Advancing timing.

[Outnumbered]

I was thinking about advancing the timing on my 87 340hp OMC King cobra to pick up some more power. At 1500 ft elevation I max out at 60 mph on gps at about 4400 rpm running a 22p 4-blade stainless. What are the pros and cons? How high can you go? Will I pick up torqe, rpm, accelleration???
The spec in the OMC manual recomends about 11-13 degrees for mid-grade pump gas and I think this is where my OMC mechanic has it set. I run at 1500 and 5100 ft elevation and have no problems with mixture or power loss going back and forth now. I usually run 89 octane because the timing doesn't require any more, per OMC. I have the stock points ignition and coil and I'm running a holley mechanical adv marine 800cfm carb.
Thanks in advance for the help,
OL

[Outnumbered]

Oh yea, its a Ford 460, OMC stock, thru-hull exhaust.

[gnarley]

OL, the timing recommendation would be & has been to advance 1 degree of timing for each 1000 feet of elevation increase to compensate for lack of air. The auto manufactures knew this & started putting altitude compensators in the computer controlled cars some time ago, as they knew this could help & you didn't have to take the car into the shop every time you drove up & down the mountains. This will help some; Not Guilty could help you better with mods to your 460 King Cobra.

[Outnumbered]

Hello.........Anybody home???????????????

[gnarley]

OL, what you didn't understand? Boat manufactures didn't put altitude compensators on boats the way car mfg's did. So if you change boating area altitudes you must change the timing to compensate for your new area & even mixture adjustment if you want to keep some of the performance, yeah you need to advance it specially if you go up to 5000' ft elev.
If you don't understand something say what it is instead of ?????????

[Outnumbered]

Gnarley, I was't responding to your reply. I was commenting on the lack of action on the boards . Seems like everyone is gone.
Anyway, I understand what you are saying. But if you read my original post, I am not having a problem with the altitude. My boat runs strong at 5100 feet and I am sure its a bit slower but I don't know because there is a 35mph speed limit on Lake Arrowhead .
Gnarley, I am not much of a gear head and I am looking for some basic advise. How far can I anvance this thing without worrying about doing some damage to the motor from detonation, pinging, etc. Seems like 12 degrees initial timing is a bit conservative, but I'm not too knowledgeable on these things. And, by the way, I am mainly looking to improve performance at the lower elevations. I hope this clears it up. Sorry if you took that last post the wrong way.
OL

[Outnumbered]

Oh yeah, thanks for the rating, I won't return the favor

[gnarley]

OL, if you can, time it & check the total advance find out how much the total is & when it has stopped advancing. Best would be 12 to 16 degrees initial timing and a total of 36 degrees at 3000 RPM, & for you maybe 3500 RPM. Remember you should NOT hear any detonation through any of the range of RPM so if you need to back it down about 2 degrees at a time. You want to be as close to detonation as possible WITHOUT detonating
And by the way I don't rate other users when I help them, I rate other users for helping me or tips I saw them post or other useful info or good knowledge! I give negative for the opposite.

[Outnumbered]

Thanks for the info, I will give it a try. Does advancing the timing give you torque, HP, or more RPMs? Not sure what to expect.
No problem on the rating thing, I just picked up a new low rating, figured you were pissed at my reply.
OL

[RandyH]

Charley,
How do you know what Detonation sounds like. I am suppose to have my total advance at 36 degrees also according to my engine builder. BBC
I run about 33 now. Cant always find 92 octane on the lake. I have Aluminum heads and all the good stuff. The solid lifter set up is loud . I have an enclosed compartment. I dont know if I could hear it or not if it happened. Is this the pinging sound I have heard in my truck before on bad gas or is it a missing sound.
I want to get to 36 degrees as it picks me up 200 RPM but I dont want to hurt my motor. 5200 RPMS now and 5400 is desirable. I am at about 700 feet above sea level also.
Thanks Charley.
Randy