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Discussion Starter · #1 ·
Ok, maybe that is a little dramatic but I put the hammer down and I immediately hear it. I know about additives. I know about octane boost and think it is a marketing ploy at best. The highest octane im seeing is 97 so what do I do to quelch this detonation on a stock engine? I'm interested in hearing everything from snake oil remedies to the meat and potatoes stuff. Engine is a 65 390/4v with the expected compression.
 

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Discussion Starter · #3 ·
Uhhhhh, dont really know. It's advanced decently far from what I remember a buddy of mine doing last year. Those marks are sure hard to read.
 

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i would set base timing again for sure
 

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Try it with the vacuum advance disconnected. If this stops the pinging, calibrate the vacuum unit. If it's OEM, the end fitting with the vacuum fitting will unscrew with about a 3/4" open end wrench. Behind it is a spring, a tube inside the spring and several washers. Add small washers or a longer tube to lessen the degrees of vacuum advance. Add larger washers to shim up the spring and slow the rate of advance. Play with it untilt the pinging stops. If it's a late model unit that doesn't come apart, insert a 3/16" or 1/8" Allen wrench in the end fitting and turn one way or the other to lessen vacuum advance. If I remember, clockwise slows the advance. If the problem is mechanical advance, take off the point plate and check the weights and springs. You can bend the spring posts out to slow the advance or install heavier springs. There are two slots that limit amount of advance. One is usually marked "10L" and the other "13L" or similar. Assemble the point cam (upper) shaft so the smaller slot is used. Check everything for wear. (Vacuum advance goes away at full throttle so it only can cause pinging at part throttle cruise and at the instant of going full throttle-it takes an instant for the vacuum to bleed down.)
 

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On 2006-06-10 17:50, v8shadow wrote:
Ok, maybe that is a little dramatic but I put the hammer down and I immediately hear it. I know about additives. I know about octane boost and think it is a marketing ploy at best. The highest octane im seeing is 97 so what do I do to quelch this detonation on a stock engine? I'm interested in hearing everything from snake oil remedies to the meat and potatoes stuff. Engine is a 65 390/4v with the expected compression.
OK...I'll be the bad guy for this one. You complain about detonation...but don't want to use octane booster or additives? OK, I can understand that, but your answer to the basic question that must come before anyone can offer a reasonable answer is:

.... Uhhhhh, dont really know. It's advanced decently far from what I remember a buddy of mine doing last year. Those marks are sure hard to read ....

You'll never be able to tune out detonation (or even know if detonation is the problem or if it might have other causes) until you know where you are starting from! If you advance the timing on any engine far enough, you can induce timing related detonation. The spark has to be there at the correct time or over time, you could seriously damage your engine or waste fuel.

FE's, especially the early 60's models, regularly came from the factory with 10:1 or better compression. They were also made to run on Leaded gasoline. The new gasoline formulations are made for cars that run under computer control (to adjust and optimize time so they can run on the new "watered down" gasoline). A points type, vaccum/centrigal advance distributor - probably original to a 40 year old engine, is way to "sloppy" to guess at timing.

Everyone that has these cars or engines in original state, has to back-off timing from where the factory set them when they were new. The bad old days of 100 - 110 octane premium at the local pump are over. Your choices...once you determine current timing
... is either backoff timing until it stops "pinging". 2. use av gas, which still has some Lead in the formula. 3. clean the engine (internally) if there are carbon deposits, hot spots in the chamber, they can contribute to the pre-combustion detonation. Of finally, rebuild the engine to compensate for the fuel available today. You might still be able to get away with higher compression - but you'll have to play with cam timing, exhaust, better ignition components and build the engine to work with what is available today.

Bottom line is you need to know where you to get where you are going. Otherwise you might end you going in the wrong direction, just as easily as stumbling on the right solution out of dumb luck.
 

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[/quote]



Bottom line is you need to know where you to get where you are going. [/quote]
HUH


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1968 mustang 306,stock ported heads,650 Holley DP,weiand Xcellerator intake, Comp cams Magnum 292,[email protected] and 518L,heddman headers,4speed with a 4.11 detroit locker.13.69 at 101 mph.

<font size=-1>[ This Message was edited by: frdnut on 6/12/06 12:10am ]</font>
 

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If your looking for somethnig to get out carbon deposits SeaFoam works well and also someone might say this is stupid put sucking up some anti freeze through the the booster vacuum line and letting it suckup and then shut the car off for some reason that **** gets carbon off really well i found out on accident once.
 

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On 2006-06-11 10:05, dbu8554 wrote:
If your looking for somethnig to get out carbon deposits SeaFoam works well and also someone might say this is stupid put sucking up some anti freeze through the the booster vacuum line and letting it suckup and then shut the car off for some reason that **** gets carbon off really well i found out on accident once.
It’s not so much of the antifreeze that does the cleaning; it’s the water, which turns to steam. The steam vapor from "small amounts" of water getting in the combustion chamber are almost instantly vaporized, that helps loosen the baked on carbon deposits off the top of the piston, insides of the combustion chamber, as well as the valves.

It’s not something that you would want to do all the time, but for a quick cleaning it works pretty well.

There was a pretty exhaustive discussion thread about a month or so ago. A lot of guy, either by bad luck (cracked cylinder wall, head gasket failure) or intentionally ("dribbling a small amount of water or water/alcohol mixture through the carburetor throat)...have spoken of their results. Then there are commercial products that you can add to the gas tank, basically naphtha or some other flammable solvent. it acts a detergent to loosen and allow the combustion process to burn off carbon deposits. Do a search to find it thread for more light reading.
 

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I have been fighting that problem with the originally a 2 bbl 66 390 in my 65 country squire,I installed a truck duraspark distributor and kept the timing at stock 66 specs and no noticable pinging with 89 octane gas. I have been wanting to ween it off premium and use regular but will settle for 89. Jeff
 

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Discussion Starter · #12 ·
I was told once that I couldnt really trust what my timing light tells me because of variations on engines with some miles on them such as timing chain stretch and whatnot. So, I timed it by ear. My chalkline is probably still on the harmonic balancer when I set base timing last year. I will retard the timing a bit from where I have it, and see about cleaning those inner deposits. I think its time to go with pointless distributor or petronix as well, if not go completey upgraded to a much hotter sparking system. Either way, Ive got a bit to go on now and I'll try it all eventually till the pinging stops when I open up them secondaries!!!
I am somewhere with none of my reference material, can someone tell me tune up specs such as spark plug gap, point gap, and base line timing for a 65 390/4v?? Thanks.
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KEN
Factory 65 Galaxie 500 390/4v
79 Mercury Marquis 351w/2v daily driver

No matter how complicated something is or seems, always start with the simple basics then work your way to the rocket science !!!
Me

<font size=-1>[ This Message was edited by: v8shadow on 6/12/06 10:33am ]</font>
 

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Retard the timing a couple degrees WITH the vacuum advance hooked up! If you leave the advance hooked up and you retard the "ping" out of it you will be right where you want to be. If you unhook the vacuum and do it that way there you are doing the EXACT same thing but going through extra work to acheive the same results.

Seafoam:

When useing seafoam to clean out an engine here is what you do.

Start and slightly warm the engine but NOT HOT! Remove air cleaner and bring the rpm's up to about 1,500, directly dump the contents into the carb in a medium flow and keep dumping until the engine dies. You should be at the last ounce or so of seafoam at that moment.

Turn off the key and let it sit for a day.

The next day start the engine and drive like normal, the sea-foam will have loosened all of the carbon that will loosen without a wire brush, you will need to blow it off, so let the engine warm up normally then go do a mile ro so like you were breaking in the rings... Romp it and decellerate then romp it then decellerate. This is all you can do with the sea foam.

But before you do all of that, change your plugs to a "Cooler" setting. That's before you re-set the timing, and before you use the seafoam. Your engine SHOULD NOT have annoying amounts of carbon build up, unless it was previously only a <U>grocery getter driven by granny or an oil burner</U>.

FE
 

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Discussion Starter · #14 ·
Last night I quickly loosened the distributor and tapped it CCW a few degrees. I did this by eyeball only and thought I would give it a whirl. I dont know how far I had it advanced before I made the adjustments, and I still havent checked the current reading but the detonation is gone as far as I can hear and it runs soooo nice now. Unreal. Could it really be this easy? Must've just been to much advance. I am going to take a few mileage readings to compare. Only difference noticed afer this adjustment; it was a bit easier to start cold (didnt need primed before starting) and is finicky starting when hot. I have no idea. After I note where I'm at timing wise, and get my mpg reading, I think I will go back to advancing it just a tiny bit to get that happy medium of maximum power with no detonation. I still plan on using the seafoam along with other ignition upgrades as well.

_________________
KEN
Factory 65 Galaxie 500 390/4v
79 Mercury Marquis 351w/2v daily driver

No matter how complicated something is or seems, always start with the simple basics then work your way to the rocket science !!!
Me

<font size=-1>[ This Message was edited by: v8shadow on 6/17/06 7:29am ]</font>

<font size=-1>[ This Message was edited by: v8shadow on 6/17/06 7:46am ]</font>

<font size=-1>[ This Message was edited by: v8shadow on 6/17/06 7:55am ]</font>
 
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