8 hose clamps and 4 pieces of rubber hose in place of 2 clamps and one piece of hose

In early August we had the Minis in the Gong annual show, and there was a good turnout, new minis I hadn't seen before and a beautiful sunny day.




However I also noticed that I now had a coolant leak from every single connection I'd just put a new hose on. I only did about 30 minutes of driving but I needed to add about 500mL of water to get me back home!



At this point there was a week to go until Rylstone and not enough free time to strip the radiator out and check all the hoses again, so Phill went with me in my Mazda. It was a smooth uneventful trip and good to see so many minis and see lots of old and new faces










I had the Monday off after Rylstone so I decided to get stuck into sorting out the cooling system. Out came the radiator for the second time in a month to try and sort the leaks. It was leaking from both ends of the bottom hose, even though the hose was new and I'd cleaned the radiator


Another job I'd planned was to lower the compression ratio. While the radiator was out it was a good time to remove the head as the coolant was already drained.



I had asked a few experienced mini engine builders for some ideas and the simplest option to see what effect lowering the compression would have was to add two head gaskets. I'd done some calculations and this would lower the CR from 11.5:1 to 10.5:1


I cleaned up the head and block gasket faces and bolted it all together with the double gaskets. The only thing that was any different was the rocker arm adjustment needed to be a bit further in than before.



All the radiator connection points and hoses were checked, cleaned and reassembled. I replaced the adapter on the heater hose with a new alloy one, and went back to a one piece hose to the heater.



So far it's all working well, it starts up and idles nicely. I'm yet to drive it and see if the tune has changed much, but the timing curve will likely need to be updated. I must have bent the fan during one of the radiator removals or when it was off the engine as now the fan has a few off centre blades and it's hitting the shroud somewhere and making a ticking noise. I thought perhaps it wasn't seated on the water pump flange squarely as it's a tight fit but I didn't have any luck tightening the bolts again