Knock knock knockin on the cylinder bore

Well so what I was hoping was a lifter problem turned out to be much worse.

I’m amazed that the cylinders are still in such good shape. All the marks on it I can’t even catch with my finger nail.

So I think the best plan of action is to just have the cylinders honed and a new set of pistons. I already have new lifters to go in it.

New oil pump and new cam bearings while I’m there.

This is cylinders 4 and 6 I only had a misfire on cylinder 4 though

Love the title! But man that sucks.

I gave your photos a hard look, I am wondering how the piston ring got out of the ring bore and on top of your piston with no holes in the block or pistons? Your cylinder head probably shows the impact marks from the ring impacts.

Ring looks in the right spot. Piston broke.

West 1 said:

I gave your photos a hard look, I am wondering how the piston ring got out of the ring bore and on top of your piston with no holes in the block or pistons? Your cylinder head probably shows the impact marks from the ring impacts.

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I’m wondering the same thing. I honestly don’t know how it didn’t damage the cylinder. It’s the lightest scratch marks. I can barely feel it with my nail.

Yes there is marks in the cylinder head that match the piston.

Cylinder 4 was the only one that was misfiring. But there was a massive amount of blow by.

I’m trying to decide if I’m going to hone it my self and put new pistons in or if I’m going to take it to a machine shop. I’ve definitely seen worse and honed with new pistons and sent it.


Either way here’s where I’m at

New pistons
New cam bearings
New hv oil pump
New lifters and trays
Hone the cylinders
Shave the heads

When I bought this it had oil consumption and I thought it was just the normal stuck rings now I’m thinking someone ran low octane for a long time and hammered the pistons with detonation but the others look fine only 4 and 6 are bad doesn’t really make much sense

SpareParts said:

Ring looks in the right spot. Piston broke.

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Part of the top ring in cylinder 4 is gone

Honing is an Art today. Properly done these engines use zero oil and the piston rings last 300,000 miles. A quality machine shop can provide a good cylinder finish with a professional hone.

Hand hones just do not provide a professional finish. You might use a quart of oil in 500-1000 miles with a hand hone. Zero oil use with a good hone done in a shop.

Ball hones are the very worse for Piston Rings. The finish left by a ball hone might look good to an untrained eye but blow that finish up and look at it with a microscope and it shows how torn the cylinder finish is.
Porfessionals advise saving the ball hones for mixing paint and keep them out of a cylinder.

My recommendation is to take it to a machine shop. In addition to a professional hone job, they can inspect to ensure that there is not something else there that you did not catch.

So after talking to the machine shop i can get the cylinders honed and heads shaved for 5-600 of course that’s if everything is within spec enough to just do a hone.
I think it will be.

With shaving the heads that’s going to increase my cr a little bit I was thinking of going with the tap -4 cc pistons to comp for that and give me a little bit of wiggle room for octane difference at the pump.

Gotta get the engine out and torn down so I can take it up there next week.

Does any one have any experience with the -4cc pistons

All aftermarket Pistons are destroked .020 to allow for rebuild changes. Milling the heads, having the block surfaced, rebuilt connecting rods etc. Your new pistons will not be an issue. If in doubt find the spec for compression distance for your OEM pistons and compare that to the pistons you are thinking of buying. Compression distance is the measurement between your piston head and the center of your piston pin.

You might verify they still Destroke .020 that was the standard up till 2019, I don't think it has changed but worth checking. If you buy forged pistons they are usually full deck height and. not destroked. Hypereutectic aluminum pistons would be destroked.
Hypereutectic pistons would be the factory piston in your engine.

Looking at these factory set cast pistons.

Also looking at dnj pistons anyone have any experience with them

I have used Sealed Power Pistons as they are a major OEM supplier. Mahle is another major OEM supplier.

Properly designed pistons work. They will last 300,000 miles and not give you any issues.

Personally that part is so critical I would stick with what worked at the factory.

If you are planning to Supercharge this engine, run Turbo’s or Nitros you might think of a Forged piston upgrade. Even with that upgrade they are not all built to the same standards so stick with a known quality provider like JE or Diamond, someone with years of proven quality.