well 2 questions actualy, first i was told that using synthetic oil stops the car from smoking, true? and also what kind of oil should i use in my 305 HO with 280,000 miles in florida? should i use the 20w-50 stuff?

 

don't think synthetic will stop the engien from smoking. i'd run 10w-30

 

I would try Valvoline Maxlife
http://www.valvoline.com/pages/produ....asp?product=7

and Slick 50® Engine Treatment For High Mileage Vehicles
http://www.slick50.com/index.htm

but it may not help much.

 

There is only one situation I can think of where synthetic could help oil burning - stuck, gummed up oil control rings that the synthetic desolves and frees up. Of course, if that's the case, the engine probably has a bunch more oil consumption source issues.

The typical small block Chevy smoke situtation is blue smoke at start-up, caused by valve stem seals. They typically have gotten hard and cracked, and no additive or "high mileage formula" is going to fix that. Some synthetics (I say "some", because there is some real junk out there) will keep seals softer and therefore help them last longer, but that won't fix cracks from hardening.

If you want to stop the smoke, replace the valve stem seals. If the smoke occurs during normal operation, especially when under power, then that's piston rings, and no oil or oil additive is going to fix them (except the case noted above).

 

it doesnt actualy fix it, i guess when it burns it doesnt create smoke or somthing?

 

.

 

With those kinda miles on that engine assuming its never been rebuilt it probably needs to be rebuilt or replaced to stop it from smoking. You could try 20 50w it might help a little bit but at a minimum your probably going to need valve guide seals.

 

use the positive seals and if you want the o ring seals. i'd stay away from the umbrella seals

 

Umbrella.

Or both. The round one is the stock type, and goes under the keepers. The umbrella go over the stem & guide itself. Doesn't hurt anything to put new stock types in when installing the umbrella type.

 

.

 

i wouldn't use umbrella seals, even if five7 likes them. wouldn't say there's anything wrong with them, but i tihnk the positive seals are better plus i run the o ring too.

 

Well, if given a choice I'd go with the positive type. I got some positive seals that didn't require guide machining several years ago, but haven't been able to locate them lately. For a quick on-the-engine fix, the umbrella would be better than just the stock o-ring type.

FWIW, on the 396, I went from umbrella to positive when I did the porting last spring. Oil consumption disappeared, and this in an engine that is used primarily for racing.

 

i found some 454 seals, from around 77 i think, for my 402 that fit on the guide without machining.

 

Lucas oil stabilizer works really well for helping cars stop smoking, but it depends on how bad the car is smoking. Plus with the miles your car has, it probably needs to be rebuilt.

 

.

 

.

 

no. sorry i don't keep track od PNs but i've never had a problem finding positive seal. alot of heads i put them on have been machined for larger springs which also machines the guide to accept positive seals. if you can't find any that fit without machining the umbrella seals would be a great second choice. next set of seals i put on i may try tefelon seals from comp or crane, rb swears by them.

 

.