Timing Question on Vortec 4.3 V6 Engine

[Chef]

What is the timing on a marinized Vortec 4.3 V6 engine for the ignition? The motor does not have a timing plate. Would it possibly be the same as an earlier non-Vortec 4.3, which is at 8? BTDC?

 

[Haut Medoc]

Re: Timing Question on Vortec 4.3 V6 Engine

Welcome to iboats.....
TB IV or TB V?.....
What year?.....​

 

[Bondo]

Re: Timing Question on Vortec 4.3 V6 Engine

Ayuh,......

Your motor Should have a Timing Mark cast into the timing Cover,........
And,....
I'd start at 6?, to 8?btc,+ see how it behaves.........

Btw,.........
Welcome Aboard to the forums here at iboats.com........................

 

[Don S]

Re: Timing Question on Vortec 4.3 V6 Engine

If you don't have a Mercruiser, it won't be a Thunderbolt ignition at all. What type distributor is on it?

 

[Chef]

Re: Timing Question on Vortec 4.3 V6 Engine

Welcome to iboats.....
TB IV or TB V?.....
What year?.....​

Carborator. Not sure on year. Will get back to you. Thanks.

 

[Chef]

Re: Timing Question on Vortec 4.3 V6 Engine

Ayuh,......

Your motor Should have a Timing Mark cast into the timing Cover,........
And,....
I'd start at 6?, to 8?btc,+ see how it behaves.........

Btw,.........
Welcome Aboard to the forums here at iboats.com........................

Yes, there is a notch in the plastic cover. Do you know if the notch is zero or 8 btc?

Thanks. That sounds right.

 

[Chef]

Re: Timing Question on Vortec 4.3 V6 Engine

If you don't have a Mercruiser, it won't be a Thunderbolt ignition at all. What type distributor is on it?

Mercruiser Thunderbolt

 

[Don S]

Re: Timing Question on Vortec 4.3 V6 Engine

You need a year or better yet a Mercruiser SN for your engine. We need to determine which type Thunderbolt ign. you have. I would guess it's a Thunderbolt V, but would have to verify with year or SN. You would need to put the distributor into base timing mode so you can set the timing with a TBV

 

[Haut Medoc]

Re: Timing Question on Vortec 4.3 V6 Engine

Thunder bolt IV or V?.......
TB V needs to be put in base mode for timing.....
TB IV does not.....​

 

[Chef]

Re: Timing Question on Vortec 4.3 V6 Engine

You need a year or better yet a Mercruiser SN for your engine. We need to determine which type Thunderbolt ign. you have. I would guess it's a Thunderbolt V, but would have to verify with year or SN. You would need to put the distributor into base timing mode so you can set the timing with a TBV

Thanks. Not sure what to do with that, but I think you can answer my question. Let me tell you a little more. I have an '87 Chris Craft Stinger that I bought with a frozen up 4.3. I replaced the engine with a Vortec truck engine from which I stripped the computers away and reused the old distributor (Thunderbolt pointless electronic). Come to find out, the Vortec has a plastic timing chain cover with no timing plate on it (because the motor was computerized in a truck). So, basically, I have the old system in my boat without a timing plate on the chain cover. So, the question is, what is the ignition timing on a Vortec engine? Is it the same as the old 4.3, or did they change it? My guess is that all small block Chevys, whether 6 or 8, is 8 BTDC. Am I right?

 

[flabum]

Re: Timing Question on Vortec 4.3 V6 Engine

If the original engine was an '87, then you have the older Thunderbolt ignition. Set it to 6* at idle (700 - 800 rpm)

 

[Bondo]

Re: Timing Question on Vortec 4.3 V6 Engine

My guess is that all small block Chevys, whether 6 or 8, is 8 BTDC. Am I right?

Ayuh,........ That is Before top dead center..........

 

[Chef]

Re: Timing Question on Vortec 4.3 V6 Engine

If the original engine was an '87, then you have the older Thunderbolt ignition. Set it to 6* at idle (700 - 800 rpm)

On the plastic timing chain cover, there is one notch without any markings (numbers). Any idea what that notch signifies, either 0 or 6 or 8? Would like to know so I can set the baseline. Thanks!

 

[Don S]

Re: Timing Question on Vortec 4.3 V6 Engine

It's 0?

 

[Chef]

Re: Timing Question on Vortec 4.3 V6 Engine

Thanks Don and everyone else.

 

[Chef]

Re: Timing Question on Vortec 4.3 V6 Engine

Ayuh.... Bondo, I'm a woman (writing for my boyfriend). It's interesting how differently you treated me in this thread, thinking I was man.

 

[Bondo]

Re: Timing Question on Vortec 4.3 V6 Engine

Ayuh.... Bondo, I'm a woman (writing for my boyfriend). It's interesting how differently you treated me in this thread, thinking I was man.

Ayuh,......... Now I'm alittle Confused,........

Have We met here before,..??
Or was it at another forum,..??

I gotta believe it's probably the Tone of the Questions,......
Rather than whether you're a Man or Woman......

 

[achris]

Re: Timing Question on Vortec 4.3 V6 Engine

Chef,

Do you have the serial number of the original engine. The year of the boat cannot be taken as the year of the engine. Was the original engine a 1987? If so, then the replacement has to be the same generation. The V6 engines have evolved over time. They started life without a balance shaft (but with fluid engine mounts), then they acquired a balance shaft. Later the heads were modified (Vortec heads added) and they changed the entire top-end configuration. The reason I said all that is to highlight that you can get into very serious compatibility issues by trying to use (particularly) ignition components and fuel systems from one generation to another.

Chris.......

 

[achris]

Re: Timing Question on Vortec 4.3 V6 Engine

Ayuh,......... Now I'm alittle Confused,........

That make two of us

Have We met here before,..??

Your past catching up with you Bond-o

I gotta believe it's probably the Tone of the Questions,......
Rather than whether you're a Man or Woman......

Or the continual ignoring of requests for information (particularly engine serial number) that would help us to be more helpful.

 

[Chef]

Re: Timing Question on Vortec 4.3 V6 Engine

Or the continual ignoring of requests for information (particularly engine serial number) that would help us to be more helpful.

Well, that's my boyfriend! I'll push him on the serial number thing. Thanks, Chris. I do believe the person who had this boat before him wasn't capable of doing much with it, so it probably had the orig. engine.