Thread: Compression is too high on my '71 460 Lincoln...

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Originally Posted by chevydrivin

How about that can of stuff they sell at wally world..........what is it in that little ole can? "112+ Octane Boost" LOL.......................

I'm not sure about that stuff, never having used it. But I'm told that the manufacturers figure one point as actually 1/10th of a point, so if it says it raises the octane 5 points for instance, it will actually raise the octane from 93 to 93.5

just dump a gallon or 5 of 114 trick in there!!!!

Originally Posted by techinspector1

I'm not sure about that stuff, never having used it. But I'm told that the manufacturers figure one point as actually 1/10th of a point, so if it says it raises the octane 5 points for instance, it will actually raise the octane from 93 to 93.5

I've heard that as well. I also have read of some tests that were conducted (I don't remember where now though...) that in some cases there were no noticeable differences after andding it, and in some cases adding the octane boost actually lowered the octane rating.

Originally Posted by 71LincolnCoupe

Paul, I am running premium gas only, and he said the compression on the cylinders was right around 200 psi. I would like to stay away from changing carbs again because this one is brand new.

I know you don't like this idea, but I would probably start with the carburetor. Although this may or may not necessarily have anything to do with your ping situation, I really think your engine should have a Holley 850 double pumper, List # 4781. It is a progressive secondary carb, so you can cruise around on the primary throttle and opoen up the secondaries whenever needed. Further, it can very well address (to one extent or another) your ping situation. See if you can borrow one from somebody and play with all the adjustable parameters. Properly adjusted, it is not too big for your engine.

Is your distributor the OEM unit or is it aftermarkent? Where is your timing set? This is also important, as are the advance cure details.

I suppose if I were in this situation, I might pull the front timing cover and evaluate cam timing. There are a lot of budget chains whose keyways are way off. I've even seen it on a CompCams 3122 double roller (as have others). If you cam timing is farther advanced that it is supposed to be, you will be shutting the intake valve too early and thereby have a greater amount of cylinder pressure. Bringing camshaft timing back to spec can very well help your situation because cylinder pressure will be reduced. Even if cam timing is spot-on, you can select the retarded position (the timing chain's crank gear likely has three keyways to choose from: -4*, 0*, & +4*) and lower cylinder pressure that way.

Between cam timing, ignition timing and carb, I'll bet your pinging could be all but alleviated.

Paul

I'm gonna print all this out and show it to the car guy when he comes back into town. Thanks Paul.

As a reference ,I have basically that same carb on a 305 and its barely rich to almost perfect.Your motor is 155 ci larger than mine...........I also agree with Paul,some fine tunning could make this work fine.........


Also 2 to 5 gallons of race fuel mixed into the pump gas,could take advantage of that compression and not break the bank.........unless this is your daily driver.......I think the general rule is about 10 to 12 percent more output from the race fuel than pump gas under the right conditions.