Learn me (more) rod knock

In reply to Dusterbd13-michael :

Amazingly, the local Chrysler dealer was able to order the supposedly NLA rod bolts up and had them in a day.  I don't recall the part number, but when I'm back over at the shop later, I'll get it for you.  I just asked the guy at the counter for con rod bolts for a 2005 PT with the non-turbo 2.4 and he had them located, though.  Alternately, you can get ARP rod bolts for the 1.8L Duratec which fit - those are the ones I have in my 2.4T in the rallycross Neon.  That's ARP P/N 251-6202.  The bearings were Sealed Power from O'Reilly and they had them in stock in the local "hub" store, same with the oil pan gasket.

In reply to wae :

Side play has nothing to do with it, and is determined by the rod and the crank, not the bearing.

If you put it together and there is zero side play, something is wrong.  Verify the existence or lack of play, it is somewhat important if there isn't enough, but trivial if there is too much.

Do you have plans on doing the oil pump and pick up as well? 

Small particles can cause the relief valve to stick. I've had one stick close and blow up oil filters (Ford currier pick up / mazda) I've had several other stick partly open thus never make 100% pressure or flow to the rest of the motor.

Well, I did some more measuring and the con rods are pretty tight but have a slight bit of movement that seems within the specs in the book for side clearance.  They feel the same as when I put the 2.4T together for the Neon, so I'm not sure if that's a good thing or a bad thing...

Early this morning, I went ahead and got the oil pan back on.  I'm not doing the pump/pickup primarily because I know this is a one-cheek job and I'm trying to not throw good money after bad for what is realistically a temporary fix.  I inadvertently put 5-20 instead of 5-30 in it, but I plan to drain out some oil to see what it looks like anyway, so I'll pull out a quart and add some 10-40 to thicken things up a bit.  

On initial start-up, it made pressure pretty fast, but was still knocking.  It seemed like the same noise, but this time the block was basically silent while the head was banging away. (heh heh).  Before tearing anything apart, I was all over the motor with the stethoscope and right around #3 and #4 on the block was just banging away like Maxwell and his silver hammer.  This time, however, just the basic whirr of a rotating assembly down there with the noise only really audible when I probed the head and valve cover.

I ran it for about 30 seconds and shut it off.  I let it sit and started it up again and let it run for about 2-3 minutes.  The noise seemed to fade, but the bottom remained quiet.  I did another 4 or 5 iterations of letting it sit and then running it for 30-60 seconds, but the temps really never got to the point that touching any part of the engine with a bare hand was even slightly uncomfortable. 

Weird thing:  Third to last time I did it, there was no knocking except for a slight little rasp when I released the throttle after revving it up.  The last two times, however, it was actually quiet.  Well, by that I mean it sounded like every other "normal" Dodge 2.4 that I've heard.  No weird sounds at all and good oil pressure all the way around.

It might last for 5 miles, it might last for 5 years, but I think I'm going to go ahead and finish bolting the motor back on to the frame, put a non-leaking oil pressure sender in it, drain/fill a quart of oil and inspect it, and then send her back into the wild.

I recently looked up the Alldata entry on the hydraulic lash adjusters (lifters) on a 3.5L dodge v6 i had put heads on. It said 'noise doesn't count unless it's done it for an hour straight'.  Chrysler really didn't want to warranty their E36 M3ty lifters, i guess. 

In reply to Vigo :

Taking a page out of the software developer''s manual?  It's not a bug - it's a feature!

In reply to Vigo :

You'd be shocked how long it can take to purge air from HLAs in some cases.

I think the procedure for the 3-liter SAAB V6 in the Saturns was to drive at 3000rpm for ten or twenty minutes.

So, if you were faced with this issue again, only had the option of a $250 junkyard engine of unknown history, would you clean/rebearing it again? Or would you skip it and just buy the question mark?

In reply to Dusterbd13-michael :

I'm not sure if I'm ready to answer that question yet.  I think for the time invested plus the dollars, it's worth the gamble, but my answer to that question would really depend on if this thing dies on my way to drop it off to her or if it's still going in a year.  I went over and got it all buttoned up last night and it sometimes has a really light knock that's coming from the top.  I suspect a wrist pin maybe because it doesn't have that light metallic ticking sound that I'd expect from a lifter and the noise isn't very prevalent in the block.  I don't really know, though -- I'm pretty much out over my skis here.  Before I drive it over, I'm going to drop a quart of 10-40 in and I might do some of the Lucas Oil Stabilizer.  When I poured out most of a quart of oil through a coffee filter last night, it looks perfectly clean at this point, but I'm going to have her bring it back in 500 miles for another change so I can see if anything else has accumulated.

Looking at the inventory of PTs in the local you-pulls, there weren't any that had any noticeable body damage, so that translated to extra risk in my mind.  Also, it's been cold as balls and I'm just too soft to want to go pull an engine in the cold rain.  So really the option would be getting a craigslist part-out engine or a full-service junkyard engine for more like $350-$400.  Of the $110-$120 that I spent to do the job, $30ish of that was the oil and filter which I'd have to do on a replacement motor, plus the replacement would probably get new accessory belts at a minimum and should probably also get a new timing kit.  So, go from $250 for a you-pull engine and add the oil change and other service bits and you're up to $400ish?  Frankly, I'd also push her hard to get an already-pulled engine even if I knew of a good one in a yard, so probably more like $500-$600 to re-power the car v/s the $110 gamble.

If this were my car, my course of action would be to slap the bearings in now to get myself back on the road and out of a $200/week rental car, and then go get the $250 junkyard engine.  I'd go ahead and tear it down, send it out to the machine shop for inspection, cleaning, head work, and honing and then re-assemble with new bearings, rings, gaskets, seals, pumps, and belts.  Then I'd either wait for a "convenient" (haha!) time or for the original motor to give up the ghost before swapping.

I say that, but I do kind of have a car that's in that exact same position that I need to get cracking on.  The difference with the Merc, though, is that spare engines are nigh on impossible to find and $10k when you do.