LS Swap Seafari 25

[doodlebug]

remember to remove the pressure relief valve and plug the hole. That joker got me when I rebuilt my 5.3 and deleted the afm.

[Xcomunic8d]

Do you mean the bypass check valve on the oil filter housing? I haven’t done anything there. I suppose I should look into it. Thanks for the heads up.

[Xcomunic8d]

Hit a snag on dbc on gen 4 engine

E38 pcms don’t support the IAC, TPS connections required for dbc. And I’m not willing to try to figure out a DBW saltwater situation.

So I found the ligenfelter trg-002 which adapts a 58x/4x engine to a 24x/1x harness. You can then use a LS1 stand alone harness and get a pcm from an early 2000’s Ls to control it. I think I’ll end up around a 2001 pcm. I’ll post more data when can on this issue.

[wattaway2]

Wish I had a bit more time as I’m on the Big Isld. Staying on a coffee farm airbnb. North of Kona(captain cook)Have to spend tomorrow getting ready for a overnight fishing trip with Kenny Lianes on the Vixen! On Tuesday/Wednesday then leaving on Thursday.
Sounds like you have a hell of a project going getting all of the electronic systems to work with each other! Been keeping an eye on your project and the good work your doing.

[Xcomunic8d]

For sure bro! I’m on Hilo side but I’m heading kona way on Sat. All those guys there are all stars. I haven’t met a bad one yet.

Enjoy. Ahi (yellowfin) is biting and ono (wahoo) is my favorite. I think there is a way forward here without the Holley terminator x. That would solve it all but this should work.

Tanks, eh. N Mahalos for da aloha!

[Xcomunic8d]

So it’s been awhile since I’ve updated this. I’ve been having a terrible time getting stuff. My wife’s school (and where our kids go) went to distance learning for 2 weeks. There have been a few cases across the campus and they had no choice. My son tested positive. He’s doing ok so far.

So I had ordered a matching gen 4 harness and pcm. That’s not gonna work. So I ordered a stand-alone LS1 harness that was labeled dbc. But it’s a dbw. So I ordered another harness and the correct 12200411 pcm and sent it to Brendan at lt1swap.com for programming.

Here I’ve been able to get the balancer back on. I had to order a 1157-0163 ls7 ($20 Chevy dealer) crank bolt and used about 8-10 1/2” washers to push that thing on. You’ll need someone with a breaker bar on the flywheel.



My plan for the coils won’t work either so I’m thinking of fabbing a bracket to go here or just screw them to transom. Thoughts? I’m making custom plug wires via a msd kit.



And here is what the raw water pump looks like when it is bolted down via bracket and crank bolt connector through marine engine depot.com



Well now I’m stuck at home for another 9 days until we all get tested. Eagerly awaiting the harness and parts. Guess I’ll do some glass work and painting as weather permits.

[FishStretcher]

If possible, mount electronics in a cooler, lower vibration environment. So the transom would be my preference.


With respect to the raw water pump. I can't tell where the bracket mounts- is it the block? This configuration means that the mass of the pump is hanging off the end of the crank, as that flat strapping won't support the pump body and in fact may add additional load. I would worry about fatigue failure from vibration.


I wonder if one from something like a 350 MAG MPI could be retrofit?


Or something like this, remote mounted: https://daviescraig.com/category/ele...ater-pumps-ewp

[Xcomunic8d]

Yeah I agree the transom is probably dryer. And will be less fab work to make an aluminum bracket off the headers.

That electric pump would have been cheaper than my scenario. And probably save hp. But I’m not sure I can return it. This is how ilmor does their Ls motors. I got the kit from marine enginedepot.com and bought the Johnson pump off Amazon.

Here’s closer up pics. No weight bearing on crank but obvious loss of hp.

Mounts to block






Has a flange that the crank bolt goes through and gives mounting point for water pump.



I’ll kick your idea around but I’m getting pretty far down the road here. That’s exactly what I needed a month ago. I absolutely would have used that. But, I doubt I can return some of this stuff. Once wiring is done hopefully can fire it up once pcm comes in from tuners.

[FishStretcher]

If Ilmor makes it I could very well be wrong.It looks a bit better supported than I could make out from the original photos. I would worry about alignment, but it's really hard to tell from here. generally, given the vibration of the system and flexure of the crank, a compliant coupling like a lovejoy elastomer jaw style coupler would be my go-to for a custom design, but if someplace reputable has engineered this, then I certainly can't validly criticize it from my living room 6000 miles away.


Not sure the Davies Craig pumps are good for salt water, although I expect they wouldn't be terrible.


Good luck, this is an interesting build!

[Xcomunic8d]

For sure. We’ll find out but as far as I can tell this “should” work. Yes I’m not the best photographer. I truly appreciate you drawing attention to a flaw that’s part of this posting.