B head porting questions

Lincoln Mark VIII Performance

  1. Stangman

    Stangman Project car a.d.d.

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    Hey guys, I just picked up some B heads off another Mark Viii engine, and I'd like to open them up and make them flow better... Then maybe finding some Cobra cams for them

    I've been told that the intake side is fine, and just to clean it up... but the exhaust side needs opened up... what about unshrouding the valves and whatnot?

    So does anyone got any pics or tips, or even a step by step on porting B heads?

    I also have an extra set of IMRC's, and an intake now that I have these heads and is there anything special I can do with these?

    I thought of taking the rods and the butterfly's out of the IMRC's and then filling the holes with JB weld and then smoothing them out...
     
  2. XLRVIII

    XLRVIII Dedicated LVC Member

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    DIY porting on 4V heads is a very bad idea if you do anything other than "cleaning em up, and gasket match".

    I know your gonna do it anyways, so...just bank on the fact of "holing" a port...just before you think you've got it right.

    you really need to get a third head and saw it up, so you can see where you're gonna be working and how little "extra" material" there is in a couple of key locations.

    ripped camel has a bum head, currently in Jamie's possession
     
  3. Stangman

    Stangman Project car a.d.d.

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    I'll have to talk to the guy I got the heads off of... I think he has one that ate a valve...

    Heck I'd be satisfied really with just doing a good "clean up" job on them and gasket matching them...
     
  4. SVO

    SVO Dedicated LVC Member

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    B/Swirl Port: (93-97 Lincoln Mark VIII, pre 99 Lincoln Continental, 96-98 Cobra).
    The first and only production Ford head with two (square primary, round secondary) intake ports per cylinder, these swirl port castings arrived first in the ’93 Lincoln Mark VIII. Aptly named, due to the way they promoted the incoming air to swirl into the combustion chambers, much like water running down the drain of a once full sink.
    Through the years these heads have proven themselves to be excellent high rpm (8000rpm+) performers—mainly in power adder applications--since their tremendous combined intake port cross sectional area and volume (when combined, a full 55cc more than any other 4.6L head design) provide for exceptional power production in the upper regions of the tach. Ironically, it’s those same big, beautiful, twin ports that also prove to be the B head’s largest inherent design flaw. The extra intake port size has a tendency to kill low/mid rpm intake port velocity and power production—hence the use of Ford’s first IMRC (intake manifold runner control) intake on the 96-98 Cobra. By allowing air to reach only one of a B head’s twin intake valves, velocity, and therefore low/mid range torque production was restored in situations under 3250rpm. Later head designs are clearly superior in this regard, which happens to be the one of the most important considerations for those wanting a stout street motor.
    There is also some controversy over the single fuel injector/dual intake port setup. Some claim insufficient air/fuel mixing because of the compromised design, however, others contest that the ability to make 1000+rwhp with only minor porting and some form of power adder is testament to the contrary. Whoever you believe, there is little doubt that even after as little as 8,000 miles, carbon and other deposits tend to form on the secondary ports, causing a major airflow impedance, as there is no fuel present to clean them. B heads feature a somewhat small stock exhaust port that really hinders flow in power adder applications. Major gains from porting come with a quality valve job, some pocket and lots of exhaust work. There really isn’t a lot of material to remove from the intake ports themselves.
    The Bottom Line: B heads aren’t the best choice for a naturally aspirated street motor. In order to really shine, they need to be paired with a power adder and a short block that can sustain high horsepower and rpm levels. These, the oldest heads, may still be a great choice for full race applications.

    Stock Intake Choices: ‘93-‘97 Lincoln Mark VIII, ‘96-‘98 Cobra.
    Aftermarket/Modified Stock Intake Choices: HCI, SSR, PHP.
    B head dimensions: Combustion Chamber: 52cc, Intake Port Vol.: 107cc primary (square), 115cc secondary (round). Intake Port Entrance: 1.500x1.300” primary (square), 1.660x1.400” secondary (round), Valves: 37mm Int., 30mm Exh.
     
  5. SVO

    SVO Dedicated LVC Member

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    I would leave the intake side with at least a 120 grit finish to help fuel atomization. Especially in the B heads where port velocity is low on the injector side!

    But remember, if your running N/A, your going to go further backwards, unless of course you plan on aftermarket cams, and adjusable sprokets and spend the $$$$$ on a built bottom end to twist this motor to the moon..

    Biggest flaws with B heads are:

    1) Single injector/dual runner design causing poor A/F mixing, and carbon/PCV deposits to build up in the secondary runners since no fuel is sprayed there.

    2) Too much intake port volume/cross sectional area. Great for 8000rpm+ forced induction apps, but not so great (compared to the newer heads) for street use.
     
  6. SVO

    SVO Dedicated LVC Member

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    Really?

    you want pics of the ports castings?
     
  7. Rich88LSC

    Rich88LSC Dedicated LVC Member

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    I agree with Tommy B heads are a completely different animal then SBF. However they are pretty cheap so it's not the end of the world if you screw one up.

    Sameless plug.... I have a set of B heads with some mild exhaust work done on them for cheap. They are bare heads.

    Cobra intake cams have more duration then the Mark cams but the exhaust cams are pretty much the same. Again they can usually be had for cheap so why not. I have custom Comp Cams/springs/retainers for sale. Not cheap but everything is NIB and I'll cut you a deal for everything.


    I wouldn't unless you have 4.10s+ and a higher stall converter. Even then I wouldn't unless you add cams/intake. What you will gain up top you will lose on the low end and on these heavy cars it's not a worthwhile tradeoff.
     
  8. MediumD

    MediumD Dedicated LVC Member

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    I do if you happen to have pics. But not because I want to port a set of B heads, just curious.

    I first tried my hand at porting on my Super Coupe's aluminum heads. I have at least 50 hours into them with just dropping the floors and cutting a better radius on the short side, a little valve deshrouding, gasket matching the heads and manifold, cutting Somender-Singh grooves, and cleaning up casting flaws.

    I wouldn't do anything more than a very basic cleanup and gasket match on 4v heads, especially B heads.
     
  9. Stangman

    Stangman Project car a.d.d.

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    I do have a line on some '97-'98 cobra cams... I have a 4.10 and a trac lok waiting to go in the car after it gets brought back from the dead.

    I dont have a high-stall converter, but how much higher would it have to be? The one I have now is stepped up mildly, further than stock, but I cant remember how much, I'll have to get with my trans builder on that one...

    What kind of Intake could I use on a '93?? with minimal modifications. AND fit under the stock hood (for now, double R hood coming later)

    As much as I'd love to have your heads/cams/retainers/springs... I'd hate to ask how much... I know those 4V valvetrain parts aint cheap!
     
  10. kustomizingkid

    kustomizingkid Dedicated LVC Member

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    Cobra cams are the exact same....
     
  11. DLF

    DLF Dedicated LVC Member

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    There are people that think the Cobra intake cams have more duration, why do you think they're the same?

    Sullivan Performance: "The Intake cams on the Lincoln are a slightly different profile."
     
  12. Rich88LSC

    Rich88LSC Dedicated LVC Member

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    When I say cams I don't mean Cobra cams I mean aftermarket cams. I wouldn't bother with Cobra cams but if your pulling the heads already.

    With 4.10s I would go at least 3500 stall but thats just me. Call Circle D for a TC.
    IIRC Cobra intakes have been done on Gen1s with cutting hood bracing.

    No ain't cheap but I want it out of here so PM me if interested I'll try and work something out with you. I have a ported Cobra intake and some other parts too.
     
  13. Rich88LSC

    Rich88LSC Dedicated LVC Member

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    +1

    My understanding is the Mark cams are more like the 03 Cobra/Mach 1 cams.
     
  14. na svt

    na svt LVC Member

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    There's a lot of incorrect information and bad suggestions in this thread

    96-98 cobra cams have 204 deg dur
    99/01's have 200
    mach, marauder, aviator, marauder, mark 8, and 03/04 cobra's have 184 deg dur

    Do not gasket match B heads, it'll just hurt flow. Also, do not by any means lower the port floor on any head.

    Finish the intake ports with 60-80 grit, 120 is too fine and will cause puddling.


    There is no unshrouding to do on heads that are going on a stock bore engine. Some bowl porting, a good valve job, and enlarging the exhaust port a little are all that has to be done to B heads.
     
  15. Icarus

    Icarus Dedicated LVC Member

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    How would gasket matching hurt flow?
     
  16. Icarus

    Icarus Dedicated LVC Member

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    Well...?
     
  17. MediumD

    MediumD Dedicated LVC Member

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    I haven't actually looked at gasket matching a B head, perhaps there's just too large of a difference, or perhaps he's concerned about increasing the already enormous port volume.

    And yeah, my intake ports look like this, I better leave them alone :rolleyes::
    [​IMG]
     
  18. Stangman

    Stangman Project car a.d.d.

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    I honestly have no idea, I was just throwing out there some possible mods for heads... I am used to pushrod engines personally... but would love to get all the "cheap performance" out of my Mark Viii as I can... If the recomendation is to leave em alone, then leaving them alone is what I'll do, lol
     

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