Fruitcake Type 4 engine rebuild - Finally started

Could you try a bigger pump jet? Assuming you already have a SVDA dizzy?

 

Right then, finished installing the engine, filled up with 20/50, brimmed and fitted the oil filter, filled the oil pressure switch port with oil, removed the spark plugs and spun the engine up on the starter using a temporary wire in the engine bay. I lashed up a pressure gauge to the pressure switch port and after 15 or so nerve wracking seconds I had 20psi on the gauge

I refitted the plugs, connected the coil and after a couple of turns the engine started, albeit a bit lumpy. I'm getting 50psi at fast idle.

I've come in now as it's mid winter in Lincolnshire and it's cold, dark and I'm hungry. I'll have another go in the morning and set the timing which may help but I think it's more due to the bellows that attach the single carb to the inlet manifolds being split as they were quite brittle when I removed them, I'll order a set in the morning.

What is the consensus for the ignition timing as Bentley gives various figures non of which match my setup. 2.0 litre, auto, progressive carb, electronic ignition with mechanical and vacuum advance?

Right now it's a quick shower a couple of some food and bed.

 

Timing 7.5 degrees btdc to get it running then 28-30 btdc max mechanical advance at about 3-3500 rpm. Thats with the vac advance hose disconnected from the distributor & blanked off.

 

Well done, sir!

 

Set the timing this morning as best as I could, thanks @Gooders, as it's running very lumpy. I can't do anything else now until the new manifold boots arrive as the gaffer tape that's holding the carb on keeps coming loose which is causing poor running!

I do have a bit of an odd squeak though, It doesn't appear to be mechanical but it does sound like a squeak I've heard before on bikes where there's a leak between the barrel and head, or head and exhaust. Desperately hoping it'll "go away" when I fit the new boots and it's running properly

 

lol the bold bit.
One type-4 trip up is the manifold/head join where the tin can get trapped at the top and hold the manifold off the head. That might explain both lumpy and squeak? You have be sure the tin in perched on top of, rather than overlapping the machined area for the manifolds when you screw it down if that makes sense. Generally it wants to overlap if you don't steer it deliberately.
Or
If you used the empi fibre gaskets, they need trimming to match the manifolds to avoid a similar situation.

Sorry if I'm teaching grandma to suck eggs.

 

Mine made a good chirping squeek from the carb manifold, sorted with a bit of cleaning manifold fettling and some decent gaskets bolted down well.


Sent from my SM-T580 using Tapatalk

 

Thanks Steve that's a good call, I'll check when I get the boots and fit the carb properly, without the use of gaffer tape . Unfortunately I'm in the middle of the mother of all thunderstorms and enough rain to last until next winter (if this one ever ends!) so hoping it doesn't float away.

 

The manifold boots arrived today, thanks Coolair, and I've finally got the bus to run properly. The irritating chirp is still there though and almost certainly coming from the left of the engine, cylinders 3 &4, I removed the inlet manifold and reseated it so I'm pretty certain it's seated properly. Looking underneath I can't see any tell tale puffs of smoke or vapour coming from the exhaust ports or around the head/barrel join. When it cools down, probably tomorrow, I'll whip the exhaust and heat exchanger off and reseal it. In the meantime here's a video of my chirp, as you can hear it's louder at idle and progressively gets quieter at higher rpm.

 

Well done, Paul, but that is quite chirpy.

 

It's definitely not on the inlet side, I've squirted Easystart around the manifolds whilst it's running and the idle stayed the same, if it was sucking that in the revs would have increased.

 

The chirp is coming from No 3. I removed the plug from No 4 and the chirp was still there, I then removed No 3 plug and it's gone completely, sadly when I refitted the plug it came back but it is starting to get a bit quieter

 

So at least you know it's a gas leak

Edit, does the chirp imply some sort of reed like behaviour, like blowing on a clarinet, air across three surfaces, rather than two? If that makes any sense, at all? Most simple air leaks I have come across make more of a ticking noise.

 

I can see something blowing about in time to the revving right at the back behind 3.
Sounds terrible BTW.
Did you wire brush top studs (the ones that get rusty) and oil them all and nut threads before you torqued? I would. Mine are rather large so I had sealing problems, I torqued them to 27/28 ft/lbs and it hasn't exploded yet. You could try 25 instead of 23 and be plenty safe I think.

 

It is an odd chirp, like having a budgie trapped in the engine I've heard the noise before on another engine and it was an air leak.

 

If (and it sounds like it is) a head/cylinder leak, it might even go away completely when it's well warmed up.

 

It's a crappy recording, to be fair the engine sounds great in real life. i can see something blowing about now you mention it, I'll investigate in the morning. Threads were cleaned before fitting but not oiled, I could have a go at taking them to 25, I'll slacken the valves and try it.

 

I will lose the will to live if I have to drop the engine an refit the bloody head, everything was clean when it went on and the barrels spun nicely in the head recesses, the shims and the head rings were the same thickness as the ones that came off. I'm surprised the head rings aren't copper, that way any slight difference in height of the two barrels could be compensated.

 

The head rings were discontinued with the advice to sling and replace with barrel shims so I'm surprised you have both.

 

Both were fitted when I stripped it down and both came in the gasket set, so I refitted them