Replace Pistons/Rings vs New Short Block vs Ignore?

Aloha!

Found this while poking around Amayama site. Partial engine assembly $4810. Not sure what is and is not included or what freight would be but this might work for some people:

Partial engine assembly for Toyota Prius ZVW30 - Amayama

 

Shipping will be on top of that. They've assured me with items without shipping cost determined they will give you a number prior to commitment.

Not sure how you determine build-date of something like that, and what pistons/rings are in it. In your shoes I would be tempted: even with the old piston rings, and especially if you stick with a 6 month or 5K mile oil change interval, you'd be good for a long while.

On the flip-side, that's a lot of $'s, install's not cheap, and there's other issues looming.

 

An installed rebuild including rings can be bought for less in most areas. But it is usually better to start with a used engine that was not run with a bad hg. The goal should be reliable 50k-100k miles for the engine, realizing the high mile car is carrying plenty of repair risk in other areas. Having the inverter issue out of the way is a plus even though the pain of being stranded away from home was fully realized once again. The smart move is to avoid that scenario with the engine.

 

I’ve got to think a factory short block or complete engine sold in 2022 would have the 2014/15 updated pistons and rings in it. No idea how to confirm that!

 

Stop going to the dealer! Almost any shop can fix those kinds of problems with used parts?

 

I didn't get too many pictures the first time I replaced a head gasket, but I'm taking the second one (on a different Gen 3) a bit more easy.

It is indeed possible to replace pistons and rings in without pulling the whole engine. No need for a hoist or a lift. Here is the short block still in place with the crankcase dropped.


This gives you access to the connecting rods from underneath the vehicle. You can then undo the 8 cap bolts with a 10 mm 12-point socket and push the rods/pistons up and out of the cylinder block.


I would characterize the extra effort over that of only replacing the HG as marginal.

 

Yes this is how it's done in all Toyota old rear drivers You just take the head off pop the pan off push Pistons up through the top. Fit new clean standard rings rods and mains.

 

Without honing the cylinders?

 

You can clean them up with a ball hone I think I've got three sizes that cover most of my old Toyota motors but you can get them for every bore size you want usually I just use a flat wheel on my drill with a piece of sandpaper in it just to break the glaze and then I have squeeze type piston ring compressors and certain sizes that I use It's like what opens a can of primer for plastic pipe You put it around the ring the pistons with the rings fitted and just squeeze it with your hand use your other hand to tap the piston into the bore the ridges been reamed the glaze has been broken.

 

Good! A few capital letters.
But that doesn't count as punctuation.

If this were a 4th grader's paper - C-
Maybe a D
Too hard to read. Too much asked from the reader.

As always,,, Punctuation is Free!

 

Looks good in there.

One thought I have when looking at that is whether the rear main seal will "play nice" and not leak after disturbing the block mounting plate.

Posted via the PriusChat mobile app.

 

The last rebuild I performed the same way on my daily driver is holding up well after nearly 3 years. No leak.

 

You did just piston and ring replacement, not aforementioned (by @Tombukt2 IIRC) arms?

How does the piston transfer go; a little heat and the connection pin can be tapped out?

Is check of bearing tolerances done, or is that just too much, opening a can-o-worms?

 

On my Gen 3 engine that I did not rebuild. And a few of the engines that I have rebuilt generally if I take the mains and rod bearings out you can use plastic gauge to check them but if you just look at them very well and they look like they can be reused I just slide a new set usually of Toyota branded mains and rod bearings the newer engines are stamped I think on the oil pan or something in that gives you your sizes for each piston and the ring set you need if you're not boring I think same with connecting rods some of them you have to look up in a chart so on and so forth but generally I'm going back standard everything including rings good quality ring makers sets will allow for o-10 overage so any honing and business that you do you're not going to remove 10,000 of material so you're good If you want to push rings and bores and check end gaps . By all means have at it you'll generally find you fall within the proper range and you just go on to assembly I tried not to overlube the pistons and/or bores. Things seat very quickly if you don't overly lube the slugs or the holes.

 

If arms = connecting rods, I replace one last time as it was very obviously bent. None of them were this time, so the original ones went back in. I do have new ones standing by just in case, but they'll be up for sale soon.

Yep. Manual recommends an 80 ºC bath, I used 2 minutes in a saucepan of boiling water (100 ºC). The hardest part was getting the snap rings off and back on.

Skipped it both times . Didn't anticipate the clearance being off, and therefore didn't have any Plasti-gauge around.

 

Unless I'm changing slugs I usually leave the rods connected to the pistons just fit standard size bearings back in the big end and off we go.

 

Can the cap bolts be reused? I saw the bolt length chart for the head bolts. Wondering if one exists for cap bolts.

 

If the shank diameter (nominally 6.6-6.7 mm) exceeds 6.4 mm, they can be reused.