Setting timing on a 1220 motor

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soufle
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Setting timing on a 1220 motor

Post by soufle »

Hi there, I've just pulled the motor off 75 1220 club, now I've bumped the cam pulley on the fuel pump (right side) and its drifted forward about 20 degrees, belts off, so wondering what action to take to get it back to correct position?

Any suggestions welcome.

Also I ripped the hyrdroneumatic pump off and the piston popped out, have I made a big boo boo doing this and can I just cue it all up and plonk the pump back on?

Cheers
Steven

ps reason I took the motor out was I found an oil leak and concluded it must be the leak back tube, where you can see the pipe its coated in oil and thE other side the pipe is dry as.

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Stonehopper
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Re: Setting timing on a 1220 motor

Post by Stonehopper »

Hi, scroll down through this link. It's from an earlier subject on timing the belts:
viewtopic.php?t=52512

soufle
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Re: Setting timing on a 1220 motor

Post by soufle »

thanks Derek, read that one already! What I am trying to understand is if I rotate clockwise the cam sprocket on fuel pump side around to original position ( belts now disconnected) where will it leave the valves in regard to timing, like where in the combustion cycle? Or how many rotations till its back where it is meant to be?

I suppose I just take the rocker covers off and watch whats going on with the valves eh.

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white exec
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Re: Setting timing on a 1220 motor

Post by white exec »

Haynes manuals for GS/GSA 1971-85 (incl 1220cc) on both ebay and Amazon, from just £3.
Will almost certainly have timing info.

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Stonehopper
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Re: Setting timing on a 1220 motor

Post by Stonehopper »

If you turn the camshaft around 360° without the belts on, it will be back where you started! Irrespective of where the other two are.
It's getting them all lined up correctly that is important. That is what determines where the cams are in relationship to the pistons on their relative strokes. Not how many times they are rotated, that's why the grooves are there - to get the camshafts in the correct sequence with the crankshaft.

The pump side sprocket needs to have the groove at 6 o'clock, the distributor side at 12 o'clock, and the crankshaft sprocket at 12 o.clock. They all have a radial groove in the outer faces. Once at those positions, you can fit the belts. Once on, check they haven't moved, then if you rotate the engine you should see the valves opening and closing at the correct points in relation to the pistons.

It's simpler than it sounds.

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myglaren
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Re: Setting timing on a 1220 motor

Post by myglaren »

I changed the belts on mine, which was a first. Stood and looked at it for a day before daring to turn the key.
Luckily (and it was more luck than skill) all worked as it was supposed to do.

soufle
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Re: Setting timing on a 1220 motor

Post by soufle »

Thanks Derek that is reassuring. Will do.
How about putting the pump back on?

It kind of flew off when I unbolted it and had me wondering about how the piston is set up in there too.

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Stonehopper
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Re: Setting timing on a 1220 motor

Post by Stonehopper »

Can't remember having any issues with the hydraulic pump, though I know I have removed it sometime in the distant past.
The books are vague on detail as well. Can't remember how the piston is connected to the connecting rod that drives it, which in turn runs on a concentric off the oil (engine) pump, so there's no timing issue there. I'd oil the piston with LHM and pop it back in the cylinder (if indeed it has come out). As the books are as vague as my memory, the valves for the hydraulic fluid are probably within the piston itself, so no timing to be done there. New 'O' ring and pop it back together. Prime with LHM from the inlet end before starting.

Needless to say - keep it all spotlessly clean on assembly.

soufle
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Re: Setting timing on a 1220 motor

Post by soufle »

Ok thanks again for info, I was just surprised how the pump body flew off when I tore it off! Must say I am beginning to really like this car, had it sitting inside for over 3 years, very little rust, all original, I'm going to put a new clutch in it, clean up the motor but no restoration work! I spent over 4 years completely rebuilding a DSpecial. Never again? Yes. I'm not even going to tart up the engine shrouds although I have sandblasted and heat proof painted the exhaust down pipes! Arrete maintenant!
Cheers Steven

I bought my D off a guy over 20 years ago and he also had a GS and he was totally sold on them and I can see why now.

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Stonehopper
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Re: Setting timing on a 1220 motor

Post by Stonehopper »

Popped off - must have been some residual pressure in there. Unusual I would have thought. Is there something in the system that is holding back?
Just a thought. If the piston was on the compression stroke, you would have thought de-pressurising the system would have released all pressure. And if the car had been standing for some time, it would have lost most of the pressure anyway.

The GS series are lovely to drive. Simpler than the D, but with everything tickety-boo the ride is unequalled. Pity they don't do sixty to the gallon, not thirty!

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myglaren
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Re: Setting timing on a 1220 motor

Post by myglaren »

Stonehopper wrote:
10 Mar 2020, 08:29
The GS series are lovely to drive. Simpler than the D, but with everything tickety-boo the ride is unequalled. Pity they don't do sixty to the gallon, not thirty!
They are indeed, I swear mine was the best car I have owned. As said, shame about the petrol economy.