Promax bearings

[Lotus 50]

A friend of mine suggests I have my 225 PM bearings changed. Plastic to steel. Is this the crank bearings? What is the problem with plastic?

I assume the actual bearings are hardened steel ball bearings. Did Merc use a plastic carrier in some engines and a steel carrier in others?

The seller told me that the rev limiter is 7000 if it matters.

 

[Dave Hensley]

The rod bearings in the ProMax had plastic cages. Tip is to replace with Merc HP steel caged bearings like a 260/280/300 had. Cheap insurance. I would change the rod bolts while I was at it.

 

[racerx]

Plastic bearings are bad if you over heat the motor...

 

[ROBERT CROSS]

225X PM no plastic correct?

Bob
:beer:

 

[hirk]

David I wouldnt take it down just to change them but if you have it apart then for sure, i don't think the failure rate is remotely close to the ring pins with plastic cages but it would eliminate that possiblity.

 

[Dave Hensley]

I agree. There is always the possibility of inducing failure with a rebuild. If the motor is on a rev limiter I would not think another thought about the bearings. Rpm's kill bearings and locating pins.

 

[FlatOutAlly]

I can attest that the plastic bearing carriers fail too.

 

[Lotus 50]

It has a rev limiter and never got near it in my first year. I did overheat a few times.

 

[suicidealli]

Amazing how the plastic cage bearings last.. They do alright in stock motors. I don't use them on any merc v6 rebuilds.

Roy

 

[Dave Hensley]

It has a rev limiter and never got near it in my first year. I did overheat a few times.

Did you determine cause of overheating?

 

[Lotus 50]

Bad water pump. It was advertised as having a new water pump. Go figure. Other than that, the motor has been great.

I won't put on many hours at high rpm. I think I'll run it another year as is and then think again next fall.

 

[fasterbass]

I reccomend the race rod brgs from pro marine . Call jay smith and get the sps bolts and top pin while you got it down.good advice and good insurance .I use jay because the rodcaps have to be machined back just a touch because the sps bolts have a one size larger head.end cap wrist pins also keep from losing bottom end charge through the pin,just a thought.Lee

 

[mtolley]

u can get eithr the sps or arp high performance rod bolts from pro marine. have used both, no issues with either. the arp are @ $8 cheaper than the sps per bolt. just tore down a '95 200 promax and it had metal caged rod bearings,albeit no the beefier caged hipo units. my '94 200 efi was the same way. the newer style hipo bearings cage is physically not the same as the old ones, and there was rumored failure with them a few years ago. i never personally saw one of the failed units

 

[dragmerc]

pretty sure the race bearings from pro are merc's race bearings. whatever you do, don't use pro's stock metal caged bearings. i've seen the cages break.

 

[mtolley]

Yea, when you order the 514r bearing, they arrive in a merc box. Got six in yesterday for a build

 

[suicidealli]

Yep Merc bearings, and the mods to the rod caps are simple to receive the big rod bolts. I do it to everyone I build. Can't get SPS bolts anymore, so we use ARP. I also wouldn't waste your money top pining your used pistons. Buy a set of vertex.

Roy