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2.5 rebuild questions

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Hey guys-


I'm a pretty good wrench-turner. Did my lift, can do most things under the hood, but never had an engine completely apart -- I mean, changed head gaskets, lifters (thanks, Jeff), etc.


I bought a spare 2.5L engine to have rebuilt, and I have no intention of rebuilding it myself -- don't have the tools or know-how. I found a guy to do the honing, boring .030, head work, etc., but he made a point to say "I don't assemble 'em -- I'll put the rings on the pistons for you, but I don't assemble them."


Now I know seating the rings on the pistons properly is important. How much know-how do I need to assemble the parts if I have no experience doing so? Should I find a place that will do the assembly and all? I'd hate to do something incorrectly and have to pull the motor again, or, worse yet, trash it. Or is this something anyone with a shop manual ought to be able to do?


One other question, maybe getting ahead of myself: when you're ready for start up on a Renix engine, how do you set the initial timing? I've always seen, on the underhood labels, that timing is "set at the factory" and not to be changed. Just point the rotor at the #1 cylinder TDC and fire her up? Or is there more to that?


Thanks for listening!


Tom :popcorn:

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You pretty much have it. The guy at the shop doesn't want to install them, because that implies warranty. Most ring manufacturers give a little booklet with their stuff explaining how to put the rings. I put mine on with the top ring towards the back (furthest from the forward notch), second ring about an inch or so from the notch, and the oil scraper rings on the opposite side, with the joint in the middle and the ends 1 inch either way so it would look like the ends were all set out into a pie cut into thirds. :wrench:


Just a side note, but the pistons are the same as 4.0L ones, except they are slightly thicker. They are what I am using for my stroker.

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a few thoughts, from someone that's done a quick and dirty re-ring on a motor.


Go buy a decent torque wrench, and by decent, I mean expensive. Harbor freight isn't gonna cut it, you NEED to have the bearing caps and head bolts torqued properly, or bad things will happen.


Since the guy machinging the block is gonna put the rings on you shouldn't really have any problems.

You'll need the tool for the rings anyway, you tighten it down and use a bit of motor oil/assembly lube in the bore, then tap the piston/rod assembly down into the block with a piece of wood, or the handle of a hammer.


The pistons aren't the hard part, it's the cam and such that can be a pain.

Is he replacing the cam bearings in the block when it's machined?

You need a special tool for those.


OTherwise the cam isn't terribly difficult, lots of lube, and slide it in.

To set the timing, you need to get cylinder #1 at TDC, then line up the timing marks on the cam sprocket with the one on the crank sprocket.

that's about all I can think of right now.

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