I have a 1970 sb350 300Hp that has been souped to about 400Hp-
It has recently had a new HEI distributor, plugs and wire. Then tuned
up. I did the new distributor primarily because the tac stopped working
but I thought I would also get rid of the ping. A Corvette mechanic
(with about 30 yrs of experience) worked on the car. The ping was
gone for about a month then started again. He redid the timing. And
said that you might want to put in GM Top engine cleaner, GM Piston
cleaner (Same thing?) . And I confirmed this with the Hayes manual
that basically says ping can be caused by carbon build up in the
cylinder. So, after all that, is it wise to use Top Engine Cleaner?
Or, could it still be something else. Pros vs Cons??

Thanks in advance. Peter

PS; In 50 degree weather I get very little ping - when it's past
75 degrees it pings all the time at any acceleration.

 

First, run a couple of tanks of good gas. See if that helps. If not, then give her a drink of water. Get it good and hot, then pour water down the carb a little at a time, holdng the RPM up so it's doesn't stall. Lots cheaper than GM's Top cleaner. Just don't dump a big bunch down the carb at once, be gentle. Little sips are the key, not a big gulp. And check your TOTAL timing- read Lars' paper on timing.

 

Thank you Tim. Appreciate the information.
Peter

 

Just curious about this one. Water isn't really something you want to be pouring into the carb, So would you be so kind to enlighten us all about this move.

 

It's an old old trick. You can use water, diesel fuel etc. I have always used a spray bottle for fear of hydraulic locking and bending a rod.

It does work.

You can also add Seafoam or a strong mix of Techron Injector cleaner to the gas.

 

I've also heard...mixing about a gallon of diesel in a full fuel tank.... if your going on a long trip and run it out. Suppose to clean as you go. I've done both with no bad effects.
Larry

 

I have had good results from TECHRON....and SeaFoam. My 01 v8 dakota wouldnt idle properly....it searched between 600 and 1300 rpm. The geniuses at the dealer said it needed a new Throttle position indicator switch. One tank with a 9 dollar bottle of techron....it idles correct again. It must clean "something".

 

Yeah but if you use the gm stuff your whole neighborhood will be in a chemical fog.

 

Also used to get the same results with STP poured slowly down the carb at fast idle. MAN will it smoke!! But it will clean the carbon off the tops of the pistons!

 

Same with the SEAFOAM...just did it this past weekend...thought the neighbors might call the fire dept.