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MG Midget and Sprite Technical - engine rotation

Chaps: I'm far too old to worry about asking a dumb question so here goes: when viewed from the front does the crankshaft rotate clockwise or counterclockwise?
Thanks!
David Cox

Clockwise, David.
The same for just about every vehicle engine, though there are exceptions. The Honda S2000 being one that goes the other way round.
It is possible to get some engines to run backwards which is quite fun!
GuyW

Thanks, Guy...just trying to get my head around how timing lights work...
David Cox

the nice thing about Snap-On timing lights is that you can set the required advance into the unit, then run the engine and adjust until the marks line up on zero with the flash.
davidsmith

yes...but I am just getting to grips with how they work. The "flash" is triggered by the 'bolt of volts' in the HT lead, at which point the crank is at 22 deg BTDC at 1200 rpm [don't have the data to hand but that sounds right...] at which point the mark on the balancer and timing chain cover will not be in sync..so presumably the timing light has a delay built in so the light flashes when the two marks align. So the 'degrees' scale is really a 'millisecond' scale...am I right??
David Cox

David, you are partly right. The timing light picks up the voltage in #1 wire and flashes the light. To correctly set the timing, you need to watch the timing marks as you adjust the distributor to advance or retard the timing until the marks match up. Tighten the distributor and recheck.

Putting some white paint in the harmonic balancer and the fixed pointer makes it easier to see the marks at times.

A timing light won't change the engine's ignition timing, the distributor controls that. Mind you, the chain must have minimal stretch, crank and cam gears have to be set correctly to begin with before anything will work properly.

Clare
Clare Ravenwood

it's a variable scale David - yes it effectively converts degrees to time, but the correction also depends on the rpm at that moment.
I've never thought about how they work before, it falls into the 'have a little faith baby' category for me!
davidsmith

or have no faith
I don't like them at all
If you try two or three of them at least one will have a different reading
I don't trust them at all --sorry said that already
willy
William Revit

Thanks for your comments...I never thought about how they work either..but then retirement comes along, you get older, nothing in the modern world seems to make sense any more so this is what happens!
Willy...you might be right. Casting the runes is as good a way as any in deciding on a course of action!
David Cox

The Honda S2000 does NOT rotate the wrong way. The early Honda FWD engines did but eventually they conformed and made their engines rotate the conventional way. They turned the Engine/Gearbox through 180 degrees to make sure the car had 4/5 forward gears rather than 4/5 reverse gears.

Rob
MG Moneypit

A longtime hotroder mate bought a pair of 350 Chevs out of a boat to build a pair of identical rods, one for a customer and one for himself
He built the first one and delivered it-all good
Then he hooked into his own--beautiful job, got it driveable for a shakedown run before fitting the body
Started first go and idled like a ripper, went to reverse out the shed and it went forwards
Tried 1st gear-backwards
It turned out that this half of the pair of engines had been modified to run the other way for the boat
Luckily it was a simple fix by replacing the camshaft ,camshaft drive and the starter motor--but it was a surprise at first
willy
William Revit

Willy,
I think it may be common practice in marine circles to have the engines spinning in both directions. This it seems, is to make the propellers turn in opposite directions to ensure the boat drives in a straight line.
I understood pre-2000 Honda engines spun anti clockwise?
The Chevrolet Corvair had a flat six which spun anti clockwise.
Jeremy T2

The F series Honda engines ran anticlockwise (prelude) and l thought that carried over into the S2000, but apparently not.
GuyW

Engines running backward brings back old memories.
I operated a marina and a customer brought me his 28'boat with a 429Ford I/O.
He wanted a valve job. As I was completely overloaded he decided to take it to a local auto service business. They removed the cylinder heads and found that both were severely cracked and not repairable. After pricing new heads he decided that a replacement engine was more practical. New engine installed and the starter would not work as it turned the wrong way. Local starter builder rebuilt it to turn the correct way. New motor was run on land with local hose supplying coolant.
Mechanic took customer and boat to a local ramp for a water test. Boat started and put in gear for test but boat went backwards piling into a seawall breaking the outdrive.
Original motor was a reverse turning unit.
Net result was a new out drive and the camshaft from the original motor installed in new motor.
Then the starter had to be rewired again to run in reverse.
Auto service dealer had to eat all the extra costs all due to not knowing original engine was turning the wrong way.
Thankfully I was glad that I did not get that fiasco.
Sandy
Sandy Saunders

David

I think a strobe/timing light set to whatever the manual says ref advance is fine for a ball park setting. However - and there is always a however in engineering - the issue is more to do with determining what the optimal advance actually is for your particular engine. Personally, I think there are too many variables to permanently abide by a manufacturer's recommendation - hence the word recommendation I guess.

My engine is modified somewhat, so I suppose the variation is greater. I have found that largely through trial and error, and subsequently rotating the dizzy slightly ACW or CW, I can refine it to return a more acceptable level of performance/economy. As others hint though, do ensure everything else - valve clearances, carb set up, rotor arm etc. is as it should be before fiddling with timing.

Naturally, and before the likes of Mr Burgess jumps in, the ideal solution would be a visit to your local tuner.
Mark Ogden

The likes of Mr Burgess maybe, including where appropriate me, but I can't ever remember seeing Mr Burgess himself jump in just to promote visiting a local tuner (nor himself). I've often seen where he's offered free advice though.

If a visit is needed to a tuner for a Spridget, B or similarly engined vehicle then I'd strongly recommend Peter Burgess.

Whoops, did I jump in there, well at least it proved the prediction, I'm here to please. :)
Nigel Atkins

I have visited Peter B in the past and can only say good things.
David Cox

I too would have no hesitation in visiting Mr B. - trouble is, I reside a lang lang way way away - further North than the vast majority of Scots even...
Mark Ogden

Another vote for Peter Burgess; we'll be having to start a Peter B Appreciation Society if it carries on like this.
Jeremy T2

"I too would have no hesitation in visiting Mr B. - trouble is, I reside a lang lang way way away - further North than the vast majority of Scots even... "

I don't know whereabouts you live, but my home (not far from Glasgow) to Alfreton is 281 miles, yet I have been to Peter's workshop for tuning twice, once with an 1800 MGB, once with my V8. I have combined the visit with a trip to the south, usually to attend MGCC at Silverstone.
Mike Howlett

Mark

It seems you have moved to Avon!
Dave O'Neill 2

Yes, BBS is determined to keep me in England! and I reside a further 2.5 hrs North of Glasgow. Not really practical - besides which there is a decent A series tuner up here in the Tundra I could call upon.
Mark Ogden

This thread was discussed between 01/03/2017 and 04/03/2017

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