I thought I'd ask for some opinions on this. I swapped in two HEI distributors into my boat which has 2 -350 horse 454's in it. Set the total advance at 38, and forgot about them. I typically cruise at about 2500-3000 rpm with the throttle about 1/2-2/3 open. What I am wondering is, should all the advance be in at this rpm, or do we think that it needs a little less to avoid detonation while under this fairly heavy load?:idea:
I will be doing some cruising this year the motors will be left at this speed for several hours at a time, want to make sure things are working efficiently, and motor friendly
I'm no expert , but I would back the timing off a little for that extra insurance. IMO 38* is a lil aggressive. The only way to know when your timing is coming in is to have somebody spin um on a machine and check um...{I think} It's alot cheaper to be sure than guess.
I would say 38 sounds a bit high also. I know a lot of guys set thiers at 36 total. Use a timing light and a friend with the boat in neutral, and you should be able to see at what rpm's it hits fully advanced.
Darrell.
I'm not sure that its all the way advanced to 38* at 3000 rpm, I'm gonna check though. The distributors have mechanical advances in them, no vacum advance. I think if you bring the advance in too soon under a heavy load it can detonate or ping. hmmm.......
A lot of variables determine the best timing setting. Cumbustion chamber efficiency, piston dome design, fuel used and spark plug heat range are a few. Reading the spark plugs will tell the story as well as how the engine reacts to different settings. Start at 32 and increase 2 degrees at a time and see if there is noticable gains. Look at the heat line on the ground strap and compare where it is at each setting. If the heat line is on the strap near the threads timing is likely too high or plug is too hot. If the line is toward the end of the strap the timing may be too low or the plug is too cold. Ideally if everyting is right the line will be on the bend of the ground strap with the timing set at 36 degrees in my opinion.
Craig
If you don't have a dial back timing light, go get one......Plain and simple, bring the Rs to your cruise RPM and dial the timing back to zero, that IS your advance at that RPM. If you do have one, why haven't you used it???.........MP
or mark 38 on the balancer
Total should be all in by 2500-2800max, compression and gas octane will determine what the total is set at, if you can get away with it 38-40 will give you better mileage, and performance!..
Total should be all in by 2500-2800max, compression and gas octane will determine what the total is set at, if you can get away with it 38-40 will give you better mileage, and performance!..
Yup
I ran 38* in my last motor with 12-1 comp and avgas and she always got with the program
I'm no expert , but I would back the timing off a little for that extra insurance. IMO 38* is a lil aggressive. The only way to know when your timing is coming in is to have somebody spin um on a machine and check um...{I think} It's alot cheaper to be sure than guess.
If he is running good gas then 38 isnt bad by any means......
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