Engine in bits for a rebore-anything else worth doing?

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ndevans
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Re: Engine in bits for a rebore-anything else worth doing?

Postby ndevans » Tue Jul 09, 2019 10:41 pm

It runs!

Only for about 30s at first, there was a strong smell of fuel. I found petrol dripping straight onto the exhaust. New fuel line either has hose clips that are too big, or is too big itself.
I put the old one back on, started it up an ran it for about 3 min, no problems. Needs mixture and idle speed adjustment, and running up to full temperature, but that's not a job for 10pm at night, not if you want to retain good relations with the neighbours!

🍺 o'clock.

Cheers N
cheers N
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philthehill
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Re: Engine in bits for a rebore-anything else worth doing?

Postby philthehill » Wed Jul 10, 2019 7:19 am

Well done. :D :D


ndevans
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Re: Engine in bits for a rebore-anything else worth doing?

Postby ndevans » Wed Jul 10, 2019 7:35 am

A note for future reference- I replaced the cam followers, as the originals were worn and pitted quite badly. When I put the head on, I had little compression, I could turn the engine with the starting handle easily.
I thought about this for a while, and thought I'd better check the valve rocker clearances. Sure enough, they were all way too tight. So I loosened then off, then set them properly, and now have resistance when turning the handle. Haven't done a proper compression test yet, that'll come when I've had it up to working temperature.
I assume the new cam followers have different floor thickness compared to the old ones, so that is why the rocker clearances had to be reset. Though I guess strictly speaking they should be reset after changing the head gasket, as that could be a different thickness compared to the old one.
cheers N
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philthehill
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Re: Engine in bits for a rebore-anything else worth doing?

Postby philthehill » Wed Jul 10, 2019 7:52 am

The valve clearances should be checked and reset if necessary whenever the head or valve train is rebuilt.

Not all cam followers are the same even if they have the same part number.
Tappet.jpg
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ndevans
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Re: Engine in bits for a rebore-anything else worth doing?

Postby ndevans » Wed Jul 10, 2019 9:50 am

Yeah, stupid of me to overlook it, but that's what happens when you're in a rush-MoT due on Friday. I think I'll postpone, got quite a few fiddly things to do before it's MoT-able, quite apart from clearing the car of all the junk that's been stored in there since September!
Cheers N
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Bowie69
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Re: Engine in bits for a rebore-anything else worth doing?

Postby Bowie69 » Wed Jul 10, 2019 4:08 pm

Well done!

Had similar when replacing a head gasket, clearly the one I replaced was about 7 thou thicker than the one I replaced it with!

All the valves were *just* held open slightly even on the base of the cam = no compression.

Scared me for just a moment as that is exactly what a snapped cam belt sounds like on a modern, but this is a minor!

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Re: Engine in bits for a rebore-anything else worth doing?

Postby ndevans » Wed Jul 10, 2019 11:26 pm

More progress. It ran for about 30 min tonight, on and off.
I struggled with the mixture-I'm using a Colortune on no.1 plug, and I can't get it lean enough to show a blue flame, the mixture screw is as far as it will go. It's not far off, as raising the pin causing engine speed to rise slightly, then stay there. I believe it should rise slightly then fall again-is that correct? It's an HIF38.
There's a rhythmic clicking sound which I was worried about, however I think it's the clutch which needs adjusting, as it disappeared as soon as I depressed the clutch.
I did a compression test, which gave readings of 145psi on no.1&2, and about 125-130 on 3&4. Should I be worried about this, bearing in mind that it's a rebored engine with new pistons and rings, and has been run for about 30min?

Cheers N
cheers N
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paul 300358
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Re: Engine in bits for a rebore-anything else worth doing?

Postby paul 300358 » Thu Jul 11, 2019 10:35 pm

Wind the mixture screw right out and start again, if you keep winding it in the tick over will go lumpy due to the bi-metal strips.

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Re: Engine in bits for a rebore-anything else worth doing?

Postby panky » Thu Jul 11, 2019 11:06 pm

ndevans wrote:
Wed Jul 10, 2019 11:26 pm
More progress. It ran for about 30 min tonight, on and off.
I struggled with the mixture-I'm using a Colortune on no.1 plug, and I can't get it lean enough to show a blue flame, the mixture screw is as far as it will go. It's not far off, as raising the pin causing engine speed to rise slightly, then stay there. I believe it should rise slightly then fall again-is that correct? It's an HIF38.
There's a rhythmic clicking sound which I was worried about, however I think it's the clutch which needs adjusting, as it disappeared as soon as I depressed the clutch.
I did a compression test, which gave readings of 145psi on no.1&2, and about 125-130 on 3&4. Should I be worried about this, bearing in mind that it's a rebored engine with new pistons and rings, and has been run for about 30min?

Cheers N
With the HIF carbs the mixture screw works the opposite way to what you would expect, winding it in makes the mixture richer. Wind it back out a couple of turns as a starting point and go from there.
Image

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Re: Engine in bits for a rebore-anything else worth doing?

Postby ndevans » Thu Jul 11, 2019 11:17 pm

Yes, I know it's cw to enrich & ccw to weaken, but it won't go ccw any further.

I'll do as suggested, and screw it all the way in, then out again. I'll make a note of how many turns it goes.
It hasn't been touched in two years, but I guess the mixture setting will need to be set up again, as I've now effectively got a slightly bigger engine. Can't remember what needle it is, and as I'm going to be replacing the HIF38 with an HIF44 as soon as I've sorted the manifold/air cleaner clearance issue out, and finished rebuilding it, I'm loathe to change the needle in the 38.
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paul 300358
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Re: Engine in bits for a rebore-anything else worth doing?

Postby paul 300358 » Fri Jul 12, 2019 10:25 am

Don't screw it all the way in, it adjusts a bi metal strip which you may damage. Wind it out and start again.

ndevans
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Re: Engine in bits for a rebore-anything else worth doing?

Postby ndevans » Fri Jul 12, 2019 10:41 am

Ok, noted, thanks.
cheers N
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ndevans
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Re: Engine in bits for a rebore-anything else worth doing?

Postby ndevans » Sat Jul 13, 2019 9:20 pm

Spent today doing the fiddly bits, like the floor, adjusting the clutch etc. Here it is in all it's glory:-

https://youtu.be/9rLOEn-92ls

Had a couple of short runs in it too, only 1 mile or so, but all seems ok. Main thing is it works-I can change into and out of all gears, which is a relief considering I've literally had the engine and gearbox stripped to their component pieces! It whines a bit, especially in 3rd, but I wonder whether that's just the new layshaft and thrust washers bedding in? Or the new 1st gear, which if I'm right, spins and is engaged with reverse all the time?
However it's a tale of stoopid failure as well. I adjusted the brakes some weeks ago, in anticipation of getting it going again soon. On the first run, to the end of the drive and back, I heard a clunking sound. Got out, had a look, all seemed well. Got back in, thought it's not right, I'd better go home & check it out thoroughly. Got 200m from home-crunch! Rear n/s wheel came off. I'd not done the wheel nuts up. No major damage, one of the u-bolts took most of the impact, which I will replace. The wheel is a little damaged on the back where it sits against the drum. Nothing I can't smooth off with a file, but it's an alloy, so do I replace it?
IMG_20190713_184151~2.jpg
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cheers N
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ampwhu
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Re: Engine in bits for a rebore-anything else worth doing?

Postby ampwhu » Sun Jul 14, 2019 7:35 am

I have a question regarding the fan fitted above. is this from an MG midget? if so, is there enough clearance from the water pump pulley and the surface of the rad?

reason I asked, is because I wanted to fit one instead of the single blade fan, but was advised it wouldn't fit as it would hit the rad.

any thoughts or can you confirm it fits well?

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Re: Engine in bits for a rebore-anything else worth doing?

Postby Propshaft » Sun Jul 14, 2019 7:43 am

I fitted a midget fan to my 1275 engine last week I have a 4 mm spacer behind the fan to clear the oil scrubber but had to take off a small portion of the fan blade to clear the top of the rad all seems to work ok off to holland in it next week

ndevans
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Re: Engine in bits for a rebore-anything else worth doing?

Postby ndevans » Sun Jul 14, 2019 9:11 am

ampwhu wrote:
Sun Jul 14, 2019 7:35 am
I have a question regarding the fan fitted above. is this from an MG midget? if so, is there enough clearance from the water pump pulley and the surface of the rad?

reason I asked, is because I wanted to fit one instead of the single blade fan, but was advised it wouldn't fit as it would hit the rad.

any thoughts or can you confirm it fits well?
No, it didn't fit. It doesn't clear the radiator at the top. As above, you could try shaving about 10mm off the top of each blade. You might even be able to raise the radiator a little if you drill new bolt holes in the radiator panel, there should be enough give in the hoses. I just refitted the Minor 2 blade fan.
cheers N
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ampwhu
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Re: Engine in bits for a rebore-anything else worth doing?

Postby ampwhu » Sun Jul 14, 2019 11:22 am

I did think so. I don't like the sound of cutting bits off the fan blade. think i'll leave as is.

thanks

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Re: Engine in bits for a rebore-anything else worth doing?

Postby ndevans » Wed Jul 17, 2019 11:07 am

Woo hoo, it passed it's MOT without even an advisory!
Embarrassingly, the MOT inspector lives down the road from me, and saw the wheel come off the other day, so no hiding that one!

All seems ok except for gearbox whine in 1st, 2nd and 3rd. As soon as I shift into 4th, it goes. Any ideas why? I have replaced 1st gear, and the layshaft, but not the actual laygear. Apart from new laygear shims and needle bearings, and new 1st & 3rd motion shaft bearings, the gearbox innards are as before.

Cheers Neil
cheers N
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