V6 Merc cranks

[CVX20SPRINT]

Will a crank from an 86 2.4 fit in an 81 2.0 L .

[TEXAS20225]

steel caged center mains or plastic

[CVX20SPRINT]

steel caged center mains or plastic

I have the 81(top bearing went out)and it's still together.A member on another forum has the 86 crank that he would part with if it fits,so I haven't seen either one.
To answer your question I have no idea.I've read about the top pinned and bottom pinned rods,but have never really seen any info on which motors had which.I have read that one can be made to work in the other though.
Thanks for the reply.

[Onetime]

Pretty sure it will fit just be sure of the correct bearings being used with the different radius journals.
Another option might be to have your crank repaired. If just the top bearing is bad you can have that journal ground and install a hardened bearing sleeve on it. A good automotive crank grinder can do this.

[tlwjkw]

They will "kinda"....There are some differences that ya need ta know about ta make it work and last. One is oiler, one is not. Different "style" (not size) center mains. Think id of top bearing will be different. They possibly have two different size (thickness) sealing rings so they would need ta be matched ta crank and block. If both have same size ya good...
Will add this though. Tha crank and what it does ya better have a warm fuzzy makin' changes like this or it just might cost ya a lot more down tha road.............jmo

[Onetime]

Didn't think the 86 was oil injected. If it is then the early crank definitely won't interchange unless you lose the oil injection.

[tlwjkw]

Gettin' a little old n foggy but think it started with tha block change in '83/'84....... merc made a big deal with it for marketin'............

[Onetime]

Understand the old and foggy thing!! Same here. Had an old 200, thought it was an 85, factory no oil injection. Probably off on the year model though.

[crankbearing]

Chris, I have a good vintage 150 2.0L crank here non-oiler what does your top bearing journal measure.

[Dave Strong]

Gettin' a little old n foggy but think it started with tha block change in '83/'84....... merc made a big deal with it for marketin'............

:iagree: The brown stripe motors, 83/84.

Dave

[tlwjkw]

I bought one of tha first prod XR2's 'round here, thinkin' '84. Never started it with tha oiler hooked up........That was when all tha oiler junk (tank, hose's n bracket junk) came in tha box with tha motor, not extra!

[tlwjkw]

Chris, I have a good vintage 150 2.0L crank here non-oiler what does your top bearing journal measure.

There ya go.....Don't even hafta put up with all those funny, crossin' tha border charges!

[Onetime]

........That was when all tha oiler junk (tank, hose's n bracket junk) came in tha box with tha motor, not extra!

Funny how that stuff is extra money now!

[crankbearing]

yes and this 150 had big rods in it as well. not sure if that was std then but that what I took out of it.

[tlwjkw]

Kinda like "bags DON'T fly free" anymore....

[tlwjkw]

yes and this 150 had big rods in it as well. not sure if that was std then but that what I took out of it.

Yeah. Little (2.0) pistons, big rods. Big (2.4) pistons, little rods......

[CVX20SPRINT]

Chris, I have a good vintage 150 2.0L crank here non-oiler what does your top bearing journal measure.

Not sure as it's still together.I kind of walked away from it a couple of years ago when I found out the bearing was noisey.Really need at least a 200 for my old boat,so I haven't been in a rush to do this one.

PS Pretty sure I talked to you a while back about building me a 200 powerhead.Had the money at the time,but the wife had other plans for it.

[CVX20SPRINT]

Pretty sure it will fit just be sure of the correct bearings being used with the different radius journals.
Another option might be to have your crank repaired. If just the top bearing is bad you can have that journal ground and install a hardened bearing sleeve on it. A good automotive crank grinder can do this.


I didn't think the repaired ones were all that dependable.
I bought a crank from a guy on Fast Boats that he swore was good.When I finally got it and checked it over either #5 or6 rod journal had a ding in,so I suppose I have 2 that could be repaired.I'd sooner get a good survivor crank.

PS The guy said he'd find me another one,but I think he moved out of the province.Haven't seen him on the site for a couple of years.

[crankbearing]

Well I can check this one out again and let you know but if I recall there was not a mark on it when I put it in the box a couple years ago.

rgds,

Dave

[Onetime]

I didn't think the repaired ones were all that dependable.


I wouldn't run a welded repaired one. The only repaired ones I've had success with are when only the top journal is done as I previously described. Would have no worries running one on production engine especially a 150 hp.

[CVX20SPRINT]

Well I can check this one out again and let you know but if I recall there was not a mark on it when I put it in the box a couple years ago.

rgds,

Dave

Thanks Dave
I'll let you know first before you go pulling it out to check it.Can you PM me a price for it?

[CVX20SPRINT]

I wouldn't run a welded repaired one. The only repaired ones I've had success with are when only the top journal is done as I previously described. Would have no worries running one on production engine especially a 150 hp.

If a person were to go this way where would you get the sleeve and do you use the stock bearing?
I actually have another crank that got left out after disassembly and is pitted/rusted where the top bearing rides.I suppose they both could be done this way.

[bobthebuilder]

pics would help.. if you have a 1 1/2 inch top journal on the crank you can get the top journal turned down to 1- 3/8 and use a 1- 3/8 bearing and seal to put it back.... I have done it several times in the past..

[TEXAS20225]

the plating on the top journal is very thin it wont turn down and the crank out of a 2.4 oiler does not have the boss's on the center mains which will let the bearing run up and down the journal if its a plastic one, there was a,guy on here a while back said he been running one two years but me i build for a living i would not put one in if it was free ihave torn several apart that had the cage destroyed because it was in the wrong one there are still a lot of 11/2 diameter top caps i have a half dozen all with steel cage's 2.4 also came with a loose bearing 13/8 top bearing i have every conceivable combo in parts also have 2.4 200 whole mota sale

[Onetime]

pics would help.. if you have a 1 1/2 inch top journal on the crank you can get the top journal turned down to 1- 3/8 and use a 1- 3/8 bearing and seal to put it back.... I have done it several times in the past..


I would not do that .... As TEXAS20225 says, if you grind a 1-1/2" top journal crank down to 1-3/8" you will grind right through the heat treated hardened surface and it won't last very long.

[Onetime]

If a person were to go this way where would you get the sleeve and do you use the stock bearing?
I actually have another crank that got left out after disassembly and is pitted/rusted where the top bearing rides.I suppose they both could be done this way.

You use a hardened inner race to production roller bearings. Commonly available from a bearing house. McGill, RBC and Torrington make them. Have the crank grinder grind the top journal for a press fit to the id of the hardened sleeve. Press or better yet heat the race and shrink fit it on the crank. Don't heat to much to lose the heat treat. After installed and cooled mike it to be sure of size and polish to size if needed. Done many this way. Never had a failure on a stock engine.

Yes you use the stock bearing.

[bobthebuilder]

The ones I had ground are still running. One I know of for sure has ran for the last 5 years on a fishing motor. But you guys are correct about surface hardening of the journals. It is questionable as to how long it will hold up.. probably a lot longer with good oil going to it where as some engines I take apart have been oil starved on the top bearing. The hardened sleeve thing is great. I did not know where to get them.. but I did get some speedy sleeves through NAPA auto parts for my personal boat trailer axles (tandem axles) all 4 spindles have them and no grease slinging anymore inside the wheels.. than I used Kodiak Red Eye protectors on the outside.. clean and neat now.
Also if you really want to have a crank journal fixed it can be done with a product called DLC the is used on HP automotive engines.. NASCAR stuff.. but it gets really expensive. My friend does that to his drag race Chevy cranks..

[CVX20SPRINT]

You use a hardened inner race to production roller bearings. Commonly available from a bearing house. McGill, RBC and Torrington make them. Have the crank grinder grind the top journal for a press fit to the id of the hardened sleeve. Press or better yet heat the race and shrink fit it on the crank. Don't heat to much to lose the heat treat. After installed and cooled mike it to be sure of size and polish to size if needed. Done many this way. Never had a failure on a stock engine.

Yes you use the stock bearing.

I'm thinking that it would cost more to repair mine than it would to buy a good used one,but I could be wrong.I've been quoted anywhere from $200(should have jumped on the $200 one I guess) to $600 for good used ones.What do you think it would cost to sleeve it?
I guess I should have said at the start that I'm not looking to go racing,just want a decent dependable motor.

[CVX20SPRINT]

the plating on the top journal is very thin it wont turn down and the crank out of a 2.4 oiler does not have the boss's on the center mains which will let the bearing run up and down the journal if its a plastic one, there was a,guy on here a while back said he been running one two years but me i build for a living i would not put one in if it was free ihave torn several apart that had the cage destroyed because it was in the wrong one there are still a lot of 11/2 diameter top caps i have a half dozen all with steel cage's 2.4 also came with a loose bearing 13/8 top bearing i have every conceivable combo in parts also have 2.4 200 whole mota sale

Thanks Texas
That's exactly the kind of info I was looking for.Not having built one of these motors before I'd like a direct fit one just to keep it as simple a build as possible.I am a licensed auto-tech and I know just about enough about these to get me into trouble LOL.I figure with the help here and a good manual I can pull it off.Just the knowledge here alone should get me through.

[Onetime]

I'm thinking that it would cost more to repair mine than it would to buy a good used one,but I could be wrong.I've been quoted anywhere from $200(should have jumped on the $200 one I guess) to $600 for good used ones.What do you think it would cost to sleeve it?
I guess I should have said at the start that I'm not looking to go racing,just want a decent dependable motor.

The sleeve costs about $20.00. Check with a crank grinder in your area as to cost grinding and installing. Best if you had a crank in hand for him to see.

Your first move should be to disassemble the engine and see what you have. If the top bearing journal is bad make sure you deal with what caused it, most likely lack of lubrication.

[CVX20SPRINT]

The sleeve costs about $20.00. Check with a crank grinder in your area as to cost grinding and installing. Best if you had a crank in hand for him to see.

Your first move should be to disassemble the engine and see what you have. If the top bearing journal is bad make sure you deal with what caused it, most likely lack of lubrication.

OK I did some research and came up with these.Is this what you're talking about?
http://www.skf.com/group/products/bearings-units-housings/roller-bearings/needle-roller-bearings/needle-roller-bearing-inner-rings/inner-rings-in-the-lr-series/index.html
Anyone know of a reason why one of these wouldn't work?
Going to check with the local crank guy and see how much to grind the crank.

[CVX20SPRINT]

OK I did some research and came up with these.Is this what you're talking about?
http://www.skf.com/group/products/bearings-units-housings/roller-bearings/needle-roller-bearings/needle-roller-bearing-inner-rings/inner-rings-in-the-lr-series/index.html
Anyone know of a reason why one of these wouldn't work?
Going to check with the local crank guy and see how much to grind the crank.

$100 to grind the top journal and polish the rest.$30 for the inner race.
What do you all think?Would you chance it on an old fishin motor?

[Onetime]

No chance involved, proven fix done many, many times before.

[CVX20SPRINT]

No chance involved, proven fix done many, many times before.

OK I think I'm going to give this a go.Things been sitting for too long.I haven't torn it down before now mostly because I didn't know when I would get it back together and I didn't want to forget where everything went.Going to be lots of picture taking as it is.

[CVX20SPRINT]

OK been doing some reading and it sounds like if I sleeve the top of the crank the tolerance between the stock bearing and the inner race I'm installing might be too tight after it heats up.Anybody have an idea as to how much clearance it requires?Got a good crank laying around that you could measure for me?

[pennman]

if you are still looking i have a nice 83' crank for 200 plus the ride.