Looking for opinions mercruiser 165 hp inline 6 cylinder 4.1l

[Vipor81]

I do have a few questions about this motor but I think I best we start at the beginning and where or what I want to do
So about a month ago I acquired my first boat off of craigslist by trading around so as of this point everything I've done there has been no money in it
So please don't judge but what I got when I did the trade for my nitro rc truck was 1976 Bonanza with 165hp mercruiser 4.1l that has a cracked block yes I knew that ahead of time I also got a second 165hp mercruiser 4.1l that had been tore down with a good block now here's my dilemma spend the money rebuild the good motor like it should be or just do a quick cylinder hone then rings bearings and gaskets to throw it back together and now my other option I've done another trade for a 1975 250cid 60k on motor ready to go keep in mind I'm trying to go no money in so question 1 I gess would be the gaskets iv read a lot that says stock gaskets can Handel straight lake water this boat will not touch salt water so do you think I would be ok 2 my intention would be to transfer all bolt on items from the marine motor to this on so with doing this do you think I could get thru a season sorrow I know it's a lot but thanks for all your help

 

[alldodge]

1976 Bonanza with 165hp mercruiser 4.1l that has a cracked block

second 165hp mercruiser 4.1l that had been tore down with a good block

now here's my dilemma spend the money rebuild the good motor like it should be or just do a quick cylinder hone then rings bearings and gaskets to throw it back together

other option I've done another trade for a 1975 250cid 60k on motor ready to go (CAR/TRUCK MOTOR)

I'm trying to go no money

question 1 I gess would be the gaskets iv read a lot that says stock gaskets can Handel straight lake water this boat will not touch salt water so do you think I would be ok

2 my intention would be to transfer all bolt on items from the marine motor to this on so with doing this do you think I could get thru a season sorrow I know it's a lot but thanks for all your help

Howdy

I'm not the grammar police but this was real tough to follow. Tried to break it up in an attempt to figure it out

Your discussing 3 engines, one with a cracked block, one which has been dismantled, and the other is a 75 automotive engine (not sure but I think it is running). You would like to know what is the cheapest if not the no money investment option to get the motor running.

The best way is to rebuild the motor, but so far as the cheapest way, I just don't know. You could use the running motor and swap the marine parts over (fuel pump, distributer, alternator and carb). The other issue is you have steel core plugs and they should be brass. You could do a quick hone, but need to mice and plastic gauge the bearings to see if they may need attention. If you can get it going you still need to know the states of the outdrive.

Since your not in salt water you shouldn't need a marine head gasket

 

[smokeonthewater]

A chevy 250 I-6 will work IF and ONLY IF it has the correct casting/holes up front for the front motor mount... The auto head gasket will not work nor will the freeze plugs... Those will all rust out in short order...

With the options you've given you don't HAVE a no money choice unless you can trade an old typewriter and a broken lawn mower for some parts.... At the very least swap out the head gasket and freeze plugs in the auto engine or mic n hone cylinders, new rings, n mic, maybe turn crank, new bearings for the mercruiser motor..... The 165 I-6 is a great engine and well worth doing right.

HOWEVER there's not much point in working on the engine if the hull is rotten out so check it out REAL close.... Also if the block is cracked there's a pretty good chance the manifold is also cracked and they can be very hard to find good used and if available new will be quite pricey.

An internal manifold crack could take out your fresh motor QUICK.

 

[Vipor81]

Sorry for the confusion yes manly talking about doing the auto switch the manafold from the marine motor is still in good order and yes the the auto block has the front motor Mont holes

 

[alldodge]

Should be worth the shot

 

[Vipor81]

Out drive was serviced at being of the season previous owner should me paperwork on it

 

[Vipor81]

Well I'll keep yall up to date on how things go soon as I get started but first thing first going to strip auto motor of bolt ons then start labeling all the wires on the one in the boat before I start the pull I'll try and get some good pics along the way

 

[biggjimm]

The proper service manual for your year & model of engine will be a huge help when you go to set everything up & get it running once its back together.

 

[smokeonthewater]

The auto engine will likely have a little lower compression ratio but will only likely cost ya just a few hp

If the cam n lifters from the marine engine are good use them.

Would be a good idea to compression test the donor engine before starting and on any engine that old I would definitely do valve seals since they are cheap and fairly easy to change.

 

[Vipor81]

Will check into compression test and valve seals thanks

 

[Alumarine]

If the motor is from a truck the cam will probably be close enough.

Here's a link to an online manual.
http://boatinfo.no/lib/library.html

 

[Bondo]

Sorry for the confusion yes manly talking about doing the auto switch the manafold from the marine motor is still in good order and yes the the auto block has the front motor Mont holes

Ayuh,.... Welcome Aboard,... When ya strip it to the Long Block configuration, the core plugs will be exposed, a brass core plug kit is cheap, 'n easy,...
Do it,.....

Then reassemble with yer accessories off yer boat motor to a runnin' bobtail motor,...

Test run it on the floor, before ya stab it into the boat,...
Pull the drive before ya do Anything under the motorbox,...

Don't worry 'bout the cam,...
Change the head gasket, the day before that one fails,....

 

[Vipor81]

It was from a 75 camaro the guy who had it was doing a v8 transplant but I also read came still shouldn't be a big deal

 

[Bondo]

It was from a 75 camaro the guy who had it was doing a v8 transplant but I also read came still shouldn't be a big deal

Ayuh,..... The "Marine Cam" legend is really 'bout the motors guys like him build with radical cams for street racin' Hot Rods,....

A dead stock cam in any production variety automobile will run, just Fine, in our production variety boats,.....
We always say use a truck motor, but I doubt a Caprice 350 is cam'ed any different,....

It's when the cam is big enough to develop that Lope at idle, yer gettin' close to danger in a boat motor,....

 

[Vipor81]

I wasn't wanting to pull the oil pan but I did notice that there is sorta a baffle in the marine pan will they be the same or do I need to switch them

 

[Vipor81]

Bondo will do with the drive thanks

 

[smokeonthewater]

Seems to me the camaro oil pan has the sump in a different place???? Can't remember for sure..

I believe the marine cam in that motor has a little more lift than the car cam but my biggest concern is that the engine has had 40 years to have had a hot cam swapped in.....

With the cam from the mercruiser engine if it's in good shape there's less chance it was messed with.

I also figured it was likely to be in better condition just based on boat motors usually having low hours.....

Go ahead and get on ebay and pick up an alignment tool for IIRC $30... You'll need it.

 

[Vipor81]

I had my maintenance department at work mill me one out so got the alignment tool for free ill check on the placement of sump if so ill just have to watch rocking the boat lol

 

[Vipor81]

And Marc c thank you for the link to the online manual it will be a big help

 

[biggjimm]

That baffle, is a windage tray of sorts, it helps keep the oil in the bottom of the pan where the oil pump pick up is & not sloshed all around by the forces of the crank spinning. Both pans should be the same.

Hey bondo, what'd you mean by lopey cams & danger in a boat? Just curious.