1978 250 six

72 luxo · Veteran Member

1978 250 six

Pontiacanada · A Poncho Legend!

72 luxo wrote:
Will this hurt my engine if I continue to drive it this way?

Yes.

Canadian Poncho · A Poncho Legend!

I bet there's a ton of carbon in that motor causing the pinging. You can run a higher octane fuel which might help. Back in the day when I had a 70 Biscayne with a 250 I'd pour water down the carb while revving the engine (so that it didn't stall) to get rid of carbon. It seemed to help. Some guys used trans fluid (lots of white smoke!). There's commercial products that may work better.

73SC · A Poncho Legend!

Why not move up in octane and see what happens or retard timing. It will cause problems eventually that will damage the engine.

72 luxo · Veteran Member

Pontiacanada wrote:
72 luxo wrote:
Will this hurt my engine if I continue to drive it this way?
Yes.

The pinging is not bad, just you can here it as described, I here new cars pinging sometimes but they have knock sensors that my inline six obviously dose not have.

72 luxo · Veteran Member

73SC wrote:
Why not move up in octane and see what happens or retard timing. It will cause problems eventually that will damage the engine.

The main reason I set the timming to factory spec was to help with fuel ecomomy, it was starting to slip a little so I thought I better check the base timming and shure enough it was at like 3 or 4 degrees BTDC. I dont want to have to run premium fuel as this is not a high commpression big block!

72 luxo · Veteran Member

Canadian Poncho wrote:
I bet there's a ton of carbon in that motor causing the pinging. You can run a higher octane fuel which might help. Back in the day when I had a 70 Biscayne with a 250 I'd pour water down the carb while revving the engine (so that it didn't stall) to get rid of carbon. It seemed to help. Some guys used trans fluid (lots of white smoke!). There's commercial products that may work better.

I guy I work with said to try that but I am afraid of hydro locking the engine and poping a rod out the block! How much water do you pour in while reving the engine? and for how long?

73SC · A Poncho Legend!

There is a Top Cleaner at the GM dealers, trans fluid is my preferred method or sea foam. You can run 89 octane not necessarily premium fuel.

72 luxo · Veteran Member

It just runs so good with the factory timming, second gear has more power, you can cruise at a higher speed with less throttle input, do you think that with the carb jetted the way the factory had it,(toronto carb set to factory metering specs) and factroy timming and todays fuel it would be impossible to run without the pinging issue? Plugs look great with no heavy carbon deposits, but I have been told that todays fuel you cant go by the plug read any more!

72 luxo · Veteran Member

427carl wrote:

The main reason I set the timming to factory spec was to help
with fuel ecomomy
        Is it a daily driver? lighter puddle jumpers are easier on fuel..
       Think about making it lighter!!
      run 1/4 tank of fuel                                                                                      take out seats and carpeting and insulation remove the spare   remove the bumpers
1000 lbs of weight will increase your fuel mileage especially if you drive it a lot

yes it is a daily driver, but the mentioned items that you say to remove are not quite feaseable, remove the bumpers! I understand what you mean as far a weight reduction but...

Canadian Poncho · A Poncho Legend!

I poured a small steady stream while revving the engine (fairly high) for about 10 seconds. Don't pour a ton at a time- just enough to generate steam. It's the conversion to steam that removes the carbon. Steam wont upset your neighbors as much as burning trans fluid.
Disclaimer: Even though I never had a problem doesn't mean you won't.

72 luxo · Veteran Member

73SC wrote:
There is a Top Cleaner at the GM dealers, trans fluid is my preferred method or sea foam. You can run 89 octane not necessarily premium fuel.

What may I ask is sea foam? Wouldn't ATF foul the plugs?

67Poncho · Uber Guru

Canadian Poncho wrote:
Disclaimer: Even though I never had a problem doesn't mean you won't.

(lol) Todd, Todd, Todd!!!! I have never used water but like previously said, there are many top end cleaners, such as GM Cleens designed specifically for this..

Personally, I love my GM penetrating fluid but it will create a little smoke... But using it cleans and lubes the throttle plates. Just my 2 cents!

-- Edited by 67Poncho on Tuesday 22nd of November 2011 08:36:44 PM

427carl · A Poncho Legend!

my uncle used to run water and salt through lots of smoke

Canadian Poncho · A Poncho Legend!

Hey, I was 18. I'd try anything once.

67Poncho wrote:

Canadian Poncho wrote:
Disclaimer: Even though I never had a problem doesn't mean you won't.
(lol) Todd, Todd, Todd!!!! I have never used water but like previously said, there are many top end cleaners, such as GM Cleens designed specifically for this..
Personally, I love my GM penetrating fluid but it will create a little smoke... But using it cleans and lubes the throttle plates. Just my 2 cents!

-- Edited by 67Poncho on Tuesday 22nd of November 2011 08:36:44 PM

73SC · A Poncho Legend!

72 luxo wrote:
What may I ask is sea foam? Wouldn't ATF foul the plugs?

Click HERE for Sea Foam....I guess I'm showing my age. biggrin

CdnGMfan · Canadian Poncho Superstar!

I had several beakers of water poured through my Chevelle right after I got it, then I took it for a drive & changed the oil after.

GM Cleens is the stuff to use; just pour it in slowly. Just before the engine stalls, dump the rest in and let it sit for a few hours. There will be clouds of smoke while you are dumping it in, but upon restart there will be very little. Take it out on the highway and try to hang in the fast lane with traffic. The car should run smoother, better and hopefully without any more pinging.

4SPEED427 · A Poncho Legend!

CdnGMfan wrote:
I had several beakers of water poured through my Chevelle right after I got it, then I took it for a drive & changed the oil after.

GM Cleens is the stuff to use; just pour it in slowly. Just before the engine stalls, dump the rest in and let it sit for a few hours. There will be clouds of smoke while you are dumping it in, but upon restart there will be very little. Take it out on the highway and try to hang in the fast lane with traffic. The car should run smoother, better and hopefully without any more pinging.

Plus one.

When I purchased my 4 speed big block Grande Parisienne, it had been a city car and was well carboned up. About a week after I got it, after a high rpm road test (!) it had a knock which turned out to be harmless carbon knock. Can of GM Cleens later, all better. Few weeks after, same thing again. Over the course of the next 10,000 miles or so, I had to carry a can of Cleens along as it developed knocks from carbon chunks loosening up at least 10-12 times. Finally it cleaned up using Cleens and the problem was solved. To me, that is the best solution. Don't give up if one can won't fix it. Wait a week or so, try another can.

-- Edited by Carl Stevenson on Tuesday 22nd of November 2011 11:56:44 PM

Lefty · Uber Guru

Could it also be caused by the fuel not having lead in it anymore,
I was getting a small amount of ping from my 6 along with "shaky II"
motion and all went away when i changed to electronic ignition.
The one that goes in the distributor so everything looks stock.
In passing how can you tell what year a 250 6cyl motor comes from ??

I replaced my 194 with a 250 30 yrs ago , got it for $100 and have not had to do anything to it
but change gaskets and carb..

and move oil dipstick.

dip stick tube_(1024_x_768).jpg motor2_(1024_x_768).jpg motor3_(1024_x_768).jpg

72 luxo · Veteran Member

Will have to try the GM top engine cleaner. Is it an aerosol or pour in liquid?

73SC · A Poncho Legend!

Glug, Glug , Glug. Don't pour it all in at once.

4SPEED427 · A Poncho Legend!

It comes in spray or liquid. You want liquid. I am thinking the part number is 993026 for the liquid but I can check for sure tomorrow if you like.

dualquadpete · Canadian Poncho Superstar!

I had my car club meeting here last night & we were talking about this same problem. Most of the members that have this "ping" thinks it the low Octane rating of our fuel. Most guys were running Petro Cda. premium at 91 Octane but when the switched over to Esso or Shell [ no ethanol in these brands]same rating, the ping went away. So in this case we agreed that the octane rating on pump was wrong or cheap fuel in prem. tank. One member also told us that 3 of his Pontiacs that sat out the season[not driven]this yr. had the neoprene fuel lines rot off & one had the fuel pump "case" rot out, all after just one yr. of not being used & ethanol fuel being used. Another member had showed us at the last meeting his Holley 850 with the float bowls "eaten' right through, again "ethanol" fuel . Shell Esso & Petro Cda. all claim "no ethanol" in premium fuel!!!!

72 luxo · Veteran Member

I just purchased this, is this the right stuff? How well dose it work?

73SC · A Poncho Legend!

You got it. Lets put it this way, Sea Foam has been in business for about 70 years I think. Where did you buy it and how much, just curious. Parts Source has it where I live.