Cam Bearings and Cylinder wall questions.
06-07-2017, 08:45 PM
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Cam Bearings and Cylinder wall questions. I picked up my short block from the machine shop today and have some concerns. By the time I got back and noticed the issues they were closed already. I wanted to get your thoughts before I called them in the morning. First I noticed when I spin the cam gear it spins freely then binds up. Almost in the same spot every time? They did put in New cam bearings in. Any thoughts on what would cause This? Second is I went with forged weisco 3.905 pistons and callies compstar H beam rods. #1 cylinder was up at the top of the cylinder when I picked it up. I spun the motor over by hand when I noticed a little scratch. Needless to say it was worse when I was able to see more of the wall. I'm not sure this was there when I dropped it off and if it was why wouldn't they mention it before they worked on it. Is this going to be a problem? See the picture below.
06-07-2017, 09:14 PM
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Is it enough to catch a fingernail? If not it might not be an issue.
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06-07-2017, 10:45 PM
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Id carry it back, not necessarily because of the scratched wall, but it sounds to me like the cam bearings are installed wrong. That binding is going to eat a bearing very quickly.
06-08-2017, 08:51 AM
#15
Possible they didn't lube the cam up at all when installing it? Id have to agree though, carry it back up there and express your concerns. Don't get pissy with them from the get go or they'll likely tell you to pound sand. I had a local machine shop do some work for me over 6 months ago and I just installed the cam last weekend finally. Lubed it up and it spun like it was riding in butter. The catch in the cam spinning would concern me. The cylinder wall looks like it might have had a small fitment issue with that cylinder and the skirt of the piston is rubbing but who knows. If the scratch was there prior, and the machining to fit the new pistons didn't completely remove the scratch, you'd think they would have suggest going to the next size up pistons so they could get all of the scratch out.
06-08-2017, 11:07 AM
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Possible they didn't lube the cam up at all when installing it? Id have to agree though, carry it back up there and express your concerns. Don't get pissy with them from the get go or they'll likely tell you to pound sand. I had a local machine shop do some work for me over 6 months ago and I just installed the cam last weekend finally. Lubed it up and it spun like it was riding in butter. The catch in the cam spinning would concern me. The cylinder wall looks like it might have had a small fitment issue with that cylinder and the skirt of the piston is rubbing but who knows. If the scratch was there prior, and the machining to fit the new pistons didn't completely remove the scratch, you'd think they would have suggest going to the next size up pistons so they could get all of the scratch out.
06-08-2017, 03:16 PM
#17
I wish someone knew why those scratches appear like that. That's pretty common, especially with aftermarket forged pistons. They appear to be caused by a piston ring because the all start at the same spot, right around where the top ring sits at the TDC.
I've had these scratches happen on a couple of low mileage engines with aftermarket forged pistons. Did you run the same 3.905" bore with forged pistons prior to bringing this into the shop? If so, there's a very good chance you didn't catch this when bringing it in.
Nobody has every had a concrete explanation as to what's happening though. Good luck.
I've had these scratches happen on a couple of low mileage engines with aftermarket forged pistons. Did you run the same 3.905" bore with forged pistons prior to bringing this into the shop? If so, there's a very good chance you didn't catch this when bringing it in.
Nobody has every had a concrete explanation as to what's happening though. Good luck.
06-08-2017, 06:47 PM
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I wish someone knew why those scratches appear like that. That's pretty common, especially with aftermarket forged pistons. They appear to be caused by a piston ring because the all start at the same spot, right around where the top ring sits at the TDC.
I've had these scratches happen on a couple of low mileage engines with aftermarket forged pistons. Did you run the same 3.905" bore with forged pistons prior to bringing this into the shop? If so, there's a very good chance you didn't catch this when bringing it in.
Nobody has every had a concrete explanation as to what's happening though. Good luck.
I've had these scratches happen on a couple of low mileage engines with aftermarket forged pistons. Did you run the same 3.905" bore with forged pistons prior to bringing this into the shop? If so, there's a very good chance you didn't catch this when bringing it in.
Nobody has every had a concrete explanation as to what's happening though. Good luck.
06-08-2017, 09:08 PM
#19
No. These are brand new pistons and rods. The scratch definitely wasn't there. He even said they would have caught that before hand. He thinks it might be a rough ring after they file fit it, he's not really sure. I dropped it off to them this morning and they will take it apart to inspect. It just sucks cuz I was hoping to put it back together this weekend. Now more waiting this sucks. The motor only had 33 thousand miles on it. What did you do to get rid of the scratches or were they not that deep?
If that were mine I'd want top see the bore and piston measurements real time before it went back together AND the ring gaps. I think the ends are exactly what made those marks BUT why do they stop? Something more to it. I can't wait to hear the answer to all this.
WHAT QUALITY MACHINE ON THIS PLANET would put that together and not see it and give it to a customer? Did you see that ELEPHANT in the room? NAAAA I don't have my glasses on.......
Last edited by RockinWs6; 06-08-2017 at 09:25 PM.
06-08-2017, 11:48 PM
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Almost impossible to get quality work done on any level. I've seen it all, you are not going to like the solution to those scratches. Regardless what caused them............its kinda like when you get the girl pregnant. Personally that 1st piston would have gone right back where it came from too.
If that were mine I'd want top see the bore and piston measurements real time before it went back together AND the ring gaps. I think the ends are exactly what made those marks BUT why do they stop? Something more to it. I can't wait to hear the answer to all this.
WHAT QUALITY MACHINE ON THIS PLANET would put that together and not see it and give it to a customer? Did you see that ELEPHANT in the room? NAAAA I don't have my glasses on.......
If that were mine I'd want top see the bore and piston measurements real time before it went back together AND the ring gaps. I think the ends are exactly what made those marks BUT why do they stop? Something more to it. I can't wait to hear the answer to all this.
WHAT QUALITY MACHINE ON THIS PLANET would put that together and not see it and give it to a customer? Did you see that ELEPHANT in the room? NAAAA I don't have my glasses on.......