Advance and retard volvo penta aq 105/100

[cyberpunx]

Hi there all i am looking for some help again, hence why im back pestering you all.
as alot of you know im doing up my boat todays topic advance and retard for the volvo penta aq105/100
does anyone know if this engine has advance and retard.
i dont have a clue what it is? something to do with distributer and timing anyway a mechanic was telling me he's pretty sure my volvo penta should have a different distributer with this on it(ad and ret)
so can anyone help me out its a 1969 volvo penta aq105/100 based on the older volvo b20 engine (im lead to believe) maybe the advance and retard has been taken off my engine can anyone shed some light on this and how would i know for sure.?

if it did have it was it only for plaining?
or what??
help thanks in advance.
Angelica will be reborn in spring photos to follow.

 

[Bilgediver]

Hi there all i am looking for some help again, hence why im back pestering you all.
as alot of you know im doing up my boat todays topic advance and retard for the volvo penta aq105/100
does anyone know if this engine has advance and retard.
i dont have a clue what it is? something to do with distributer and timing anyway a mechanic was telling me he's pretty sure my volvo penta should have a different distributer with this on it(ad and ret)
so can anyone help me out its a 1969 volvo penta aq105/100 based on the older volvo b20 engine (im lead to believe) maybe the advance and retard has been taken off my engine can anyone shed some light on this and how would i know for sure.?

if it did have it was it only for plaining?
or what??
help thanks in advance.
Angelica will be reborn in spring photos to follow.

The distributor is the device which times and sends the high tension voltage to the spark plugs. The timing is not only critical but it also varies due to different conditions of the engine load and also engine speed.

On basic engines the distributor may only have automatic advance and retard provided by centrifugal weights within the bottom half of the distributor.

This system retards or sets the spark to occur at or after top dead centre when the engine is at rest and then as the engine starts and speeds up the weights on the governor cause the distributor to time the spark sooner than top dead centre for better efficiency. some times this mechanical advance ceases to operate any further after about 2000 rpm.

Some engines also have in addition a vacuum advance system and this is usually visible as a small pancake shaped thing sitting on the side of the distributor body. This contains a device which is actuated by the air vacuum in the manifold going to the carb. When you accelerate the vacuum reduces and this causes the pancake device to turn the distributor to retard the spark. as the vacuum increases then the distributor advances.

We need to check a manual to see what you should have however meanwhile
providing the distributor is set to an optimum position either using a timing light or flywheel markings you should be fine until it is confirmed if you need the vacuum system . If it is missing and should be there then you could be getting slightly incorrect spark timing especially when trying to get on the plane and once you are on the plane. That is if you go that fast. I shall check in the marina later which should be fitted as a pal is more familiar with Volvo petrol engines.

 

[cyberpunx]

"Some engines also have in addition a vacuum advance system and this is usually visible as a small pancake shaped thing sitting on the side of the distributor body. This contains a device which is actuated by the air vacuum in the manifold going to the carb. When you accelerate the vacuum reduces and this causes the pancake device to turn the distributor to retard the spark. as the vacuum increases then the distributor advances."



i Think this is the type i was told off where on my carb there is an extra tube coming out the side of the carb but its been blocked with cork and unused.
i am keen to find out what if at all i need this.
i dont go onto the plane . but its not to say i might not.
ive just had the engine re conditioned and that mechanic never mentioned anything to me about this.
only later a good friend who happens to be top mechanic mentioned it.
i appreciate help and if you happen to get advice please let me know thanks again
john

 

[VicS]

Hi John,

Unfortunately the AQ 105 is no longer listed on the parts websites however
I think, but by no means sure, that the distributor on the AQ105 does not have a vacuum advance device although the car engine does. (and so do some of the other AQ series engines.) A car mechanic would almost certainly expect to see one.

It does have the weights advance system that Bilgediver describes and I hope the mechanic who reconditioned the engine made sure that these moving freely, not rusted up.

There's no timing adjustment screw like many distributors have. To adjust the timing you have to slacken the clamp and rotate the whole distributor body. (you normally do that anyway but when there's a screw adjustment you use that for the fine adjustment)

 

[Bilgediver]

Hi John,

Unfortunately the AQ 105 is no longer listed on the parts websites however
I think, but by no means sure, that the distributor on the AQ105 does not have a vacuum advance device although the car engine does. (and so do some of the other AQ series engines.) A car mechanic would almost certainly expect to see one.

It does have the weights advance system that Bilgediver describes and I hope the mechanic who reconditioned the engine made sure that these moving freely, not rusted up.

There's no timing adjustment screw like many distributors have. To adjust the timing you have to slacken the clamp and rotate the whole distributor body. (you normally do that anyway but when there's a screw adjustment you use that for the fine adjustment)

As Vic is suggesting there are some Volvo engines which do NOT have vacuum advance and derive ALL the advance from the distributor weights.

You can check yours is such a distributor if you have a mechanic friend byy setting the points and then setting the static timing using the marks on the front damper/pulley. You then run the engine up to 2500/3000 rpm and see how much the timing has advanced. It seems that a Vacuum less distributor will apply 30 degrees advance in this test where a distributor for use with a vacuum unit will give less advance on just the weights. with the rest coming from the vacuum unit.

Your boat should operate fine so long as the distrubutor is correctly set and the timing strobe light will tell this. It is best to rub the timing marks with chalk to help see them better.

If you need further help come back here and I shall try and find an AQ in the marina to see exactly what the marks look like.


This will give some idea.


http://www.mechanixtrix.com/Article/Article.aspx?ArticleId=236

 

[VicS]

Done a bit more research and am now certain that the AQ105 does not have a vacuum advance system. (read the text of the manual as well as looking at pictures!) The six cylinder AQ165 does have it though.

The owners manual describes the routine maintenance of the distributor and the timing. There is a photo and description of the timing marks.

Download the manual from HERE Just enter AQ105 in the engine type box.