Rebuilt 1275-running a bit "out of sorts"

[ndevans]

Ok. Torque to 45lbft for the first great cycle, then 50 for the second?

[philthehill]

No
Go straight to 50lbf ft. You have got the new 'A' Plus studs.
BL Wksp manual says nothing about doing the torque in two stages.

If you are concerned about going straight to 50lbf ft you can build up to 50lbf ft in say two phases but do not run the engine at 45lbf ft and then re-torque to 50lbf ft.
Make sure that you follow the tightening sequence each time.

[ndevans]

Ok thanks Phil, I've checked the new studs, they are a mixture of tapered heads, and flat heads with a Y stamped in them, so all the higher torque type. Watch this space! (though probably not until Sat will I get it started)

Cheers Neil.

[ndevans]

Progress report. The head is back on. I torqued it up to 25ft-lb, doing the rocker pedestal nuts at the same time. I then took the cylinder head nuts on to 50. My only reservation is that the gasket, a Payen composite one in a nice shade of green, seems to slightly overlap the bores. Didn't think to take a photo, and it's all back on now.
I've also made a slight alteration to the cooling circuit. I wasn't happy with the way the copper pipe that runs along the head to the radiator bottom hose sat right on top of the stud for the thermostat cover. It has to be in this position to line up with the stub in the bottom hose, but even then, it only just reaches, only about 6mm of pipe enters the hose.
I assumed this was due to the big valve head being slightly deeper than the standard 1098 item, but I now understand they are all the same. It may be due to the slightly different position of the thermostat cover, rotated a little compared to the 1098, just enough to move a stud into the wrong place.
Anyway, I have used a 1/2"-5/8" hose adapter to run a piece of 5/8" hose up from the bottom hose over the rocker cover, and another 1/2"-5/8" adapter to connect to the 1/2" hose coming from the radiator (I don't have a double ended 1/2" coupler, which is why I've used 5/8" hose).
New fuel line is in position, but not bent and formed to the correct shape yet, and not coupled up. That leaves the exhaust pipe to refit, radiator to refit, fluids to replace, and battery to recharge and refit. Oh yes, and the whole interior needs refitting......

Cheers N

[philthehill]

Overlapping the bores is a no no.
The head gasket should not overlap the bores.
The copper gasket in the link below is the one to use -
http://www.minispares.com/product/Class ... o%20search

[ampwhu]

i have payern BK450 gaskets in my spares.

[ndevans]

Thanks both. I've spoken to the supplier, I won't name them, to spare their blushes, but they have agreed to refund the price of the gasket. I have a spare copper one, which will go on this evening. When I get a chance, I'll get a photo of the gasket in situ.
Cheers N

[ndevans]

Here's the faulty gasket, a Payen AF470. You can see the gasket is overlapping the bore on the exhaust side. There's actually no block surface visible from above on the exhaust side, and about 1-2mm of block surface visible on the ignition side.

IMG_20201204_212856973_HDR~2.jpg (695.38 KiB) Viewed 11270 times

IMG_20201204_212840123_HDR~2.jpg (757.53 KiB) Viewed 11270 times

IMG_20201204_212829818_HDR~2.jpg (614.08 KiB) Viewed 11270 times

Replacement is better, although not obvious from the photos. There is block surface clearly visible all around each bore.

IMG_20201204_214450650_HDR~2.jpg (466.52 KiB) Viewed 11270 times

IMG_20201204_214439479_HDR~2.jpg (622.34 KiB) Viewed 11270 times

[ndevans]

Good progress being made. The fuel line is in, fluids refilled apart from water, carb & exhaust refitted and connected up, tappets adjusted, as it seems a prudent thing to do after the head has been off (I set them to 0.305mm/0.012" inlet, 0.38mm/0.015" exhaust), distributer refitted. To do is refill water, fit battery and give it a go. Too late now, I value my relationship with my neighbours!

Cheers N

[oliver90owner]

apart from water

Not sufficiently confident to fill with ‘coolant’ (water/antifreeze mixture)?

[ndevans]

No, I'm going to put water and coolant flush in, give it a short run, then change it for a proper coolant mix. Should be able to do all that in one evening.

[oliver90owner]

Had that not been done at the rebuild? And it is not just a short time since the engine was supposedly overhauled previously?

[ndevans]

I've flushed it out a couple of times, but only using a hose in the pipes and block, not used a flushing agent in the water. I'm not convinced I've got all the sludge out of it, which is why I'm doing it again.
The engine was rebored last year, since then the engine has largely been ok, aside from the head gasket failure. It's been a bit rough, but I've sorted that now, and I'm hoping that the higher torque on the head bolts will cure the slight weep of oil from the head near no. 1 cyl. It's literally a tiny weep, it's not actually losing any more oil than I'd normally expect. I've checked the head, and it's looking square to me, against a straight edge. If this doesn't cure the issue, then I'll live with it until the head next needs to come off, then get it skimmed square.

[ndevans]

Well done.
Fill with cheap oil or flushing oil - run and then drain. Re-fill with top grade oil and enjoy.

Do not forget to retorque the head to 50lbf ft after the first heat cycle.

@philthehill - I re-torque after it has cooled down, not while it's still hot I guess? My instinct is wait for it to cool, but I had to ask....!

cheers Neil

[philthehill]

Initial retorque after it has cooled down.
Retorque after 500 miles.

[ndevans]

Ok thanks Phil.

[oliver90owner]

Well, I have never done it that way and never had failures - apart from the infamous 2 1/4 Landrover diesel (a conversion to diesel from the petrol design). That likely isn’t as many heads refitted as PTH but includes motorcycles, cars, tractors (both petrol/TVO and diesel) and a whole load of stationary engines, chainsaws, etc. There is usually a reason for gasket failure, which will recur if not remedied.

Cast iron engines are always brought up to operating temperature and retorqued hot. Aluminium heads must be retorqued when cold. I can assure you that tractor engines do not get retorqued again after several hours of running. And neither did these cars when new, I would suggest.

[ndevans]

Success, it runs, and sounds quite smooth. Started 1st time as well, which I've never known after a rebuild!
I've taken it up to temperature and run it for about 30min with engine oil flush and rad flush in. Currently the oil is draining, the water will be drained after I've had tea.
One downside though is it's weeing water from the 1/2"-5/8" coupler on the heater return (I have left off the copper pipe that runs along the top of the head, and connected to the bottom hose using 5/8" hose and two 1/2"-5/8" couplers. This is because the copper pipe does not align properly with the bottom hose, and I was not happy with it). I also seem to have a split bottom hose, which isn't helping. I can get new hoses tomorrow.

Cheers N

[les]

I’ve read stuff on this hot/cold retightening business, which include cast iron Hot, cast iron Cold, aluminium Hot, aluminium Cold. Its Cold tightening for me every time, after all the initial Cold tightening held up, so the second Cold tightening must do the same. It’s just a case of checking after settlement.

[philthehill]

See Morris Minor wksp manual issue 5. 37720. First 500 miles Free Service

Item No: 3. Tighten cylinder head and manifold nuts to recommended pressures(torque).

The head was always tightened after the first 500 miles as part of the after sales service.

The same 500 mile tightening process should be carried out after the head has been removed and the head gasket replaced.

The cylinder head studs should be torqued cold in the order set out in the wksp manual. The studs/nuts should not be lubricated otherwise the torque applied to the stud will be excessive and may snap the stud/strip the nut.