Should I be using lead additive in my Gas?

[Saginaw Bay]

I was just reading through the owners manual I downloaded.
My engine is a 1972 302 (888?)V8.

It states Detonation can be caused when using unleaded gasoline.
Further states that valve damage may occur.

Now, at WOT I get a backfiring condition through the carb, could this be caused by that?



Any insight here guys?


Am I just reading too much into this?

 

[Bt Doctur]

Re: Should I be using lead additive in my Gas?

Back firing thru the carb just says a spark/ign. source is happening at the wrong time:
Cracked dist, cross-firing (plug wires bad/improperly routed/ touching each other.)
Cracked/ carbon tracked dist cap
carbon button in cap
coil tower cracked
burnt/bent valve
carbon hot spot
too lean carb jetting
poor fuel flow resulting in a lean condition

 

[HT32BSX115]

Re: Should I be using lead additive in my Gas?

Howdy,


You cannot buy "lead" any more. It's banned (unless you run AVGAS or "offroad" racing fuel)

I am skeptical of lead substitutes anyway.....

Now, at WOT I get a backfiring condition through the carb, could this be caused by that?

That could be due to a burned valve or more likely mis-timing or a severely worn out distributor(advance mechanism) and/or the stuff BT mentioned!!!

If it's been pinging badly, the damage may already be done...

 

[Bondo]

Re: Should I be using lead additive in my Gas?

I was just reading through the owners manual I downloaded.
My engine is a 1972 302 (888?)V8.

It states Detonation can be caused when using unleaded gasoline.
Further states that valve damage may occur.

Now, at WOT I get a backfiring condition through the carb, could this be caused by that?


Any insight here guys?


Am I just reading too much into this?

Ayuh,... I think you are,... By your symptoms,...
My 1st guess is it's goin' Lean....
It's a fuel delivery Issue,... Start with the fuel Filters....
After that, it's Test to see where the problem is, it can be anything between the tank to the carb, or either, or all...

Of course, it may also just need a Full,+ Complete Tune Up as well,... Donno the History...

 

[havasuboatman]

Re: Should I be using lead additive in my Gas?

Bond-o is right. Sounds like you are leaning the motor out on the top end.
To be an ignition timing issue your timing would have to be so far advance that that the engine would barely run if it ran at all.
Now, if you have alot of crap built up inside that engine from, say, usinge a parrafin based oil like penzoil you could have valves that are sticking. This is especially true if the boat has spent alot of time not being run recently.
Your motor is old enough to qualify, but while I have encountered this alot in old automotive applications over the years, I have only seen it once in a boat.
By the way, the reason lead was used was to protect against pitting of the valves and valve seats should any forigen matter be there as the valve closed. The idea being that these particles would be coated in lead softening the material at the time it was trapped.
Also, don't waste your money on av-gas. It's got better octane (around 100) but it, too is unleaded. If you can pump it into your car at a gas station, it's lead free. Period.

 

[Saginaw Bay]

Re: Should I be using lead additive in my Gas?

Well,
This old girl will be getting new plugs, wires,cap , rotor, condensor, and coil.


We will see where that gets us.


Thanks for the help!

 

[havasuboatman]

Re: Should I be using lead additive in my Gas?

It just boggles the freaking mind.

 

[Bondo]

Re: Should I be using lead additive in my Gas?

Well,
This old girl will be getting new plugs, wires,cap , rotor, condensor, and coil.


We will see where that gets us.


Thanks for the help!

It just boggles the freaking mind.

Ayuh,... Ever get the feelin' yer talkin' to Yourself,..?? I do....

I guess he can change the fuel filters, After he hangs a piston...

 

[HT32BSX115]

Re: Should I be using lead additive in my Gas?

Also, don't waste your money on av-gas. It's got better octane (around 100) but it, too is unleaded.

Um, Sorry to differ...........

All AVGAS now is pretty much LOW-lead (100LL-BLUE)) not NO-lead.............

100/130 (also called AVGAS 100-GREEN) may still be available and there is a new specification UL82 (which IS unleaded)and eventually(&hopefully) will be certified as an 80 octane replacement but it's nowhere to be found......


The last spec for 100LL was 3.2 ml tetra-ethyl lead per gallon.


Cheers,


Rick

 

[Saginaw Bay]

Re: Should I be using lead additive in my Gas?

Ayuh,... Ever get the feelin' yer talkin' to Yourself,..?? I do....

I guess he can change the fuel filters, After he hangs a piston...

And YES a fuel filter, Meant to add that, but was hurried out the door at time of posting that. I WILL BE doing the fuel filter along with the other things.

 

[Saginaw Bay]

Re: Should I be using lead additive in my Gas?

And, No, you were not talking to yourself.

I came here to ask for help. You offered your insight ( which I appreciate), I will be following the advise you give.

Look, instead of saying something like "I am talking to myself...."
Assuming I am ignoring your advise. Maybe reminding someone of your preception of his oversight on the advise you give.

I do indeed intend to replace the fuel filter, along with the other things I listed.

Your insight is APPRECIATED.


Good Day.

 

[billy4hp]

Re: Should I be using lead additive in my Gas?

Backfiring through the carb at WOT or near WOT (heavy load) can also be a condition caused by a flat cam or a cam that is losing a lobe...

Since your 888 is a flat tappet engine this is something I would also check...

If you find that the camshaft is NOT the issue, I would recommend an oil change using a Phosphate / Zinc additive to prevent your camshaft, lifters and rocker arms from wearing out prematurely...

Engine oils were reformulated a few years back and a cost cutting measure was to remove the Zinc and Phoshpate since the flat tappet cam is now a dinosaur as far as oil manufacturers are concerned...

JMHO... My credentials, engine builder and engine dyno operator since 1989...

Good luck...