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PostPosted: Thu Sep 26, 2019 8:15 pm 
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drmini in aust wrote:
1071 S wrote:
drmini in aust wrote:
Looks good Timmy.
The steel bush is hardened silver steel, it's about HRC 50.

GR and I measured these cheap plungers at HRC 3 hardness a while back. Dead soft free machining steel.
The more expensive en24t ones were not much harder. :(


so Kev, do you harden the end of the lever or is there a preferred version that's OK as is??

Cheers, Ian


Ian, I find the heavy duty arms like Tim's are pretty hard, the ball is heat treated unlike the current plungers.
Original BMC plungers were over 50 HRC you cannot file them.


I assume the heavy duty arms ...and the flat release bearing (as in Tim's photo) are readily available in Oz (Karkraft??)

Cheers, Ian


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PostPosted: Thu Sep 26, 2019 9:04 pm 
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Yep, all from Karcraft

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PostPosted: Sat Jan 18, 2020 8:52 pm 
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timmy201 wrote:
Thanks Clip, the gated shifter would be a fun idea


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Nice work! What are the boots on your pot joints? I'm changing to an engine with pot joints and didn't know the boots were a thing.

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PostPosted: Sat Jan 18, 2020 9:04 pm 
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They’re just the standard boot you get on a new pot joint or a rebuild kit

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PostPosted: Tue Feb 25, 2020 8:28 am 
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I thought I'd provide a bit of an update since the engine has gone in. First up here is a video from the first oil pressure crank to the first drive:
https://youtu.be/7D9Q9XthYbo

I've done a fair bit of work changing the jets and other parts in the Dellorto to get the tune pretty close. But as much as I love the Dellorto, I've also always wanted twin HS2 carbs like a Cooper S, so I have nearly completed assembling them and hopefully I'll have them installed in the next few weeks. I have standard red springs and M needles from a Cooper S, so hopefully this will be a good staring point.
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The heater has been added back into the engine bay, this also works really well to help the radiator keep the car cool - it'll stay on 80-85 degrees the whole time which is around the thermostat opening temp.

I've also added the tappet cover breather back to the engine - previously I had left it off as I was trying to fit an extra engine steady, but it was too hard to fit in with all the other parts in that area. I have also been using a catch can on the breather line to remove any contaminates before they go into the air filter. It has picked up a bit of stuff - mostly water and a little blowby.

I have been tweaking the advance curve as I was getting a bit of pinging, and I've current got the vacuum advance removed as this was adding too much timing where I didn't need it. The advance curve still needs a bit more work to get it 100%

I've now got over 1000km on the engine, so it is time for an oil change and a check over everything.

The engine has lots of grunt down low and it's really fun on the road. It will easily spin 1st and 2nd gears from a standstill and I'm even able to accelerate up hills! It could probably do with some larger chokes in the Dellorto to make the most power up top, but I like the low down grunt it has now, and it's probably good for longevity to keep the RPM down
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The gearbox is a delight to use, a bit of an acquired taste, but it shifts very positively and the throw is surprisingly short and there is minimal slop to the system. It's great to have 4 working synchros and the slightly lower final drive makes it nicer on the highway. I will need to get the speedo recalibrated to match as it currently is a little out. The clutch works great with all the new parts and the pedal is pretty light, especially compared to some other blue dot diaphragms I've tried.
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So overall the project was a huge success, the car drives much better than I was expecting - it's smooth and plenty of grunt and has the overall period look that I was aiming for.

Thanks to Justin, Kevin, Phill, James, Trevor, Wayne & Dean for the hand in assembling and sorting parts and working on the car (apologies if I left anyone out). GR for the engine/head work and answering questions. Thanks also to everyone on Ausmini who helped out with technical questions, or left encouraging messages - you helped me make it through :D

Stay tuned below for the next long term project...
viewtopic.php?f=5&t=99579

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PostPosted: Tue Feb 25, 2020 12:16 pm 
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Very nice work there Timmy. You must be stoked! Looks and sounds 10/10!

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PostPosted: Mon Mar 02, 2020 2:00 pm 
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Thanks Joe!

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PostPosted: Mon Mar 02, 2020 5:37 pm 
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Hey Tim, that sounds soo good!

Love that twin SU setup too. I’ve got a HIF44 that’s reliable and sucks fuel like no one’s business but I can’t say it’s going to stay. There’s something about seeing a really nice twin SU setup on an A series that just looks right, so if you end up not wanting them, let me know :P

It’s so great to see another Mk1 that’s been kept original looking but tweaked to make it something bloody awesome! You’ve done an awesome job. Much respect.


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PostPosted: Fri Apr 17, 2020 4:42 pm 
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Thanks Clip, sorry I forgot to write back here. Yes the HIF44 probably makes the most amount of sense but I’d rather have the twins instead, it’s just what I’ve always wanted and they are period appropriate

The twin SU’s are now installed and need the final bit of tuning to be completed. The engine has just about reached the point of completion, nothing much left to do with it now but enjoy it!
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PostPosted: Wed Dec 22, 2021 5:14 pm 
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This is a great read Timmy, very inspirational for my 1098 build. Hoprfully mine doesnt take as long to build.. HAHA

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PostPosted: Wed Dec 22, 2021 8:20 pm 
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MINIRO wrote:
This is a great read Timmy, very inspirational for my 1098 build. Hoprfully mine doesnt take as long to build.. HAHA

I was lucky in my case that the existing engine was running ok and I wasn’t in a hurry (at least until our daughter was getting close to being born and I was told to get it finished)

I’ll have to go through and update all the photos someday, Flickr annoyingly went from having unlimited free photos to having a $50 fee per year for more than 1000 photos :(

So how has the 1100 engine been running since April 2020?
It was running decently on the twin HS2 carbs, but it was a bit quiet for my taste with the metal airbox. I swapped to some Ramflo filters and it gave it a bit more noise which was nice. I still was having a weird issue (which I’d also had with the Dellorto) where the vacuum readings from each carb were different and I couldn’t quite figure it out. I ended up putting the Dellorto back on as I was a bit more confident in it
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Here’s a quick video of the sound before and after with the HS2 filters


And the Dellorto back on


In September 2020 I was driving home from work (about to start my holidays) and it blew the head gasket between 3&4 cylinders. Obviously this was a huge pain, but one bonus was it gave me a chance to strip the top end and see how it was all running in since the build about 12 months prior. The cam & followers still had a perfect surface & the rocker pads were nicely centred on the valve stems too. Overall I was really happy with how it all was going (apart from the head gasket). I replaced the gasket and it’s been running great since
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When I’d been trying to diagnose the head gasket on the side of the road I thought it might have shorted the Accuspark blackbox again (as I’d had one die in September 2019). I tried bypassing the blackbox and in doing so I fried the electronic module in the distributor. When I got the engine running again I used a standard 25D & points and bodged a mechanical advance. It ran ok but I didn’t think it was up to the full potential of the engine
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I have been struggling with getting the timing exactly right for this exact engine combo. The main area I’m having issues is around the 3000rpm mark. It seems to be fine under full throttle, but part throttle it’s pinging. It’s always done this since I built the 1100 engine, so I’m not sure if it’s a compression ratio problem or something else.

At the moment I’m back to a 25D and blackbox with an electronic module. It’s running 10 degrees of base advance in addition to the numbers below. I’m still having the same issues around the 3000rpm mark, and I need some more time to try out some ideas
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The other things I’ve done was to change the speedo drive gears in the gearbox so that I can use my 850 speedo (which is geared for a 3.76 diff) with my current 3.44 diff. I also changed a leaky water pump

I’ve bought a few sets of SU H4 carbs which are 1.5”. I’m working on getting a twin set of these built up to replace the Dellorto. They were used on the works racing minis in the 60’s in the UK as they fit onto the standard Cooper S HS2 manifold. I think they also look really cool
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I also put on a rebuilt Gemini starter motor as the old Lucas unit was getting a bit tired
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Overall, it’s been a really nice, grunty engine. Lots of low down power, starts up easily and it’s nice and smooth too

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PostPosted: Wed Jan 17, 2024 11:36 am 
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It's been nearly 10 years since I started the engine project, so I've gone back and updated most of the missing photos. I've also got a summary of the last 3 years below

When we left off in 2021 the initial Cooper S twin HS2 carbs were sold and I was running the Dellorto DHLA again. I was still getting the intermittent pinging at around 3000rpm at part throttle.

I stripped down the Dellorto, checked over everything, added a new bearing seal to the spindle and sealed all the manifold threaded ports. I also added a soft mount kit (the type with the rubber O-rings). Overall this helped a little, and the carb was much cooler as the soft mount kit also acted like an isolator.
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I had a reoccurring fouling on #4 spark plug, so bad that it'd foul up while driving. After a bit of searching I found one of the screw in spark plug leads wasn't making decent contact. With some modern push on leads it was running nicely again
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In July 2022 I had another head gasket failure, again between 3&4
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When I'd had the previous failure in 2020 I'd used my spare copper gasket as there wasn't much in stock at the time. It was a very similar failure to the previous cheap copper gasket in 2020. Once I got the engine running again I noticed the base timing was 20 degrees, which would have put max timing at 40 degrees. I have no idea how it had got to this point, normally I'm pretty careful with the timing
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While the head was off this time I gave it a good clean and decided to check the volume of the combustion chamber. They measured up at 24.6cc, so with my flat top pistons, 1100 bored out 080 over & a couple thou deck height the compression ratio ended up about 11.2:1 . This is quite a bit higher than I was expecting, but it does explain the issues I had getting an appropriate timing curve & the intermittent pinging
Image
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This time I was able to find a Victor Reinz head gasket. It lined up much better between the 1/2 and 3/4 cylinders and doesn't overhang the bores which is an improvement on the previous ones I've been able to get
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While this was all apart I had an O2 sensor bung added to the manifold, so I'd get better readings at idle.
Image

It was back running again now, and with the idle mixtures able to be read on the gauge I started adjusting the idle mix screws and jets to get the reading better. BUT - still getting the 3000rpm pinging
Image

I made some adjustments to the dwell setting on the blackbox to increase the dwell time and increase the spark energy. This helped to some extent, but didn't solve the problem. Next I changed it to 60 degrees at all RPM points (the same as a points system) and there wasn't any improvement

Initial dwell setting
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After
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Now we are up to 2023:

I just kept having problems with the Dellorto keeping the mixture under control. If I put in a lean idle jet I'd get excessive bogging to the point it was hard to drive. With a richer idle jet it'd drive around at 10:1 and foul up the plugs. I couldn't get a decent middle ground. I stripped and checked the carb another few times but I couldn't see anything obvious, so I'm going to get it checked out by someone else
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April 2023 I lost a core plug on a MITG drive and had to get towed home. I've since replaced all the core plugs. At this point I took off the Dellorto and sent away the chokes to be resized (in hindsight a rebuild would have been a better option) as I was just sick of how it was driving
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I had bought some dual HS2 carbs on a Peter Manton manifold many years back and decided now was the time to rebuild them and use them.
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The dual HS2 drove really nice! They were smooth, quiet and had a very good throttle response from idle. With a few days of tuning it was driving perfectly, good pickup from idle and cruise mixtures were exactly where they should be. However there was a significant performance difference compared to the Dellorto
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Next up the HS2 carbs started running really weird, and they'd go full lean on the gauge while idling. I did all the usual checks and couldn't figure it out - so back on with the Dellorto! But then the Dellorto had the exact same super lean running. I ended up stopping around the corner from home when the fuel pump stopped. The wiring was very poor and it'd been starting and stopping the pump. That explains why both sets of carbs were running super lean!
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So now with the fuelling mystery solved and the Dellorto still running poorly I put the HS2 carbs back on again (which is how it is today). It runs fine, a liitle rich on full throttle but otherwise ok. However the 3000 ping is still there
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Getting to December 2023, I swapped from the standard 3.0ohm coil to a 1.5ohm coil (a Bosch SU12R). This coil makes approximately double the power, so to make sure the remainder of the system can cope the dwell curve was updated to a setting of 27 degrees at idle to a max of 60 degrees at 5000rpm. I have noticed a slight improvement with the extra spark, it'll run cleaner at a leaner mixture and starting performance is slightly better too.

During 2023 I regained my appreciation for SU carbs so I decided to track down a HIF44. While the dual HS2 have been good, with the Manton manifold they are restricting performance and obviously there is twice as much to tune and make sure it's the same side to side. I figured the most simple thing would be get one single big carb.

This carb came with a Metro manifold and all the brackets to work on a mini. I've since got a gasket kit, some extra needles, throttle cable etc and hopefully this will be ready to use soon. At this point of the project I just want it to work and be reliable as I've definitely spent more time off the road than on in the past few years due to various issues.
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At this point I'm still getting a ping at 3000rpm on part throttle, despite only 15 degrees of timing and rich mixtures. I think at this point the only cure will be reducing the compression ratio down to an acceptable level for 98 octane fuel. I've tried everything I can think of and it's the only thing left. My ideas range from:
Double head gasket
Send the head away for modification
Machine a dish in the pistons? (There’s no other choice in +080 than flat top)
Get a 998 crank and pistons

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PostPosted: Wed Jan 17, 2024 6:33 pm 
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do you get any run-on after you turn the ignition off?

what plugs are you using? tried a colder heat range?

timmy201 wrote:
While the head was off this time I gave it a good clean and decided to check the volume of the combustion chamber. They measured up at 24.6cc, so with my flat top pistons, 1100 bored out 080 over & a couple thou deck height the compression ratio ended up about 11.2:1 . This is quite a bit higher than I was expecting, but it does explain the issues I had getting an appropriate timing curve & the intermittent pinging
Image


there's nothing to stop you grinding the beak back in the chambers and deshrouding, that'll give you a few cc - theres a pretty sharp angle from the face to the chamber, that'll heat up a lot

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At this point I'm still getting a ping at 3000rpm on part throttle, despite only 15 degrees of timing and rich mixtures. I think at this point the only cure will be reducing the compression ratio down to an acceptable level for 98 octane fuel. I've tried everything I can think of and it's the only thing left. My ideas range from:
Double head gasket forget it
Send the head away for modification just do it yourself, there's nothing to it - for the little bit you need, it's nothing special. A battery drill and a couple of cheap burrs/stones/sanding flappers
Machine a dish in the pistons? (There’s no other choice in +080 than flat top) nah
Get a 998 crank and pistons no..

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PostPosted: Wed Jan 17, 2024 6:48 pm 
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I get run-on very rarely now. It used to be pretty common a few years ago before I changed to cooler plugs and dropped the idle speed

I’m using BP7ES plugs

I’m hesitant to modify the head myself as it’s the most expensive part of the whole car!

By my calculations I’ll need approximately another 4cc of volume in the head to drop the compression ratio down to 10:1 . Ideally I’d like to be able to use 95 octane fuel safely (rather than 98 and $20 of octane booster)

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PostPosted: Fri Jan 19, 2024 5:42 am 
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Nice work there Tim. Am I reading correctly that you saw better performance in the Dellorto vice the twin carbs? How does the HS4 stack up against the dellorto?

While you are still troubleshooting, I think you've best going with a double head gasket to see if reducing the CR is what the engine is wanting - cheap and quick way to diagnose. If it's happy there, then completely agree with getting a few cc from grinding the beaks down on the cylinder head. You've definitely got the skills to do that job with a basic rotary tool and a course sanding bit.

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