306 SBF pinging and smoking

[BruiserOutdoors]

Running a 306 sbf with about 10-12k miles since it was built. It has a moderate cam in it. Bought the motor from a local bronco brother. I heard it run and got to ride along prior to buying the motor. It seemed to check out for the most part.

When I installed it, I installed an msd billet distributor and edelbrock avs2 carb. I did not install the vacuum advance mechanism due to being in a rush for an event. Now under moderate to heavy throttle, the motor will ping. It has always seemed to run rich and smelly, and now seems to smoke white smoke out of both tailpipes when warm. It has true dual exhaust, no crossover H pipe.



Are these issues related? Did I cause damage by not having the timing setup correctly?

How can I tell if its bad rings or valve guides?

Cause of the pinging?

 

[73azbronco]

How many miles did you put on it?

You probably didn't break it. But start of white smoke is not good, coolant may be getting by head gasket. Sure it's not a little blue as in oil smoke? Might try a coolant leak check, autozone has the tool, easy peezy, cheap.

Details of cam? Motor details if any? Flat top, forged, compression ratio, etc.

Not installing advance kept it from pinging.

What octane you running? Try 91 for a while. I would not add octane booster, that stuff is more voodoo than science.

What is base timing? What is full advanced timing?

Hypereutectic pistons? Iask as they do not like pinging or advance beyond 30 degrees, or they blow a hole in them.

 

[BruiserOutdoors]

How many miles did you put on it?

You probably didn't break it. But start of white smoke is not good, coolant may be getting by head gasket. Sure it's not a little blue as in oil smoke? Might try a coolant leak check, autozone has the tool, easy peezy, cheap.

Details of cam? Motor details if any? Flat top, forged, compression ratio, etc.

Not installing advance kept it from pinging.

What octane you running? Try 91 for a while. I would not add octane booster, that stuff is more voodoo than science.

What is base timing? What is full advanced timing?

Hypereutectic pistons? Iask as they do not like pinging or advance beyond 30 degrees, or they blow a hole in them.

I think its blue smoke. looks white to me but my mechanic friend said blue if I recall correctly. I've put about 500 miles on it

306/307 ci
0.040 over
e7 heads
roller cam
will update specs later.

 

[Madgyver]

pinging = too much timing

 

[BruiserOutdoors]

Motor specs finally…


302, .40 over(307), E7 cast heads ported heads from Power Heads in CA, Comp cam XE264HR, Comp Cam 1.7 roller rockers, edelbrock air gap intake.

 

[bmc69]

pinging = too much timing

That^. What octane fuel are you using?

 

[BruiserOutdoors]

That^. What octane fuel are you using?

I can't remember what fuel I was running but likely 87 (haven't run it much since last summer), I am going to be driving it about 100 miles tonight to run the current gas out of it, then switch to premium (92).

could the timing and lower octane cause the smoking issue I have been noticing? Did I damage the pistons or rings?

 

[Broncobowsher]

Most of the time a 347 is built with high compression. 10:1 or greater is very common. This requires high octane fuel. And a proper tune up.

Detonation is hard on engines. You can hurt them with too much detonation. Modern cars have knock sensors that keep the engine from hurting itself. Old school engines don't. Yes, you can damage the engine.

 

[Speedrdr]

It’ll be $$$, but if you have access or a “friend” in the aviation field, get some 100 octane low lead Av gas to mix in with 87 octane pump gas. I mix mine so the EB doesn’t complain.
My Engine build is either 10.5 or 10.8 compression ratio. It doesn’t really like pump gas

Randy

 

[BruiserOutdoors]

Most of the time a 347 is built with high compression. 10:1 or greater is very common. This requires high octane fuel. And a proper tune up.

Detonation is hard on engines. You can hurt them with too much detonation. Modern cars have knock sensors that keep the engine from hurting itself. Old school engines don't. Yes, you can damage the engine.

Its just a 307, probably closer to 9.5:1 compression ratio

 

[cldonley]

It’ll be $$$, but if you have access or a “friend” in the aviation field, get some 100 octane low lead Av gas to mix in with 87 octane pump gas. I mix mine so the EB doesn’t complain.
My Engine build is either 10.5 or 10.8 compression ratio. It doesn’t really like pump gas

Randy

100LL AvGas is currently $6.80 a gallon at my airport. Only additive in AvGas is lead, at something like 100ppm. No ethanol, detergent, etc, etc, just good 'ol fuel.

 

[BruiserOutdoors]

92 octane seemed to help. ran about 8-10 gallons thru it last night, just shy of 100 mile round trip. will check timing tonight.

 

[Speedrdr]

100LL AvGas is currently $6.80 a gallon at my airport. Only additive in AvGas is lead, at something like 100ppm. No ethanol, detergent, etc, etc, just good 'ol fuel.

It’s a lot pricier here in north Mississippi. At that price I’d get a fuel tank (100 gallon or more) and have it on hand when needed.

Randy

 

[cldonley]

It’s a lot pricier here in north Mississippi. At that price I’d get a fuel tank (100 gallon or more) and have it on hand when needed.

Randy

Dang. I thought 6.80 was pretty bad. Even with my employee discount it's terrible.

 

[BruiserOutdoors]

Running 92 octane seems to have resolved the ping. still smokes slightly when warm. hardly visible but noticeable.