Offshoreonly.com - Backfire Issue, need advice.

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Again thanks for all the input. We put the boat in the water this afternoon and test ran it. It ran strong. But discovered blown head gasket on Rt side of left engine. Seeings how we're gonna have the left intake off anyway, we may just go ahead and put the blowers back on now.

OK then...you guys are probably getting pretty good at this by now !!! LOL

Where there is a will there is a way (and a grinder and a cut off saw and a welder). Never could get the MSD units to work, put the ground and the hot straight to the battery, no dice. The tech support guy said to ground the heads to each other then to the negative battery post with 10 gauge wire. I decided to modificate (my own word) the HEI's. This is the first vehicle I've ever owned with blowers and I like it. I have some nicer looking plumbing coming for the carbs. Just happy to hear them running....

https://youtu.be/_W1LQeRN2YU

Quote:

Originally Posted by hblair (Post 4434121)

Damn distributors....I knew it !!! LOL Sounds sweet !!! Oh.and....BTW...I "Modificate" things all the time !! LOL. Must be a "Southern" thing !!!
Enjoy it and "Roll Tide" !!

Quote:

Originally Posted by MILD THUNDER (Post 4432846)

Looks like 320 bucks for the Marine DUI setup? Their site shows that they don't sell a different advance curve kit for their distributors, and that they tune them for your engine when you purchase them. If you want a rev limiter, which I would think every hi perf marine engine should, thats another 145 bucks. So, looking around 465 dollars, for an ignition you can't tune yourself, no things like custom 3d programming, pre selectable marine timing curves by turning a dial, start retard, idle stabilization, data logging, and so on.

Thats a tough call. For around another 75-100 bucks, you can get into a Daytona ignition, that has a ton more features. I think its well worth the extra cost, to have the capability to run lots of timing at idle, pull it back off idle, ramp it in per RPM based, or go 1 step further, and use a map sensor, and have a 3d timing map.

With that being said, I do understand guys liking the simplicity, and 1 wire hookup of them.

I've seen 3 DUI marine distributors come apart.been a couple years but 2 went out in 1 summer and the other went 2yrs later.went w/ gm hei distributors small cap 2 wire hook up.been fine.If we're to do it again,I would go w/ the Daytona set up.very nice piece.

Does the MSD distributor need to be phased? or is that something different than when I had to phase my TB distributors when I went to my Crane HI-6M's? Just curious, I'm really ignorant when it comes to ignition/timing:)

Quote:

Originally Posted by Rookie (Post 4434211)

Different.

You had to phase the TB's ahead because to change advance electronically takes varying amounts of retard. You can't advance something (electric) in time that already happened (mag pickup event), but you can delay it. That's why kind of hard to understand, but easy once you get it.

Say you advance dist 50* in position:

To get 30* advance, the electronic modules retards (waits) 20*
To get 20* advance, the electronic module retards 30*
To get 10* advance, the electronics module retards 40*.

If you set distributor in 10* in advance. How does a module go into the futre and advance it 20* ? It can't.

You can't begin a spark before the magnetic (or optical) trigger happens. You can only do spark it at same time, or later on.

==========================

TB's have a fixed rotor position.

Now, the coil in plug hei's and many points distributors used weights and cams. The rotor position changed as rpms climbed to change the timing. Ths they where called mechanical advance. The magnetic pulse and energy from coil didn't change timing, the relationship of the rotor to the cap terminals did.