Replated Cylinder, is this a problem

[griffbones]

Hey fella's
I just got a cylinder back from replating and it looks like someone got a little heavy handed when they relieved the exhaust bridge, and made a gouge below the bridge and kind of burnished the cylinder above the bridge. I can't feel anything in this burnishing above the bridge, but they definetly took the cross hatching off.
My questions are:
1. Is this normal when having a cylinder replated?
2. Will this effect compression in any way if I can not feel a low spot?

I do not have an accurate means by which to measure the inside of the bore, as I only own outside micrometers at this time. I really can't feel a low spot, but I am not convince that would tell me anything anyway, since my finger tips don't measure in ten thousandths of an inch. LOL

I did slide the ring down to this area when checking the ring gap, and I could not see any light between the ring and the bore. The gap measured the same in this area as it did a little higher up in the bore, if this means anything either?

Photo #1 Photo #2

 

[whenfoxforks-ruled]

If you do not have the tools, improvise! Use the new piston and feeler gauges. Push the piston up until the skirt reaches the bridge and measure the gap. It should be at least .002 clearance. The bore should be a little tighter. Who ever plated this has taken a very light abrasive tool and polished the bridge. I have seen a lot more aggressive relief work before! Some plated reliefs can be as much as .004. How was the ring gap? What is the skirt to bore clearance?

 

[griffbones]

I am mainly concerned about the burnishing above the bridge where it looks like they buffed off the cross hatching. I don't know if this is normal, as I had only had one other cylinder replated before, and it didn't look like this, but it was sent to the master himself, Eric Gorr.
The ring gap checks to be right at .012. I don't have a bore gauge yet, and I didn't try placing a feeler gauge between the skirt and the cylinder out of fear of scratching the cylinder wall
A very well respected plater did this work so I imagine everything is ok, but you never know for sure.
I guess I am just after opinions and if it is normal to see this buffed or burnished look around (above) the bridge on the cylinder wall?

 

[whenfoxforks-ruled]

I had some issues with a 134 bridge being too tight, Of course Eric took care of it. It did not look like yours though. Did you have any other work done at the time it was plated?

 

[griffbones]

Nope, no other changes, this was just sent for a basic replate with NICOM and diamond honing. They deffinetely buffed down the exhaust bridge, which is good, but it looks like the buffer got away from them. As I said, I can't feel a low spot above the exhaust ports but they sure buffed off the cross hatching in that area and it concerns me.

 

[griffbones]

Well I talked to the plater today, and it turns out that Eric Gorr taught them to do it this way on these cylinders. The purpose is to have a slight transition from the relieved bridge to the compression area of the cylinder and not just a ledge or jump-up in height all at once for the ring to catch on.
Makes sense to me, and if Eric says to do it this way, then it has to be correct! :cool:

BTW thanks to whenfoxforks-ruled for his time and valuable input! :cool:

I love this web site! :nod:

 

[Pete Payne]

The exh bridge should be relieved .002 -.003"

 

[BryanHadley125]

Re-plated cylinder: no cross hatching on exhaust bridge

Just wanted to say thanks for the post on relieving the exhaust bridge. I just got my cylinder back after getting it replated and thought they messed up. Didn't know the exhaust bridge is suppose to be smoothed down and will not have any cross hatching.