Announcement

Collapse
No announcement yet.

Twin SU HS4 & SU HIF4

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
  • #1

    Twin SU HS4 & SU HIF4

    Anyone know if I can replace the twin HS4s on my 1.8 B series with later HIF4 carbs given the correct inlet manifold?

    Thanks in advance.
    Tags: None
  • #2
    Re: Twin SU HS4 & SU HIF4

    Message originally posted by: Stefan Carlton
    The best place to ask would be here : http://www2.mgcars.org.uk/cgi-bin/gen5?runprog=mgbbs but, you won't have a problem.

    The Marina B series is essentially the same as the MGB B series, albeit it's the earlier 3 bearing model. Other differences are towards the rear of the engine (clutch, flywheel, gearbox and I believe the crank design is different). So anything you can do to the engine in the B, you can do to the engines in our Marlins

    Be warned tho, the 3 bearing model can't take to much power through the crank due to the flexing so whilst as HIF's won't increase power to much, changing the head/cam will We're also stuck only getting to 5500 rpm before you start to get into the danger zone.

    Personally I'm looking towards strengthening the bottom end in a similar fashion to what you do with Minis (cross bracing and the like) and then look towards a supercharger. Hehe.

    Comment

    • #3
      Re: Twin SU HS4 & SU HIF4

      Thanks Stefan, I've just posetd on the other forum too. Years ago an MG specialist did tell me my block was MGB with Marina head - I didn't think there was any difference. I did just read something about the different carbs using different distributors?

      Comment

      • #4
        Re: Twin SU HS4 & SU HIF4

        Message originally posted by: Stefan Carlton
        you what? Different dizzy's with carbs? News to me and I read up on all this sort of stuff as a hobby (not saying much mind, I do miss things). The change in HS4's to HIF4 carbs won't be significant enough to warrant a new distributor, maybe if you headed for Webbers and needed a very large advance in timing, but even then thats weird

        All you'll need to do is get hold of a decent manifold (Peter Burgess' MGB book tells you all about them), and change the timing as needed - no need to change other components.

        May I ask why the change incidently? I wouldn't have thought the lateral G on the Roadster would be high enough to warrant the cost of getting new Carbs (the reason they were put on Minis was due to fuel starvation in cornering apparently).

        Aren't the "Marina" heads just different valve design?

        Comment

        • #5
          Re: Twin SU HS4 & SU HIF4

          Message originally posted by: Don Sayers
          Actually, Stefan the Marina 1800 was always fitted with the 18V engine which had five main bearings. The heads are the same. The Marina actually got this engine before the MGB did. The only difference between the two type 18V engines was the crank. the MGB had a forged crank the Marina a Cast one. The MGB engine has a different sized spigot bearing in the end of the crank and I believe different fixings for the flywheel. It can be nearly impossible to identify which car an 18V engine came from as they can be interchanged quite easily. Many rusty Marinas were raided by MGB owners wishing to upgrade their tired Three bearing engine.

          I am certainly intending to up-grade from twin HS4's to HIFs, they are much more reliable.

          Comment

          • #6
            Re: Twin SU HS4 & SU HIF4

            Reason for the change was that I think the carbs need recondtioning and a cheaper option seemed to be to replace with a 'new' set of HIF4s that were on e-bay - didn't win 'em in the end though

            Comment

            Previous template Next
            Working...
            X