Cylinder wall condition, should I be worried?

[gezed]

Alec's did the machine work and I did the assembly, they did a good job, only complaint is that there may have been some miscommunication but I think when they decked the block they were under the assumption I wasn't using a MLS head gasket, the surface still had ridges from the decking passes, didn't think too much of it til i found coolant in my oil pan

I don't think its because of ring gap, they were filed down to the specifications sheet that came with the pistons and i checked them myself with feeler gauges before installing, checked the skirts and they seem fine, the dry film lube is still on the pistons a few has a streak or 2 on them, I think bearings are okay, I will check soon

during assembly all main and rod bearing(ACL) clearances are checked with plastigauges and they were all within spec of FSM while being a little on the higher side which is not bad

I think it may be debris that got into the motor but i just dont know at what stage did that happen, I assembled the motor inside my house and i kept everything as clean as possible

[nimblestix]

Okay,so these things happen. I understand now the whole situation.

The scoring will be okay just hone it out and clean everything really well. Double check you clearances while your at it.

I was assuming you we're having a shop do the labour and my apologies had I maybe spoken too soon, however if there was some sort of mistake found in the end it's better to have made it yourself than have it made by someone you've hired.

I don't think you have a lot ahead of you as far as work goes so long as your tolerances were in check when you assembled her. As you said maybe there was a little debris that found its way in, and caused some havoc.

Good luck man.

[gezed]

what confuses me is that there hasn't seem to be any sign of compression loss across the cylinders, but I guess its cause the scoring isn't deep enough or high enough on the cylinder to show any problems

in any case, I guess im looking at a hone and new rings...

[MarusGTR]

what confuses me is that there hasn't seem to be any sign of compression loss across the cylinders, but I guess its cause the scoring isn't deep enough or high enough on the cylinder to show any problems

in any case, I guess im looking at a hone and new rings...

In your case (but I am inexperienced in the matter) I'd consider that the rings may have caught/fused the slag and still seat the walls properly in the scoring. I'd be inclined to change rings anyway.

[Terrh]

Is that picture of the worst one?

What do you use this for?

IMO I'd leave it alone if it wasn't burning oil and had good compression. Hone + rings means possibly pistons and bore. And it definitely means new bearings and a crank polish. And I doubt you're doing this yourself, so you're looking at adding a grand to your bill, best case. And $2k+ worst.

Also, as with EVERY aftermarket forged piston, if you don't warm up your car for at least a minute or two EVERY TIME before you drive it, your cylinder walls are going to look like **** immediately.

[gezed]

wouldn't I be able to hear the piston slap when cold?

[Blackcossie]

I'm going to venture out on a limb and say a torque plate wasn't used in the boring process.

[gezed]

whats the result of not using a torque plate?

[Blackcossie]

Cylinder distortion, once you install your head the clamping force causes the cylinder to slightly loose it's shape. A torque plate simulates that clamping force and still allows the cylinder to be machined. The result is a perfectly round cylinder once the head is installed.

[Blackcossie]

Did the builder provide you with a spec sheet? Do you know what the piston side wall clearance was?

Your picture shows that your engine does not have enough cylinder wall clearance. Either from not machining enough clearance into the bore ( super tech pistons are 4032 alloy and are classified as low expansion pistons, I would still have a hard time installing them at the recommend .0025 clearance especially without a torque plate) or you severely overheated the pistons or the cylinder distortion was not accounted for in the boring process.

Your pistons will also have matching galling on them.

[gezed]

the afr was fine so I dont think the pistons ever overheated, but as for the use of torque plates I wouldn't know, the machine shop I went to should know what they are doing, I gave them the spec sheet from Supertech that came with the pistons to do the clearancing, I did however use ARP hardware which they were not aware of

[Blackcossie]

If a torque plate was used they should have asked for the headgasket and head fasteners to attach the plate. Some shops bolt on everything else, like motor mounts and such, to be certain the bores are completely distorted.

[gezed]

well then....i guess torque plate was not used

[mightyrocker]

I'm on the same page as everyone else here; improper piston-wall clearance. If there wasn't a torque plate involved or the piston-bore clearances don't match the expansion properties of the piston that will easily happen. Your skirts will be able to tell you more.

fingers crossed that all it needs is a hone!! =]

[Blackcossie]

Sadly most machine shops don't use them on specialty motors like the RB, $500-800 for a properly made torque plate and the builder doesn't want to flip the bill. Unless they specialize in RB's they probably don't have one.

I had a hell of a time getting a torque plate for the RB26 from one of the most recognized manufactures in North America. It took them 3 try's to get it right, I had to provide them with a head gasket at one point even though they had it listed on there website.