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-   -   Ls1 upgrade questions (https://www.offshoreonly.com/forums/general-q/284076-ls1-upgrade-questions.html)

spectras only 09-05-2012 01:32 PM


Originally Posted by mike tkach (Post 3769749)
almost all i o marine engines are car engines adapted for marine use,mostly small&big block chevrolet.

^Yes^.

Have been using automotive crate engines for over four decades. Other than the obvious,marine carb,alternator and starter, installing brass plugs and cams more suitable for marine use, proper break in like 20hrs prior going to WOT, maintenance is the most important, like changing oil @ 50hrs at the minimum and the engines will live as long as the so called 'marine' engine.
When I did a project with a friend, chose the ZZ572 automotive crate engine for a single engine install in a rather large boat. Needless to say, nay sayers doomed us from the beginning,lol. We have close to 400hrs on the engine running hard in the ocean,crossing between the mainland and Vancouver Island on weekends.We've encountered problems with the Stelling headers, with the inner wall cracking at the flange, dousing an exhaust valve, dropping it. We tossed the headers and had Eddie Marine make a tall s/s risers for the EMI alu cast manifold, combatting reversion with the wet exhaust system. Not a problem since.Here's the link of the build if anyone care to read it.
http://www.riverdavesplace.com/forum...ead.php?t=4456

Wes Burmark 09-05-2012 07:23 PM

We have 105,000 miles on the LS1 in our Corvette. Still hauls ass, still gets close to 30 m.p.g. on trips, and uses zero oil (Mobile 1 5w30) between changes. The LS1 makes about the same H.P. as my 6.2 MPI iron Mercruisers but I'll bet it weighs several hundred pounds less. There is no easy way to get more H.P. in the 6.2s but the LS1 is just crying for bigger heards and a slightly bigger cam. 400+ H.P. comes fairly easy. Add the additional cubic inches from the LS2 or LS3 and you have even more power and no additional weight. The LS7 in my Z06 was scary fast. I can only imagine a pair of those in a 29 Scarab or Fountain.

balinsteadt 09-05-2012 10:43 PM


Originally Posted by balinsteadt (Post 3768378)
most people will tell you automotive engines have no buisness being in the water...

My thoughts: Your gonna spend a FORTUNE to bring these automotive engines to a standard thats acceptable/reliable in a marine application. I would think it would be more widely accepted to sell your wrecks till you have the coin to do a marine build from the ground up or at least start with a marine rebuild.

shows what I know.. haha!! Good luck! :lolhit:

professor_speed 09-06-2012 12:41 AM


Originally Posted by Adamcoover (Post 3769991)
Currently a 70 mph boat. I want to be in the low 90 range

Your boat seems to run well for that hull and power.(most seam to run around (65-68 gps) It seams that it takes around 475-500 per side to go around 80mph. I thought I remember it taking around 650hp per side with a -2 shorty to low 90's I read about a 29 sometime ago with procharged 434 sbc's for some reason this hull seams to be sticky, and pretty heavy also I remember that it got squirrely around 85 ( I was looking in to this same set up if I bought one but I went a different route)

Adamcoover 09-06-2012 01:12 PM


Originally Posted by professor_speed (Post 3770648)
Your boat seems to run well for that hull and power.(most seam to run around (65-68 gps) It seams that it takes around 475-500 per side to go around 80mph. I thought I remember it taking around 650hp per side with a -2 shorty to low 90's I read about a 29 sometime ago with procharged 434 sbc's for some reason this hull seams to be sticky, and pretty heavy also I remember that it got squirrely around 85 ( I was looking in to this same set up if I bought one but I went a different route)

It gets alittle silly at 70 but im using stock sloppy ars steering as well so tha could be alot of it. Whats the bravo 1 capable of safetly handling? Im very good with maintaning everything but whats to much? I wanna do the boat over the winter and play over the summer not be out blowing drives and screwing around.

JRider 09-07-2012 07:55 AM


Originally Posted by 92nsx (Post 3769949)
Pretty much what I know, the difference between marine and auto engines is tolerance. Marine are set up "loose", and water pumps/ cooling. But also remember marine engines are always under load, compare to automotive there now. Take that hot rod mag article and see what happens when that 5.3, or ended up being a 4.6 or something, engine is held at WOT for 10 min.........

FYI...gm holds them wide open on test stands for a hell of a lot longer than that!

Adamcoover 09-07-2012 09:48 AM


Originally Posted by JRider (Post 3771558)
FYI...gm holds them wide open on test stands for a hell of a lot longer than that!

FYI you willin to sell what's on the end of your boat lol

HTRDLNCN 09-07-2012 10:11 AM

only the blue Merc engines are different internally, the standard black Merc engines have same exact internals and clearences as an automotive engine..

bor 09-07-2012 10:47 AM

ls marine
 
I build a ls 2 into marine version ,got a new l 76 truck engine from the newer trucks which is a ls2 block whit ls 3 heads on it and a high truck intake ,making 360 hp

We stroked that whit a compstar kit to 408 and upgraded the valve train ,timing gear and put in a bigger cam and a ls2 intake to get it fit under the engine hatch and maked it dry sump whit ls 7 oil sytem ,cooling sytem I used from pcm .
The headers I dyno whit where cmi s but there high and didn t like the collector so switched to a set lightning .

It make s 560 hp @6100 rpm and max tq is 550 ft lbs @4700
and tq is real flat from 3000 -6300 rpm above 500 ft/lbs

know have 20 hrs of use and like it every time if I go out ,this engine push real good and screams for more !

here are some video s !

http://www.youtube.com/user/phantomlspower?feature=mhee

enjoy .so far 96 mph but still testing props and spacers .

professor_speed 09-07-2012 05:06 PM


Originally Posted by bor (Post 3771694)
I build a ls 2 into marine version ,got a new l 76 truck engine from the newer trucks which is a ls2 block whit ls 3 heads on it and a high truck intake ,making 360 hp

We stroked that whit a compstar kit to 408 and upgraded the valve train ,timing gear and put in a bigger cam and a ls2 intake to get it fit under the engine hatch and maked it dry sump whit ls 7 oil sytem ,cooling sytem I used from pcm .
The headers I dyno whit where cmi s but there high and didn t like the collector so switched to a set lightning .

It make s 560 hp @6100 rpm and max tq is 550 ft lbs @4700
and tq is real flat from 3000 -6300 rpm above 500 ft/lbs

know have 20 hrs of use and like it every time if I go out ,this engine push real good and screams for more !

here are some video s !

http://www.youtube.com/user/phantomlspower?feature=mhee

enjoy .so far 96 mph but still testing props and spacers .


Ls2 intake with ls3 heads? did you mean ls3 intake? ls2 is cathedral port, ls3 is square. the power production looks good and that boat looks like it runs hard. Im working on a similar project.


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