Pair of Stock LQ4s in my Boat, Bit of a How to, or at least how I did
08-11-2020, 04:36 PM
#1
Pair of Stock LQ4s in my Boat, Bit of a How to, or at least how I did Hey all. For those looking to marininze the LQ4, here's some video of what I did to repower my old Bayliner Bounty 2850 with a pair of LQ4s. I'd think it would be very similar for 5.3/4.8 versions.
The outdrive running gear is Volvo 280. The original engines were carbed 305s.
Manifolds:
https://www.youtube.com/watch?v=CK3e...ature=youtu.be
Engine Mounts:
Crank
Pump:
I have since found that the lower bracket is not really needed. The stiff hoses will hold the pump housing from rotating
Flywheel cover (Bellhousing):
Flywheel and coupler:
Fly by wire throttle:
Oil pan modification for twins:
Priceless:
Chay
The outdrive running gear is Volvo 280. The original engines were carbed 305s.
Manifolds:
https://www.youtube.com/watch?v=CK3e...ature=youtu.be
Engine Mounts:
Crank
Pump:
I have since found that the lower bracket is not really needed. The stiff hoses will hold the pump housing from rotating
Flywheel cover (Bellhousing):
Flywheel and coupler:
Fly by wire throttle:
Oil pan modification for twins:
Priceless:
Chay
08-11-2020, 05:13 PM
#2
A couple of notes:
1) HP tuners used, converted to 1BAR Speed density so I could loose the MAF and it runs open loop
2) I made a digital guage pod system that shares the ECM tach, oil pressure and temperature signals, and also monitors bilge pump etc
3) Cooling:
i) installed a 160 degree thermostat
ii) installed half cooling system, so glycol in block only
iii) installed 'U' loop on the water pump side ports, 5/8 to 3/4 so the thermostat functions properly
iv) Installed custom T so that the steam vents (2 In front) and the throttle body de-icing continue to function
4) Electrical: I customized the stock engine harness (Removed a tonne of stuff). I added a standard gm intake air sensor to make of for the loss of the sensor in the MAF. I added a control box for each engine containing fusing as per stock. It also contains a relay for the fuel pump (Ecm controlled), and a 'power in start or run' to reduce fatigue on the boat style ignition switch and separate the ignition feeds to the various circuits. The electrical box also makes for an easy spot to disconnect the engine wiring (Other than the main +, - leads) if the engine needs to come out.
Chay
1) HP tuners used, converted to 1BAR Speed density so I could loose the MAF and it runs open loop
2) I made a digital guage pod system that shares the ECM tach, oil pressure and temperature signals, and also monitors bilge pump etc
3) Cooling:
i) installed a 160 degree thermostat
ii) installed half cooling system, so glycol in block only
iii) installed 'U' loop on the water pump side ports, 5/8 to 3/4 so the thermostat functions properly
iv) Installed custom T so that the steam vents (2 In front) and the throttle body de-icing continue to function
4) Electrical: I customized the stock engine harness (Removed a tonne of stuff). I added a standard gm intake air sensor to make of for the loss of the sensor in the MAF. I added a control box for each engine containing fusing as per stock. It also contains a relay for the fuel pump (Ecm controlled), and a 'power in start or run' to reduce fatigue on the boat style ignition switch and separate the ignition feeds to the various circuits. The electrical box also makes for an easy spot to disconnect the engine wiring (Other than the main +, - leads) if the engine needs to come out.
Chay
08-16-2020, 09:18 AM
#4
Registered User
Join Date: Aug 2020
Posts: 0
Likes: 0
Received 0 Likes
on
0 Posts
My first reply, how did I get so lucky... I say I'm lucky because i joined this forum to gather info about doing an LS swap on my 1979 IMP X250 that had twin 350s. I was planning on going with LQ4 engines from 1999-2000 because those had iron blocks and heads, which would allow me to use raw water cooling.
08-18-2020, 12:06 PM
#5
You could do raw water-remember to change the freeze plugs to brass.One nice thing is you don't have to worry about the intake as it's dry.
Some will tell you the head gasket needs to be changed. Not sure on that---Honestly I like the closed cooling so I don't have to deal with all the goodies.
Another challenge will be to find the low value 140f thermostat-Unless you run in fresh only in which case you can use a 160 which is available.
Also, check out the web as there are some aluminum manifolds/risers out there now. Or you would do the stainless but there is a lot more work involved to build them or $$$ to buy.
https://www.cpperformance.com/p-1045...-53-60-62.aspx
https://www.hardin-marine.com/c-2078...cessories.aspx
Assuming that you are going to get rid of the AC compressor and the power steering pump there is an alternative belt routing/shorter belt so you don't have to get an idler pulley.
http://bdturnkeyengines.com/no-ps-pump-belt
Hope that helps.
Chay
Some will tell you the head gasket needs to be changed. Not sure on that---Honestly I like the closed cooling so I don't have to deal with all the goodies.
Another challenge will be to find the low value 140f thermostat-Unless you run in fresh only in which case you can use a 160 which is available.
Also, check out the web as there are some aluminum manifolds/risers out there now. Or you would do the stainless but there is a lot more work involved to build them or $$$ to buy.
https://www.cpperformance.com/p-1045...-53-60-62.aspx
https://www.hardin-marine.com/c-2078...cessories.aspx
Assuming that you are going to get rid of the AC compressor and the power steering pump there is an alternative belt routing/shorter belt so you don't have to get an idler pulley.
http://bdturnkeyengines.com/no-ps-pump-belt
Hope that helps.
Chay
Last edited by Cfoss; 08-18-2020 at 12:13 PM.