Hi All,

Well after doing 800 odd km last weekend on the Rylstone Classic, the dellorto just has to go. Its just so loud up hills under load.
I used to do some hillclimb and sprints but this no longer interests me, I want to do some more cruses and weekends away. I have an old 1.75 SU and manifold that could be fitted to quieten down things (needs a rebuild)but I'm not sure if it will be big enough for my motor. 1340cc 286 cam big valve head, ported 1.5 rockers, Maniflow exhaust etc.
It really doesn't bother me if the top end performance isn't quite so good... any thoughts or alternatives on carburation, mainly would the 1.75 SU be up to the job.

Cheers, Richard.

I dynoed my 1412 stroker (now in Gafmo's van) with both the 45 Dellorto 38mm chokes) on a ported Redline manifold, and an HS6 SU on a near stock Minispares manifold.
[edit] Cam was an RE13, rockers were modded Toyota Corollas, 1.46:1. Head was ported by me, with Mk2S valves in it. C/R 10.5:1.

45 Dellorto gave 114HP @ 6500 and 108 ft/lb,
the HS6 SU gave 113.6HP @ 6500 and 113 ft/lb. Much better midrange.

It was much quieter with the SU...

[edit] Runs were done on GR's engine dyno, not a rolling road.
HS6 chart:


[edit 2] Here's the 45 Dellorto chart:

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

That sounds awesome to me, so with the correct needle it should be a goer! Better low to mid range is what I'm after and quieter.
How would I find out what needle is in the carb and what should be in it so I can at least drive to the tuner? Cheers

Usually an OA6 works, or a KV.

re the dyno run I now think the SU manifold used was an RE7, not a Minispares. Needle was OA6.
I changed to the Minispares when I fitted to the car, so I could actually fit a filter on it. Needle then used was a KV.
Last 2 motors I ran for people with Minispares manifold, all needed a KV needle.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I have a cast iron manifold, see pic. Would this be ok or would it be better with a minispares type? Thanks.

That manifold will not flow well enough. It's only a HS4 one.

I would buy a Minispares one from Karcraft or wherever, then get GR to port it.
Use either an HS6 carb (modded by GR), or an HIF44. Sorry I have no idea what needles work in the HIF44.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks Doc!!

When you buy the manifold, check the 4 slots for the studs align the ports properly. I have seen a couple that were 3mm out horizontally. I had to TIG weld one end of both the flanges and then remachine them, and the slots.
Not good enough, Minispares. We deserve better.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Didnt GR get 140hp out of a single 1 3/4 SU just to prove it could be done?
Should be enough for most minis.

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1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

Yes he sure did, it's on a 1400 stroker in his LS.
Manifold is an RE7. Cam is an RE282 I think, but he has developed newer cams since.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

These will be going on my car in the near future Richard , ( don't you say a word Mick ) .

Ha ha Goodie. My lips are sealed

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

They look very pretty Goodie twin HS4's ?

Ok so I've measured the hs6 needle and it's 2,1 at the top and 1.5mm at the base... Any idea if this is the correct one based on previous specs? Cheers

Pull the needle out and check for its ID on the round bit at top. But that diameter at top sounds too small for an HS6.

I would start by buying a new (genuine) jet for an HS6 (.100"), and new needle.
Note that HS2s and 4s only have .090" jets. They and their needles won't work in an HS6.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.