mk1-forum.net

The Howley on my 1480cc road engine is getting a bit tired and
I need to replace it...

It is possible that the ports are a bit on the small side, but what
I do know is that this manifold gave "noticably" more bottom end
than the MiniSpares one that it replaced. This was when the same
engine was "only" 1380cc... The MiniSpares manifold was also quite
a few years old and they may have changed the design since.

Presently the spec is:

74mm x 86mm = 1480cc

Ally Head - CR 11:1 Appx - 1.5 rockers
Rimflow Inlets - 1&15/32" (1.468" or 37.3mm)
Rimflow Exhausts - 1&7/32" (1.218" or 30.9mm)
(NB - These are "proper 37.3mm" valves,
not 1&7/16" (1.4375") = 36.5mm, "rounded up to 37mm".
(Please note, MiniSport customers))

HS6 Carb, Internally modded, radiused stack and K&N
Kent Megadyne 276 Cam, 270/280 degrees
Programmable 123Ignition Distributor
Maniflow Medium LCB
PlayMini system from the "cat-flange" back
... and it's got a chrome coil!

Any suggestions on a suitable replacement manifold?
(And, no, I am not looking for suggestions such as
"put a Weber on it").

I would, however, look into the possibility of using a HIF7
or HS8 carb should information come to light that these
would be feasable and better...

Would these carbs be too big?
I am thinking that the injection throttle bodies are larger than the
1&3/4" or 44.5mm that the HS6 has - I know nothing about the
injection engines, but a quick read told me that the throttle bodies
are 48mm and that a 52mm version is available...

Ian

There is a lovely Mikuni conversion available that I would love to investigate but my funds are going elsewhere right now.

Being a Road Engine, I'd be inclined to go a little smaller than 'bang on' or bigger in Carb Size, also with the 276 Cam, I wouldn't feel it would warrant mush more than the HS6 (or a HIF44 perhaps). But if you don't mind me saying so, it's a little bit of an odd combination with a head that has such big valves, I feel you're loosing at the bottom with the big valves and loosing at the top with the Cam - just my thoughts.

Maybe a good time to learn about Injection, there are a number of 'kits' about these days, that even I recon I could fit. It will really improve the bottom end but I doubt you'd see any top end gains.

maniflow steel manifold maybe?????, http://www.maniflow.co.uk/index.php?vie ... oduct=1098
( it only states 1.5+ 1.75, but i bet of you talk to them they do with for what ever size carb you want)

i have there twin carb inlet , runs much smoother than the single alloy 1.75 i first started with. but i did have the ports of the head matched so everything flowed better,that also helped,

Graham Russell does a very neat looking alloy manifold for single HS6 or HIF44, this is his RE7.

The 7 refers to the length, so quite a bit longer than the Howley, and may require bulkhead to be modified.

Graham Russell manifold is a nice piece, big chamber at carb face and 36mm ports at head face .
It mesures 5 inches from head face to carb face, so it should fit an HS6 on big blore block wihout bulkhead mods... i have one to be used on a 1360 soon... , so far was tested on a 998 bored to 1060 + 270 cam + HIF44, torque low down was ok.

Spider wrote:<SNIP>But if you don't mind me saying so,

... of course not...

Spider wrote:it's a little bit of an odd combination with a head that has such big valves,
I feel you're loosing at the bottom with the big valves and loosing at the
top with the Cam - just my thoughts.

I've done three ally heads like this now and the dyno shows gains throughout
the rev-range compared to similarly modified 'S' sized Rimflow valved heads.

I am talking about Aldon Automotive here, and these people commented on it
being a good, strong engine. This was in its 1380cc guise, with a 286 Scatter.
Another local dyno op who specialised in Formula Ford 2 Litre engines also
made similar remarks.

The other engine currently using an ally head to the same spec is a 1330cc
engine with a 643 cam in it. The rest of the spec is almost identical to what
is detailed above. Although this one has not been dyno'd yet, it does have a
fantastic "bottom"... It was swapping an ally head to this engine that proved
to me that my heads were not causing low down poor running - The problem
turned out to be manifolds that were too large, the LCB being the first to be
sorted, then the MiniSpares inlet was junked in favour of the Howley.

The 1330cc with a 643 was still better low down than the 1380cc with a 286 scatter,
so when the latter got re-built as 1480cc, a tamer 276 cam was installed and this
again has made the engine much nicer to drive. At some point fairly soon, both
engines will be dyno'd and comparisons can be made. I'm not hugely worried
about achieving "big" hp figures, I'm more interested in having civilised motors
that don't stink!

That Russell manifold looks nice, but I don't think that it would fit in there with
an air filter and a radio... The steel Maniflow would need various bosses added
for my servo and distributor vacuum... The injection would be doable, but I
want to keep the two engines fairly compatible for the purpose of "borrowing"
parts from one to use on the other - Two sets of injection would be twice as
expensive and twice as much work.

As it's only the water heating spouts on the Howley that are rusting away, it
may well be that I just get this fixed up and keep things the way they are.
I have too many projects on the go at the moment so I am really only looking
at any option that is either a direct swap, or else requires virtually zero mods...

Ian

ianh1968 wrote: The steel Maniflow would need various bosses added
for my servo and distributor vacuum...
Ian

I thought that the vacuum port used for a distributor was on the carburetor or throttle body? At or around the blade ' fully closed' point so as you opened the throttle you got less vacuum effect and hence less advance to prevent tip in detonation.

First time I've heard of one being connected to the manifold, how does it go?

smithyrc30 wrote:I thought that the vacuum port used for a distributor was on the carburetor or throttle body? At or around the blade ' fully closed' point so as you opened the throttle you got less vacuum effect and hence less advance to prevent tip in detonation.

First time I've heard of one being connected to the manifold, how does it go?

This was done to lower the emissions at idle, because the port is covered at idle speeds there is no vacuum advance.

ianh1968 wrote:

Spider wrote:<SNIP>But if you don't mind me saying so,

... of course not...

Spider wrote:it's a little bit of an odd combination with a head that has such big valves,
I feel you're loosing at the bottom with the big valves and loosing at the
top with the Cam - just my thoughts.

I've done three ally heads like this now and the dyno shows gains throughout
the rev-range compared to similarly modified 'S' sized Rimflow valved heads.

I am talking about Aldon Automotive here, and these people commented on it
being a good, strong engine. This was in its 1380cc guise, with a 286 Scatter.
Another local dyno op who specialised in Formula Ford 2 Litre engines also
made similar remarks.
.........................................................................................................
As it's only the water heating spouts on the Howley that are rusting away, it
may well be that I just get this fixed up and keep things the way they are.
I have too many projects on the go at the moment so I am really only looking
at any option that is either a direct swap, or else requires virtually zero mods...

Ian

I'm no good at the SNIP - sorry!

OK, I mis-read your first post, I read it as a 266 Cam,,,,,,,, Got ya now. Yes, sounds far less 'curious'.

Would you be able to cut the steel heater tubs flush on the Howley and tap what's left to take some BSP hose barbs? Be a couple of quid cheaper than Injection.

smithyrc30 & Smiffy:

It's a 123Ingnition distributor and you can plumb it in where you like...
... either to the original spout on the carb, or via a tapping in the
manifold to give a MAP (Manifold Absolute Pressure) reading.

Either way, it's easy to program the vacuum advance to suit.

There is also a lower RPM threshhold on the vacuum, so you can
set it to only work at engine speeds above idle.

Spider wrote:I'm no good at the SNIP - sorry!
OK, I mis-read your first post, I read it as a 266 Cam,,,,,,,,
Got ya now. Yes, sounds far less 'curious'.

I was getting a bit confused, there...

Spider wrote:Would you be able to cut the steel heater tubs flush on the Howley
and tap what's left to take some BSP hose barbs?

This was exactly what I had in mind and I should be able to sort this out
for myself. The other option would be to cut the spouts off and get someone
to braize in some new longer ones.

Ian

I seam to remember that Vizard found the Oselli Torque Master was just as good as the Howley. They do turn up on Ebay now and again.