1842 replies to this topic

[Mini Manannán]

RE Performance centre in Bury. I guess this used to be Rally Equipe many years ago. I phoned them and told them that I wanted the carb needle profiling to get it to run right. They told me they could do it but I've had that many disappointments on this build, I'll have to see how it goes. If they can sort it out it will be an awesome engine. If they can't, I'll have to put a mild cam, a stock distributer and sort the fuelling out myself. There are not many people left who understand carbs, timing and fuelling on old skool cars. It's all laptops and diagnostics these days which I find kind of sad.

I haven't been but have been recommended AB Garage near Chester: 53°10'43.4"N 2°59'34.2"W
Unit 167B Castle Close/Manor Lane, Deeside CH5 3QX, United Kingdom
https://goo.gl/maps/GcdZTz96aSgmoPCq8

[Bobbins]

Or maybe speak to Dave Gemzoe, might be more local to you: http://www.gemzoe.com

Dave's fastidious about detail, he works from home but has full rolling road and workshop facilities.

Stu.

[Mini Manannán]

Or maybe speak to Dave Gemzoe, might be more local to you: http://www.gemzoe.com

Dave's fastidious about detail, he works from home but has full rolling road and workshop facilities.

Stu.

 

Where is he Bobbins?  Nothing on that site seems to work, even the link to the new website...

[Bobbins]

Or maybe speak to Dave Gemzoe, might be more local to you: http://www.gemzoe.com

Dave's fastidious about detail, he works from home but has full rolling road and workshop facilities.

Stu.

 
Where is he Bobbins?  Nothing on that site seems to work, even the link to the new website...

Netherton, Wakefield, WF4 4NJ

[1330RG]

Pete i know its ages from you but Airey tuning in alresford are the daddies of carb tuning, used them years back on my 998 that frankly was silly fast! And i will be straight back with the new build!!

http://www.aireytuni...blet/index.html

May even just be worth a chat for advice even if nothing else.

[Petrol]

Thanks for the advice guys. It's much appreciated.

 

Here is where I'm up to with it.

I struggled running it in because I can't find a suitable needle for the carb. I ended up with the best compromise of a bit rich at the bottom end, then pulling the choke out to get it to pull past 4K revs. I've tried varoius needles but is seems to want a huge amount of fuel when the revs rise. It's done over 1000 miles now so it's off to RE performance tomorrow who tell me they can profile a needle to sort it. Fingers crossed. I'll post up the results.

I decided to go local for starters, if I'm not happy with it I might go further afield to get it running spot on.

 

Pete

[Petrol]

I would take me a week to described what happened when I got the car on the rollers but in short.......
The guy knew his stuff big time. He has been tuning Minis going back to the old days of Rally Equip and that would be 70's - 80's.

After driving the car and a couple of runs on the dyno he realised there were problems. Partial throttle hesitation being the main issue.
He modified the needle in a pedestal drill (better than using a file on it) to get the fueling right, then adjusted the timing for max hp but the hesitation was still there. He also watched the piston lift in the carb by putting a rod in it whilst driving on the dyno.
After 3 hours of dyno runs/ driving the car, he held held his head in his hands.
I then had a big conversation with him. He appreciated how much time and effort had gone into the build but was gutted he couldn't sort it. I then told him I hadn't modded the carb or assembled the gearbox (whe he noticed was crunching) so he lightened up a bit.......

Then we stripped the carb.....

 

He recommended that I fit a stock 1 1/2 HS4 carb rather than the RetroMinis modded Hif 33 that's on on there now. The fuelling was right but it wasn't burning properly indicating a carb problem.
When he drove the car after setting it up as best he could, it sounded flat when I stood at the side of the road.
It made 40HP at the wheels.

 

 

I've had the wind taken out of my sails yet again and feel let down with suppliers who claim they know what they are doing but in reality, know nothing. The 2 things RetroMinis built for me have failed.The carb and the gearbox.

I was at RE performance for a total of 5 hours. The guy charged me nothing.... That's 5 hours on the dyno from an old skool guy who was gutted he couldn't sort my car. He couldn't understand what had been done to the Hif because there are ports in the throttle body that effect piston lift.
Confused? The morale of the stopy is stick to respected suppliers.


Me? I wish I should have fitted the twin 1 1/4 SU's I had. They would have worked!

 

Pete

 

 

 

[timmy850]

Wow, what a pain. Hopefully it’s an easy swap to another carb and he’ll be able to tune it properly

I think these days as bigger carbs are so cheap (compared to the 70’s) I’d rather just get a bigger 1.5 or 1.75 SU and not bother modding a smaller one for more performance.

[Midas Mk1]

What spring type are you running? Nowt wrong with HIf’s imo, 38’s work in the same principle as 44’s.

What cam are you running?

Edited by Midas Mk1, 27 December 2019 - 09:16 AM.

[hazpalmer14]

What spring type are you running? Nowt wrong with HIf’s imo, 38’s work in the same principle as 44’s.

What cam are you running?

A 44 will flow enough to 300hp as proven by matt Woods. And a 38 is ideal for a small bore. I had one to go on a hot 1098

[phil hill]

 

What spring type are you running? Nowt wrong with HIf’s imo, 38’s work in the same principle as 44’s.

What cam are you running?

A 44 will flow enough to 300hp as proven by matt Woods. And a 38 is ideal for a small bore. I had one to go on a hot 1098

 

I think the problem will be with what-ever the modifications were upsetting the air/fuel ratio, not the carb itself.

 

Phil.

[Petrol]

 

 

What spring type are you running? Nowt wrong with HIf’s imo, 38’s work in the same principle as 44’s.

What cam are you running?

A 44 will flow enough to 300hp as proven by matt Woods. And a 38 is ideal for a small bore. I had one to go on a hot 1098

 

I think the problem will be with what-ever the modifications were upsetting the air/fuel ratio, not the carb itself.

 

Phil.

 

It seems that's the problem. If I fit a stock carb I'll know straight away if it's sorted it.
The cam is pretty wild for a 998, it's a kent VP3 but I can live with little torque at the bottom end. I can't live with massive hesitation though.
Here's a vid of it on the rollers. It sounds flat as hell to me and I know something is sadly wrong.
 

 

 

[1330RG]

Out of curiosity what had been sone to the modded carb?

And have to say big fair play for them not billing you for 5hours of dyno time. Proper service that and rare to find a company that cares about the customer experience these days.

[phil hill]

Do you know what spring is fitted to the dashpot, and what grade of oil are you running in the damper ??

 

I would have expected that the dyno operator who seems to know his biscuits would have made sure the piston was at maximum lift at peak torque, or suggested a different spring if not, and the damper oil can make a difference on pick-up.

 

In my MG with Rover V8 (pair of HIF6's) definitely likes heavier oil (like 20-50 engine oil) but the mini with twin 1.5" SUs prefers 10 weight fork oil.

 

Just another random pair of thoughts/things to try.

 

Phil.

[evoderby]

@petrol

 

Sorry to hear about the problems you’re experiencing. Especially since I feel the troubles are caused by more than just a carb problem. No matter how much retrominis’ carb mods have or have not upset behaviour under transition, when the piston is fully up under wide-open-throttle allowing the carb to flow the maximum amount of air accordingly (as checked by the RR operator) and AFR is good (as you state) THIS IS IT as far as max power is concerned. 
 

Driveability aside, I gues 40 Bhp @ wheels isn’t exactly what you were hoping to achieve. Sure there are carbs that are able to flow more air than your current one, I just don’t miraculously see them adding the 25 odd HP your ‘screamer’ seems to be missing. Things like fuel droplet size and atomization do have a minute effect on power but are unlikely to be noticed on anything else but a full blown engine dyno....basically when AFR’s are correct you’re good to go. There’s no such thing as ‘good mixture ratios that an engine is unable to burn due to carb problems’.....there simply isn’t.

Edited by evoderby, 30 December 2019 - 04:38 AM.