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MG MGF Technical - Adjusting Timing

Can the timing on a 1.8MPi be adjusted using a strobe lamp and moving the angle of the distributor or is the timing completely controlled by the MEMS unit and unable to be altered without a testbook etc?
Bob Millar

Timing is done by the MEMS, the distributor only distributes the sparks. I'm not sure the MEMS can be told to change the timing, for that you need a Emerald ECU (~£400).

Why do you want to change the timing?
Will Munns

Didnt want to but was just curious. Last car I owned had a distributor-less ignition which you couldnt alter but wondered if it could be done on the F as it had a dizzy
Bob Millar

If you look under the cap you'll find it only has a rotor arm in there, clamped to the end of the camshaft.

So no weights or points, or any of those nastys to catch you out!

It is progress, honsetly ;-)
Will Munns

And it is impossible to turn the distributor anyway: securely bolted at four points to the cylinder head!!! ;o)

As Will says, ignition timing purely controlled by MEMS. ICON and similar interceptor chips work by altering timing, and here the gains are modest 2-3 bhp... with less of a safety margin for poor fuels.

I sense that the Dark-side is strong in you master Bob ;o)
Rob Bell

Q. What about the addition of Vernier pulleys to standard cams..... would these be of any benefit....?

Discuss....
tim woolcott

>securely bolted at four points to the cylinder head!!!
two ;-)

>What about the addition of Vernier pulleys to standard cams.....

This would alter the cam timing, not the 'timing', again a very few BHP might be gained, but the system would have to be set up on a RR, money would be better spend on hot cams.
Will Munns

I was wondering about the timing beacuse I'm now using Optimax and could I advance the timing slightly to take advantage of the higher RON???

> I sense that the Dark-side is strong in you master Bob ;o)

Very true. Crying out for more power! Exhaust is definitely next on the list. waiting to hear feedback on the SELOC forum about the Larini systems I mentioned on here last week. £210 for a SS sports exhaust is unbelievable but I'll wait to hear what the elise guy thinks first
Bob Millar

Now Tim, only YOU would bring that topic up ;o) LOL Answer summarised as "modest gains, but at what cost?" ;o)

Okay, two bolts Will ;o) LOL

>>I was wondering about the timing beacuse I'm now using Optimax and could I advance the timing slightly to take advantage of the higher RON???<<

You could certainly do this: you'd need an interceptor chip to do it sucessfully, and ideally a session on a RR to get the timing set up correctly. And then you'd need to keep to that fuel (problem if availability becomes scarce?) You could certainly gain power by pursuing this route - but it's a high hastle option IMO.

>> waiting to hear feedback on the SELOC forum about the Larini systems I mentioned on here last week. <<

Looking forward to that too Bob: the twin bean-can silencer arrangement looks awsome. But I suspect that the Elise system is different to the one sold for the MGF; there is at least 100 quid difference in the asking price :o(
Rob Bell

Will

"This would alter the cam timing, not the 'timing', again a very few BHP might be gained, but the system would have to be set up on a RR, money would be better spend on hot cams."

But with hotter cams you will need the verniers anyway so money not necessarily wasted if this is the ultimately desired route. Would the verniers really have to be set up on the RR. If the verniers are correctly installed a little bit of extra duration can be added with a little bit of knowledge of the cams (ie not me)
tim woolcott

I think the bean can silencer arrangement is not CAT friendly :o(
tim woolcott

verniers are not 'required' for changing the cams.

The duration would not be effected by verniers, duration is the amount of time that the cams hold the valves open for, verniers simply move the open/close points forwards/backwards by a small amount.
You would probebly have to set them up on a rolling road because the diffrence they would make would be dependant on gas flow characteristics, and you are unlightly to feel the diffrence on the road.
Will Munns

Although verniers are not required when fitting cams is is advisable, I believe that the grind on the cams does not necessarily align with the original cams and sticking the original pulleys back on will result in a very lumpy idle rather like that if the Elise 160.

Sorry got the definition incorrect didn't mean 'duration' but timing.

I know this is a little different but when I first had my new cams fitted the verniers were not exactly timed correctly, it car drove like a bat out of hell, or at least that is what it felt like with a sudden rush of umph at 4K. Once timed correctly the car idles like a dream and power is delivered far smoother. With a new ECU the exhaust valve could be timed more agressively with some benefit to the resultant curves. When all said and done the standard cams probably wouldn't benefit from the verniers but it provokes some interesting thoughts though..... :o)
tim woolcott

Will is right Tim - duration isn't altered by a vernier - the only way to achieve that is by having a different grind on the cam. What you could do is alter the timing overlap between inlet and exhaust cams, which, as we know from your experience, can alter where peak power comes in, and how hard it comes in ;o)

But refer to earlier answer: "modest gain, but at what cost?" ;o) ;o)
Rob Bell

m...u...s...t... ... t...y...p...e... ... f...a...s...t...e...r...
Rob Bell

A long duration cam with lots of overlap will lead to a powerful engine at high RPM (on cam) and a lumpy idle (off cam), altering the vernier will alow you to adjust the overlap and trade some torque for some BHP. This is what the VVC does dynamicly, and why you really want a rolling road to work out exactly what you were playing at.
You could probebly incresse the peak BHP, at the cost of mid range torque and smooth idle using verniers and the standard cams, but it would be difficult to tell if you were robbing peter to pay paul, or if you were just robbing peter to incresse the differenial.
Will Munns

This thread was discussed between 03/11/2003 and 04/11/2003

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