Hmmm, so I wonder what caused the bearing wear then? Sounds like you were pretty careful to clean out everything internally when the engine was put together.

So I dropped everything at the machine shop today. And by everything, I mean the block, crank, pistons, rods and existing bearings. Short block.

https://cimg1.ibsrv.net/gimg/www.mia...2ffa7afc92.jpg


https://cimg8.ibsrv.net/gimg/www.mia...b312141484.jpg


They gave me the good news, rod bushings are available, they had them in stock.
But, piston skirts are scuffed, so are the cylinder walls, and a hone is in order.
The machinist refuses to use existing rings in newly honed cylinders, so he will try to source a new set. Apparently, they are made to order around here.
They are practically new, but I will leave that decision to him.

I learned an interesting tidbit about bearings..
Apparently, "Taiho" is the bearing manufacturer for almost all Japanese automakers, and they have a distributor over here...
I have a friend who owns a parts business, and he sourced a set of "Made in Japan" + 0.25 mm main and rod bearings for a killer price ($30)
He gives me parts at cost, or with very minimal markup, he's pretty cool that way.
So, I will essentially be going with OEM bearings this time around.

All the machine work, including line-bore checking will take about a week, which will give me time to do some cleaning and also focus on the active hood vent project I had suspended since this noise issue started.

Just a thought:

Could this have anything to do with the deleted oil jets?
I had to delete them after a long discussion here on this forum after the engine started consuming excessive oil - roughly 1 liter every 120 miles or so.
Deleting the jets cured the oil consumption problem.

Please show pics of the bushing, that can help us here. I would think if it is a lack of oil (due to no oil jet), there would be a visible amount of damage to the bushing.

I'm sorry I did not take any close up pics of the bushing, but it really did not have any signs of oil starvation, just excessive play.

I must be the first one ever to have such a problem with M-Tuned rods...

Could this possibly be a consequence of the belt driven supercharger with added stress and harmonics on the engine internals?

I am a devout atheist.
I was called a Godless Commie as an insult once, and I really liked it, and adopted it as my username in all the internets.

IIRC Pat had oil burning issues with lightly used rings and a fresh hone on one of his engines. I'd side with your machinist as well.

Rings only break-in once. He's right to exchange for new. Especially on a forced induction build. Even if reusing pistons you replace the rings when the pistons are removed. They wear into specific patterns of micro-grooves. It's almost like fingerprints in that every one is unique.

This isn't to say that the engine won't run on used rings because it will, but they don't ever work like new again. You don't want the extra blow-by on a freshly rebuilt engine for a few dollars difference.

I dont think deleting the oil squirters would have anything to do with bushing play. There are a lot of engines that dont have oil jets and its just primarily for cooling down cast pistons so they dont assplode.

I need your input in an important matter...

We can not get exact size rings for these pistons locally.
The problem is the top ring; it's supposed to be 1 mm thick, and we can only source 1.2 mm rings.
The machinist tells me they can machine the top ring grooves to accept the 1.2 mm rings.
I am kinda hesitant, but I will give him the OK if you guys do not see a problem with this.
The rest of the rings are fine, meaning, they will be exact fit.
They will be made to order, and they have a warranty.
What do you think?

@Savington, what do you think?

Hard pass

Does that mean no?

Incidentally, I just got off the phone with JE tech support, and they told me to go for it by all means..

Sigh.

My guess was wrist pin as well after watching the video. The telltale is that the ticking goes away completely on decel.

If your piston MFG told you it's OK, then go with that. Make sure you ask them which side should have material removed (top or bottom). Ringland thickness is one of the more important aspects of piston design, so mucking with it without express approval from the piston MFG is a dangerous game.

I'd be really nervous because this is something that I've never even heard of prior to this thread, and if it goes wrong you're totally screwed and have to re-do everything

I asked about that.
They will remove equal amounts from both sides.
I was told 0.1 mm from either side will not compromise the structural integrity of the pistons.

Apparently, this is more common practice than I would have guessed around here.
They do it on all sorts of pistons, forged or not, to install custom rings.

There are some specialist shops making all sorts of custom parts for race engines.

One more question:
Crankshaft is being ground 0.25 mm. I know 0.25 mm does not go deep enough to remove the surface hardening on the crank.
Do you guys think I need to take it in to get it surface hardened anyway, or will I be opening a can of worms with such a move?

Oh, I AM really nervous.

Machining the piston for a larger ring is done in the automotive industry, although typically on large pistons that are not cheap to replace. It's possible it is done in areas where parts aren't available, but you can't put material back if it goes wrong. Sav hit one of the key aspects, in that it could possibly weaken the piston, I'm not sure how sensitive the piston is though. The second thing, is that the tolerances in the ring grooves are very important to performance. For instance, if the clearances are too tight, the piston could pinch the ring and cause a scuff. Too loose has been linked to ring breakage in the long term. I'm not saying they can't do it, but it makes me a little nervous. FYI, I design pistons and rings for a living.