30 replies to this topic

[Dave33]

providing you can here the detonation noise this is fine,but if you got a stripped down car without a standard airbox and exhaust then you may have trouble hearing this which will eventually damage something,so use the plug reading method to get a general idea of whats happening.theres a link on here somewhere for this.
With regards to the timing,advancing or retarding will have an effect on the power curve,max advance will make the engine responsive and snappy where as retarding the timing from here will give less response but more revs before dropping off power,known as overrev,so you can hang on to a gear between corners without having to shut off or shift up.
Regarding the cam timing,if someones spent money buying a performance cam,obviously they want it to work as it should.If its not set to whats recommended by the cam manufacture,you will be losing the performance you paid for.
An engine can perform OK with it being out,but this is only a perception that its running fine.
Without setting it properly you will never know how its supposed to perform.
Its a pain,yes,but its a waste of money if you just leave it.
dave

Edited by Dave33, 24 June 2010 - 11:17 AM.

[Cater_Racer]

Thanks everyone, again I'm endebted to you all.

It was 16 btdc at 1200 rpm, I found out why................................

The diaphram on the dizzy was pressed against the oil pressure sender, you couldn't retard it any further!!!!

I removed some of the sender head with a dremel, and now I can get it to 8 btdc pressed hard over, but using the info given I've ended up with around 12 btdc @ 1200rpm.

It seems a little smoother and response is still good. As Dave33 says, it maybe will help with trail braking into apexes, less shut-off.

I'll give some road miles over the next few weeks, I've got some time before the next event.

Cheers

Cater

[bsirrell]

i am gonna put a timing light on mine tomoorow, but today looking at the alignment marks i only have 5 peaks they are all the same size, (cater described them as on big and 4 smaller ones)

I dont want to assume, but is 0 at the front (closest to the front grill)

and then its 4, 8 deg etc ans it moves back in to the engine?

[01smartc]

No the other way round - 0 is at the top then 4, 8 etc going down

[bsirrell]

No the other way round - 0 is at the top then 4, 8 etc going down

ta

[Pigeonto]

The diaphram on the dizzy was pressed against the oil pressure sender, you couldn't retard it any further!!!!


I believe you may have spent time unneccessarily. If you take the dizzy out and turn it back a tooth then it will be in a position where its clear of obstructions.If you need more movement maybe invstigate that . DONT FOR GODS SAKE drop the dizzy drive into engine

[zef]

When I try time my girlfriends mini (998 mayfair, stage 1 kit) with the vac pipe off it's fine and drives great but if I connect the pipe up after setting the timing the revs increase and the timing advances 20 odd degrees. Any ideas as to why?

[lrostoke]

because the vacuum advances the timing thats its purpose.
Just lower the tickover with the adjusting screw.

[samsfern]

Don't waste 'time' - timing in that cam - it will be fine at dot to dot. But with that engine spec - you probably need to modify the dizzy advance curve - read Vizard. Meantime - just advance till it pinks then back off slightly. And do check the vacuum advance is working as it should.......

id hate to have an engine built and setup by you, sorry.

I build and setup aseries engines quite often for all sorts of purposes, and would never set a non-standard cam up
dot to dot, my dti gauge comes out when im setting up cams, nor would i "just" advance the timing till it pinks then back it off slightly, ive seen what damge can happen if an engine isnt setup correctly.

Edited by samsernie, 02 July 2010 - 10:33 PM.

[zef]

because the vacuum advances the timing thats its purpose.
Just lower the tickover with the adjusting screw.

Ah but the thing is the screw backed right off. Not had this happen before usually the timing doesn't alter that much at tick over.

[Ethel]

It should be stamped on the vac advance can how many degrees advance it gives- it would give around 20 odd degrees when added to centrifugal advance. If the idle can't be reduced look for air leaks - engine breather, throttle bearings etc.

[Dave33]

Don't waste 'time' - timing in that cam - it will be fine at dot to dot. But with that engine spec - you probably need to modify the dizzy advance curve - read Vizard. Meantime - just advance till it pinks then back off slightly. And do check the vacuum advance is working as it should.......

id hate to have an engine built and setup by you, sorry.

I build and setup aseries engines quite often for all sorts of purposes, and would never set a non-standard cam up
dot to dot, my dti gauge comes out when im setting up cams, nor would i "just" advance the timing till it pinks then back it off slightly, ive seen what damge can happen if an engine isnt setup correctly.

My thoughts entirely,
Theres a mention of 'vizards book' regarding the advance curve,but no mention of him expalining how important it is to time the cam in accurately?
Dont recall The wizard saying 'advance til detonates then back off' either....
This is bad advice, if someone with little knowledge of mechanical requirements goes ahead and does this they could easily end up with a wrecked engine.
dave

[Shifty]

I use the advance till pink and then retard method, and have done for years.

I really don't consider this to be bad advise, its an accepted technique for setting the timing. Yes it require some experience or common sense, most jobs do. If anyones unsure of their abillity to carry out such an adjustment then they should seek expert advice.

[Cater_Racer]

When I try time my girlfriends mini (998 mayfair, stage 1 kit) with the vac pipe off it's fine and drives great but if I connect the pipe up after setting the timing the revs increase and the timing advances 20 odd degrees. Any ideas as to why?

Blocked air filter.

[zef]

When I try time my girlfriends mini (998 mayfair, stage 1 kit) with the vac pipe off it's fine and drives great but if I connect the pipe up after setting the timing the revs increase and the timing advances 20 odd degrees. Any ideas as to why?

Blocked air filter.

I changed the airfilter for the one of my Elf which ran great. I'm leaning towards a worn vacuum advance unit. I'll change the distributor for the one off my spare engine and try it again.