Offshoreonly.com - Driving advice for a 99 Daytona Eliminator 28 TD

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Quote:

Originally Posted by articfriends (Post 4357599)

When we dynoed my 540 boat motor with blower belt off, my 600hp Pontiac car motor and several circle track we found that there was a sweet spot where motor made peak hp, then there would be a spot where it made same hp about 2 degrees higher but was on edge of detonation or simply no gain, then we would go 2 more degrees and find power decaying 10 to 20 hp. On the pontiac we did a tune for scca racing where we pulled 10 degrees of timing and it loses 120 hp. IF your motors like 36 total at wot lets say, at 50 they should be down well over 100 hp , that number is suspect as it should have detonated itself apart by now. I would do a leakdown test as the rings would be broken or soft now IF it was detonating alot aside from lifting a head gasket or burning holes in pistons which you would know

Smitty, I know when jetting two-stroke sled engines you could jet them so lean that they were on the other side of the "bell curve". Meaning they were so lean they couldn't make enough power to do damage. Just curious if the same would be possible with timing?

Okay, just got in from double checking the timing with a second light. It was definitely 22 at idle and 50 at full advance on both engines. Adjusted both engines to 8 degrees idle and 36 full advance. Had to adjust my idle up as I retarded the timing but other than that they run fantastic. I pulled a couple plugs from each engine and they looked a little rich, but absolutely no signs of detonation. They were perfect. Again not sure how this is possible, but I think the motors are okay, and hopefully I just found a bunch of extra horsepower. The one engine did have a little rich spot in the lower rpm's with the higher timing. It would stumble and cough once in a while, it would even die once in a while when I went to get on plane. This seems to have gotten a little worse after retarding the timing. I think the timing was compensating for an overly rich condition before and now that the timing is corrected it has gotten worse. This was all done on the hose but I think we are making progress.

You could also cut water channel grooves leading up to the thru hull pickups, but yes at least trim them shorter.

Looking forward to hearing good results

Quote:

Originally Posted by rob vanharten (Post 4357778)

It could be because your initial timing now really sucks.

But never change your correct total for better initial. Change your initial and keep your correct total.

Lock them out if need be:bestwishes:

Quote:

Originally Posted by offshorexcursion (Post 4357800)

You could also cut water channel grooves leading up to the thru hull pickups, but yes at least trim them shorter.

Looking forward to hearing good results

I dont like going through the bottom period, the boat I just removed two from had wet coring because of them. Although they were sealed with silicone, not 5200. Even if they are trimmed they still slow the boat down, sucks that he would have to get the holes repaired to go back to the drive pickup.

Did you ever figure out your timing issue?

Quote:

Originally Posted by JRider (Post 4362839)

Did you ever figure out your timing issue?

Yes, it turns out my distributors are actually msd hei's. I ordered two msd spring and bushing kits, and installed the lightest springs and the largest bushing. I now have 18 degrees initial, and 36 degrees total. Hoping these make a lot more power now. Also have imco -2's coming and trying to figure out the best way to trim my pickups. I am hoping to unlock 20 mph.......:)

Cool! I cant wait to see the results, who knows, we just may cross paths next summer. With the imcos you really wont need those pickups, they intake a LOT of water.