Accelerating from 40-50mph my engine pings. No loss of power or backfire and idles super. Fuel is european octane 98.....That's different from RON 98 in USA!!! Don't know which one is higher but i think USA RON 98 is higher Octane rate. Ignition is stock (with points) adjusted. Vacuum hose not hooked because it will ping more then. Carburator was a bit lean but it's now adjusted more rich. Probably never been rebuilt Thermo works well on snorkel airfilter housing. Thermostat is OK. Heat riser valve on exhaust manifold works well too. It opens max when warm. Heads have never been off from this almost 40 year old engine so it's probably carbon on valves and on top of pistons???? Any experience or tips are very welcome, thank you!
Try backing off your initial timing about 2 or 4 degrees (retarded). I run mine like that all the time so I can use cheaper gas. On hot dry days though, I still need high octane or it will ping anyway. That's not something to take lightly, pinging can and will damage your engine. It's like hitting it with an air hammer! ou:
OK, thanks but then it will run terrible at idle. I have it TDC now. How about a Fel-Pro gasket and get rid of the carbon. The original steel gaskets are very thin, 10:25 compression is too high i think when using todays fuel.....Thanks for the tip!
i agree on the back off timing, change gas filter too. it can affect cruise if it is restricted(lean) going to fel pros will help some , you might want to flush cooling system/go 160 thermostat. check for vacuum leaks and overheating as with out the vacuum advance and you still ping ,something else is wrong. what is dwell/timing set at? right sparkplugs?you try colder plugs
i know it's not stock but you could get a msd ready to run distributor. that way you can fully adjust the entire timing curve. what to do is get an adjustable timing light, the ones with the dial on the back. check your total timing around 3000 rpm's. you shouldn't go beyond 34 - 36 degrees. the msd unit is electronic and will provide more spark also. i have run cars with that compression, cast iron heads and 92 - 94 pump gas with out issue with msd distributors. you could use another brand but msd is real good and they can use a stock gm dist. cap and rotor.
4 degrees retarded shouldn't affect your idle too much. You need that vacuum advance connected to make it run cooler (which helps prevent pinging). It also makes gas mileage. Also, perhaps you should have your distributor re-curved. Maybe someone was screwing with it and it's advancing too fast? Also, Andy is right........try a cooler thermostat, but keep in mind an engine will only run as cool as the radiator has the capacity for. A new radiator almost always runs way cooler than an old one. Ping is increased by hot temperatures, dry air, and advanced ignition timing as well as carbon build up. I doubt carbon is the main cause of your problems though. :Smarty:
OK thanks all. But when i set my distributor timing on the block later then 0 TDC it will run less good idle and it will perform to slow. Connecting the vacuum will provide less fuel and run cooler but it will certainly ping easier with less throttle and that is worse. Thermostat is cool already, i have NGK Plugs they replace Delco R 44TS Thanks again and more is welcome!
what are the points set at?(dwell) you should be able to set it at least 4 degrees advance. are you sure the radiator is not pluged? i think you should get a points conversion kit for your dist and reset your timing to 4 advances and start from there. also put a temp guage on it to see your actual engine temp it will perform worse with less timing so you need to find you why its pinging rather then the retard quick fix. look for vacuum leaks also.that will lean it out you have a bigger problem that you need to find try turning on the heater full blast at 40-50 and see if it lightens up then its a cooling problem ,check the radiator cap also might not hold pressure either way keep looking
Keep in mind these engines were made in a period of time when the gas had higher octane, and contained lead. Today's fuels cuase problems like you have.......it's not really all just about octane. You can get an adjustable vacuum advance that you can set so that it waits longer until it advances the timing. Also, as I stated before, 4 degrees won't really hurt performance much at all. Yes, the idle speed will be slower, but you just turn the idle speed back up to where it should be with the adjustment screw on the carburetor. Without your vacuum advance connected, your gas mileage must be horrible! :shock:
Points are OK and set stock. It all looks new under the distr. cap, no rust good springs all good. Timing is good. I will check temp with meter. I have been driven a 1968 Riviera on LPG that absolutly did not ping because LPG has a very high octane rate. Lead was supposed to cool down the valves right? LPG let the engine run hotter but without any problems. I had an Impco liquid set up (Impco is made in the USA) Anybody heard of LPG? They use it in Canada on trucks and bus too i have heard, it is very cheap. On the highway at 60-70mph i do 15.5 miles on one gallon. I think that is pretty good without vacuum, what do you think?
I do 15.5 miles on the gallon on the highway 60-70mph without vacuum advance...how's that? Nobody touched it, it's stock and works fine, weights, springs, all good, no wear! OK, MSD, but what happens when there is too much carbon Paul? Will it ping too with MSD? To be honest about the conversion kit (i do not mean MSD Paul)...i think it's a bit bullshit you know, points work perfectly and on a stock engine you don't feel the benefit. I have payed a lot for it on my 68 Riviera and it did not start better, drive better, or less gas/mileage....just no adjustments have to be made, that's all. I am almost sure that it's temperature (if too hot) and carbon on top of pistons and valves...i hate to take the heads off because the weather is so good now! If anybody has another trick to eliminate or look at...i am all ears!
TDC is the correct timing on your engine. Is it the stock points distributor?(1111335) Make sure the vacuum advance is hooked to manifold vacuum. If it pings without the vacuum advance hooked up, check the total timing. see if someone has put lighter springs in the distributor. That combined with a vacuum advance that has not been limited, will make it ping. Are you sure of your timing light? Try another. Also, what shape is your balancer in? If the outer ring slips, the timing mark is useless. You can check that with a piston stop.
i dont think its carbon as much as overheat and upgrade from points from my experiance has seen a better running car. you might need headgaskets or a radiator or vacuum leak but i think you are running hot and setting points can affect that also you could try mixing your antifreeze 50/50 with water otherwise you still have a major problem i could be the harmonic balancer slipped too i have seen it but not common is a plugged muffler or crushed exhaust either way you still have a big problem and your trying to quick fix keep looking
Look for the info at this sight showing how to set up a 30 degree mark on the damper. Or using a timming light with an advance dial. Make sure you are not exceeding 36 degrees total (vacuum disconnected) Check the spread between min and max degrees and modify for proper idle setting and 36 degree at rpm tops. you may need soft springs in the dist. to allow mid rpm to check the top end advance. I've had 401 and 430 Buicks run on regular gas, steel shim gaskets and stock "10 to 1" pistons. They ran hot too! BUT DID NOT PING after I super tuned them.(90,000 miles of carbon). After making sure the dist. range and timming is set, only then can you get to know your engine. DO THIS NOW even if you have to mail it to someone. My 401 had a bad damper rubber and the timming could not be set. Replaced it. My 430 had problems due to restricted original head pipes. I replaced them and gained 100HP.(over heating, pinging, no power) My 430 also had carb gasket problems due to the manifold heat riser trought just behind the front q-jet bolds.(vacuum leaks, pinging) Check these out AFTER you set up your distributor.
as far as using an msd set up it just allows for full adjustability. like someone else said these engines were built for leaded high octane gas, not unleaded lower crap that is out there today. there is a complete tread somewhere on this board that i believe larry wrote up and it explains how th whole timing curve works. search it, give it a look and go from there. that is also true about a clogged radiator. i had an old chevy blazer that would ping on the highway but the temp gauge told me it was hot, replacer thew radiator and it was all set. i would rig up a temp gauge to monitor that first. if there isn't an issue there then reseach your timing situation.
I don't mean to hijack this thread, but can you really use the stock looking G.M. type cap with an MSD distributor? I have the new ready to run type, from the GSCA. I believe it is the standard MSD red cap w/the wire holder on the top that says msd. I was looking for another option to keep it more stock looking. Regards, John.o No:
Just to toss in my 2 cents, I had a 68 Riv. 430 that i built and it to had a pinging problem i tried every thing including water injection(witch did work by the way) and this was with a pretty stiff cam in it. What finally cured my pinging was a 2 1/2" exhaust system. This reduced back pressure and cyl.head temp.All this was done doing all the advise that you are recieving here. I later went to an HEI dist. witch i modified ( no vac. adv.) using a Pontiac adv. plate to restrict. the mech. adv. and gave me a near perfect adv. curve using diff. adv. springs.Oh and my 430 with the steelhead gaskets,10 off the heads and 20 off the block and 60 over was right at 11.1 A 160degree t-stat helps allot to.
