4.3 Rebuild Cam and Carb suggestions

[napaautohastings]

I recently purchased a 1990 Rinker 186 with a blown up 4.3 Alpha 1. I am hoping to bring the HP up a little with the rebuild. Probably unshourd the valves a little and add a roller cam and 600 cfm eldelbrock marine carb and maiifold. Has any one had any expierence with this combination? Does anyone have any suggestions for specs on a cam. I think I will need stock idle and power to around 5000 rpm if possible. Also the original motor detonated #1 cylinder but the others look fine anyone have any ideas what caused this? I want to make sure I fix the problem before installing the new motor.

 

[MooseHootie]

Re: 4.3 Rebuild Cam and Carb suggestions

2 OR 4 Barrel on the motor know? I have the same set-up. I bought vortec heads, 600 holley, and edelbrock 2114 intake. Engine should have 225 horses.

 

[napaautohastings]

Re: 4.3 Rebuild Cam and Carb suggestions

It has a 2 Barrel.

 

[MooseHootie]

Re: 4.3 Rebuild Cam and Carb suggestions

Check post just edited.

 

[Bondo]

Re: 4.3 Rebuild Cam and Carb suggestions

Also the original motor detonated #1 cylinder but the others look fine anyone have any ideas what caused this?

Bad Timing,...........<br />A Lean Condition,.........<br /><br />You should already have a roller cam in that motor,..???<br /><br />Anyway,.....<br /><br />Instead of grinding on a set of Heads,........<br /><br />Go find yourself a Mercruiser 4.3LXH Cam,+ lifters,......<br />A Set of Vortec Heads,+ a cast iron 4bbl. manifold to mount that Edlebrock on..........<br /><br />That'll put you up near 220/225hp,........<br /><br />Proper Tuning will give you Great Power,... Idle to 5000rpms,..... No Problem...............

 

[napaautohastings]

Re: 4.3 Rebuild Cam and Carb suggestions

It does have a roller cam. What is the LXH cam? Turns out this motor is a rebuilders motor already bored to 040. I'm going to look it over very closely as Ive seen some pretty funky things done to rebuilders motors. I might be looking for a new core. Is the 4.3 marine block, crank, rods the same as an automotive?

 

[KaGee]

Re: 4.3 Rebuild Cam and Carb suggestions

The blocks are the same except for the freeze plugs should be brass in a marine block and the cams are different.

 

[Bondo]

Re: 4.3 Rebuild Cam and Carb suggestions

Look for a motor out of a Truck,.......<br /><br />Alot of Pickups,+ Vans used the 4.3l........<br /><br />The LXH was the name of the motor After the Vortec Heads,+ Intake were added............<br />The Cam might be the Same Cut as was used before,... I Don't Know......<br /><br />If your starting Fresh,...... I'd look for a Late Model Vortec Truck Block for a Core...........<br /><br />I believe that would Update your Power by 2 generations of 4.3s......

 

[napaautohastings]

Re: 4.3 Rebuild Cam and Carb suggestions

I have located several Vortec blocks and I got one for free. I'm tearing it down this weekend and seeing if it is useable.If not I know where their are 4 more. After reading the other posts and some other information my only concern in using the vortec is that it raises compression. I am going to check into a little further before proceding. I am going to check with my engine parts supplier and see if he has a piston with slightly lower compression. The regular vortec engine can get away with the higher compression as the computer will live off of the knock sensor and the computer will retard the timing as needed.Bondo,thanks for all of the information and please keep it coming it is really helping.

 

[bluewater19]

Re: 4.3 Rebuild Cam and Carb suggestions

You can still use the higher compression vortec motor in your boat. YOu have to run 89 octane minimum. I have a 2003 4.3 in my glastron and made bondos mods to my 1991 bluewater The bluewater runs great with the higher compression. <br />Make sure your timed correctly and use 89 gas.

 

[napaautohastings]

Re: 4.3 Rebuild Cam and Carb suggestions

Vortec it is then. We live in the land of 93 octane ethanal so it should be fine. Somewhere I saw mentioned about making some changes to the 600 cfm marine carb. I think it had something to do with the secondarys. Does anyone have any suggestions about that and also in a post above bondo said to use a cast Iron manifold for the 4bbl. why not the aluminum eldelbrock for that is drilled for marine thermostat? Hope I'm not making a pest of myself, I just want to get it right the first time and you guys have been down this road before> Thanks Again.

 

[Bondo]

Re: 4.3 Rebuild Cam and Carb suggestions

A Couple of thoughts,.......<br /><br />Not much Saltwater in Nebraska,..... You'll Probably do Just Fine with an Aluminum Manifold...... You'll Still want to use the Brass Core Plugs in the block,.....<br /><br />Very True,.. the Vortec motors Love the added Compression,... And the Heads can handle it,... There's also pistons that mirror the vortec head, to give you the Needed Quench(.040 I Believe),+ Still lower the Compression if you think it's Nessessary,....... Just use a "D" shaped dish piston........You Don't Need a Computer to Tune a Vortec motor,.........<br />Without the Proper Quench,... A Vortec motor is Just Another motor.........<br />

Make sure your timed correctly and use 89 gas.

I'll add,.......<br />Keep an eye on the Timing,.... It'll be Critical.......<br />And,.... I think it's Much More Important to Make Sure you don't get into a Lean Condition,.......<br />Than whether you're running Whatever Octane...........<br /><br />The Edlebrock Preformer Carb is the Same Exact Carb as the Merc./Weber,+ the Old Carter AFB Carbs..........<br />It Shouldn't need much Tuning, right out of the Box,........ But,... If you want to play around with it,.. Get a Carter Strip Kit,... I Think Edlebrock has something similar now,..... It's a Box Full of Needles,+ Jets,+ Springs,+ Etc....... <br />Reasonably Cheap Too.............<br /><br />Just Don't get it Too Lean..............<br /><br />Good Luck,+ Keep Us Posted..........