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Blackbox air filter replacement.

Discussion in 'Engine & Transmission' started by glow-monkey, Nov 10, 2008.

  1. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    Ok finally got around to ripping out the blackbox so i thought i would post up what i did.

    The main problem is there are no available bolt on filters that I could find on the market for the solex's. So the choice was buy new carbs around $1000-1500 depending on the choice of carbs and thats if you fit it yourself add a couple of hundred to that if you get your mechanic to do the job. The solex's are a damn good carb if they are maintained and i have not long had them cleaned up, so really I just couldnt justify the expense for the minimal extra power gained by replacing them over getting them to breathe better, so what next.

    There are a number of options for replacing the blackbox and keeping the standard solex carbs, from adapter piping and fitting pancake filters (like the webers) or unisocks or foam beehive filters, or a set up like Tom's (ttmck) that run a pipe between the two carbs with a central filter.

    In the end I decided to go with seperate pod filters and my own custom design for the fittings, honestly I had no idea what i was doing so really anybody can do this.

    So to start I opened the manual sat at the back of the van and tried to work out what was what, this was harder than I thought as none of the pics in the manual really looked like what was fitted to the van and with the black box in there most of it was hidden, i knew from a previous breakdown that the hose connected to the right side of the original intake caused the car to run like crap when it came off so assumed i would need to reconnect that, and the other fitting that connected to the same point seemed to run back to the intake, this I identified as the thermostatic vacuum. (see pic) this I concluded i wouldnt need.
    [​IMG]
    The only other fitting that connected to the box came off the top of the left carb, and according to the manual seemed to be part of the central idling setup, the only thing I could see was that to tune the carbs it said must remain connected, again i thought thats gotta stay, so that was the start of the plumbing design, two pipes had to stay.
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    Last edited: Nov 10, 2008
  2. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    I decided on Saas pod filters as they are twin cone (more intake area) and cotton so washable and still able to filter fine dust although i would probably cover them with stocking if i was planning on a really dusty trip.

    These puppies are huge so mounting them directly over the carb was out, so I was going to need an elbow, and the opening at the back of the pod to the intake is 3inch(75mm) so some way of reducing this to fit the carb(62mm). thankfully the ricer industry has led to a huge range of silicon fittings reducer and elbows being available for modding turbos. I also decided i wanted to fit heat shields and have something solid to fit the vacuum pipes to. so decided to stick a length of pipe inbetween the pod and elbow, 3inch(75mm) to 2inch(50mm) reducers are readily available and so is 50mm alloy pipe so choice made, only problem was i couldnt find a 2inch(50mm) - 2&1/4inch(62mm) elbow so had to settle for a 2-2&1/2(65mm) and make a sleeveup to go around the top of the carb. The fittings were simple, the left side could be tapped into the 50mm pipe with little or no mod to the fittings, the right side (idling vacuum) i was going to braze in a a copper pipe as a connector but found that the original vacuum fitting was removable from the black box so just tapped it in. So ordered the fittings cut the pipe hand bent some 20x3mm alloy rod into brackets and the pods were ready.
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    Last edited: Nov 10, 2008
  3. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    the removal and fitting was surprisingly straight forward and simple. Black box came out, vacuum fitting came out of right side by removing a retaining clip, spreading the flat intake pipe a little and it fell out, the toughest part was finding an o ring to make the sleeve for the carb. I managed to get some rubber rings from the plumbing supplies store these i had to cut and join to give me the width i needed as they were tapered, images show them before i rubber cemented them together. These i later replaced as the slipped off whenever i tried to tighten the clamps on the elbow. In the end I used some rings cut off a 50mm silicon pipe this stretched (with effort) over the 62mm carb and gave exactly the right diameter for the reducer elbow.
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    Last edited: Nov 10, 2008
  4. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    So here they are in place.
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  5. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    ANd how it looked before and after. (the before shot was taken prior to the engine rebuild a yr ago thats why the silver paint looks so cruddy its not fresh)
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    Last edited: Nov 10, 2008
  6. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    Does it make a difference? other than just to the looks, Hell yeah.

    The sound is fantastic, especially with the lid up, but even driving. and power is noticeable, especially mid range power, best example of this is I now make it about 700metres further up the Toowoomba range before i need to drop back to 3rd, and believe if i wanted to let it struggle that it would actually pull all the way up in top gear although i havent tried this is as it is one of the worst things to do to an aircooled engine or any engine.

    Fuel economy is marginally better but that is affected by the fact that the sound and extra power has made me a little more heavy footed off the start.

    cheers Glen
     
  7. nikferatu

    nikferatu Active Member

    Messages:
    1,447
    Location:
    Bracken Ridge, Brisbane
    Top job mate that looks very impressive. I would like to order one immediately.
     
  8. francispj

    francispj Member

    Messages:
    175
    Location:
    Adelaide
    Man , I like what you have done - I only posted a query about this last week - mainly 'cos I couldn't get to the distributor easily but the mid range power has given me another reason to spend more money. Who has the items you listed - I really am excited about doing this. (I need to get a life)
     
  9. Joel

    Joel New Member

    Messages:
    120
    Location:
    Northern Rivers NSW
    tidy install bet it sounds good

    just one thing i noticed tho

    the thermo valve you've fitted to the rhs filter is gonna do nothing excpet cause a vac leak but thats only if it still works
    99.9% of them dont after 30+ years

    its purpose was to open the flap in the bottom of the old black box that ducted hot air off the heads when the temp was cold enough to call for it

    but now thats gone it has nothing to connect to and with the outlet port of it left open if it does still work it will just suck in air which will cause the engine to run lean

    best thing to do would be remove that silicon hose and cap off the connection where it comes off the metal balance pipe

    HTH
    Joel
     
    Last edited: Nov 10, 2008
  10. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    The blue silicon fittings, I got from a shop in Bris that does up Ricers (doof doof cars, over-turboed ultra-lowered, excessively blinged, nissans and hondas) but any turbo supplier should have numerous sizes, the alloy pipe and rod came from my metal merchant in Toowoomba and the pod filter from an online car accessory store, Supercheap has some silicon pipework I have recently noticed, other than that ebay search silicon pipes and you will find them, and search pod filters and again heaps to choose from.
     
  11. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    Joel, yeah there are a few changes I want to make, e.g. the fitting on the left side I want to take the original metal pipe out and replace it with some flexi tubing, that will make it a little easier to leave connected to the 50mm pipe when i need to remove the elbow from the carb for tuning etc.

    As for the vacuum piping, As you can see the diagram of the central idling system is not exactly the same as the piping in the photos of the engine from above (I dont have the mixture distributor #4 in fig 5.3) and the diagram doesnt seem to have the vacuum pipe tapped into it. Im not sure if the fitting works or not, it did seem to lock if you sucked on one side, or blocked it while sucking on the other, all I do know is when the black box was still in, if the tube to the idling pipework came off then the car would not idle, lost power and basically shut down the left cylinders. I intend to play around with it a little and see what makes a difference now that i have this setup, also it has to go in for a tune up in the next few weeks and I will see what the mechanic thinks when he gets a look at it, if its not need then it will be removed and rather than block the hole where the fitting was i will replace the 50mm pipe as i have plenty of it lying around.

    Thanks for the info. will keep you all posted on any changes I make.
     
    Last edited: Nov 11, 2008
  12. syncro

    syncro Well-Known Member

    Messages:
    10,044
    Location:
    Southern Highlands
    You may need to make the mounts a bit more flexible as they are mounted to the body and the engine moves a fair bit.
     
  13. Vanders

    Vanders Active Member

    Messages:
    1,450
    Location:
    Launceston, Tasmania
    I thought the same thing Phill. Some sort of rubber mount between the strap and where it connect to the body would probably give it enough flexibility.
     
  14. glow-monkey

    glow-monkey Active Member

    Messages:
    1,319
    Location:
    Kenilworth QLD
    Yeah i thought about that when i first made the brackets, the alloy does allow a fair bit of left to right flex though, and the silicon elbows are also quite pliable, you can hold the hold the pipe near the pod and move it around in a circular motion and get a good 10mm travel in any direction, after a couple of weeks driving (including about 30kms of forestry dirt road) nothing seems to have loosened or moved.
     

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