crank interchange

[Mirage 659]

I have a 2.5 block (OG 280933) that Im rebuilding for my drag boat. I want to know if a Non-Oiler crank from an early 2.4 that I have will work in this block. I can only find these numbers on it, its either 66 or 99 stamped on one throw and what looks to be R3 or R7. I have measured the top brg dia (1.375) and it is the same as my 2.5 crank (350690). The rod jounals are both .830 mains are also both 1.180. Ill be using topguided rods, so will this work?

[outasite]

The problem is the center main journals,having shoulder or not having one.I think it can be done with the right bearing combo,but someone that knows for sure will chime in.I think the 2 litre crank is a better match,as i don't think is has shoulders.There are threads that cover this,and every time it comes up I always say I'm going to write down the info, but never have.

[motorheadbishop]

Yes, I did one and it worked well...
Just a PIA figuring out the ID and OD on every bearing and ordering the
correct ones the first time, BUT yes it did work...

[TEXAS20225]

well i gotta disagree i get a chance at rebuilding a motor 25/30 time a year there is only ONE way, it must have the center main boss's, the steel cage bearing do not come in the right diameter and nobody make any thing close the early 2.0 crank with 9 ring and the 1/12 diam bearingcap works great as it DOES have shoulders wide ones like the bottom guide crank. i just took a 99 200 efi down for rebuild some one had installed a 2.4 crank in it it lasted for bout 4/5months before it started distorting the plastic cages then the bearing got out of the cage it wiped the front the crank and the block and was still running except number 5 lost compression due to trash transfer from exploded lower center main also every parts book ive ever looked i warns against this type installation

[motorheadbishop]

Texas, we turned that motor 9400 pass after pass...
sold it and it aint missed a beat since... juss sayin...
it took a couple shots at the pro marine book, but found the
correct ones and fit like a gloove...

I will see if I can find the part numbers I used when we put it together...

We boat year round, and it probley has over 400+ hrs on it at least by now...my buddy runs it with us every weekend...

[TEXAS20225]

maybe it had main boss's and you did not know! it im a dealer for pro marine aint no such steel caged bearing for the 2.5 crank is all i can tell you, tell me which one you bought after builingr over 200 motors i thought i had this figured out

[outasite]

This time around I'm taken notes!!!

[tlwjkw]

there are only three types center mains made. two are plastic caged and one is metal... one plastic is small od for tha 2.4 (non-fat block) other is bigger od for 2.5 style or "fat block", all of which have ta be big od plastic... plastic HAS TA HAVE THA SHOULDERED MAINS...metal will be non-shouldered....they will not work on a shouldered crank... all early, non fat block, 2.0 motors I've seen have tha small plastic, oiler or not.....all early "prodcuction", non fat block, 2.4's had metal caged... hi-perf 2.4's (were non-oilers) had small dia. plastic same as production 2.0's.
there is no metal cage that will fit tha "fat block".....

METAL=NO SHOULDER...PLASTIC (large or small od)=SHOULDERED.

will give ya this..they're are some that have been very, very lucky goin' against tha grain (most didn't know any better) but usually get caught up with....

this is strickly V6 parts.....maybe ya might mix in match junk from an in-line or something else Merc makes but why.

did I miss anything bobby?

[TEXAS20225]

no sir you are 100% still connect to this particular situation:iagree: i took some pix of the destroyed lower main, the plastic cages were distorted so bad they actually looked like they were built on a angle where the bottom of the cage had been wearing off and finally got twisted around till bearings dropped out race was still on seat pin though ill dig it out of the scrap so you can look at it after you get caught up remodeling yer house "AGAIN" you might splain the the metal cage bearing have the ends caps or side actually make up for the no boss situation as it become the boss it self

[dwilfong]

So a early 2.0 and a non oiler HP 2.4 will have the bosses on the center mains to run in a 2.5?
Now what about if thy have the 1.5 top bearing?
I have one I got off Ebay for $200.
What is needed to run this in a 2.5 with the small top bearing cap?
Also what are the part # for the bearing that will work best?

[tlwjkw]

shouldered crank will run ina 2.5...think 2.0/2.4 shoulder is a "tad shorter" than 2.5 but will run.....

don't remember all tha junk 'bout top bearing...always had choices on tha shelf if crank didn't have one...

stator mountin' will have input on top design. 16 fits all..40 is different...may need ta do a little modifyin' for tha 40...

[Mirage 659]

Just got to love a good dis-cuss'n, but anyway "outasite" you got me think'n, I do have an early 2.0 block, has head bolt on liner and a smaller bolt pattern then the early on liner 2.4, and I belive that this crank came out of it, so it looks like it will work. Any body know what rods where used in this motor(2.0) so I can sift thru my rod collection and find the ones I need for this project. And what main and rod brgs do I need.

[tlwjkw]

metal caged rod bearings...2.5 center mains.....that motor had bottom guided 5250's seems like?...gonna depend on pistons...2.5 "store bought" pistons except first 245/260/fat blocks use top guided pistons.....

[Mirage 659]

The 2.5 has small top guided rods in it, was wanting to use big rods, if the 2.0 used them I would replace the small ones with those. Somewhere Tx. is that close to Nowhere Tx. LOL

[tlwjkw]

rods are rods...doesn't make any difference little or big with a lake motor. ...maybe ina 10 grand plus, BIG compression, modified hot rod,...bottom guided will need some machine work ta work on tha pistons....or find '91 2.5 200 pistons...been lotsa "discussions 'bout it on here.......


"next door"

[Mirage 659]

Not for a lake motor, its a drag motor for my jaguar, 5 petal front, 4 petal reeds ,machined chest, 20 carbs, 260 flywheel, will set on 280 1 pc. mid. want to run 110 oct. Need to get heads cut for that. I know that the rods and pistons that are in the 2.5 now are top guided, it has been worked on, not a stock motor. So what you are saying is the 2.0 rods would be bottom guided?

[TEXAS20225]

all rods prior to the 2.5 motor are bottom guide and some of the early 2.5 were bottom guide 141 rods are top guide ,the difference in bottom guide crank and top guide crank is the width of the boss's on the cranks its clear to me after tearing up a 5/600 motors what is what;) plus this will make it more confusing bottom guide rods are a .100 thousandths to wide for top guide pistons so you can get then cut down .050 off each side and they will work , somewhere in texas is where tommy lives in his traveling home, south padre, corpus, fla, where ever he want to!!!!! life is good huh Tom

[TEXAS20225]

oh yeah forget what it came out of as far as trying to identify what it is,:iagree: figure out what a crank with boss's looks like then you will know for sure ,ive found out its sometimes a part in in something its not even supposed to be there in the first place

[tlwjkw]

first of all if ya doin' all that with buildin' a real stem winder motor don't go throwin' a bunch a used parts on tha rotatin' assy. especially rods, pistons n bearings... might be right back ta square one lot sooner than ya want.........jmo

its gooood bobby! gonna be home for a while accordin' to tha BOSS!

[dwilfong]

I have looked at new rods and there are a few different 141 options. What as far as available new 141 rods are the best to spin up.
Part # would be nice :)

[tlwjkw]

a 9 was tha 280 rod but any as long as they have tha bigger rod bolts...have known some that turn "stock" 141's pretty hard with no problems....Merc stuff, no after market.

[timmc6]

Jmo if you are gonna race,turn it up 9000 or over don't use 141 rods they are WILL break and if you have the same luck we had we saved 2 reed cages and a flywheel out of a whole nice motor!!!jmo Rod failure just like RBT described!!! 10.000.00 loss :eek:

[dwilfong]

Ok so let me ask this? If you use a older crank with the center main bosses to fit a 2.5 and the crank has the bosses for the bottom guide rods. now if you use the old big bottom guide rods and cut the tops for new top guide pistons.
What do you do to the bottom of the rod?
Will it still bottom guide?
Then it will also top guide?
Not a good thing I am thinking.
Am I looking at this wrong?
Could use some clarification.

[outasite]

The bottom guided big rod 5250 can be converted to top guided.A machine shop must grind .050 off each side of the rod.Then there are spacers to shim the piston end.At that point. It's top guided.

[dwilfong]

So nothing needs to be done to the bottom?
Use the 2.5 bottom rod bearings?

[timmc6]

Okay ,if you want your motor to live at High rpm don't use the 141 rods ,it ain't a piston fairule it is the whole motor, Jmo

[TEXAS20225]

the thick spacers are only needed if your running a bottom guide piston on a top guide rods(tg rod 100thou narrower) just cut 100 thou off both end of rods u will be ok but Tim and Tommy are correct take a good look at those economy parts your assembling the will never look like that again if you spin it on up or wont look like anything after it unravels powers sells some nice chatfields for 650 suck it up

[tlwjkw]

really don't think ya gotta worry to much with a carb motor like ya described...........'less your in Florida:reddevil:

[dwilfong]

Ya I guess Merc 2.5 ain't any different than any other eng. Pay for it now or pay more later.
so who has theses Chatfields?
Is that $650 each??????

[mrcrsr]

brendan powers cuts rods to top guide, bottom guide measures .812 wide, top guide .712.if you are going to turn this 9k i wouldn't do it with a stock rod though. as far as 1.5" upper journal, use a 260 upper bearing cap(260 has 1.5" journal), i've used the 150 cranks before. i've used the 2.4 cranks in the 2.5's, but haven't used a non oiler style. i've always kept the mains to the block- use the center mains that would go with the block. i'm getting reading to put one together now. i remember t rex had a big discussion about all this as well. if someone has some pics of the different main journals post them up, even though it may be difficult to see the differences in a pic

[Mirage 659]

Ok so its not a 2.0 crank jusy an early 2.4 hers a pic of the rod and main journal315226

[TEXAS20225]

this crank will work in a 2.0 or 2.4 with steel cage bearings on the mains the 2.4 steel cage main will NOT work in a 2.5 it too small in diameter if you look at the center main in the pix there nothing for the plastic cage to ride on it works itself back and forth till it grinds the cage away sometimes very quickly other time it takes a while but it will eventually destroy itself

[Mirage 659]

Thats what I needed to know. Guess Ill just use my 2.5 oiler crank. Thanks for everyones advice

[mrcrsr]

i pulled out a couple of cranks last nite, the earlier 2.4 cranks will not work, as they don't have the surface for the plastic bearing retainer to sit on. i know the later 2.4 crank had it. also pulled out a 150 crank(1.5" upper bearing) and it had the spots for the plastic bearings to sit on, but i'm unsure of the year of that crank. i took pics with my phone, i'll try to post them up later to clear up any confusion. i know other people have gotten away with running an earlier 2.4 crank but it isn't worth the chance.

[mrcrsr]

315244 here are the 2 different style main bearings you can see on the plastic(which is the later style) that there is nothing holding the needle bearing retainer from contacting the sides of the crank

[mrcrsr]

315245 here is the 150 crank you can see at the top and bottom part of the journal a large supporting area on the crankshaft flywheels that the plastic parts rides on

[mrcrsr]

315246 here is the 2.4 crank

[tlwjkw]

Ya'll puttin' to much emphasis on what it came out of.....

shouldered center main will run in anything 2.0, 2.4, 2.5 (small/large OD plastic bearing)

non shouldered center main "pre fat block only" 2.0, 2,4 (metal caged, lipped race)

link doesn't work on my computer?

[mrcrsr]

And what happens when you have a used crank you bought that has no bearings on it? This makes it easier for people to tell what they have. i put the pics up with my phone, i can open them with google. is anyone else having a problem opening them? unsure why the first one shows the pic, the other ones i have to click on.

[tlwjkw]

if ya buy a used crank ya better know what ta look for and not worry what it came out of 'cause tha seller just might be a bull shiiter...........

[tlwjkw]

clickin' on it shows up "invalid"....

[dwilfong]

So who has the part # for the 260 large top bearing career and bearing ?
Or a ser# for a 260 that will have it to look it up.

[tlwjkw]

try this.............

https://webapps.brunswick.com/literature/literatureSearch.do

[dwilfong]

OK so what years and what eng have the 1.5 cap and bearing.
Thy don't specify what is what.
Could use some clarification.

[tlwjkw]

'91 ta '95 should be same.. try part number 847523 a2 for assy, 74248 for bearing.... but some older production had 'em also...

[mrcrsr]

the earlier 150 has it as well up to 1987. i'm in the process of building a 2.5/200 thats modified rite now, using the 150 crank with a 260 upper cap. you could put a wanted up in the parts wanted section for a 260 upper cap, the upper bearing in pro marine is pn 320. i can't figure out why those last 2 pics came up as attachments, i did the the same way as the first pic. here's something interesting i just noticed in the pro marine book, the od of both bearings is the same(1 3/8 and 1 1/2 journal size). i've never tried to put the larger bearing into the 200 cap, anyone tried it, or is the height of the bearing different?

[dwilfong]

So You are thinking that I can put the 1 1/2" bearing in the cap that came on the my 240SJ block?
Did you get the carbs I sent ya?

[mrcrsr]

carbs are here, those are for that project, haven't had a minute to open the box yet! just got done putting a modded 3 litre on a skater. i'll try later today to get the measurements off the bearings and see if it will work, kinda funny i never noticed the bearings od are both the same, definetely would make it cheaper to do the swap.

[dwilfong]

That would be the BOMB if it works.............................

[TEXAS20225]

well let me cause some more heart burn the top bearing for the 1.5 dia was on quite a few the early motas and on some 2.5 ( not talking 260 ) but the one with the full stator ring around the top has to be modified to get wires out with no hassel but chew on this all the 1.375 loose bearing caps will take promarine 320 top bearingwhich is 260 and fishing mota ive just modifeid 5 top caps that are 1.5 for 2.5 apps so if you got lots of parts and lots of make it work in you nothing is impossible us old geezers worked on a close budget for a while did we not Tommy

[TEXAS20225]

Charlie only the loose bearing steel cage top cap will work with the full ring around it,and the only 2.4 crank ive ever seen with main boss's was out of a 90 model Bridgeport and it was 9 ring

[dwilfong]

I got the part that the early full ring for the stator 1.5 top cap will work with a slot cut for the wires to come out.
Now will a 1.5 bearing fit in a late 2.5 1.375 bearing top cap?
If so what bearing do you use?

[tlwjkw]

did we not Tommy

all true bobby.. that's why our main focus was "shoulders or no shoulders".......that's something we couldn't "adjust" with a screw driver n hammer!:reddevil:

[mrcrsr]

Thanks guys! Just did some measuring of stuff I've got here and came to the same conclusion! Thankfully I've got a 260 top cap set aside for the 200 I'm building. Just took apart a 2.4 and made quick work of the stator ring with a cutoff wheel

[dwilfong]

So you have to have a 260 1.5 top cap or the old 2.0 1.5 top cap?

[dwilfong]

315311315312OK the one on the left is off a 240SJ
The one on the right is off a 2.4 200.

The newer one is a full ring with a small out side OD bearing.

The older 2.4 has a parting top ring and a big OD bearing.

SO will a 1.5 ID bearing work in either of theses?

[TEXAS20225]

no reread #50

[dwilfong]

So the one on the right. loose bearing top cap.
No 1.5 bearing will fit in it?
Sorry but it is not very clear when you explain it.

[mrcrsr]

If you don't have one ask Bobby(Texas) and he might sell you one. I didn't even get to measuring the od of the cap to see if the 2.4 would exchange with a 2.5 I'm using a 260 cap, I'm guessing if I needed to I probably could machine the smaller 1 3/8 cap to accept the 1.5 bearing, I just bought a mill. Bobby I'll probably be pm,ing you to ask you questions about the mill!

[Mirage 659]

Thats what I was going to do with my contestant, a rubber main brg 2.4 crank with a 1.5 dia top brg. Press out older small brg, install 1.5 brg
problom solved

[dwilfong]

Went over to Face book and found plenty of people with 260 1.5" top caps.
No problem took 2 minutes.
Problem solved..................................

[TEXAS20225]

dwilfong when you get that 260top cap it will have a plate with 3 screws in it on the bottom side if i remember right plate does not hold bearing in the cap its pressed in. the left top cap that i pointed out that will work will be the exact same bearing od as the 260 cap the old race must be removed and same as 260 bearing pushed in it cost me 16.50 for bearing and 3.00 and change for new seal plus i remove apart of ring to make wiring easy as to not have to stuff it under the ring i added one more threaded hole 10/24 for the one i removed when i cut the ring and did a slight mod so 40 amp stator would work or 16 amp as it sets i thought it was a easy fix sorry i did not explain it clear enough

[TEXAS20225]

i guess im just a old geezer ive never bought anything off face book:D

[outasite]

i guess im just a old geezer ive never bought anything off face book:DNever knew you could buy anything off face book till about 5pm last nite:iagree:

[mrcrsr]

Same here is there a buy and sell on there?

[dwilfong]

I have the race out of the 2.4 cap. heat it up till it is 215 and it drops right out. Put it back in the same way.
the OD of this race is 59mm or 2.321"

The Pitchlign TJ-75117 1.375" in the 2.5 cap has a 2.06 OD
The Pitchlign TJ-75129 1.5" has a 2.25 OD
There is also a TJ-75318 1.5"with a 2.375 OD
What am I missing?
Is there a different bearing that is 1.5" that will drop in the 2.4 cap?
Go to the page High Performance Boating on face book. Lots of good stuff on there.
Also Hydrostream boats and there are many more.
That's how you got those carbs from me threw Brad.

[dwilfong]

Found it the Phitchlign RBC SJ 7274 is a 1.5 with a 2.06 OD full complement bearing rated at 9000RPM max.
That will drop in the 2.5 cap.
OK so you can replace the 1.375 bearing with a 1.5 in the 2.5 top cap.
Dang I almost had heart burn over this. LOL
So to recap you can use any crank that has the shoulders on the center mains in a 2.5 block with the 2.5 bearings.
If it has a 1.5 top bearing you can get a new bearing and make it work in the 2.5 top cap with the small 1.37 bearing.
Just that simple or am I missing some thing?

[TEXAS20225]

talk about clouding the water :rolleyes:i dont know about all those number ???? i gave you a number for a bearing that mercury says will work and ive been using it for at least 10 years with absolutely no failures, 2.5 fishing motor cap is plastic cage get by that first,a 2.5 is a150,175,200,225,260,280,300 drag so when you say 2.5 its a loose statement because there were least 4 different caps for them!!! 260 early models are small bearing with guts permanent in the bearing( not plastic cage) Merc made another change in mid 90's to a big bearing neither of which is a plastic cage the 225 promax is a plastic cage but what you need for your early merc crank which is a 2.5 bearing number 320for the fixed or loose 2.4 cap at pro if you pull the catalog up on line it has pictures , i personally never found a bearing like what your describing because i went with what was proven

[dwilfong]

No cloud just went to the RBC web sight and looked up the bearing # that is in the cap now. Got the size and specs and found the 1.5 bearing with the same OD and height. also handles more RPM.
Just went to the manufacture of the bearing to get the poop.http://www.ebay.com/itm/271762511459?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Here is what I got coming.

[dwilfong]

here is the speck sheet on the bearings.
http://www.rbcbearings.com/literature/pdfs/RBC-rb.pdf

[dwilfong]

315445315446
Here is a pic of the bearing in the cap. This is off a O ring head 240 Sport Jet block I am using.
Steel non removable double captured cage.

[mrcrsr]

No cloud just went to the RBC web sight and looked up the bearing # that is in the cap now. Got the size and specs and found the 1.5 bearing with the same OD and height. also handles more RPM.
Just went to the manufacture of the bearing to get the poop.http://www.ebay.com/itm/271762511459?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Here is what I got coming.
i don't see any problem with doing that

[wogi]

great thread:cheers: Thanks a lot you guys