First Time Engine Rebuild

[bmcecosse]

How can the thermo gasket slip out of place? It's held by the 3 studs.....and cork is much better, although cornflake packet is fine too. Run a drill bit down the 3 thermo cover holes to clean/open up the holes v slightly - and grease the 3 studs before fitting. And NEVER any nasty sealant anywhere on the engine - why would you?? You seem to be drawn to it like a moth to a candle ! The sump corks should be 1/4" above the face - why on earth did you trim them ?? I doubt 1/8" will compress the cork sufficiently. And as mentioned earlier - I too have never had any leaks from the cork sump gaskets when oil soaked and fitted correctly..... Don't slavishly follow the Manual - it was written 50 + years ago!!

[edd_barker]

So the workshop Manual is out by 1/8th of an inch for a key measurement? I can't believe that!

I don't think they were 1/4 proud before I cut them, trimmed maybe 1mm off max.

Will have to wait and see.

Thermostat gasket squeezed out rather than slipped, from memory I may have used Hylomar, and probably over tightened it. Live and learn! No sealants used so far on this build.

[philthehill]

The cork thermostat gasket is not that robust even though held with the three studs and can be deformed/squashed out of line between the head and thermostat housing whether it has been greased or not.
The later paper gasket is the better gasket and has better structural integratory and I would never use a cork gasket unless absolutely forced to do so.
As regards the distance that the corks seals should stand proud above the sump - the correct distance of the cork is 1/8" or 3.2mm. 1/4" is too much and may get trapped between sump flange and block flange as per the diagram AA27 in BMC wksp man sect AA34.
Whilst the BMC workshop is there for guidance - if there is a measurement provided it should be adhered to. The only deviation as regards a standard engine that springs to mind is the increasing of the exhaust valve gaps to 15 thou instead of the 12 thou stated in the manual to compensate for unleaded fuel.
Phil

[bmcecosse]

Depends how hard you press the oiled cork into the sump flange - as to how much is left proud. I would have expected them (at that price) to be the correct length. Never had any bother with thermo cork gasket - maybe now they are not really 'cork' and perhaps thinner than before.......

[Declan_Burns]

I also made new timing marks.
Regards
Declan[frame][/frame]
Starting to look good[frame][/frame]

[Fingolfin]

Declan, like everything you do, that's a beautiful arrangement. Looks like it's original equipment. And what a gorgeous engine!

[philthehill]

Just right for use with a strobe light to check the ignition timing setting/advance.
Phil

[bmcecosse]

Indeed - but check it to what though - that's the question ! Every engine will have different needs..... and without a Dyno or a Rolling Road....

[philthehill]

The timing should be initially set as per the manufactures specification to give a datum point.
The timing can then be adjusted to suit the engine after one or more road runs.
Just adjusting the distributer to get the best road running can hide/mask the fact that the mechanical advance or vacuum advance is not working to best advantage.
The strobe light is essential if you want to get the best out of your distributer in that it shows the ignition advance at any specific revs and which can be compared against the manufactures specification for the distributer.
The data regarding ignition advance at specific revs is also set out in the BMC wksp manual for the specific engine/distributer used.
Whilst I agree that fuels have changed and the timing needs of the engine may be different - but if the basics are not able to be attained there is little point in trying to tune an engine to attain the maximum power/fuel economy.
I will not ditch my adjustable/variable strobe light just yet as it tells me exactly what my distributer is doing through a range of revs as regards advance and there is no other way of telling if the advance is doing what it should.
I have used engine analysers sufficiently to understand the benefits of having a means of checking that the advance curve is as it should be.
Phil

[oliver90owner]

Philthehill,

What a very good response! I, too? think along the same lines as you. Getting a base line can often lead to the owner recognising a developing or newly apparent fault, or slight loss in performance. It is easy to sort out the wheat from the chaff among the responses and yours is spot on.

Timing marks were put there by the manufacturer for good reason and not only for the advanced diagnostics of the day. Even though these engines are relatively long in the toot, it still requires an open mind to consider all the possible causes and not just present a tunnel vision type of response. A timing light was a superb diagnostic tool in its day and the most accurate way of resetting the timing, after ccontact breaker points adjustment and/or replacement.

On another note, the head needs torquing down a little better! it looks, to me, just like an original engine would. A credit to the builder for original external appearance.

RAB

[amgrave]

I have ditched my strobe now as I find all older engines timing is retarded compared to manufacturers setting with today's fuel. I set the timing by turning the engine by hand till TDC on number one then back a bit between 5 to 10 deg's before. I then start the engine and turn the distributor slowly each way till the engine tells me it is happy (warm engine of course). In the past when I have checked the timing with a strobe after doing it my way (I know a song about that) I find the timing is about 3 to 4 deg's retarded to the manufacturers spec. My 1300cc Escort engine's timing was supposed to be 10 deg's before but it ran better and for years when set to 6 deg's before.

[oliver90owner]

I would quite agree that modern day fuels require different settings than original spec for these engines, far back in the last century.

But, nevertheless, any new setting can be easily read off using the strobe. This new setting is then the base line for later ignition adjustments. Setting it to that same point, if removing/altering the contact breaker points is so easy .

Any change from that best running position can be noted, to indicate further checks/regular maintenance may be required to ensure the timing (@ whatever RPMs the readings might be compared). If slow speed is correct, but no or an unexpected change at higher RPMs, or on deceleration, might indicate automatic advance problems without further ado. Far easier to alter the timing by the odd degree or two prior to road testing, as well. I wonder how one would do it otherwise? Rely on a lamp across the points?

So, a simple and easy diagnostic tool. Not to be underestimated, or ditched, as there are no simple alternatives, such as plugging in a computer, for most home maintence or tuning. Just as useful as a vacuum guage for balancing multiple carburetors, I daresay.

RAB

[liammonty]

Totally agree! I'm not chucking mine out any time soon!

[philthehill]

I have ditched my strobe now as I find all older engines timing is retarded compared to manufacturers setting with today's fuel. I set the timing by turning the engine by hand till TDC on number one then back a bit between 5 to 10 deg's before. I then start the engine and turn the distributor slowly each way till the engine tells me it is happy (warm engine of course). In the past when I have checked the timing with a strobe after doing it my way (I know a song about that) I find the timing is about 3 to 4 deg's retarded to the manufacturers spec. My 1300cc Escort engine's timing was supposed to be 10 deg's before but it ran better and for years when set to 6 deg's before.

I agree in setting the ignition timing as you describe above - but how do you now know that the auto advance is doing what it should be doing against the distributer manufactures advance specification?
i.e. that if you set the ignition to 6 degrees static and the auto advance gives an extra 20 degrees - giving a total of 26 degrees
Do you get 26 degrees at the specified revs or more or less. The more or less has a bearing on the performance of the engine.
Phil

[bmcecosse]

I'm interested to know what settings you use! What vacuum advance do you use (there are various) and is it connected before or after the throttle plate, and what mechanical advance do you use - again there are numerous different ones, not to mention the different springs...... There's no doubt a good 'mapped' system would be nice - but sadly my lack of electronic nouse stopped me ever getting round to it. The Mini lads speak well of the Megajolt system, especially for low down torque improvement. Most advance systems 'give up' at 3000/4000 revs anyway.

[bmcecosse]

If you have the markings - then the strobe will certainly confirm that 26 degrees - but how to determine that '26 degrees' is the ideal setting at that particular engine operating point is the tricky part - without a rolling road.... it certainly won't be anything derived from the original manufacturer's settings!

[amgrave]

That's true Phil and is relevant to an engine within manufacturers specifications but it might be beyond most home mechanics on here. If the engine has a bit of wear in it and changed components then the manufacturers spec re curve no longer applies and the modern fuel has an effect on it too. I listen to the engine and it tells me if it is happy or not and the feedback from normal running too like lack of power, noises and smoothness. She soon lets me know if she's not happy

[philthehill]

Amgrave
My comments relate to a standard engine - yes the ignition timing can be adjusted to take account of replaced components, modern fuel and wear but you still cannot get away from the fact that a strobe is the only way that you can check that the ignition advance is working any where near what it should.
If you want the best out of an engine you need to maximise everything not just by it feels right.

bmc
My ignition settings have no bearing to the discussion.
But for clarification my 1380cc fully prepared competition engine has electronic ignition, no vacuum advance and the settings and ignition advance curve are set to suit the build of the engine and which were determined from extensive engine dyno testing.
The strobe is used to ensure that the ignition advance follows the build advance curve at all times and does not drop off.
As regards a standard engine my views on the use and results of using a strobe are clearly set out above.
Phil

[BLOWNMM]

When I got my car home from the dyno tuning session I decided to record the ignition timing for future reference. The timing light I used was an 'advanced' timing unit where it can show TDC pulley mark and TDC reference marks. When the advance facility is used to coincide the TDC pulley mark with TDC reference mark the advance is displayed in degrees on the display panel. This display is in units of 0.5 deg. In the case where I need to do something to the motor which changes this reference it is easy to use the timing light to revert to the original setting without having to go through the tedious proceedure of 'best idle' then 'pinking test' when driven especially with high frequency hearing loss. I would never consider using my car with a blown pressure of 15.2 PSI without knowing that my timing was right for fear of melting pistons or burning out valves.
https://www.amazon.com/INNOVA-5568-Pro- ... B000EVU8J8

The above is a copied and pasted post by me in the thread 'Midget engine rebore'. The use of a timing light can apply to any motor to accurately reset the timing if disturbed for any reason. In the case of my motor I can use the advance facility on the light till the TDC mark on the timing case is coincident with that on the crank pulley. Then I can increase the motor RPM and observe that the distributor advance mechanism is operating correctly. This can apply to any motor modified or not. If there are no TDC marks on the motor or pulley then paint them on or do as Declan has done.
Bob

[RobThomas]

Shame the sidevalve has such a ridiculous position for the timing marks. You need eyeballs on a flexible 18 inch stalk. I like the Ford idea of a drilling in the cover and cam pulley that line up when you get to TDC and can then stick a pin in there to keep it in place.
There must have been some slop in the crank pulley on mine and they cut a new Woodruft key slot. The TDC mark is miles from TDC. On a scale of 1 to 10, that is an 11 on the annoying scale.

On the SV engine the data suggests 18 degrees of baseplate (36 of crank) advance at max and then tinkering. Bob, do you have any view on the validity of this setting? 36 sounds on a non-boosted engine a lot to someone who used to build aero engines with a max of 24 degrees. OHV conversion.