Ive been playing around with my timing to get it just right.
I can get it to run really good, but then it backfires LOUD, almost like a gunshot, when i turn the engine off. A guy at work nearly shit his pants when i turned my engine off in the carpark. Big flame shoots out too.
Right now ive got it to run pretty good, but it still backfires when i turn it off, but its only small, more of a quiet 'pop'.
Its probably as good as im gonna get it.
Now the problem, when i check the timing with the gun, its all over the place. Sometimes the white line is on the complete opposite side of the pulley to the numbers..?? and other times its around the 9o'clock mark, if you imagine the pulley as a clock face.....
Is it just that my timing gun is stuffed. I use the lead closest to the front of the car.
Thanks
Mike
Really weird timing readings.
Started by
_mike_nofx_
, Jul 05 2006 04:45 PM
21 replies to this topic
#2
Litre8
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Posted 05 July 2006 - 05:25 PM
Is the balancer loose? They can end up walking around when the rubber deteriorates.
#3
_[BOTTLEDUP]_
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Posted 05 July 2006 - 10:49 PM
what ignition system are you running?
#4
_rorym_
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Posted 06 July 2006 - 08:51 AM
Mike,
I am with Howard...I bet my left one the outer ring with the timing mark on your harmonic is turning/spinning on the inner bit. Rubber breaks down and allows it to slip.
Rory
I am with Howard...I bet my left one the outer ring with the timing mark on your harmonic is turning/spinning on the inner bit. Rubber breaks down and allows it to slip.
Rory
#5
_Yella SLuR_
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Posted 06 July 2006 - 10:39 AM
Also check for play in your dizzy. Are you timing it with the vacuum advance line to the distributor removed? Remove it, and see if it stops the wanders. If so, your may need the dizzy regraphed.
Few things to try there anyway.
Few things to try there anyway.
#6
makka
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Posted 06 July 2006 - 12:31 PM
im with Howard and Rory, spun balancer
#7
_devilsadvocate_
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Posted 06 July 2006 - 12:50 PM
agree, for engine to still go with timing marks out 180deg....balancer is slipping.
How can you test for this otherwise? Off the top of my head:
Perhaps put car in gear, tighten fan belt and either using fan or screwdriver between fan bolts, attempt to rotate the engine.
Or look at central part of balancer under timing light, not sure what they look like exactly without one in front of me, even a dab of liq paper on the edge of the end of the crankshaft..... if it stays still under the timing light and the marks on the outside dont.....definitely outside and inside arent spinning together.
How can you test for this otherwise? Off the top of my head:
Perhaps put car in gear, tighten fan belt and either using fan or screwdriver between fan bolts, attempt to rotate the engine.
Or look at central part of balancer under timing light, not sure what they look like exactly without one in front of me, even a dab of liq paper on the edge of the end of the crankshaft..... if it stays still under the timing light and the marks on the outside dont.....definitely outside and inside arent spinning together.
#8
_jimjet61_
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Posted 06 July 2006 - 12:52 PM
Im going with the crowd also, with the balancer, but might want to check that the centrifugal advance moves freely and there are no broken advance springs. Also check the earth to the base plate Is it a points type Dizzy, if so may pay to check points are not pitted, seated correctly, return spring has good tension and that the condensor is not loose has good connections and has the right resistance. Finally drive gear has all its teeth and roll pin not sheared.
#9
gtrboyy
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Posted 06 July 2006 - 01:41 PM
If it has the standard balancer change it as it will only cost $20 or less for peace of mind,then you can find out if it's that or the dissy.If you rev you car hard frequently then you shouldn't have the standard balancer on it anyway as they aren't very rev friendly.
#10
_torana_
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Posted 06 July 2006 - 01:52 PM
possible spark tracking in dizzy cap maybe?
Make a mark on your harmonic balancer from the inner to the outer and see if it moves when lit up by timing light
cheers julian
Make a mark on your harmonic balancer from the inner to the outer and see if it moves when lit up by timing light
cheers julian
#11
_mike_nofx_
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Posted 06 July 2006 - 09:44 PM
Thanks heaps for the tips. It is electronic ignition, and thats about all i know. I have been checking with vacuum hose attatched. I will block it off and try.
This weekend i will re-check the timing and if the balancer is slipping.
In the mean time, how bad/unsafe/dangerous would it be to drive if it IS slipping?
I really only need to drive it tomorrow (friday) to work, then i will check it all out this weekend.
About a new balancer, where can i get one? any auto shop?
If the balancer is tight and has no probs, how do i tell if its a standard or better-than-standard one?
and the backfiring? any ideas there?
Also, a tune is on the cards for the next couple of months. Im guessing they will also do the timing.
This weekend i will re-check the timing and if the balancer is slipping.
In the mean time, how bad/unsafe/dangerous would it be to drive if it IS slipping?
I really only need to drive it tomorrow (friday) to work, then i will check it all out this weekend.
About a new balancer, where can i get one? any auto shop?
If the balancer is tight and has no probs, how do i tell if its a standard or better-than-standard one?
and the backfiring? any ideas there?
Also, a tune is on the cards for the next couple of months. Im guessing they will also do the timing.
#12
_draglc_
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Posted 06 July 2006 - 10:02 PM
A good balancer, like a ross or a powerbond is from $120 to $250+. But hey, if you can get someone that knows what theyre doing, tuning a car with a slipped balancer isnt really an issue. Its all about listening to the engine, and knowing how well its running, though theres not many people who can do that these days...
But for peace of mind, you can just go buy a new one, if your doing timing with a light, and at idle its + or - 30 degrees, its obviously the balancer.
The main concern, other than timing of course, is that it could fly forwards and through your radiator, though ive only ever seen them go backwards towards the engine.
If i were you, id just go find standard one at a wreckers, in good nick and swap it over, will do in the meantime, you can at least set the timing!
If you want to fork out later for a good one, that will handle the rpm you want to give the engine, then by all means do that!
A1
But for peace of mind, you can just go buy a new one, if your doing timing with a light, and at idle its + or - 30 degrees, its obviously the balancer.
The main concern, other than timing of course, is that it could fly forwards and through your radiator, though ive only ever seen them go backwards towards the engine.
If i were you, id just go find standard one at a wreckers, in good nick and swap it over, will do in the meantime, you can at least set the timing!
If you want to fork out later for a good one, that will handle the rpm you want to give the engine, then by all means do that!
A1
Edited by draglc, 06 July 2006 - 10:02 PM.
#14
TerrA LX
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Posted 07 July 2006 - 12:49 AM
to check the balancer paint a line accross the outer to the inner and run, you will soon see if the line is no longer lining up. if you do replace the balancer, dont forget to seal the end and you may as well replace the crank seal while you got it off.
other thing to look for is condition of distributer cap etc, can you swap with a known good dizzy to rule out cross fire.
back fire is usually caused by a lean condition.
when you get the timing right and if the problem persists check for main jet blockage on carb model or idle lean and if accompanied by run on check for high idle by either adjustment or idle solenoid, binding linkages etc.
other thing to look for is condition of distributer cap etc, can you swap with a known good dizzy to rule out cross fire.
back fire is usually caused by a lean condition.
when you get the timing right and if the problem persists check for main jet blockage on carb model or idle lean and if accompanied by run on check for high idle by either adjustment or idle solenoid, binding linkages etc.
#15
_Yella SLuR_
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Posted 07 July 2006 - 06:34 AM
Would the balancer outer not be held in place by the pulley attached to the inner ring of the balancer and the fan belt? My experience with loose balancers is they make a hell of a racket before they let go (VN Commonwhore).
I'm still thinking that the turbo is sending weird signals to the dizzy. I'm also wondering if the turbo sends stronger signal to the dizzy at idle, and therefore if stronger springs not put in the dizzy, or not regraphed, would not be getting full vacuum advance, due to parital advance at idle. Have you ever had the dizzy adjusted to suit the turbo, or have you just put in a standard normal aspirated electronic dizzy (still has vacuum advance). Just thinking out loud, could be a load of crap, but could be checked out by a place that specialises in tuning turbo cars. Those guys are pretty cluey about how these beasties work.
Can check the above by keeping the timing light on while you pull the vacuum line to the dizzy to see if any change in the mark anyways. Should give you a feel for what's going on.
Wouldn't a turbo car go lean when switched off anyway while the turbo keeps spinning while fuel is cut off?
I'm still thinking that the turbo is sending weird signals to the dizzy. I'm also wondering if the turbo sends stronger signal to the dizzy at idle, and therefore if stronger springs not put in the dizzy, or not regraphed, would not be getting full vacuum advance, due to parital advance at idle. Have you ever had the dizzy adjusted to suit the turbo, or have you just put in a standard normal aspirated electronic dizzy (still has vacuum advance). Just thinking out loud, could be a load of crap, but could be checked out by a place that specialises in tuning turbo cars. Those guys are pretty cluey about how these beasties work.
Can check the above by keeping the timing light on while you pull the vacuum line to the dizzy to see if any change in the mark anyways. Should give you a feel for what's going on.
Wouldn't a turbo car go lean when switched off anyway while the turbo keeps spinning while fuel is cut off?
Edited by Yella SLuR, 07 July 2006 - 06:37 AM.
#16
FastEHHolden
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Posted 07 July 2006 - 08:42 AM
turbo may be spinning but its not doing anything...there is vacuum in the inlet manifold...I think the bang is just from not having the timing set correctly.
Another easy way to tell if the balancer is OK ( on red 6) is that with the keyway at 12 o clock, the timing mark is at 11 o clock...if its anything else the outer ring is slipping...and I have seen them walk forward..on a VK Commodore...the rubber fell out and all that could be heard was a "ting ting" sound of the outer ring rolling and flopping around....I told the guy he shouldn't drive it and that they were cheap to replace....but he new better...and drove it until the crank snapped.
Yours should be ok to drive provided it doesn't come apart.
Another easy way to tell if the balancer is OK ( on red 6) is that with the keyway at 12 o clock, the timing mark is at 11 o clock...if its anything else the outer ring is slipping...and I have seen them walk forward..on a VK Commodore...the rubber fell out and all that could be heard was a "ting ting" sound of the outer ring rolling and flopping around....I told the guy he shouldn't drive it and that they were cheap to replace....but he new better...and drove it until the crank snapped.
Yours should be ok to drive provided it doesn't come apart.
#17
_dave720gtr_
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Posted 07 July 2006 - 01:49 PM
The back fire is a common thing with draw through turbo set ups useing SU OR CDs carbi when you switch it off the turbo draws fuel / air still. then all it takes is A HOT spots on any one of the combustion chamber and BOOM!
cheers
cheers
#18
_Yella SLuR_
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Posted 08 July 2006 - 08:20 AM
The turbo race cars usually flame out when the ignition is turned off.
#19
MRLXSS
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Posted 08 July 2006 - 03:15 PM
would one of those turbo timer things help... or just let your car run at idle for a while???
I also think its the balancer....
Maybe check your dizzy cap is ok, it might be cracked and not sitting properly which means it can jump all over hte place and backfire etc...
I also think its the balancer....
Maybe check your dizzy cap is ok, it might be cracked and not sitting properly which means it can jump all over hte place and backfire etc...
#20
_mike_nofx_
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Posted 08 July 2006 - 09:15 PM
Ive been looking into turbo timers, I have noticed waiting a little longer before turning the engine off will make the backfire smaller/quieter.
As for the dizzy cap being cracked (Havent checked yet) and sparks jumping, wouldnt that make the car run shit? it runs good still.
I still havent had a chance to check if the balancer is loose yet.
As for the dizzy cap being cracked (Havent checked yet) and sparks jumping, wouldnt that make the car run shit? it runs good still.
I still havent had a chance to check if the balancer is loose yet.
#21
TerrA LX
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Posted 08 July 2006 - 10:25 PM
^ yeah it would probably run sh?t and i may have misread the Question a little, i didnt realise u running a turbo.
#22
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Posted 09 July 2006 - 05:19 AM
oh and if you do replace the balancer and the seal dont forget to lube the seal with a bit of vasoline and it is advisable to seal the seal to the cover with grade 3 sealent (brown goo).
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