Volvo AQ130C max timing advance ?

Amigo_nz

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Hi, can anybody tell me the maximum safe advance timing for the volvo penta AQ130C ?. The manual says set to 27deg to 29deg advance at 2000rpm which we have done. Using a strobescope on the pulley we are reading 38deg !. (12 deg at idle) The distributor is a Bosch with centrifugal advance. There appears to be no tension on the thicker spring, so the weights are going fully out. Is this normal, or shoudld there be some resistance to limit the total amount of advance at higher revs. Thanks in advance. Mike
 

Maclin

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Re: Volvo AQ130C max timing advance ?

Regarding this...:
"The manual says set to 27deg to 29deg advance at 2000rpm which we have done."

How was this done?

The reason I am asking is I am not sure how you do that without using a stroboscopic dial-back type timing gun.

So your next sentence about "Using a strobescope on the pulley we are reading 38deg " was very confusing to me.
 

Amigo_nz

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Re: Volvo AQ130C max timing advance ?

Thanks for the reply Maclin. Sorry, you are correct i didn't explain it quite right. The advance timing at idle was set to 12 deg with the scobscope gun aimed at the timing marks on the front pulley. The revs were then increased to 2000rpm and the timing marks checked against the marker on the pulley. At this rpm the scobescope indicated an advance timing of 38 deg. The manual says it should be 27-29deg. Cheers Mike
 
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Maclin

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Re: Volvo AQ130C max timing advance ?

Thanks Amigo, that is what I thought you did. I can only state that it seems that the weights do swing out too far and that a different spring or springs should be used, although even thicker springs will let them swing out more at the top RPM's.

If this is the stock distributor then springs are probably the only method needed to adjust the total advance to stay at 27-29 at the 2000rpm. If it is not a direct replacement type then it may need different weights with a smaller pivot slot or other method of limiting travel.
 

Amigo_nz

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Re: Volvo AQ130C max timing advance ?

Thanks for the reply Maclin. I noticed on an old post (2009) from the late Don S, that timing should be set to 32deg to 36deg at 4300rpm on the AQ115, so i assume this would be similar on the AQ130. I am fairly sure now that i need to try and find some new springs to better control the centrifugal weights. Having searched the net for the last few nights there dont appear to be aren't any around, so i am going to try and modify some from another distributor, or play around with the original ones. From what i have read, it appears the setting should be about 10deg at idle, 27-29 at 2000rpm and 32-36deg at 4300rpm.
 

Maclin

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Re: Volvo AQ130C max timing advance ?

"From what i have read, it appears the setting should be about 10deg at idle, 27-29 at 2000rpm and 32-36deg at 4300rpm. "

That sounds like a good and safe and proper advance curve to me.
 

Amigo_nz

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Re: Volvo AQ130C max timing advance ?

I spent some time over the weekend and managed to effectively shorten up the heavy spring to remove the play. Previously the soft spring was trying to do all the work, hence the high reading at 2000rpm. It took a fair bit of trial and error to get it right but i think i will now live with what i have. I now have ...at 1000rpm (10), 2000rpm (27), 3000rpm (32) and at 4000rpm (36). But at 4600rpm i am getting around 38deg which i am assuming is okay, as i still don't know what the limit should be for these motors when running 98 Octane fuel and compression of 9.5:1. At one stage i had 41deg at 4600rpm, but decided that was a bit too high. I do spent a lot of the time at a cruise speed of 4300rpm to 4600rpm, so the motor will generally be running with the higher timing advance. Hopefully i don't have any major problems over the summer. Thanks for you help.
 
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