It varies depending on the configuration, but I generally would not get closer than .050 myself, preferably .100 or so.
Found 2 Metal Shavings in oil. What now?
- Thread starter jmillsUT28
- Start date
It varies depending on the configuration, but I generally would not get closer than .050 myself, preferably .100 or so.
EllowViper
Enthusiast
The scoring on the skirt is called "black death" by my machinist...from running too close of a piston/cylinder clearance on boosted applications. Not sure if that term is an industry standard since I had never heard it refered to as that. When I was redoing my bent rod, I had a bit of scoring but nothing like this...and I was running .005 piston to cylinder clearance @ 10 PSI. Another builder PM'd me stating they, on occation, run as much at .008 skirt to cylinder clearance on boosted engines but advised to make sure the engine is warmed up well before any serious driving. I'm running around .007 or so right now with no issue on my Diamond slugs. Even when I significantly bent that one rod, the crank it did not hit the piston like this one did...but put a nice nick in the top of the connecting rod. Not sure why the piston has that chunk out of it if everything is straight and true. Also, I assume no windage tray on this build since from what I can tell, the billet mains did not rertain the stock main bolts with the attachments for the windage tray. Unless the pics are not showing the mains with the extended bolts.
vancouver-gts
Viper Owner
Sorry ,didn't look at the pictures before, just read what the OP said earlier.
.Now I see the boss missing a chunk .Obviously these are aftermarket pistons with beefier crowns for forced induction with slightly different wrist pin location from stock may be? Shouldn't the bosses have been milled down to have proper clearence for the counterweights and balance the rotating assembly afterwards? Sure shows sign of aluminum hammering on the counterweight.Are the rest of the pistons show critically close clearences? Scoring on the piston face could be problem with too much expansion? What is the piston to cyl wall clearence? I'd tear done this engine and check it thoroughly myself.Dan, have you had your shop in California prior to NY? I'm asking because a friend of mine has a silver 1999 GTS that's been modified by Viper Specialty in California.He bought the car from the States years ago.
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I wouldn't jump on wall clearance just yet. The engine has obviously had some material go through it, that is obvious from the piston damage and bearing condition. That quite possibly could be the culprit of the accelerated skirt wear. I have seen plenty of engines which were running the correct wall clearance end up with skirts looking just like that, only because they had material in the oil.
Generally, we run .004-.005 P/W clearance on our forged pistons, and do not see scuffing. However, different manufacturers use different alloys with different coefficients of thermal expansion. If you go too large, the pistons rock when cold [loud], the pistons overheat due to reduces wall contact, and blow-by increases. If too small, they will scuff, or at worst, seize in the bores.
I am fairly sure in this case that the counterweight DID NOT contact the piston. This has nothing to do with counterweight to boss clearance. I feel that something which was loose in the engine got caught between the counterweight and piston boss on the down-stroke, causing what you see. This is evident by the fact that none of the others have damage, and the dimples on the bottom of that piston are indicative of something very hard being tossed around the rotating assembly.
Generally, we run .004-.005 P/W clearance on our forged pistons, and do not see scuffing. However, different manufacturers use different alloys with different coefficients of thermal expansion. If you go too large, the pistons rock when cold [loud], the pistons overheat due to reduces wall contact, and blow-by increases. If too small, they will scuff, or at worst, seize in the bores.
I am fairly sure in this case that the counterweight DID NOT contact the piston. This has nothing to do with counterweight to boss clearance. I feel that something which was loose in the engine got caught between the counterweight and piston boss on the down-stroke, causing what you see. This is evident by the fact that none of the others have damage, and the dimples on the bottom of that piston are indicative of something very hard being tossed around the rotating assembly.
I have not been over this whole thread, but is this a stroked engine? I have seen piston pin boss damage like this on these types of engines. Need more info to speculate.
Hey Dan-
If I recall, yes it was.
However, by looking at the counterweight, the damage is not indicative of a contact issue- the wear is on the corner edge of the weight, and actually off-center of the pin boss, in an area that would actually be further from the closest potential contact point. The typical "overstroke" contact issue would wear the center of the pin boss, and wear the ~20 degrees or so that the crankshaft sweeps BTDC.
Its very odd- but if I was to take a wild guess, something was pulled/fell into the rotating assembly, bounced around a bit between 9/10, knocked off part of the pin boss, and then either that piece or the original that caused it all managed to lodge itself in the block somewhere around the edge of the weight, where it wore that down. It probably fell out later, or is possibly still lodged up top somewhere that the counterweight and main saddle are the closest.
JohnnyViper
Enthusiast
just read this whole thread and learned a bunch, thanks guys
jmillsUT28
Enthusiast
Well it's been over two months now! Finally should have all of my parts to me tomorrow and have this guy running next week. Had to get customer made JE pistons made. Took a while to figure out what I needed as there were no numbers on the pistons.
Question: Does anyone know how many pounds I need to torque the WSB connecting bolts to? It has Eagle connecting rods on it.
Question: Does anyone know how many pounds I need to torque the WSB connecting bolts to? It has Eagle connecting rods on it.
Black Moon
Enthusiast
Call one of the builders like Dan at VSP.
Must have missed this long ago, but no, I have never been located in Cali, nor do I know of any business with the same name out there. I also cannot think of a Silver 99 I have done anything extensively on.
jmillsUT28
Enthusiast
I found the specs on eagle website for my bolts. It was 76 pounds. Got the cylinder looking perfect and have it speced out to what je told me to.cleaned it well and installed the new piston, rings, bearings, and rod. Will post up some pics when I get close to a pc. Hoping to work on it tonight and all day tomorrow. Should have it running Tuesday. Will keep everyone post. Thank you so much for all of the help!!
uvbnbit
Enthusiast
Awesome! We'll probably go in on Thursday night. There's a post in ToD thread with hotel info at ******* Barrel exit.
jmillsUT28
Enthusiast
What a rebuild! Seemed like it took a year to get all of the parts I needed. But finally at 2:30am last night I got the car running. Started on the first try! Very good oil pressure and is running great! So happy to have this guy up and running. Will post some pictures of the cylinder and piston installed after I did the honing. Going to do the break in today and change the oil late tonight. Then going to the Viper meet this weekend! Perfect timing! Thanks to all that helped me and gave me advice. Huge thanks to Doug Levin for countless hours of help and Mike for coming up to help me with the final assembly.
Jon
Jon
01sapphirebob
Enthusiast
Glad to heard she is up and running.
Black Moon
Enthusiast
Good to hear it is up and running!! Nice job!
I learned a ton from reading this too.
Sorry to hear you had to deal with it, but I guess as you said earlier in the thread, you got some good experience tearing it down! (now, I'm knocking on wood hoping I never have to get that experience ).
I learned a ton from reading this too.
Sorry to hear you had to deal with it, but I guess as you said earlier in the thread, you got some good experience tearing it down! (now, I'm knocking on wood hoping I never have to get that experience
).TowDawg
Enthusiast
Glad to hear you got it going and will make the TOD trip!
I'm definitely glad I read the thread and saw the mention of Blackstone Labs for oil testing. I did an oil change Tuesday night and saved some in a tuppewear container to put into my test kit and send off when my kit arrives. Since this is the first oil change since the complete Arrow rebuild (except for their break-in drain and fill), I am really interested to see what results I get, and it should give me a great baseline to track this engine, since I'll essentially be testing it from brand new.
I'm definitely glad I read the thread and saw the mention of Blackstone Labs for oil testing. I did an oil change Tuesday night and saved some in a tuppewear container to put into my test kit and send off when my kit arrives. Since this is the first oil change since the complete Arrow rebuild (except for their break-in drain and fill), I am really interested to see what results I get, and it should give me a great baseline to track this engine, since I'll essentially be testing it from brand new.
jmillsUT28
Enthusiast
Just got done putting 700 miles on the engine this weekend. The engine sounds and runs great! Broke it in for 500 miles then the last 200 miles I really tested it. This car has so much power. Before I took it apart it hit 767rwhp on a very rich tune. While rebuilding this engine I found out that it only has stock heads!! Also from what JE said the engine looks like it was blown up before and someone put the busted up piston back in.
They figured this out once i sent the piston to them to have the new ones machined. Turned out I had to get the accurate measurement of the bad cylinder. It was a little egged shaped so I had to do some honing. That is why I could not find that one piece of the piston. What I'm thinking is that the previous owner blew the engine and messed up the heads. He pulled the heads and put stock ones on. Might have to get some greg good heads and see what power it will make.
All in all I think I could have gotten away with not taking it apart but now I am happy that I rebuilt it correctly and it should run great for many years to come.
The bad cylinder:
Rebuilt Cylinder:
They figured this out once i sent the piston to them to have the new ones machined. Turned out I had to get the accurate measurement of the bad cylinder. It was a little egged shaped so I had to do some honing. That is why I could not find that one piece of the piston. What I'm thinking is that the previous owner blew the engine and messed up the heads. He pulled the heads and put stock ones on. Might have to get some greg good heads and see what power it will make. All in all I think I could have gotten away with not taking it apart but now I am happy that I rebuilt it correctly and it should run great for many years to come.
The bad cylinder:
Rebuilt Cylinder:
99 R/T 10
Enthusiast
This car was built for power. If you get a set of Gregs heads on it, you will be deep into the 800's in terms of power.
By the way, did I mention I have a set of Greg's heads for sale................
By the way, did I mention I have a set of Greg's heads for sale................
