4.3 Liter V-6 Short Block

C

Captianloud

Seaman Apprentice
Joined
Jan 16, 2006
Messages
43
Hello new to the forum, I search for this but didnt find any results. <br />1994 Mercruiser 4.3 L V-6. What makes this short block different from the automotive 4.3L short block. Will it bolt up?<br />I bought a 94 Bayliner w/ a 4.3 knowing the engine was run while low on oil, he lost oil pressure. I have not ripped into this yet. But I would rather just replace the short block than rebuild the bottom end. All other marine components are functioning, intact and reusable. <br />I know the cams are different. Crankshaft is the same. But are the blocks the same? Will it bolt in. I am fully capable of making slight modifications. I understand the importance of using marine gaskets and seals, as well as using the other marine components. I can drill and tap holes to relocate drain/freeze plugs. Remember that I have the complete old engine to use as a template, and/or for parts, brackets, and other miscellaneous salvage. I dont want to spend $1100 for the short block when I can pull the engine out of an Astrovan or S10 at the local u pull it yard for $50. <br />There has to be a fellow gearhead out there that knows. <br />Any advice would be GREATLY appreciated. <br />Thanks in Advance!,Capt...
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,082
Re: 4.3 Liter V-6 Short Block

As long as the Vintage is the Same,........<br /><br />They're All the Same Casting,....... With All the Same Holes............ ;) <br /><br />Welcome to the forums here at iboats.com...........<br /><br />There's Plenty of Motorheads knocking around Here.............. :D
 
W

whywhyzed

Banned
Joined
Feb 1, 2005
Messages
1,871
Re: 4.3 Liter V-6 Short Block

I recall reading here that the truck applications used mechanical pumps with same mounting as marine...but car 4.3 used electric fuel pump so no spot for your marine lift pump.
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,082
Re: 4.3 Liter V-6 Short Block

Originally posted by hystat:<br /> I recall reading here that the truck applications used mechanical pumps with same mounting as marine...but car 4.3 used electric fuel pump so no spot for your marine lift pump.
Click to expand...
Car,... Truck,.... Marine,.....<br /><br />The Differences,...whether it's the Fuel Pump Boss,... <br />Or the Counter-Balance Shaft,....<br />Or,... Any of the Other changes that have occurred over the years,........<br /><br />Is All About the Vintage of the particular Block........... When was it Cast.......<br /><br />In other words,........<br />All of the blocks lost the Fuel Pump Boss at the same Time ...........<br />And,.. Of Course,.... They Gained the Counter-balance Shaft, at the same Time ..... ;)
 
KaGee

KaGee

Admiral
Joined
Aug 14, 2004
Messages
7,069
Re: 4.3 Liter V-6 Short Block

In other words, try to find a short block from around 1994. <br /><br />If the block came from an auto, replace the cam with the one from your existing motor, provided it is still good. <br /><br />If the block came from a truck, use it as is. The cam is close enough not to matter.
 
C

Captianloud

Seaman Apprentice
Joined
Jan 16, 2006
Messages
43
Re: 4.3 Liter V-6 Short Block

Thanks guys I'll keep you all posted on my progress. <br />Ran into the balance shaft difference but had not thought of the fuel injection concern for fuel pump mount. <br /><br />Bondo, did GM run the marine and automotive block changes concurrently? <br /><br />Thanks for the help.
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,082
Re: 4.3 Liter V-6 Short Block

Well,....... The Bean Counters will tell you that Everything is Bought/Installed with "On Time" deliveries,......<br />But,... Even without Warehousing,........There's Still a Lag in the Flow pipeline,..........<br /><br />Basically,.........<br /><br />Mercruiser Buys GM truck engines with an "On Time" delivery,............<br /><br />So,........ <br />Ayuh,..... The Changes happen Reasonably Concurrently............................... :D <br /><br />Don't forget the Vortec package,..... It happened around 1996/7.............<br />A 4bbl.Carb.,+ a matching manifold is Good for 25/35hp................ ;)
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,074
Re: 4.3 Liter V-6 Short Block

Capt. You might want to do some tests on the old block. Compression, oil pressure ect. Those motors are pretty tough. I ran my '88 4.3LX for a few minutes without any oil(pan leak) and twice(I have no idea how long) with low oil(oil filters rusted through). I was going to change the main and rod bearings after the pan leak(parts are very cheap), but never did. It still runs very well with good power.<br /><br />If compression and oil pressure is good (and no bearing knocks), you may want to water test it.
 
4

4.3sunbird

Seaman
Joined
Sep 8, 2005
Messages
73
Re: 4.3 Liter V-6 Short Block

so does your boat have a mech. fuel pump hanging on the block or an electric pump ?<br /><br />my 92 boat is carbed but has electric pump ... If not I would have had more trouble finding a automotive block to use<br /><br />I believe 85 was the only year of 4.3 in automotive that had a finished fuel pump boss<br /><br />if you have electric pump you are in good shape <br /><br />change out the freeze plugs for some brass ones and use marine gaskets putting it back together atleast the head gaskets<br /><br />I put 96 up heads on mine and bought a mercruizer 4 brl intake to fit the 96-up heads<br /><br />btw Im using a 91 model block .. there are several changes in the 4.3 auomotive engines thru the 90's that they didnt make in boats<br /><br />being 91 mine is roller cammed but no counterbalance where my 92 boat did not have roller cam but it did still have a fuel pump boss on it<br /><br />I have a bunch of info somewhere on my computer about all the 4.3 differences I'll see if I can find it <br /><br />RED
 
KaGee

KaGee

Admiral
Joined
Aug 14, 2004
Messages
7,069
Re: 4.3 Liter V-6 Short Block

According to the place where i got my short block from, here is the progression...<br /><br />4.3L ENGINE pre. 1986 chevy {2 piece rear main seal}<br /><br />4.3L 262 ENGINE 1987 to 1993 chevy (1 piece rear main seal)<br /><br />4.3L 262 ENGINE 1994 to 1995 chevy 4.3 Vortec, balance shaft, Roller cam, and roller lifters.<br /><br />4.3L Vortec ENGINE 1997 to 2001 chevy <br /><br />Hope it helps.
 
Silvertip

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: 4.3 Liter V-6 Short Block

The AWD Astro/Safari Van 4.3 V6 had a balance shaft in 1992 and also had the "spider" fuel injection setup. This was an engine code "W".
 
C

Captianloud

Seaman Apprentice
Joined
Jan 16, 2006
Messages
43
Re: 4.3 Liter V-6 Short Block

Sunbird4.3<br />Hey Red, I've got the boat, taking it to Ramster's house Tues. Plan to remove the inner cowlings of the boat to facilitate pulling the motor, plan to remove the outdrive (merc alpha one) and prep the engine for removal. Have to wait till the cherry picker gets there for that. But I have the engine stand all set up in my garage ready to go.<br /><br /> Not sure if its mech or elec fuel pump...<br />Mines got the 4 barrel already, was that ever an option or was it a hop up? I'll have a good look at it tues night I'll find out if its the weber or the quadrajet. My heads say vortec on em already? So whats the deal with the 96 heads? Also I wanted to ask can you tell a big difference in vibration going from the motor with balance shaft to the motor without balance shaft. If you had to do it over which would you chose? What pitch prop are you running?
 
C

Captianloud

Seaman Apprentice
Joined
Jan 16, 2006
Messages
43
Re: 4.3 Liter V-6 Short Block

Kagee, <br />Thanks for the info, I really appreciate it.<br />That what I got, Vortec, balance shaft, roller cam.<br /><br />Upinsmoke,
 
C

Captianloud

Seaman Apprentice
Joined
Jan 16, 2006
Messages
43
Re: 4.3 Liter V-6 Short Block

Upinsmoke,<br />Did that have the roller cam, not sure what you mean about spider fuel injection.
 
You must log in or register to reply here.
Top