Smoking

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oliver90owner
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Re: Smoking

Post by oliver90owner »

kevin s wrote: Sat Jul 09, 2022 8:15 am This is the breather set up, as far as I can see threre is nowhere on the carb to put it, the rocker cover cap has a breather hole in it.rps20220709_081329.jpg
If this breather hole is open, this crank case pressure waffle seems fairly un-connected to this smoking. Is the rocker cover vented to atmosphere? If so, there is not going to be much pressure in there.
kevin s
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Re: Smoking

Post by kevin s »

It has a vent hole in the cap and there is no evidence of any lack of breathing ( it doesn't even leak any !)

My working theory (based on looking at the pictures I took) is the base of the valve cap is hitting the top of the stem seal and pumping oil past it, simple solution might beto go back to the minor shrouds (it didn't do this on the original engine), another thought is if ford kent seals will fit as they are thinner.

We are on holiday at the moment and will take a closer look when we get back (first thing is to fix the fueling issue though which I think might be the filter king regulator)
kevin s
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Re: Smoking

Post by kevin s »

Didn't get a chance to look at the valves but seem to have sorted the rough running, no oil in the carb dashpot, dropped some 5w 20 engine oil in (all we had to hand) and it drives fine again, carb does look past it's best though, piston seems quite loose in the bore, more so than I have seen on an SU before. A bit more impetous to get the rwin carbs rebuilt and fitted.
kevin s
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Re: Smoking

Post by kevin s »

Finaly got round to looking at it today, Andrew said it had developed an oil leak, that was simple the rocker cover gasket was leaking, Andrew hadn't tightened up the bolts enough.

Then we looked at the valves again, this is one valve at full lift.
rps20220823_153216.jpg
rps20220823_153216.jpg (85.93 KiB) Viewed 1089 times
Measuring the height and comparing it to a valve cap resting on a spare head says there is very little clearance between the two, and looking closely the tops of the stem seals are begining to get mashed, meaning the valve caps are acting like a piston and pushing oil down the stem. So I think I have 2 options

1 take the seals out altogether.

2 fit Ford kent seals which are thinner and are the umbrella type which seal against and move with the stem and act like an umbrela.

Need to make a tool up to get the caps off first though.
philthehill
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Re: Smoking

Post by philthehill »

Have you fitted the right valve guides?
Have you fitted them the right height above the machined spring seat?
I note that you state that you have fitted the 'A' Plus valve guides.
The valve guide height for a Minor head should be 19/32" (15.25mm) above the machined spring seat.
The valve guide height for a 940 head with top hat seal is 13.72mm above the machined spring seat. (with care that could be taken down to 13mm.)
A difference of approx 2mm.
The Minor head valve guide and 940 head valve guide are of different lengths. Care should be taken that the right length valve guide is fitted.
I would suggest that you have fitted the wrong valve guides and additionally incorrectly set the height above the machined spring seat.
I would also suggest that you remove the head, replace the inlet valve guides with the ESM shorter valve guides with top hat seal retaining groove and set the height of the guide above the machined spring seat to 13.72mm.
https://www.morrisminorspares.com/engin ... l-p1209547
Top hat seals should not be fitted to the exhaust valve guides.

kevin s
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Re: Smoking

Post by kevin s »

The guides were fitted to the standard minor height (the 4 exhaust ones were done professionally when they fitted the hardened seats, I machined a tool to do the inlets to the same height as the originals and the 4 already fitted) they didn't protrude far into the enlarged port so I would suggest they are the right length (they were the ones for a minor from ESM), the second head I measured is a std minor with the non grooved guides, they were around 15mm as you say, with the minor spring cap resting on top there is only a mm or so clearance with the valve lift we have

What I didn't realise was the grooved guides sit 2mm lower than the std minor ones, it looks like they need to be 2mm lower if we use the A+ seals then, Initially I will try one of the solutions above but as you say it looks like long term we need to remove the head and knock the guides down a couple of mm.

I also compared the spring caps, the A+ ones look a little thinner, so another possibility to gain a little clearance may be to machine a mm or so off the bottom of the cap, I'd just need to check how deeply the collets sit.
oliver90owner
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Re: Smoking

Post by oliver90owner »

I also compared the spring caps, the A+ ones look a little thinner, so another possibility to gain a little clearance may be to machine a mm or so off the bottom of the cap, I'd just need to check how deeply the collets sit.

I would be very careful with machining off ‘a mm or so’. High lift cam, compressing valve springs more than design?…
philthehill
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Re: Smoking

Post by philthehill »

Kevin s
Many thanks for the updates posted above.
The collet sits quite deep into the valve spring cap and having just measured a cap with collets fitted the max that can be taken off the bottom of the cap is 1mm max.
Whilst there are slight differences between the valve spring caps the main consideration is the depth of the bottom central boss of the cap because that is what will foul the top hat seal.
Personally I would not wait but remove the head and do the valve guides because if the top hat seal disintegrates due to contact with the valve spring cap and the seal particles get into the oil ways it could restrict or not allow oil to get to a critical bearing. Better to be safe than sorry.

kevin s
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Re: Smoking

Post by kevin s »

I think we'll just take the seals out for now to avoid the risk of debris getting anywhere then when we change the inlet and exhaust manifold lift the head press the guides down another 2 or 3 mm and die grind them flush in the ports.
philthehill
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Re: Smoking

Post by philthehill »

Sounds like plan to me but I am interested to learn how you are going to remove the inlet valve spring caps without removing the head??
Possibly fill the combustion chamber with rope??
No doubt you are aware that the majority of top hat seals are kept in place by a spring, it does not just hang in there.
https://www.morrisminorspares.com/engin ... pe-p830169

kevin s
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Re: Smoking

Post by kevin s »

I used to do it on Fords using a dummy rocker shaft with the rockers removed (I have a couple of old ones kicking around) and forked lever hooked around it, I was planning something similar, for the valves either rope as you say or compressed air through the plug hole if I can find the fitting I used to use.
kevin s
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Re: Smoking

Post by kevin s »

Here's how I will pop the valve caps off in situ,

One simple tool.
rps20220826_191233.jpg
rps20220826_191233.jpg (61.12 KiB) Viewed 954 times
On the A+ it fits under the rocker.
rps20220826_191321.jpg
rps20220826_191321.jpg (68.3 KiB) Viewed 954 times
I think for the pressed ones in the car i will need to slide the rocker sideways like this.
rps20220826_191814.jpg
rps20220826_191814.jpg (73.6 KiB) Viewed 954 times
So the process will be:

-Rocker cover off
-Undo the adjusters.
-Hold the valves up with rope or compressed air
-press down on the far end of the bar
-pick the collets out
-release the bar
-lift spring and cap off
-pull the seal off
-reverse to put it back together

Hopefully should only take a few minutes to get the 4 seals out.
philthehill
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Re: Smoking

Post by philthehill »

Kevin
Many thanks for the above information and photos.
I may well have a go and make a similar tool.
Phil

StillGotMy1stCar
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Re: Smoking

Post by StillGotMy1stCar »

Ditto :)
Thanks kevin, I’ve saved your images in my Moggy folder for future reference.
I will also be making a similar tool.

Regards John.
kevin s
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Re: Smoking

Post by kevin s »

Finaly got round to fixing this today.

To recap, when I fitted thd valve guides I fitted the A+ones which carry a seal but didn't realise they need to sit 2.5mm lower than minor ones, this has meant with the higher lift cams the seals have been hitting the spring cap and pumping oil down them.

So using my home made tool and a length of soft rope I popped the springs off.
rps20221103_191853.jpg
rps20221103_191853.jpg (73.18 KiB) Viewed 822 times
Using an old guide, and a piece of tube that was a good fit over it and 13mm longer I knocked the guides down 2.5mm, then popped a new seal on.
rps20221103_191541.jpg
rps20221103_191541.jpg (78 KiB) Viewed 822 times
Put it all back together and in 40 minutes all 4 were done.

Didn't seem to smoke but needs to go on a longer run to be sure, my son has gone out in it tonight so I'll find out later.

This is the old and new seal, the old one has opened up noticebly, it was loose on the valve stem.
rps20221103_191643.jpg
rps20221103_191643.jpg (77.98 KiB) Viewed 822 times
philthehill
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Re: Smoking

Post by philthehill »

The moral of this story is to use the correct valve guides and associated seals relative to the head.

kevin s
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Re: Smoking

Post by kevin s »

It's always what happens when you start modifying / improving things, yes it would have not been an issue if we had used all std minor parts but then we probably would have had a bit of smoke at idle and higher oil consumption, the combination of the longer guides and higher lift cam were the root cause plus my lack of familiarity with this specific family of engines. At the end of the day you live and learn, the next one will be an 1275 A+ maestro engine.

My background in engines has been Ford lotus twincam and rover V8's what has amazed me with the A series is how much even at the detail level they kept changing, on the Ford engines in particular many of the parts are interchangeable from the first pre crossflow to the last engines in the 80's.
philthehill
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Re: Smoking

Post by philthehill »

Many of the 'A' Series (803cc, 949cc. 1098cc & 1275cc) engine parts are interchangeable and even some of the parts from the 'B' series engine can be fitted to the 'A' Series.
You do not have to use standard ex-factory Minor parts all of the time, you can use and incorporate later improved parts when rebuilding the 'A' Series. Considered selection of those later/nonstandard parts is the imperative.
Below is a Maestro 1275cc 'A' Plus engine fitted to a Minor
Maestro engine 2.JPG
Maestro engine 2.JPG (1.37 MiB) Viewed 771 times
Not an easy job these days as the fitting kits from Southam Mini Centre are no longer available. There are quite a few posts (using the search facility) on here on how to do fit the Maestro engine to a Minor.
Good luck.
Phil

kevin s
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Re: Smoking

Post by kevin s »

Yes we have a cunning plan involving an mx5 gearbox, hopefully we will get back on with it this winter, really need a 3d scan of the back of an A series engine too if any one has one.
philthehill
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Re: Smoking

Post by philthehill »

For general consumption: -
The back of an 'A' Series engine will not really help as the Maestro engine has an additional housing on the back of the block which contains the lip seal which rubs on an extended flywheel mounting flange. That housing has to be retained but modified.
Below is the Maestro seal mounting housing: -
Maestro rear engine seal plate.jpg
Maestro rear engine seal plate.jpg (414.94 KiB) Viewed 738 times
The rear of the Maestro engine block is slightly different to the 1275cc in line block.
I would suggest that a 1275cc in line rear engine plate is your best guide.
Note the modified seal housing between the Maestro block and the gearbox bellhousing in the photo below: -
Maestro engine 1.JPG
Maestro engine 1.JPG (1.32 MiB) Viewed 736 times
This pushes the engine forward so the engine mount towers have to be reversed/swopped from side to side.
I see that you have already given some though to this conversion in thread
viewtopic.php?p=677528&hilit=maestro+engine+fit#p677528

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