Distributor advice

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cadboy
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Distributor advice

Post by cadboy »

I am thinking about changing my distributor.

my car has 340 with electronic ignition MSD pn6425 and I think blast 2 coil.

I am not sure what the distributor is but it is not MSD.

There is an issue with it as the engine runs hot at high RMP.

Any help and advice on what to change to match the set up.

thanks guys

Ali
MilesnMiles
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Post by MilesnMiles »

Ali, why are you focusing on the distributor? There are many reasons for a motor running hot at high rpm.
I would look at coolant flow through the rad at high rpm, the possibility that the bottom hose is pinching shut (my 340 used to have one that did),
Is the ignition timing correct, is the block silted up.
Have you been through those parts yet?
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Dave-R
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Post by Dave-R »

Most temperature problems are down to timing. If the distributor has never been modified I can tell you now the timing will be far from ideal for modern fuel.

Also it might be running lean at high rpm. But unless you get the timing curve right first you can't look into that.
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cadboy
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Post by cadboy »

I had Pete and Guy check the time last outing at Shakey and it was found that the springs in distributor don't seem to be working and also no vacuum.
I may be wrong but the timing was good and Pete advised to change the springs and then try.
so I am only thinking that if I go for a new distributor then it may be easier to set up.
All the coolant system has been checked and works okay.
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Dave999
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Post by Dave999 »

standard dizzy with a recurve kit from turnip would do the job.

Dave
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cadboy
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Post by cadboy »

Dave999 wrote:standard dizzy with a recurve kit from turnip would do the job.

Dave
Sorry Dave you may to explain a little bit more on this kit, link to where to get one and how to get it fitted and working.

I have never played with the dizzy and tuning before, but willing to learn.

Cheers
Ali
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Dave-R
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Post by Dave-R »

Lots of posts on here about ignition timing tuning. It's been gone over so many times. It involves restricting the amount of mechanical advance in the distributor so you can run lots of initial timing. This makes the engine run better on modern fuel, starts easier, runs cooler, and runs cleaner so you don't get smelly exhaust.
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Dave-R
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Post by Dave-R »

You can use the simple FBO kit from "Turnip" on here. About £25 I think?

1 . Set the basic timing for total mechanical spark advance.

Run your engine and, with the vacuum advance disconnected, turn the distributor advanced and listen to the rpms of the engine increase.

They increase because the engine "needs" the advance to burn the fuel efficiently.

There will be a point where the rpm increase starts to level off. Stop advancing the distributor at that point and adjust your carb to bring your idle speed down to 800rpm (800-900 auto with big camshaft) and check that the engine will still start OK. If the starter motor struggles or kicks back, back off the timing a touch and try again.

Use a timing light check to see how much initial you now have.

Deduct that number from 34 and that is the number of degrees your distributor needs in it.

Use the FBO kit to modify your distributor so that when you re-time your engine you have your new initial and a total of 34 @ 3000rpm.

If you do this you don't *need* vacuum advance but on a street car it can increase your MPG some.

2 . Set the vacuum advance for total ignition advance.

a/ After the basic timing has been set for total
mechanical spark advance, disconnect the vacuum
advance hose at the carburetor . Connect a vacuum
gauge to the carburetor's vacuum advance port and
route the gauge and hose into the passenger
compartment . Place the gauge in a location that an
assistant can read the gauge while the vehicle is being
operated.
b/ With the vehicle in operation, note the maximum
amount of vacuum generated by the engine while in
gear and being held at a steady speed between 2000
and 4000 rpm.
c/ Stop the vehicle, turn off the engine and connect a
timing light to the battery and number 1 spark plug
wire.
d/ Start the engine and raise the idle speed to 2600 rpm.
Connect a vacuum source to the distributor's vacuum
canister and draw vacuum up to the reading noted in
step b.
e/ Note the total advance shown on the harmonic
balancer.
f/ Total advance, mechanical plus vacuum, should be
52°. Disconnect the vacuum source and insert the
allen wrench into the internal vacuum canister
adjusting screw . Turn the allen screw (clockwise to
decrease, counterclockwise to increase) to obtain 52°.
Reconnect the vacuum source and recheck the
timing . Continue repeating this procedure until 52° is
reached.
g/ Remove the timing light and vacuum source.
Reconnect the vacuum advance hose . Reset the idle
speed too your original setting .
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cadboy
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Post by cadboy »

Thanks Dave,

I will try that first.

Great help :thumbright:
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Dave-R
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Post by Dave-R »

It is only once the timing is spot on that you can even start looking at things like carb tuning.

Good luck with it. :thumbright:
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Dave999
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Post by Dave999 »

yeah turnip can get you a kit with springs that work and a special easily fitted device that allows limiting of advance

you dismantle your dizzy

put it in a bag

lever off the advance thingy from the top of the shaft (it fires off a small snap ring hence the need for the bag or leave the felt pad in under the rotor)

pop in the Turnip/FBO limiter and springs

put the advance bit back on and push the snap ring back over the nipple on the top of the shaft with a bit of 8 mm I/D tube.

the instructions explain


Dave
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Dave-R
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Post by Dave-R »

Normally that is a circlip Dave. Fine circlip pliers remove it. Or a pair modified to do the job. ;)
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