225 assembly

[KIRCHNER]

at did sometempting to put my 2.5 back together after machine work. question do i use sealer on the case halfs? also best position for block when putting the slugs back in? uncharted territory at this point for me. any build tips would be super. i have the tools,thanks ArtK

[LakeFever]

Yes to sealant on the case halves. It’s locktite 518

piston install I just stood the block on top of a piece of plywood on my workbench and layed in on the exhaust chest to install the piston and stood it up on the exhaust exit or base of the block to tighten the caps on. I had no studs in mine though. Could be done standing up for the whole assembly though it’s not really hard. Just be sure to use 2 cycle oil where need be and I used Vaseline on the roller bearings for the piston pins. You coat the pin with Vaseline and lay the needles up in a tight row and roll the pin over the bearings to pick them up. Worked great for me. Installing the pistons is not easy without the merc circlip install tool though.

Do you have the manual? There’s a lot of info and details about what products to use on what part and torque specs etc you’ll need to follow. It’s a great manual step by step it’s all in there

[skialot2]

I bolted my 2.5 onto my standard harbor freight engine stand. Can rotate it to any position that is comfortable. I liked horizontal for the cylinder I was working on so the piston doesn't drop down after setting the rings and bang the crank. Vaseline works great. I used it for years building transmissions. For these engines I used needle bearing assembly lube. It's extra sticky and dissolves fast and clean. For the loose needles in the wrist pins I used a short socket, shorter than the connecting rod is wide. Slightly smaller than the piston pin diameter. I used an extension as a handle. I stood the socket in the connecting rod and stood the 29 needles around it. Then left the socket in to hold the needles in place. Put the whole assembly in the piston with the washers. Put the extension through one side of the piston into the socket. Than pushed the pin through the other side. Used the extension to wiggle the socket to help align the needles and washers. Pushed the socket out with the pin. Basically an improvised version of the real tool. But it is not $200+

[KIRCHNER]

ski, if i stand it upright, won down t the crank have a tendency to fall out? i only have 1 piston/pin to re-assemble, what happened piror to this failure, 5 needles got trapped in the case somewhere and 1 stood upright,drove itself down thru the piston,thru the rings 1/2 way down the side of the piston. but the cyl. head is unmarked,strange. 1 sleeve needed. other 5 cyl look good,still have cross/hatch marks. would you re-ring the other 5? psinow @ 140-145. thanks for the help, ART

[skialot2]

I leave the 2 end caps snugly bolted in the block half. It holds the crank in place. Then just loosen them a little to drop the front half on. If I took the pistons out I would replace the rings. But you could reuse them if still good.

[skialot2]

Chris Carson will put a sleeve in for you for a great price. I just sent my block to him. Give him a call 305-394-3354. He is a great guy.

[LakeFever]

ski, if i stand it upright, won down t the crank have a tendency to fall out? i only have 1 piston/pin to re-assemble, what happened piror to this failure, 5 needles got trapped in the case somewhere and 1 stood upright,drove itself down thru the piston,thru the rings 1/2 way down the side of the piston. but the cyl. head is unmarked,strange. 1 sleeve needed. other 5 cyl look good,still have cross/hatch marks. would you re-ring the other 5? psinow @ 140-145. thanks for the help, ART

sounds like you might have dropped a piston ring locater pin. It’s fairly common. I would pull all the rods and pistons out to inspect all for cracked rings and or loose pins. Replace plastic bearings with steel caged bearings along with new rb8000 rod bolts. Inspect the crank seals and whatnot too. Just a good going through you might as well take the time to make sure everything is in good health while you have it apart. Check the reeds too for cracking or not seating flat. Probably a good idea to replace them while you’re at it. Clean and flow the injectors while it’s down too. Delete oil injection and epoxy fill the cavity. There’s a lot of great little mods you can do that cost next to nothing and basically bring the power head back to as new or better condition.

[KIRCHNER]

I leave the 2 end caps snugly bolted in the block half. It holds the crank in place. Then just loosen them a little to drop the front half on. If I took the pistons out I would replace the rings. But you could reuse them if still good.

ILL inspect all, do the end caps get sealer? what about the cork around the case?

[tlwjkw]

sounds like you might have dropped a piston ring locater pin. It’s fairly common.

that is mostly referring to tha hi perf, big rpm stuff, nic and forged pistons.. not so much with production stuff.. 245's, 260's were notorious for shakin' 'em out.. think merc started top pin with tha 280's after a little customer, something they are good at, R&D!... jmo.

[skialot2]

The end caps have orings. Orings never get sealer. They get grease. Manual calls for Quicksilver 2-4-C w/Teflon. For the case halves, the manual calls for Loctite Master Gasket #203. I have always used YAMABOND IV. I have a tube from 30+ years ago. it's still good.

[KIRCHNER]

chris has my case already. i think i got the bases covered now. if i re-ring seems like there are choices? i uses the thin rings i know. the bores are nikasil,correct?

[NZ Sidewinder]

I use loctite aviation sealer on the block halves.
As for fitting pistons.
For me, best way is to have the block on a plywood bench sitting on the exhaust chest.
Crank in.
I rock the block toward me to get a piston in one bank and rock it away from me to get a piston in the near side bank.
So I'm working upside down.
This way the crank doesn't fall out.
I always use a combination of fingernails and plastic stick to get the rings in, never ring compressors.
I get boxes of 100 cotton buds and use them with acetone to clean out the rod bolt threads.
Also use the cotton buds to put locktite in the rod bolt threads.
I never put locktite on the actual rod bolt. Alway in the rod hole.

[tlwjkw]

the bores are nikasil,correct?

not if its a 225 block.. only nic are tha 245/260, 280, drag...........

[KIRCHNER]

its a 96 super-mag 225. rings? steel sleeves?

[tlwjkw]

Steel sleeves.... chrome rings..