Engine "rebuild" questions

[jdblood202]

Alright, so here's the deal. The car is a 1990 gs-t. A little bit ago while I was replacing my exhaust manifold gasket, I noticed a couple of my cylinders looked a little wet, and the valves looked like they could use some cleaning. At a bare minimum I plan to pull the head, replace valve seals, lap the valves, etc. Now, I'm not quite sure what to do with the bottom end. After almost 30 years and 200k miles, I think it's pretty safe to assume the cylinders are a little out of round. I do plan on eventually bringing the block to a machine shop, get the cylinders back in shape, line bore, all the good stuff. However, that probably won't happen for at least a year or 2. In the mean time, would it be bad to re-ring and hone? I see alot of conflicting opinions on whether this is good or bad. I do plan on "cleaning" up the bottom end as best as I can, run a pipe cleaner as much as I can in the coolant ports, pull and clean up the oil squirters, etc. I'd just like a solid opinion on a re-ring and hone, or should I just stick to the addage, "if it aint broke don't fix it"? Also, how are replacing the freeze plugs on this block? I've done a few on jeeps, is it kind of the same on the eclipse or should I leave it to the machine shop? Thanks for the help guys.

 

[motomattx]

Leave the rings alone, to actually really hone the cylinders the block has to go to a machine shop, your probably thinking of using a parts store "hone" which is nothing more than a glaze breaker best suited to lawn mowers and low expectation V-8's.

Back in the day those things were considered acceptable before they new better and could actually measure things well enough to realize that they are junk and do more damage than good, that was also during the time that they thought that a parts store ridge reamer was ok to use too for a re-ring, and at that time it was probably ok because engines didnt last much more than 50k miles between teardowns and didnt need to because the cars they were in didnt last more than 5 years, they also didnt make much power, your talking 150hp or so from a 350 V-8, but for some reason those tools have lived on in infamy on parts store shelves, I use better than that on a push mower just to be up front with you.

The only reason to hone is to break in new rings, if yours are working ok (less than 20% leakdown) and not using oil then no reason to mess with them, you can only make things worse with nothing to gain, I have ran several 4g63's past 300k and they had good crosshatch and good leakdown when taken apart for engine build projects, the bearings are what you want to look at for wear if your looking to freshen things up and buy some time, but again if they dont have gouges or wear past the top layer then you are better off leaving them be even though messing with them gives people some type of peace of mind or sense of accomplishment or they just like to play mekanik or something apparently, but I would resist the urge to play show and tell inside that thing unless you have to, Mitsubishi used million dollar machinery to get that thing perfect, you wont do it justice with a Harbor Freight drill and a $20 Vatozone cylinder "hone".

Things to replace would be seals and gaskets, clean the lifters or replace, knock sensor replace (whether you think it looks bad or not) etc.

 

[jdblood202]

I gotcha. Yes, my knock sensor does need replacing! And that's kind of what I was thinking. I haven't done a compression or leakdown test yet, but the bottom end hasn't given me any reason to believe anything needs immediate repair. I want to do seals and gaskets, and work on saving up for the machine work I eventually want done. Even so, I'm not looking for a billion hp, it's only a FWD, but I do plan on at least upgrading to a 16g turbo sometime in the future.