Gary Sharpe engine fiasco

My dear mother told me I invented dirt.

 

Happens here every day. Someone posts a few pretty pictures of some engine parts and everyone piles on and compliments them on their wonderful work. I do it for a living and cannot tell from a few staged photos what is good and bad work.

 

The honing looks terrible but this is no way to diagnose your problems. Diagnose first, take apart later. It is best done on a motor that is still capable of running. With the cylinder sealing capability of modern rings 8-10% is not great but no reason on it's own to take a motor apart. Stop now and try and figure out what you have going on. I think the oil pump scenario is a real reach. Dry sump systems have so much scavenge capacity it is hard to buy even if it was a plausible scenario. Witch hunts like you have embarked on cost a lot and do not usually end in a satisfactory conclusion.

From the pictures I strongly suspect you'll find OE pistons with new rings and OE liners that were honed, poorly, probably without ever even being removed.

 

I got a lot of phone calls and PM's but never expressed an opinion here.


Lots of good, established shops around the country with well earned reputations that are respected by their peers. Never understand why people jump on the band wagon of someone who appeared out of nowhere and receive the internet 72 hours of experience seal of perfection.

 

Those are not oilers. They are piston coolers. The rod bearings supply the lubrication quite well on their own.

 

With the nozzles broken the oil spray was no longer directed at the bottoms of the pistons, so I'm not sure I buy the theory that this is what caused the smoking on startup. After all, oil is constantly being sprayed from those nozzles, so if it was getting past the rings it'd be doing so the entire time the engine was running and not just at startup.

The theory that the broken nozzles led to low oil pressure at idle seems like a valid one though.

 

Can Nikasil cylinders be honed? I understand that the Nikasil coating is only about 0.05 mm (0.002 in) thick.

 

Have no experience of ferrari but on a ns400r motorcycle they can get a light ball hone but if they have any damage then they could not.

We used to give them a light hone and replac rings each season when racing

Again mo idea on ferraris.

 

Personally havent seen a ferrari squirter, but often theres a valve that opens in certain pressure. As u dont really need to cool pistons at idle

 

With the correct hone, yes. But with the wrong hone all that happens is it screws up the surface as in the picture.

And yes, the hardened surface is quite thin and why those cylinders are considered worn out with very little wear.

 

The old bugger is getting a bit of a hard time on here, be fair now

 

And long may you continue to enjoy the retirement mate, i much prefer it to 12 hour week on, week off shifts

 

1st time i have seen this on a car engine but the big 520 mm diameter diesel pistons we had used this system. 2 sprayers per piston and they used to have seperate filters but off the main oil gallery.

 

Agreed. Looks like the new pistons probably broke the nozzles a long time ago and that is a likely cause of lower oil pressure. Since you can surmise that the pistons didn't recently break the nozzles you can also conclude that the recent "smoking at startup" is being caused by something else.

The mystery still remains how oil got on top of the piston after shutdown. That just seems more likely to be a head issue than anything else. It would have been interesting to see some pictures of the heads.

 

No, Nikasil is not to be honed.

Nikasil is more like a dozen microns thick than a thou.

 

Yes, although the honing process is more about breaking the surface glaze. Here's an interesting technical article about Nikasil and the process. Flex-Hone® Blog- Brush Research Manufacturing's Company Blog: The Flex-Hone® for Nikasil Engine Cylinders

 

Excellent point. Some squirters do indeed have check valves, although I think that the main purpose is to prevent draindown. I wonder what "low idle oil pressure" means in this case. I can easily see a case where the check valves (assuming they're present) are overcome but at the same time the orifice size of the broken squirters means that the oil supply is compromised in other areas.

 

Thanks David thats exactly what we used.

 

I've used Flex hone before in the industrial world - good stuff.

The picture I posted shows the cross hatch marks which I believe are OEM as I don't have any evidence that the bottom end of my motor had been torn down prior.

 

Bob is the flow not proportional to the square of the area so 8 would be 64 and 80 would be 6400 so the flow would be 100 times more if pressure was same?

Been 30 years since school so maybe I am out too lunch.

 

That's right (good memory).