Detonation/OverHeating

I have a 70' 350 SP engine, and as the engine warms up, I get more and more detonation. I think its from overheating. But all I have is an Idiot Light, and I don't know if it works or not?, Question is, how can I test if It works, or should i install a Guage(difficulty of install?).

Or... What could be another cause for the delayed detonation, I hate it!@#, sounds like the valves are gona fly off, but it only happenes under higher acceleration.

Thanks for any input.

 

Don't take overheating or detonation lightly, it will ruin your engine and fast. If it was me I'd go to the nearest parts store and buy a temp gauge and install it. It's easy and they come with instructions. When you get the cooling problem solved, if there is one, check the ignition timing and if the engine is stock, set it to stock specs.

testing the temp sender would require submersing the sensing bulb into water at or just above the designed switching temperature. At that point there will be continuity from the wire connector to the base of the sender. To test the light ground the wire, the light is supposed to come on when it gets grounded.

 

Thanks for the quick reply, I will go and buy a temp guage asap. (or should i just buy a guage set?, oil presure, water temp, and batt?), what should be the correct timing for this engine, i havent checked it in a while. And what should the water temperature be at?

My dad keeps telling me to use lead additive, but i keep forgetting to put it in before pumping, could that help with the problem I have?, and will it hurt the engine not ssing lead additive? Thanks

 

You don't need lead additive unless towing a heavy load. What you do need is octane, plenty of it. Use 93 grade and add an octane booster. If your timing is not too far advanced, then octane is your problem.

 

The more gauges, the merrier...imho. Just get some good ones, the $10 sets aren't accurate. Sunpro, Autogauge, etc are ok, I really like Faria marine electric gauges, they're better made and cheaper than automotive gauges.

A REAL lead additive is going to be hard to get, and poisonous as all get out. Better to keep the engine cool, and maybe back off the timing if need be. Read the sticky at the top of the "Sparky's Corner" forum, lotsa good info there.

Buick 350's are prone to detonation, especially when they get above 180 degrees. Make sure your cooling system is top-notch, clean, good fan clutch and fan shroud ducting, 180-degree t-stat, and it'll prolly still get up to 200 on a really hot day with the a/c on, then start pinging under load. I end up backing off my timing during the summer, and pushing it back up in the cooler months.

 

cool it down

my sons car had the same problem...most likely the radiator is just plain worn outand besides they are just too small !!...we installed a radiator from a 70 455 and then after removing the mechanical fan installed an electric model from a 2000 camaro...works like a champ and we can sit in any traffic andput all the timing we need ( we have an adjustable vaccum advance) with an hei...what a difference !!

 

I have the same problem with my 350... hope you have more luck getting it worked out than I did :TU:


(I have a new 4 core radiator, 160* t-stat, timing at stock, then retarded, then new distributor timed at stock, then retarded, cooler spark plugs, I run 93 with an octane booster, and just recently found out that this year my carb decided to stop working properly)

 

check your plugs

sounds to me like you may just too lean...although thats where the power is it also is ping time...check your plugs and if need be maybe your carb is just too lean..

 

Detonation is also caused by foreign material in the combustion chamber, i.e. bits of metal or even carbon that once it gets heated up (or when the engine is under acceleration) glows bright orange. Then on the compression stroke it creates a second flame front, sometimes before the spark plug has a chance to fire. Then when the spark plug fires, the plugs flame front and the second flame front collide and you have detonation. I doubt lead additive will help, if anything it could be the culprit. The lead will "coat" the valves, and that coat will/could heat up and cause detonation.

Hope you get this problem sorted out asap Slawek. :TU:

 

Start with the timing, after you've got the cooling issue solved. I use a new 4 core rad and a 180 deg therm works like a champ, even the trans stays cooler with the bigger rad! If a lean mixture could add to your problem then you should check your fuel supply.

I had a plugged fuel sock in the tank and I kept plugging fuel filters. I dropped the tank, (found the buildsheet), cleaned the tank with carbcleaner, bb's, and trans fluid. Then I blew the fuel lines out with air and I haven't plugged any filters yet. Car runs better with just those changes.

 

Here is an article that may help. Ian
http://www.streetrodstuff.com/Articles/Engine/Detonation/

 

I got the timing done. According to a timing guide I found on they site. I set it that I have 30* mechanical advance + stock vacuum advance. Pings with vaccum off or on. I bought a guage set today. I'm gona install it tommorow, and see if i'm overheating.

 

Ok, I got the guages in and it works good, I only drove it once but I didn't remember what temps it was at.
What kind of driving procedure should I do to see if I'm overheating (70 GS350)? Thanks.

 

I did the timing according to your guide, I had it set around 30 and it pinged horribly, so I backed it off alot(15-25*). Where can I get springs that that are fully engaged at 2500RPM? My distributor is stock with new cap, rotor, points, condenser, wires and plugs, but still the original vacuum canister.
I'm gona make my own vacuum advance plate, looks simple.
Thanks

PS: How about the possible overheating problem?

 

I was having a pinging issue as well. Try 93 octane with some NOS brand octane booster. If you can get some 100 octane try mixing with some of that as see what happens. My detenation has stopped after trying this. A temp gauge is a cheap easy instal. Try flushing your cooling system and add some Red Line water wetter additive with a 160 stat and you will notice a lower engine temp. Of course, listen to Larry and all his information! Your timing may be to far advanced. Mark

 

A lot of great advice posted here.

But, if all else fails, there is one surefire solution that, IMHO, beats running racing fuel, and costs maybe $45 one time:

http://cgi.ebay.com/ebaymotors/ws/e...tem=7983106913&category=42604&sspagename=WDVW

Solved all my (20+ years) of detonation issues the day I installed this kit. Certainly not everybody's first choice fix, but one that works better than any other I've tried.

p.s. Here's an even better model:

http://cgi.ebay.com/ebaymotors/ws/e...tem=7983001662&category=42604&sspagename=WDVW

 

Thanks, I'll try higher octane, or the water injection.
I'm gona get new springs, are these ok? Do they sell springs at autozone or napa?
And, is the stock vacuum advance limitable? Because I don't really want some fancy one.