crank siezure

[ebynus]

I used a crank out of a 2.4 175 late style block in an early style 2.4 bout an 86-87 model. had to replace the mains to the smaller od style in the older block used the upper bearing end cap and bearing off the late model block 2.5 style. fired it off and ran maybe 5 seconds and siezed. Ya should of done a little more research. can some body maybe tell me what my dumb a** did wrong.

[ChrisCarsonMarine]

Call during business hours for explanation,305 394 3354,chris

[Tripps]

i would like to hear the reason also tripps

[ChrisCarsonMarine]

I'll explain later or tomorrow,chris

[dez nuts]

i would like to hear the reason also trippsSounds like you didn;t use the right center main bearing for the crank you used they have a shouldered crank and a non shouldered crank it it is very critical that you use the right bearings when mis matching these cranks, also your old crank is a bottom guided setup and the newer one is a top guiged setup so if you used the older crank in the newer setup with the newer rods you are top guideing and bottom guiding it but i would say without a more detailed explanation and part numbers of what you used that you used the wrong center mains on the crank and they bound when they slid down on the non shoulder crank. Dave:cheers:

[tlwjkw]

Rods make no difference. Its tha mains and top bearing. Like ya say, shoulder and non-shoulder, big journal and small journal top.........

[TEXAS20225]

main bearings have metal cages???

[ChrisCarsonMarine]

Close,dave.There are Several styles of crank used over the years in the 2.0,2.4 and 2.5 engines.Start with 2.0+2.4,Several combinations,differences being type of center main used and size of top main.The top main can be changed in the cap,so either crank can be used in 1976-1991 motors,2.0,2.4 and 1st year only 2.5[1991].Starting in 1985 these cranks were machined for an oil pump drive gear,still interchangable,if no oil injection.The real trouble is mismatching the center mains,easy mistake to make,if your not paying attention.First look at the two styles of bearings,one has an open ended outer shell,matched with needles carried in nylon cages,this bearing must be run on a crank with a flanged,or shouldered center main.This crank does not have a simple radiased curve where the bearing surface meets the counterweight,but has a flange,or flat machined surface on the counterweight designed to support or ride on the nylon cage,holding it centered on the bearing surface....The other outer shell is not open ended,but actually overlaps the ends of the needles enough to hold them captive,and maintain their alignment on the bearing surface.This bearing style uses a light metal cage,also held captive,to align and space the needles.This bearing needs more room between the counterweights for clearance,due to the captive ends,hence the crank is ground with a simple radius where the main meets the counterweights,with no flange,or thrust-like surface.One must remember the crank height is controled by the bottom main roller bearing,which is trapped between a block flange and the lower main cap,and there must be some available movement up and down in the center mains,to allow height ajustment.So,heres the trouble.When the open ended bearing shell/nylon cage setup is installed on a non-flanged crank,pre-mature wear takes place,usually eventually the cages wear away at the bottoms,causing center main failure,eventually.Way,way worse,when the captive type shells are installed on a flanged crank the shells will typically install,and look fine,but will bind and rub when the lower main cap is tightened,and the crank is lifted to correct height,they then burn up-fast,and by that time you don't notice the extra friction,because the engine is now asymbled.I think this is what happened to you,sorry,Chris:(

[T-REX]

An eazy thang to remember....U kan go UP, but kan't go back!!!!

U kan use a 2.0/2.4/2.5 crank in a 2.5 block....U KAN'T use tha LATE(big block, 2.5 style) crankz in tha early 2.0 and 2.4's(witout special center mains)...Tha FAT BLOCK 2.4's fall in tha same class az tha late 2.5's and 2.0's!!...

[tinker060]

Rex, I think in your case you can only go down, God will only put up with so much from a crazed, immoral cajun..........................................:thumbsup:

Jon

[T-REX]

Dammit Jon......Why ya start dem rumors????????

I ain't all cajun!!!!!!!!:eek:

[ebynus]

goes to show been doin this 10 plus years and learn somethin new CANT USE A SHOULDERD BEARING ON A SHOULDERD CRANK. just cuz the od of the bearing fits the block and sits in the dowels in the block dont make right. built many outboards butt they werent frankenstien mixed and matched. crazy thing is rotating it on the bench with the flywheel felt smooth as silk like chris said when it loads and race meets crank the golding begins. yanked the dowel out of the block spun the race in about 5 sec. any way right bearings little polishin and cleanin shes up and runnin. another one chalked up on the dumb a** board. And thanx for the input guys!!!