does anyone know/ can find out what is done to a hif 44 by GR for high BHP use? (i seem to have read that the float valve is drilled bigger or something but i can't find it anymore).

cheers?

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no time to finish me bleedin car ..
1982 Blue-White Roof.

http://aseriesmodifications.wordpress.com/

I know he puts a radius on the mouth of the carb, for starters...

Float valve in my stroker's HS6 is standard, GR's mods were putting a 5 or 6mm radius entry on the intake, and milling the leading edge of the jet bridge down so it's square.
Not sure about a 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.

i have this baffling fueling problem/timing ..which is starting to drive me nuts.

it is a HIF44 using a Keith Calver alloy donut in an ITG filter

the needle that was modified at the last RR session is way thin on top. even though, this does not result in adequate fueling past 4K.

it needs more fuel. if i pull the choke it will pull quite good past 4K all the way to 5500 then it sort of drops the ball again if on any load
when i just floor it from low revs and let it pull through the gears as much as possible it is better than doing the same thing more gradual.
the engine sounds and feel much happier when given more fuel past 4K.

I fitted a heavier spring .. this does help in acceleration a bit as it keep the piston down more enriching the mix. tried a dipperent damper in the dashpot.



furthermore it has an annoying tendency to kangaroo a bit it steady speeds ( shure you lot should know the cure for that one )

the jet is quite a way down in the bridge (as it is nearly turned all the way down. as far as it will go. I can't help thinking that for the sucking (and atomising) of fuel it is better to have it somewhere near the surface of the bridge (?)

i can see squaring of the bridge doing something for airspeed (and thus fuel delivery).


So far i have done a lot of tweaks but so far they fail to blend ..it all does something . mostly good but not quite what it should be.

I use a Minispares medium size alloy intake. the GR designed manifold has a lot more volume so i dug out a larger MG metro part and extra spacer to see it that helps things..

it does do something..but not al that much


AArrrrGH..
Oh having to change stuff in the rain adds to the fun

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no time to finish me bleedin car ..
1982 Blue-White Roof.

http://aseriesmodifications.wordpress.com/

Do you mean if you look at the needle carb right-way up the top part of the needle is really thin? Most of that area is idle and low speed fuelling IIRC... which wouldn't affect the higher rpm. It needs to be thinned down at the lower end of the needle to get more fuel up top...

Whats the motor? 1275? Is it worked?

On a normal/mild 1275 even, the 1.75" SU will be adequate... If your talking 140+ HP (or Banana's in the UK) then you might be running out of fuel in high revs.

Have you had the air/fuel tested? I mean with a proper broadband meter?
Thats where I would start. It might be starving for fuel, but then again might be something else.

If its a 998/1100 then you more than likely are not running out of fuel unless you are not getting enough up there (fuel pump prob, float prob, blockage, etc)

Has the carb been rebuilt?

Peter.

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Click here for the Turbo Conversion Thread!

the engine is the one in the RE13 thread.

1310cc
RE13 (104.5 LCA version)
MS forged rockers (too much ratio @1.56)
Fully Ported head (Vizard pattern with some tweaks by me) 35/29

filterking fuel pressure reg
Lucas 65D dizzy with fixed advance (

it has been on a RR (which is a pretty good one setting up stuff for the european formula fords and Le Mans outfits) but it was a total pig there. AF dropped like a stone after 4K

80 isch flywheel banananas/120 newtonian metric curly wurlies at 4000 prm (but with extra fuel ( choke) it just start to pull well at 4K )
100km/h in 2nd gear...

power is sort of hinted at but it just does not drive all that well.

carb has been rebuild since.

according to the company that sold the rebuild kit it is normally supplied with a 0.070 float valve ..i would liked a 0.096. but i think i'll just redrill an old one to 2.5mm/0.100. lap it in and see if it does not leak to bad ( it is pretty vacuum tight as it is anyway)

and i managed to get it running a lot better than when if came of the rollers (?!).. but alas i have tried some other stuff out ( manifolds/dampers/mixture/timing) and settiing are once again fully off by now.



spraycanman.. i'm in europe so up is down

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no time to finish me bleedin car ..
1982 Blue-White Roof.

http://aseriesmodifications.wordpress.com/

Answer the question about the needle. If it was modified, sounds like it wasn't modified correctly.

I don't know a lot of this stuff, be to me it sounds like you just need a different needle.

yep i need a different needle. but that is not really the point here.


the needle that is in there is thin around stations 12-16 and really thick around 1-2.

it it pretty rich at idle and too lean up top. (AF >1:16 isch).

so if the carb is the bottle neck i want to find out now not while on another 500 aus$ dyno session.


the mods to the bridge of the hs6 look interesting.

i guess that it unshrouds the holes into the lifting pistons


Per suggestion of Vizard i bored the float valve to 2.5mm (slightly bigger than the large 0.096 version (that is in a hs6 i think) and a lot bigger than the 0.070 that comes as standard).

edit.

lapped it in with tooth paste.. seal is good now.

and a lot cheaper than another float needle For 25 bucks

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no time to finish me bleedin car ..
1982 Blue-White Roof.

http://aseriesmodifications.wordpress.com/

The bridge mods may scrape you an extra hp or two (or 5, depending on your spec) but it's not going to solve a 'major leaning out' at high revs.

Do you have measurements of the modified needle? Or at least which needle was it based on? A 1.75" MAY not be the best you can have if your head work etc is all spot on, but again I don't think it would be as dramatic as a choke point. More just a case of not getting everything you could. If the needle is ball park (but how do you know?) I'd be looking at fuel pump/pressure, float valve etc.

You say way thin at the top does that mean by the dash pot or at the bottom of the needle. My last engine was almost the same as what u have got but 1330cc. Sounds to me that the needle is not right i will got to my shop today and see what needle i used in car at that stage

When GR and I engine dynoed the 1412 stroker recently at 113.6HP (RE13 cam, Toyota Corolla rockers, GR manifold, HS6 carb, Vizarded head) we ran an OA6 needle. This was run with NO filter.
Not sure how that relates to an HIF44 carb though.

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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.

Going with WINSU it suggests BAP so I compared that to what the Doc suggested OA6 which is very close but leans out more than EAP.
Cheers Pete

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A recent study found the average Aussie walks about 900 miles a year
Another study found Aussies drink, on average, 22 gallons of alcohol a year
That means, on average, Australians get about 41 miles per gallon

Kind of makes you proud to be an AUSSIE

I think I found the problem (I have been at it for about a month now, it was about time I made some progress).

The modified needle was such that it needed the jet to be fully down to give anywhere near a decent mix. This pretty much puts the jet orifice about 15-18 mm down in the bridge and i think this plays havoc with the signal/atomisation/fuel delivery (choke is seperate and is not affected thus explaining the large and positive effect )

I will be having a chat with the dyno guy about that

Swapped a standard MG metro spec bell housing and needle and damper assembly. Thus basicly returning it to standard

now the jet was pretty much in the starting position as it should be (only slighly below the bridge).

the engine is now pretty happy at higher rev as well, pull smoothly ,idles reasonably and i am confident that the further fueling should prove fixable on a dyno.

I now think that all needle swaps and modification should be first made without altering the basic jet position at all.


it has a BDL now .. i think it need to be a bit richer all the way up top but i want to change back to the smaller manifold without changing anything else. The transient response could be better tough i feels a tad sluggish..and likes to launched into the rev band. I hope that a further tweaking of ignition map ( geting the unit this week) and fueling will sort this out.

it will now go into low warp mode after 4K and pull harder after 5K (
due to the high ratio rockers i reckon).. but not as hard as it did when the old needle and full choke where in it.. but it only work when you did a full bull start keeping the revs high from standstill and through the gears..

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no time to finish me bleedin car ..
1982 Blue-White Roof.

http://aseriesmodifications.wordpress.com/