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Welcome to FordPinto.com, The home of the PCCA => General Help- Ask the Experts... => Topic started by: LongTimeFordMan on October 18, 2017, 03:12:55 PM

Title: Su HIF 4 intake manifold for 2.0 pinto...
Post by: LongTimeFordMan on October 18, 2017, 03:12:55 PM
Hi..  not sure where to post this but as part of my engine rebuild I am fabricating a plenum intake manifold to mount a pair of SU HIF 4 carburetors on my 73 pinto.

If anyone is interested I can post some pix and comments on the results when it is finished.
Title: Re: Su HIF 4 intake manifold for 2.0 pinto...
Post by: dick1172762 on October 18, 2017, 03:43:06 PM
I'm always interested, so post the pictures.
Title: Re: Su HIF 4 intake manifold for 2.0 pinto...
Post by: LongTimeFordMan on October 18, 2017, 10:00:21 PM
I an fabricating the manifold from thinwall steel tubing.  A sort of log or plenum with short runners betwen the head and the plenum.

2 1/2" plenum with 2" long, 1 3/8" diameter runners.

SUs mounted side by side like on an mgb

I have the tubes cut and will prolly be having a friend weld it up this week.

Ill post pix as soon as Its assembled.
Title: Re: Su HIF 4 intake manifold for 2.0 pinto...
Post by: Wittsend on October 19, 2017, 02:45:26 PM
II I've had very good mileage experience with SU carburetors.  My 240Z once got 33 MPG all be it on a flowing but congested freeway trip where 50 MPH was the average (in a 55 MPH time period).  My Volvo PV544 got 36 MPG. I still have a Datsun 510 with Datsun Competition SU carbs/intake.  I have no mileage data on that.

You may find this amusing but I once took a standard Datsun 2 bbl. down draft intake and built a triangular box to adapt a Datsun 2000 (1-3/4" SU). Believe it or not it actually worked and at that, half way decently. It was two 90 degree angle sheet metal plates. One piece angled over the other with the bottom opening cut out to that of the hogged out primary/secondary holes. I had a friend still in high school weld it up for me in class.  To mount it I had a set of internal bolts that went through drilled out holes on the outer part of the manifold and I overshot after the angle ended to provide a place for bolts in the inner side of the manifold. Likewise the mount for the carb had welded in bolts.  Since none of the surfaces were very flat I used thick cork as gaskets.  Pardon my talent-less drawing skills but here is an illustration of what I made. Hey, I was only 19 and in the world of Datsun's in 1975 SU's were "Cool."  I was poor but still found a way.
Title: Re: Su HIF 4 intake manifold for 2.0 pinto...
Post by: LongTimeFordMan on October 19, 2017, 04:25:36 PM
Here are some pix of the unwelded manifold. The runner tubes will be about 2"  long and obviously trimmed flush with the mounting plate once the welding is done.

The carb mounting plate will accommodate the SUs with the stock plastic spacers and spacing to to allow for factory MGB linkage.
Title: Re: Su HIF 4 intake manifold for 2.0 pinto...
Post by: LongTimeFordMan on October 19, 2017, 04:36:20 PM
Phone rang and I forgot to add the pix..

Here they are
Title: Re: Su HIF 4 intake manifold for 2.0 pinto...
Post by: LongTimeFordMan on October 19, 2017, 04:50:28 PM
Well after working with mgb's for a number of hears, I do think SU carburetors are undesestimated, especially the later model HIF bottom bowl, temperature compensated ones.

I think its probably because they tend to last past their optimum tune life and develop worn shafts, ets which dont cause catestrophic failures , just annoyances and that folks dont take the time to tune them properly.

The last MGB I had in los angeles was redone in 2002 with HIF s and  they ran fine till i sold it in 2014 when I moved to texas. The only routine maintenance/tuning I did was to wipe the dust out of the bores every 2 years or so.

Idle adjustment didnt seem to need any attention once it was done initially.
Title: Re: Su HIF 4 intake manifold for 2.0 pinto...
Post by: LongTimeFordMan on November 03, 2017, 11:29:08 PM
Good news is that the manifold is welded up.  Bad news is that during welding the plate that mounts the manifold to the head warped.

My plan is to have several beads of weld built up around the ports then have the welds truex up by using a surfasing machine.

This should also tend to clamp the gasket better and aleviate problems with having debri between the head and mounting plate preventing a seal..

Will update when i have more info.
Title: Re: Su HIF 4 intake manifold for 2.0 pinto...
Post by: dick1172762 on November 04, 2017, 10:25:44 AM
All the home made intake manifolds I made for V8's back in the 60's / 70's I always bolted the intake to a cylinder head to prevent warping. Worked very well.