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Mjit

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Posts posted by Mjit

  1. There not shear bolts according to the Moss parts catalogue either.  There should be 2x 152597 shear bolts holding the steering lock to the column and a separate pair of UKC7070 bolts for the clamp that holds the rack to the car.  Looking at the diagram the speedo trip reset should be attached to one of the upper clamp bolts, as it is on the Mk IV.

     

    That said UKC7070 isn't a standard (or should that be Standard) bolt code...

  2. Don't bother with a replacement alloy block, go for one of the steel ones.

     

    The wooden spacers go in to slots in the ends of the block and swell when they absorb oil producing an oil-tight seal.

     

    Based on a Spitfire the job can be done engine-in but it's hardly the most fun you can have with your overalls on.  In addition to the book steps:

    1. Start by removing the sump plug a say or 2 before - the more little drips of oil come out the fewer will land on your face!

    2. After you've removed the 2 screws holding the block to the block inside the sump cover it should be free - but you'll be fighting at least it being a firm fit and maybe loads of sealing gunk.

    3. In my experience the wooden wedges won't be.  They will be wood but just blocks, not wedges so you'll need a sharp chisle to give them a taper and remove excess width in order to get them started.  You then need to hammer them home - with almost no room to swing a hammer at them.

    4. Back to the sharp chisle to trim them flush with the block - and it needs to be sharp or you'll just start pulling them back out.

  3. Yep, this is what you'd expect.

     

    The effective difference between an alternator and a dynamo is that the former can react to the demands on the electrical system by increasing its output. The headlights take a lot of juice and there's no such thing as a free lunch so for the altanator to generate the extra juice it has to increase it's load on the engine. In a modern car this all gets fed back to the ECU to automatically increase the fueling to keep the correct idle. In ours idle is basically 'how much the throttle is open by default' so you have the same fueling but an increased load => lower RPM, just like going up a hill without moving your right foot.

     

    Start by making sure you're choke is set up correctly, so the first part of the choke's movement pushes the tickover cam and increases tickover - without opening the choke.  You can now do the following:

    1. Increase the tickover a little for the winter months when you'll be doing more night driving.

    2. When gets dark in the summer give it a little bit of choke.  I'm not talking cole morning starting choke, just that first bit to press the tickover cam and give you those few extra RPM at idle.

  4. Roger, the thermostat opens progressively over a narrow temperature range. Anyone know what this is? I'll guess at 5'C. Under normal driving conditions the stat only partly opens - the engine temperature never gets that high because there's not much power for long enough and cooling is ample. It's only when you indulge in really spirited driving, you're stuck in a jam, the ambient's very high or some combination of these (amplified by removing the engine mechanical fan) that the stat fully opens. At this point, if nothing changes, then the engine temperature will probably continue to rise. It only levels off when heat loss equals heat generation inside the engine. So I think that the fan switch should trigger somewhere near the stat fully open temperature because that's an indication that the cooling system needs some help.

    I think there's 2 reasons for the gradual opening:

    1. While you don't want things to get too hot you do want them to get hot-enough as engine efficiency does change with temp. The cooling system has to be able to cope with the hot ambient/traffic jam worst case though and with an all or nothing thermostat you'd just get no cooling or over-cooling. If the 'stat only opens 50% only 50% of the coolant goes through the rad and gets cooled and when this mixes with the uncooled 50% the average temp. is higher.

    2. Something that could trigger quickly and accurately would have been much more expensive than a slow-acting bit of wax and a spring, which is all the 'stats in our cars really are!

  5. But I still don't see why the fan has to operate before the radiator is getting to hot?

     

    The following numbers are made up but say fan kicks in when the water coming out the engine hits say 110C and out at 90C. When the water in the top hose hits 110C the bottom hose might still be at 90C with the average water temp in the system at 100C. If the cooling fan kicks in at this point ('stat in top hose) it's only got to cool the water by an average of 10C before it kicks back out. If it's in the bottom hose the water coming out the engine may be at 130C before the bottom hose reaches 110C, with an average temp in the cooling system of 120C and the fan needs to run for longer to get the average temp down by 30C.

     

    I think I will leave Spitty's were it is as it was ok in the heat of Spain

    Like I said mine's in the bottom hose too and the real temperature differences between the top/bottom hoses are probably just a couple of degrees :)

  6. Technically top is best.

     

    The fan and radiator are there to stop the engine getting too hot and in the top hose it means the fan kicks in as soon as the water coming from the engine gets too hot and doesn't kick out until the temperature of the water throughout the engine has come back down.  In the bottom hose you have to wait for all the water in the radiator to get hot (and so that in the engine to get even hotter) before the fan kicks in and it will kick back out as soon as the water in the radiator get cool-enough (and before it's actually made it to the engine).

     

    That said I've had mine in both at one time or another and can't say I noticed any practical difference!

  7. One easy way to test for an air leak is to pull on the choke when you have the issue.  An air leak turns the mixture weak and the choke richens.  If the engine runs better when you pull the choke it's an air leak, if not it's something else.

     

    Check the breather hoses between the carbs and the rocker cover.  Had similar problem where car would run normally till I mashed the pedal.  Turned out one of the breasher hoses had a 50% split right on one of the hose clamps (there ironically to try and stop air leaks).  Normally it sat closed but the extra vibration when pushing it would open the split, letting a load more air in - only to close up again when the RPM dropped.

  8. Terrible thread abduction I know but as I don't think there's anything to add to Pete's answer to the question...

     

    always recheck thebhub bearing endfloat after a few miles
    tighten the castle nut lightly nipped and back off 1 or 2 flats then insert new pin.

    these must not have any preload or you will seize it very quickly

     

    How DO people tighten their castle nuts?  The book says finger tight, then back off till you can get a pin in and that's what I do - but always tend to get advisories at MoT time.  Is this just MoT testers not being used to the Triumph setup as everything tends to be of the pre-load design these days or should I be going tighter, or do I need new bearings?

     

    I'm rather paranoid about this because years-ago a friendly MoT station said "The hubs were loose so we tightened them up for you rather than fail the car on it".  I was on the M32 in Bristol when the now over-tightened bearing friction welded it's self to the stub axle leading to the stub axle breaking and meaning it was only the inner bearing and brake disk in the calaper keeping the wheel on!

  9. You might need to tweak the seating of the steering rack when you fit the UJ - that's the issue/solution I had.

     

    You often find that the rack mounts hold the rack slightly (or if using solid mounts quite a bit) above the chassis cross-member, so there's a bit of front/back roll before one end or the other of the locating 'blade' on the rack touches the chassis.  It's only a little but of course a 1mm there is more like 1cm at the steering column shaft where it passes through the suspenssion turret.

     

    Loose the rack mounts and rotate so you can fit the UJ with everything clearing, then tighten up the rack before re-checking clearance.

  10. Do the TSSC have any members in Japan, only I can't help thinking some of the Kei sports cars could be a good hunting ground for alternative seats?

     

    OK, you're basically looking at buying from Japan with the associated curreny exchange/shipping/import duty costs but even the latest generation of cars are limited to 1.48m wide, the same as a Spitfire and something along the lines of the Suzuki Cappuccino must have similar seat size restrictions...

  11. Height (of driver/seat) seems to be the only real issue with MX5 seats - even freshly refoamed standard seats can't touch the MX5 ones for comfort and support.

     

    I'm a 5'6" short-ass so the extra height isn't an issue - still looking through, rather than over the windscreen - but the taller you are the more you're going to need to compromise your driving position to fit.  My advice is try to find someone with them already fitted and arrange a try-out.  I'm in south London...though the car's currently at JY Classics getting some TLC :(

  12. So after a faultless summer I take the Spit. away to north wales for a week and...something's up with the clutch!

     

    When I press the clutch pedal it will either feel normal or I could get lots of slack and the bite point anywhere between normal and the floor. The general trend seems to be a normal pedal when downshifting after driving, coming up to a roundabout for example. Shuffling forward in a queue or pulling away is when it seems to be lower.

     

    The fluid level isn't going down so I'm guessing the piston's sticking in the master cylinder, but only just so the vibration of driving at any speed is enough to shake it free.

     

    What do you guys think? Agree with my diagnosis or anything else it could be/I can test for.

     

    Thanks

  13. Just drive it and burn off some fuel to start with (so there's no risk of the level being higher than the sender hole), then pop out the fuel level sender.  Chances are you'll find the sender float half full of petrol due to a pin hole leak or maybe a miss-bent arm.

     

    If it's a leaking float, replace it.  If not get the level down to the point you can empty the petrol in to jerry cans (if you disconnect the fuel pump feed you'll probably find it syphones naturally).  Pour a couple of litres back in and then set the arm so it's just lifted off the bottom test (a multi-meter set to resistance should help you judge this from outside the tank).  Finally put the fuel back in and fill 'er up.  You may not get a full needle when full - but you will know that an empty needle still means a couple of litres to get you to the nearest pertrol station!

  14. One came fitted to a performance engine I had built by one of the well know Triumph specialists and I was a little concerned by how much oil it was using.  Thankfully it was a friend's yellow car behind me when I started up and discovered where all that oil was going.  Over-supply to the head, straight down past the valves and out the exhaust.

     

    Took it off and been much better since!

  15. some nasty resistive plugs with an R in the suffix

    "R" suffix or prefix...?

     

    Nothing wrong with using R prefix plugs in one of our cars - and a few benefits if you're using electronic ignition/radio/satnav/etc.  They just have a resistor built in to reduce electrical noise that can interfear with other electical systems in the car.  About the only factory/dealer-fit item that could be helped is the radio but many of us have added more than that these days.

  16. To clean the tops of the pistons:

    1. Get the worlds supply of blue engineers paper towel and a pot of Vaseline.
    2. Get 2 of the pistons to TDC, then back them off a little.
    3. Apply the Vaseline (that will dissolve to nothing harmful in the oil when the engine runs) liberally to the tops of the 2 bores near TDC then turn the engine to that TDC.
    4. Fill every hole you can see with paper towel.
    5. Clean up the pistons at TDC wiping/blowing/vacuuming off the detritus.
    6. Yank out each of your paper towel hole fillers in turn and replace with new (the idea being to drag any detritus that may have got caught up and away from the engine).
    7. Turn engine away from TDC a bit and wipe away the Vaseline (that should have caught any small bits) with more new paper towel.
    8. Rotate the engine till the second pair of pistons are at TDC and repeat.
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