4.3 marine swapped for a van 4.3

[brunolund]

hello, just bought a '96 lund tyee with a 4.3 engine. there is water in the oil(unknown reason, but knew about problem before i bought boat.) I haven't torn the engine apart yet, but am curious as to whether or not a 4.3 from a 95 astr van will fit? all i would use from the van is the block, as it's seen some miles, just wondering if the cranks and all other internals will fit? also are the mounting holes the same for the externals? Also thinking of going to a 350. what would be entailed in that swap? I have an older(mid 70"s) 350 ready for a home, but nowhere to put it, is it at all worth it?

 

[dcg9381]

Re: 4.3 marine swapped for a van 4.3

I haven't played with a 4.3, but I know they come in several head configs.. I'd check that first.

 

[watermellonI]

Re: 4.3 marine swapped for a van 4.3

The 4.3 in the van would probly be your best bet, there very similar engines you ll need to marinize the engine, change head gaskets and check the flyweel of the marine verse the van, but all in all the 4.3 for 4.3 is little less compicated, no mounts to worry about and that sort of thing. you will need to find out where the water came from originally, I would start in the exhaust y pipe, see if that flapper got sucked in backward.

the pros know the rest of the details for ya, this should give you a startin point.

 

[Bondo]

Re: 4.3 marine swapped for a van 4.3

all i would use from the van is the block

Ayuh,....... It Should be the Same........

Going to a V8 will bring about Another whole Can of Worms........

 

[Chris1956]

Re: 4.3 marine swapped for a van 4.3

Bruno, You need to find the source of the water. I would bet on a '96 motor the exhaust mannys are the culprit. Pull 'em off and see if they rotted out. The elbows usually go first, and the elbow to manifold area is next.

If you go with the swap, you should use the van motor complete, except for intake and exhaust manifolds, starter, ignition and alternator, which are marine specific. Also put in brass freeze plugs, if your's are steel.

If you find out the exhause manifold is bad, it is possible that the motor is still good, especially if it has not been run too long with water. Change the oil and mannys and run the bloody thing for an hour and recheck.

 

[wncrjb]

Re: 4.3 marine swapped for a van 4.3

Hello Bruno,
You might want to check a few things first. Around 95-96 is when GM started introducing the NEW vortec head design engines. A few quick checks are to compare both engines to see:

1) Are the valve covers plastic composite or stamped steel?
2) Are there 8 bolts holding the intake manifold to the head, or 12?
3) Is the timing cover a plastic composite material or stamped steel?

If both engines are the same as stated above, they are completely inter-changeable.

Beginning in late 95, The newer design vortec head had the composite valve cover and timing cover. The intake was also changed to accept the new head and only used 8 bolts instead of the older design 12 bolts to attach to the head.

The motor mounts and the engine coupler remained the same.

The newer heads will yield about a 25 HP gain.

The newer heads will fit the older block but you will need the newer intake manifold too.

Also, if it does have the composite timing cover, and you remove it to change cams or timing chain, or whatever, you must replace the timing cover. It is suggested that you never re-use the composite timing cover, although I have heard of a few people doing it without any leaks, but I would not recommend it.
Hope this helps,
wncrjb

 

[brunolund]

Re: 4.3 marine swapped for a van 4.3

thanks for the info, i haven't checked anything yet, hope to this week. Is it possible for water to get in the oil through the exhaust manifolds? i didn't think it was.

 

[Chris1956]

Re: 4.3 marine swapped for a van 4.3

Bruno, If the manifolds leak, water goes into the cylinders and leaks past the rings into the crankcase.

 

[John_S]

Re: 4.3 marine swapped for a van 4.3

Unless your boat is severly underpowered would stay with V6.

MikDee has posted a link in the past, with a ton of GM 4.3L V6 vintage info. A search may find it, or maybe he will repost it

 

[John_S]

Re: 4.3 marine swapped for a van 4.3

I had the link saved at home:

"http://www.s10forum.com/forum/f107/the-holy-grail-of-4-3-info-131868/"