No timing marks??

[RCSConstruction]

2000 volvo penta 5.7gs/sx
Bought a regular chevy plastic timing cover for my motor. It was the same as the volvo penta cover with exception of having to plug up crank sensor hole.
The cover only has a V notch and the Harmonic balancer has the TDC mark only.
I did my timing by ear/feel but would like to have complete control of my timing.
Is the notch in the cover a TDC or the BTDC mark?
Is there a timing light or meter that can tell me my timing? (haven't used a timing light in years)
Do I need to buy timing tape for the Harmonic Balancer?
Thanks in advance for your thoughts/advice.

 

[bruceb58]

Re: No timing marks??

Buy an "AdvanceTiming Light". There is a dial you turn on the timing light to line up the marks and then you read the number of degrees off the dial.

 

[Reel Poor]

Re: No timing marks??

The notch in the cover is TDC

 

[John_S]

Re: No timing marks??

You should have multiple timing marks on the harmonic balancer with the composite cover??? I'd get the tape for the correct diameter harmonic balancer. The advance timing lights are nice and good for checking the total advance. Most have an inprocise dial, so wouldn't try to set base timing using the advance dial.

 

[bruceb58]

Re: No timing marks??

Most have an inprocise dial, so wouldn't try to set base timing using the advance dial.

I would disagree with that. Although I have only used two, both were very accurate. if you set it at 0 degrees you could see the mark at ...lets say 6 degrees...rotate the dial to 6 and they line up perfectly with 0.

 

[John_S]

Re: No timing marks??

Bruce,

I have to check the brand/model, but think mine is an Accutron. Mine, plus the Craftsman I've used had a pot on the back. The scale has very tightly packed adjustment marks. Alignment of the hash marks can differ just from viewing angle. When I say improcise, I am only talking a degree or two. The timing tape is not expensive.

 

[bruceb58]

Re: No timing marks??

I did my timing by ear/feel but would like to have complete control of my timing.

Timing by ear/feel should not be done and can possibly damage your engine if you have your timing off enough. You need to put the ignition system in base timing mode before you time the engine.

Do you own a Volvo service manual?

 

[RCSConstruction]

Re: No timing marks??

Timing by ear/feel should not be done and can possibly damage your engine if you have your timing off enough. You need to put the ignition system in base timing mode before you time the engine.

Do you own a Volvo service manual?

I have a standard timing light and just guessed on 6-8 btdc after I lined up the timing marks.
What do you mean by base timing mode?
I am about to buy a Innova 5568 advance/rpm/dwell light.
Worst comes to worst I guess I will rig a timing tab some how.
Thanks for the replies everyone.
P.S.
Have all 6 VP manuals for my boat.

 

[bruceb58]

Re: No timing marks??

In the manual that covers the electrical, it will have the procedure for putting the ignition into base timing mode(if required) depending on the type of ignition system you have.

The ignitoin sytem typically can adjust the timing based on certain factors including RPM and signals from knock sensors. You have to disable this feature when setting initial timing which is called the "base" timing.

It is possible that you don't have to use a base timing mode. You just need to check your manual to make sure.

 

[Tail_Gunner]

Re: No timing marks??

I have a standard timing light and just guessed on 6-8 btdc after I lined up the timing marks.
What do you mean by base timing mode?
I am about to buy a Innova 5568 advance/rpm/dwell light.
Worst comes to worst I guess I will rig a timing tab some how.
Thanks for the replies everyone.
P.S.
Have all 6 VP manuals for my boat.

Umm RCS dont you have electronic ignition???? If i remeber right you are also carbed no efi right?

 

[John_S]

Re: No timing marks??

Has the balancer been replaced? You should have the 8" diameter balancer with timing marks. The older one was 6 3/4" diameter and could come with additional timing marks, or the more common, single TDC mark. GM went to the 8" at the same time they went to an updated crank and rods. Not sure, what, if anything, would be caused by running a different diameter balancer. They sell tapes for both sizes.

I agree with what others have said about not doing it by ear and most likely volvo has something similiar to Merc's Thunderbolt V base timing mode.

 

[Coors]

Re: No timing marks??

I don't think the balancers interchange, due to a balancing issue.

 

[John_S]

Re: No timing marks??

As I said, I am not sure. I have not seen any direct link between that crankshaft change and the HB, outside of the change happening around the same time. Also, the 305 and 350 share the same harmonic balancer, but the recipricating masses are different. Harmonic Balancer is a bit of a misnomer. See below for a better description:



Harmonic balancer
From Wikipedia, the free encyclopedia
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A harmonic balancer (also called crank pulley damper, torsional damper or vibration damper) is a device connected to the crankshaft of an engine to reduce torsional vibration.

Every time the cylinders fire, torque is imparted to the crankshaft. The crankshaft deflects under this torque, which sets up vibrations when the torque is released. At certain engine speeds the torques imparted by the cylinders are in synch with the vibrations in the crankshaft, which results in a phenomenon called resonance. This resonance causes stress beyond what the crankshaft can withstand, resulting in crankshaft failure.

To prevent this vibration, a harmonic balancer is attached to the front part of the crankshaft. The damper is composed of two elements: a mass and an energy dissipating element. The mass resists the acceleration of the vibration and the energy dissipating (rubber/clutch/fluid) element absorbs the vibrations.

Over time, the energy dissipating (rubber/clutch/fluid) element can deteriorate from age, heat, cold, or exposure to oil or chemicals. Unless rebuilt or replaced, this can cause the crankshaft to develop cracks, resulting in crankshaft failure.

There has been a trend at times by some "performance enthusiasts" to remove the harmonic balancers on their cars. The argument is that they aren't necessary and their mass reduces the performance of the engine. Others argue that this is not worth it, because the danger of damage to the engine from the vibrations the damper is intended to prevent is too high.

While net engine output can be increased without harmonic balancers, in professional race cars harmonic balancers are still commonly equipped, for reasons ranging from safety concerns to regulations. Almost all modern car manufacturers, even "performance" car makers and specialty tuners, include a harmonic balancer on their vehicles, and removal voids vehicle warranty.

Retrieved from "http://en.wikipedia.org/wiki/Harmonic_balancer"

 

[Coors]

Re: No timing marks??

I don't know the new engines, but it seems around the '70s and '80s there was a change from internal balance to external, or vice versa; the cranks, balancers, flywheels would not interchange.

 

[RCSConstruction]

Re: No timing marks??

Umm RCS dont you have electronic ignition???? If i remeber right you are also carbed no efi right?

It's not points. Not HEI either. Did volvo penta install petronix type triggers in the distributer?? It looks like Petronix but is not. They call it breakerless??
Carbed 4bbl, yes.
Have a MSD marine ignition I have been wanting to put on but just too much going on with it.

 

[RCSConstruction]

Re: No timing marks??

Has the balancer been replaced? You should have the 8" diameter balancer with timing marks. The older one was 6 3/4" diameter and could come with additional timing marks, or the more common, single TDC mark. GM went to the 8" at the same time they went to an updated crank and rods. Not sure, what, if anything, would be caused by running a different diameter balancer. They sell tapes for both sizes.

I agree with what others have said about not doing it by ear and most likely volvo has something similiar to Merc's Thunderbolt V base timing mode.

Don't have the boat in front of me but would have to say it is a 8" but I will check. Same year 305/350, has to be same harmonic balancer, no?
It runs fine,no pinging,no bogging, and plugs look good. I musta got lucky by "guessing".

I would break out my manual but they are safely bagged and in my boat at the shop...... Which by the way will have had my boat for 2 weeks for a bellows/U-joint/cable change...... I knew I should have just done it myself...so much for convenience.

 

[RCSConstruction]

Re: No timing marks??

I don't think the balancers interchange, due to a balancing issue.

Should both be internal balance, no?

 

[bruceb58]

Re: No timing marks??

Yes...your engine is internally balanced.

No...the harmonic balancer does not balance the engine. It reduces the resonant frequencies.

 

[Coors]

Re: No timing marks??

Bruceb, when did the externally balanced end? I seem to remember it being tried by gm, back in the day..Seems like it didn't last long, 3 years?

 

[bruceb58]

Re: No timing marks??

Some engines are externally balanced. 454 is one of them.