5.0 Gipwtr Remove TBI and add Carburetor

[jetdoctor2002]

Hi All,
I have a 99 5.0 Gipwtr that is in good shape. I have been going through the fuel system. The Achilles heel of these engines are the fuel pumps, and the vapor trap. Having an automotive background, I figured that EFI would be a good thing on boats. The pump is in the tank, and the fuel recirculates taking care of phase separation with ethanol fuel mixes......
Errrr, boats engines don't work that way. The USCG regs mandate that all pressurized fuel has to be located in the footprint of the engine. The vapor trap on this engine is obsolete, crusty, and no parts are available except old stock when they show up on Ebay. I assume that the module that replaces the high/low pressure pumps/vapor trap on later engines could be retrofitted, but these were painted inside. This has caused it's own set of problems.
Researching what other people have done, and considering why I am using an automotive engine, I have decided to convert the Gi engine to a GL. I can get the carb adapter, and Holley 2300s are not hard to come by. Parts hang on the wall at any Oreilly auto parts. The low pressure pump could be used, but a Carter P4389 could also be a candidate. At $55 a pop, the Carter pump could be replaced at regular intervals.
My question is what to do about the distributor. I am assuming that removing the ECM will render the stock distributor useless, but it sure looks like a Delco Voyager EST. The wiring diagram shows the distributor wiring running through the ECM. Should I buy a Delco EST distributor or a Performance Distributor HEI setup? The HEI only needs a power wire and a safety switch. Thanks for any insight,
Doug

 

[Scott Danforth]

first, the paint on the inside of the fuel module is no longer a problem

for the dizzy get the delco. HEI has no place on a boat (only DUI has a SAE J1171 cert and that one is iffy at best use the wrong ignition and boom). all electronics must be SAE J1171 compliant. your dizzy most likley is a voyager. understand the boat wiring and oil switch ignition cut-off systems prior to doing anything. the ECM cuts off the dizzy if you have no oil pressure. your ECM is operating like a relay in this case

Volvo used holleys, however I would be in a 4150 instead of a 2300. must be a marine carb or boom.

its not USCG regs mandating the fuel system. its logistics for building the boat, etc. boats generally dont know what motor is going in them until the last moment. so a complete self-contained "box" is easiest to install.

your not converting anything. block and heads same between boats and trucks. difference in cam profiles, ignitions and fuel systems. do your due diligence and research prior to doing anything.

Oreilly auto parts does not have marine carb kits. Napa does carry marine stuff.

carter pump will last longer than the boat if you keep the fuel system maintained however you need an oil pressure switch and a relay (go back to the research)

 

[jetdoctor2002]

Thanks for the reply.
This is the carburetor I am planning on using. This is going on a fishing boat, so I do not need a 4 barrel. There have been intrepid soles that changed to a 4 BBL on VP SBCs. All that you gain is a couple of hundred RPM up top.
https://www.summitracing.com/parts/qft-m-500/overview/
This is just a Holley 2300 marine that has been hard coated. I boat in salt water, which is part of the reason for the switch. Running raw water through a bunch of small passages is asking for trouble. Float bowl gaskets and power valves are readily available. Cleaning out a clogged metering block is a 4 bolt job.
I understand about the oil pressure safety switches, and how it interacts with the starting system. Everything will be wired with marine wire. I have the tools and parts to deal with the connectors. What I am wondering is if the engine already has a Voyager distributor that simply needs to be rewired? If not, Michigan Motorz has a kit.
I have used DUI distributors in the past on trucks. They do a nice job setting up a custom advance curve. The system is inductive, so it is very efficient at the RPMs that boats run at. They also have a super hot spark and do not draw a lot of amps. If I had a hot rod lake boat, it might be just the ticket. They make a line that is USCG approved.
Cheers,
Doug

 

[Lou C]

I would go with 4bbl, it is nice to have the better top end of the 4bbl and you can really feel it. The Holley that will work with the standard cast iron spread bore intake is the spread bore style 4175. No adaptor needed if you go with this carb.

https://www.summitracing.com/parts/hly-0-80552

 

[Scott Danforth]

not only does the 4 bbl give you better top end, it gives you better meterability of idle and better midrange too.

 

[jetdoctor2002]

Hmmmm, I do have a good marine Quadrajet that I removed from the VP 4.3. It would need different metering rods, but I can get those from Cliff Ruggles in Ohio. The secondaries are a lot easier to tune than a Holley and less prone to open at cruise. The biggest downer with Q jets are that the main jets are located on the bottom of the float bowls. They are prone to clogging in their nether regions.....Q jets do have nice low/mid range power. This would certainly be the cheapest option.
Cheers,
Doug

 

[jimmbo]

The 500cfm(378 cfm when flow rated like a 4bbl) Holley 2 bbl is about the perfect size for a 5 liter spinning 5000rpm. The only advantage a 4bbl may offer, is a smaller bore/venturi size and because of that, a slight increase in low rpm throttle response. A better choice would be a Holley 650cfm Spreadbore(like the Q-Jet) , here the primaries are really small.
Volvo made a very good 4bbl intake for the SB Chevy, it was used on the 2 bbl engines with an adapter to mount the carb.
I have done the 2bb to 4bbl swap on my 2002 VP 5.7, there the 500cfm 2bbl is too small(was pulling 4.5 inches of manifold Vacuum at WOT, and putting on the 650 Holley did give me an additional 450 - 500 rpms, enough that I had to add go up in pitch to keep the rpms down. WOT manifold vacuum was about 1 - 1 1/2 inches.

https://www.holley.com/products/marine/marine_carburetors/parts/0-80552. It is a 4175, not a 4160 as stated at the top of the page, further down they get it correct


This one is sized perfectly for a 5 liter running at 5000rpm
https://www.holley.com/products/marine/marine_carburetors/parts/0-80402-1

 

[QBhoy]

I would just sort out the niggles of this engine. Once done...they are great.

 

[jetdoctor2002]

This engine has an EST distributor. It is wired like the Delco Voyager, except for the 4 wires going to the ECM. I assume that this is to retard the timing. I have been waiting for the ayuhhh pointing out that the engine will run fine with that plug removed. I suppose that this is better than spending $500 on a Delco voyager kit and having someone point out that the VP 5.0 already has one.
The Holley 4175 seems to be calibrated to a 5.7 Vortec engine. It would need extensive tuning to work on a 5.0. If I had the baseline jetting like I have for the 2300 carb it might sway me.
https://forums.iboats.com/forum/eng...be-gained-adding-4bbl-to-5-0l-volvo-gl-vortec
Cheers,
Doug

 

[Lou C]

You might want to call Holley tech support as to which carb would work best on your engine...

 

[Bondo]

I have been waiting for the ayuhhh pointing out that the engine will run fine with that plug removed.

Ayuh,..... Welcome Aboard,.... I try not to comment, when I don't know the answer,.....

That said, if doin' what you propose, I'd go with a 4bbl carb, 'n the proper intake manifold, over a 2bbl, 'n adapter,...

 

[Lou C]

You might want to call Holley tech support as to which carb would work best on your engine...

 

[jetdoctor2002]

Ayuh,..... Welcome Aboard,.... I try not to comment, when I don't know the answer,.....

That said, if doin' what you propose, I'd go with a 4bbl carb, 'n the proper intake manifold, over a 2bbl, 'n adapter,...

Hi Bondo,
Actually, you have already given me some good advice on my boats transom. Guys like you and Don have probably forgotten more about boats than I will ever know. My gut says throw a 2 bbl on the engine like VP did. The 5.0 would probably do just fine with that carb. On the other hand, everyone who has commented here has suggested that I use a 4bbl, I have to admit that I don't know what I don't know. I do not have a lot of experience with I/O power boats, so maybe the 4bbls will work better. The rub is whether I can get it set up properly. Hopefully, I can find someone that can give me some baseline jetting. Modern fuels do not color plugs like Mobil premium did back in the day.
Cheers,
Doug

 

[jetdoctor2002]

I would just sort out the niggles of this engine. Once done...they are great.

I agree, the GM TBI injection was an elegant design and generally trouble free. The problem is that the system on the engine that I have is reaching it's expiration date. Since the system is obsolete, and VP is a low unit production operation, parts are not available. That is why people who have 80s trucks that do not need to pass emissions are throwing a carb and a HEI distributor in them and motoring happily. I just want to have a boat that will run well, and be easy to maintain without a lot of proprietary parts.
Cheers,
Doug

 

[jimmbo]

Here are some specs for the 500cfm from the VP service manual

5.0GL-A/B & 5.7GL-A/B Models
Volvo Penta #3858334 500 CFM Model 2300-2V
Pump Lever Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.010-0.015 in. (0,254-0,381 mm)
Choke Unloader. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.300 in. (7,62 mm) Measured Lower Edge of Plate
Choke Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Notches Lean
Initial Idle Mixture Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3/4 to 1 Turn Off Seat
Main Jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Power Valve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5
Float Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Parallel to Fuel Bowl When Bowl Inverted
Choke Vacuum Qualification . . . . . . . . . . . . . . . . . . . .0.315 in. (8,00 mm) Measured At Lower Edge of Plate
Pump Cam Position (yellow cam) . . . . . . . . . . . . . . . No. 1 Hole of Cam and Throttle Arm5.0GL-D/E Models


5.0GL-C Models
Volvo Penta #3863242 500 CFM Model 2300-2V
Pump Lever Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.010-0.015 in. (0,254-0,381 mm)
Choke Unloader. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.300 in. (7,62 mm) Measured Lower Edge of Plate
Choke Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Notches Lean
Initial Idle Mixture Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3/4 to 1 Turn Off Seat
Main Jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Power Valve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5
Float Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Parallel to Fuel Bowl When Bowl Inverted
Choke Vacuum Qualification . . . . . . . . . . . . . . . . . . . .0.315 in. (8,00 mm) Measured At Lower Edge of Plate
Pump Cam Position (yellow cam) . . . . . . . . . . . . . . . No. 1 Hole of Cam and Throttle Arm5.0GL-D/E Models

 

[jetdoctor2002]

Good News!
Ok, for anyone who is contemplating this swap, the VP Gi engine has the Delco EST distributor like the Voyager sold in kits around the web. I verified this by pulling up both distributors for the GL and Gi 5.0 VPs. The GL engines have a mechanical spark advance. The Gi engines have a reluctor, coil, and module. The module is VP p/n 3854003, which crosses to Delco D1965A and GM 10482830 or Sierra 18-5107-1. This is the marine module, and is different from the car module. The car module has a small advance curve as a limp mode, and will need to be hooked up to an ECM to calculate total spark advance. The marine modules have a total advance of 20degrees, in a straight linear progression that is all in by 3000 rpm. This means that if you have a TBI GM based engine, and you want to swap to a carburetor, all you need to do is pull the 4 wire plug from the ECM and cover the hole. You will need the shunt to set base timing.
I did a search for the GM 10482830 module, and found the advance curve etc. I also read about people who had been sold one of the $500 Voyager kits while converting a TBI engine to carburetor. They figured out later that they already had this ignition which the company who sold it to them also knew..........
So, the distributor that is on the engine will be getting some love and new parts so that there are spares on the boat in case of trouble.
Cheers,
Doug

 

[QBhoy]

Think I may have been confused earlier. The Gi sounds like the single point injection VP...maybe it’s the gxi I was thinking of. Is this the VP equivelant of the MPI ?

 

[jetdoctor2002]

You are correct. The GXI is a different animal. Those engines just have a distributor with no timing parts in it. Timing is via a hall effect sensor acting on the crank pulley. The engine I have is just a TBI. The latest engines are really complicated.
Cheers,
Doug

 

[406Maverick]

Good News!
Ok, for anyone who is contemplating this swap, the VP Gi engine has the Delco EST distributor like the Voyager sold in kits around the web. I verified this by pulling up both distributors for the GL and Gi 5.0 VPs. The GL engines have a mechanical spark advance. The Gi engines have a reluctor, coil, and module. The module is VP p/n 3854003, which crosses to Delco D1965A and GM 10482830 or Sierra 18-5107-1. This is the marine module, and is different from the car module. The car module has a small advance curve as a limp mode, and will need to be hooked up to an ECM to calculate total spark advance. The marine modules have a total advance of 20degrees, in a straight linear progression that is all in by 3000 rpm. This means that if you have a TBI GM based engine, and you want to swap to a carburetor, all you need to do is pull the 4 wire plug from the ECM and cover the hole. You will need the shunt to set base timing.
I did a search for the GM 10482830 module, and found the advance curve etc. I also read about people who had been sold one of the $500 Voyager kits while converting a TBI engine to carburetor. They figured out later that they already had this ignition which the company who sold it to them also knew..........
So, the distributor that is on the engine will be getting some love and new parts so that there are spares on the boat in case of trouble.
Cheers,
Doug

Sorry I know this is an older thread but hoping someone can expound on what was said here. I am converting a Gi back to carbureted and am hoping to reuse my distributor if possible. (This means that if you have a TBI GM based engine, and you want to swap to a carburetor, all you need to do is pull the 4 wire plug from the ECM and cover the hole. You will need the shunt to set base timing.) What is meant by "shunt to set base timing" ?? Also, by "covering the holes", do I just seal up after I unplug the distributor from the harness?