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Driving to gym tonight no issue, but coming home engine started pinging when pushing it over half throttle. Was running at 180 deg (as usual) and oil pressure was good. The air filter is pretty clean and same tank of gas for last couple weeks so no change there. Engine is a 350 with no cats ec. Should I start trouble shooting by checking the plugs?
If you're going to fiddle with these old cars you need some of those low tech tools to play with.
Orielly's has a pretty good timing light with a tach for around $100. Does it seem to stay idled higher when you come to a stop? Another easy check is to pull the vacuum advance and plug the carb port, with the engine at idle use a vacuum pump and actuate the vacuum advance to see if the idle rises and the timing changes, if it don't you vacuum advance mechanism could be stuck in the advance position.
If you're going to fiddle with these old cars you need some of those low tech tools to play with.
Yes I need some tools. Engine is not stock, but don't have any information on the internals at all.
I've used vacuum and timing gauges, but its been quite a while. I can still do light stuff, but no longer have the patience or energy for bigger projects. In fact I may have to switch to a C6 before long
Orielly's has a pretty good timing light with a tach for around $100. Does it seem to stay idled higher when you come to a stop? Another easy check is to pull the vacuum advance and plug the carb port, with the engine at idle use a vacuum pump and actuate the vacuum advance to see if the idle rises and the timing changes, if it don't you vacuum advance mechanism could be stuck in the advance position.
I was wondering about the advance. That is the only good way to check it as I don't have a vacuum pump. Does not idle high once choke is off.
Yes I need some tools. Engine is not stock, but don't have any information on the internals at all.
I've used vacuum and timing gauges, but its been quite a while. I can still do light stuff, but no longer have the patience or energy for bigger projects. In fact I may have to switch to a C6 before long
Thanks for your help tonight!
Hey, no problem. Lots of good(and few bad) folks on here to help you out anytime. Bluedawg knows his stuff.
I saw a C7 drive by me the other day and it looked to me like a larger version of a lotus elise.
Understood, I wish they had made it a little longer and ditched the tail lights. It took me awhile to even like the C6. I have a 64 and a C5 and still like the C5 lines, but then, I'm old. I think the C7 appeals to the younger folks. Lotsa gingerbread.
I was wondering about the advance. That is the only good way to check it as I don't have a vacuum pump. Does not idle high once choke is off.
I don't know, but you might be able to suck on the hose to see if the idle rpm increases, or use a set of needle nose vice grips and choke the line off while its still attached to the carb to see if the idle rpm decreses when you do. Another thing to check out is pull the cap and rotor, inspect the springs on the mechanical advance maybe one came off or is broke, but you'd think that would keep it idling higher than normal when you let off the accelerator, check the action of the weights to verify if they retract, lub the mechanical advance mechanism with wd40 or another lybricant before you put it back together, make sure the distributor isn't loose.if you can borrow a bore scope, look in the spark plug holes to see if you have carbon built up on the Pistons that would create a hot spot, you would need to look at each one. Does the engine want to diesel when you shut it off? Does it seem to start differently?
Last edited by bluedawg; Aug 28, 2015 at 03:03 AM.
I don't know, but you might be able to sick on the hose, or use a set of needle nose vice grips and choke the line off to see if the idle goes down when you do. Another thing to check out is pull the cap and rotor, inspect the springs on the mechanical advance maybe one came off or is broke, but you'd think that would keep it idling higher than normal, lub the mechanical advance mechanism with wd40 be fore you put it back together, make sure the distributor isn't loose.
Driving to gym tonight no issue, but coming home engine started pinging when pushing it over half throttle. Was running at 180 deg (as usual) and oil pressure was good. The air filter is pretty clean and same tank of gas for last couple weeks so no change there. Engine is a 350 with no cats ec. Should I start trouble shooting by checking the plugs?
Pulled the cap off the accel dist and found its electronic. Cap and rotor looked good and dist was not loose. The hose to the erg was loose at the valve so I put a clamp on it. Drove the car and for the most part no pinging. There may have been some pinging when lugging it up a hill and then flooring it, but not as noticeable as last night.
I am wondering if there could be a small vacuum leak somewhere that caused the pinging. Would a vacuum gauge be useful as I don't know the cam specs or how much vacuum it should have.
Also pulled a couple plugs so far and they clean and light gray. They are AC r45ts, should I go one step colder and get some r44ts?
Oh BKbroiler- I have had the same gas for a couple weeks so think that's probably not the issue.
Engine not pinging, then later on the same tank of gas, engine is pinging screams vacuum leak to me. Vacuum systems are tight just before they develop a leak, then you don't get the advance that you need. Yes, it COULD be a number of other things, but a sudden propensity to ping is most likely caused by something in the vacuum system losing its seal.
Testing vacuum now will be helpful, but especially for a non-stock engine, having a baseline would be even more helpful. Failing that, I would go all Eagle Eyes on the vacuum advance hoses to see if something looks dry rotted, loose, or had worked itself off of its connection, and go from there.