Engine Timing

[sebas54]

Hi, I have a 1988 4.3l gm I/o.

I was told to check the timing by Bond O because when the engine is above 3300 rpms it makes a weird sound sometimes. It sort of sounds like a rusty metal on metal, or scratching/rubbing noise. Anyways, Bond suggested it was detonation. I was thinking that it was my water pump cirrculator but havent had the time to change it yet.

Can somebody please explain to me how to check the timing. I payed a mechanic to do it last season but there were no marks on the balancer/flywheel so he stuck his finger in to the spark plug hole and waited till the compression stroke.

I am going to buy a timing light but dont know what I am doing. I wish I was able to hire a mechanic to do it but I am a college student with alot of debt.

Please give me some insite on what I should do.


Thanks for all the help.

 

[Don S]

Re: Engine Timing

If you don't have a timing tab on your timing gear cover, then there is no way to time it properly. The thumb over the plug hole will tell you when you have found compression stroke, but you can't even exact TDC without the tab with the degrees on it.
Is this a Mercruiser, OMC, what? Does it have points type distributor or the Merc DDIS digital system?

 

[sebas54]

Re: Engine Timing

It's a Mercruiser. I think that it's a point type distributor.

 

[Don S]

Re: Engine Timing

Do you have a timing tab? Here is where to look.
Might want to post a picture of your engine in the location shown.

 

[sebas54]

Re: Engine Timing

Thank you.

I will be taken a pic and posting it once I get a chance.

I dont have a timing light. I don't know what timing light I will need. Inductive or digital. What are the differences. I want to buy the least expensive one. Thanks again.

 

[njlarry]

Re: Engine Timing

I've had decades of success with a cheap unit brought at an auto store (pepBoys??) don't rememeber where. It has alligator clips for the battery and an inductive pickup which also is handy for checking if one plug is not firing.

 

[sebas54]

Re: Engine Timing

I would like to buy a timing tab for my engine since there is none. I found some at

http://www.jegs.com/p/Mr.+Gasket/744171/10002/-1/11353

Which one should I buy?

It's a 1988 gm 4.3l

Thanks

 

[brunolund]

Re: Engine Timing

that engine should have the timing pointer spot welded to the timing cover.look about 1:30-2:00 o'clock on the crank balancer. it will be lined up with the balancer,not the pulleys, so it may be hard to spot.

 

[Boatist]

Re: Engine Timing

First thing you should buy is a Service manual. It would have already paid for itself.

 

[Don S]

Re: Engine Timing

Hmmmmmm,:redface: I guess I misread the original post, I thought it was a 3.0L engine.
Since it's a 4.3, it's considered a SB (Small Block) in your Jegs link then just measure your vibration dampner diameter

 

[sebas54]

Re: Engine Timing

So, the timing tab from the JEGS link will fit and be accurate? All I have to do is measure the damper and oreder either a 7" or a 8"?

The old damper is welded on the timing cover but the majority of it is broken off so it is unreadable.

Thank you.

 

[Don S]

Re: Engine Timing

So, the timing tab from the JEGS link will fit and be accurate? All I have to do is measure the damper and oreder either a 7" or a 8"?

That's all there is to it.

The old damper is welded on the timing cover but the majority of it is broken off so it is unreadable

I'm assuming you meant tab, not damper, you may have to remove some of the old tab but be careful. If you break the spot welds that hold it on, you could end up with a couple holes to leak oil out of.

 

[sebas54]

Re: Engine Timing

I just order a timing light but it's not an advanced timing light.

Do I need to have the advanced timing?

Thanks

 

[Don S]

Re: Engine Timing

You don't "need" it, when you get the timing pointer just measure between 0 and 10 degrees, then multiply by 3 and put put another mark on the balancer at 30?. That will be close enough for checking advance timing.