RichieP

Mark - I realized what you meant about Alusil process after I already posted a reply to your comment. Cylinder 1 was damaged but not so much so that the pitting couldn't be removed with boring. The Nickasil coating brought the cylinder bore back to standard piston size. I considered boring and proper refinishing of the Alusil block but could not locate a KS oversize piston for my motor. If one was available I image in would cost an arm and leg to purchase. My other option was an aftermarket forged piston with skirt coating but between the machinst possibly not finishing the cylinder wall properly and not really knowing if the coated piston would work I opted for the Nikasil plating.

All- I'm confident that US NiCom will fix any deficiency that exists. I was looking for input on the pic to determine if there is or isn't a problem. I know that may be hard to do looking at a pic on the internet and I may need to just need to have a local machinst and give me his opinion.

Without going into too much detail I've had one problem after another with DHL, UPS and FedEx that I don't want to ship the block across the country again unless I absolutly have to.

Thanks to everyone for their input. It's encouraging to see so many enthusiast willing to help.

mark kibort

Got it. Yes, i saw your other post regarding the Alusil process. Thanks

The one thing i was thinking of was to just get another block, and use your stock pistons. the nicasil process is about $1500 with boring i would imagine.

a new core block, that is in good shape might only cost this much with a set of pistons too with shipping. (and you dont need to buy after market pistons and you have a block using the stock design.)

Im still a little nervous of the nicasil and JE piston match. Since anderson has had such good luck with stock stuff, with the Holbert /928rennlist 6.5 liter block, we bored, nicasiled and used JEs with special rings. In retro spec, we did this for avoiding the cost of new or used 968 pistons. However, looking back, just a bore and Alusil lap and paste costing only around $1000 and a set of $1000 or even $2000 968 pistons, this might be a more economical way, and certainly a little more of a proven end result. But, Joe Fan has had a lot of luck with his Nicasil block. All this is still mind bogeling when you think of all the factors that could destroy the block at 6500rpm.

mk

RichieP

I had the block looked at by a local machine shop and they agreed that cylinder # 8 is done wrong. To make matters worse when he measure the bore it came out 3.939" or 100.050 mm. If I'm not mistaken that's beyond the maximum bore size for a group 2 piston. How can stuff get screwed up so bad???

docmirror

People not paying attention to their job. Very sorry to hear this. I don't know what to do now. Roger at 928sRUS can help you, but it's not gonna be cheap or easy.

BC

They need to redo that bore. Or all of them. It was a mistake and it should be rectified.

GregBBRD

I agree. Ask them to redo it correctly. We should not have to settle for second quality work.

Carl Fausett

Richie -
1) If that cylinder is different than the other 7, and
2) If you can feel those scratches with your fingernail, then I think they are too deep and I'd like to have it repaired for you.

Because US Chrome uses a diamond hone, on occasion, a piece of the diamond hone grit will break off of the hone stone. This looks to me like what happened. I already contacted US Chrome about it for you.

BUT - we still have to wait for the UPS inspector to review the damage they caused before we ship the block back up here to me.

atb

Richie,

They should be able to redo the bore. I think they can go a max of 30 thou thickness on the bore, thats a total of 60 thou total bore reduction. Your #8 is currently only .05mm or 2 thou over. There is definitley enough head room there to add another thousandth to the bore to bring back to 100mm I would think.

I'm sorry this happened to you. I've got a block there right now awaiting the process, hopefully your experience will wake up whomever fell asleep at the switch.

mark kibort

Ive always wondered, what does the nicasil add to the bore diameter (or subtract) do they make the coating thinker than needed and bore away the excess? what is left as far as residual coating?
The block sure looks ugly after the process. Is that due to a chemical etch for the entire block and then just a coating on the cylinderwalls? or do they plate the entire block and is that why the thread holes need to be chased in preparation for assembly after the process?

MK

RichieP

All - Thanks for the support and recommendations.

Carl - I have a report from a local machinist that says in his words... "# 8 cylinder is bad - grooved!!".
I also had a local engine builder tell me we won't assemble it the way it is.

I have no doubt that US Chrome will fix the problem, I just don't understand why it wasn't inspected after the work was done. Now I'm not even sure the bore size is what it should be for the group 1 pistons I supplied. I know they've done these engines before but do they know the piston to cylinder wall tolerence to properly size the bore? I know you'll oversee the process of getting this problem resolved. Heck, that's why I sent the block to you and not US Chrome directly. You know these engines better than they do.

We can talk about replacement pistons once UPS settles the claim and US Chome mics the bores.

Carl Fausett

I'm speaking with Scott at US Chrome about it this morning again. I sent him your pictures.

I agree that bore should not have gotten past US Chrome's inspection. But worse, it should not have gotten by MY inspection. I am embarrassed to say that it obviously did.
I inspected the block before I packed and shipped it to you and obviously did not see that bore. That's my fault.

We will make it right. Unfortunately, the problem is complicated by the damage caused by UPS in shipping. As soon as the UPS inspoector gets there to look at your pistons, lets get that block back up here.

docmirror

Asked and answered back in post 2, 5, 7, 34.......

You're lucky that they are gonna take care of this. Hope it works out well and all you are out is time.

Carl Fausett

Richie -

Just got off the phone with Scott and US Chrome and its a freebie to you.
I want to add that they offered yesterday to fix it for free even before they saw the picture you sent. I did not have to beat them over the head to do it.

A few words about the finish you see. The RVK cuts (Valleys) are very deep in this diamond-none finish we spec at US Chrome. This is deliberate and normal. It hold oil on the cylinder walls better and aids lubricity.

The RPK finish (Plateau) on the 928 block is a plateau finish, meaning the last thing they do is the plateau cut to finished bore size. All the peaks are knocked off in a plateau cut.

The human fingernail can feel about a .010 (a ten thousandth), so if those final cuts can be felt at all, we can assume they are .010 deep at least. As long as you do not feel a ridge, this cut would probably not harm your engine at all.

BUT - you are not happy with it, and it IS iffy, so we want it corrected for you.

atb

Richie,

Care to share the nature of the damage in shipment? It may assist others in what they need to look for in packing their blocks.

Also, I'm curious if you provided US Chrome with a bore spec. If they weren't aware that you had sent them an OEM piston, your bore spec is going to be off. I've never heard of somone using the Mahle or KB with a Nikasil Bore, typically the cylinder is coated to accomodate a domestic piston. The point being that a domestic piston is typically bored for a .0025-.004 piston to wall clearance, and OEM piston is bored/honed to a .0008 clearance. If they assumed that they were given domestic pistons, you're going to have too much cylinder to wall clearance for your stock pistons, they won't expand like the domestic forged units. Not trying to rain on your parade, but if your block is going back it would be good to have this checked out while it is there.

RichieP

Carl - Thanks for posting and for calling me to ease my concerns. As I said throught out my posts I have no reason to believe that US Chrome will not make good on the block. I just needed help determining if there was a problem with the bore or not. You and Brendan are right that it's difficult to evaluate the bore from high-res pic which is why I took it to a machine shop for a second opinion.

Adam - It looks like UPS tried to pick up the box with a fork lift running the blade into the box that contained the pistons. The oppsite corner (bottom) of the box is dented as if the box fell and there is a long piece of tape running down one side of the box almost like it tore under it's own weight and was re-taped.

I planned on doing a simple rebuild so the stock pistons were shipped with the block to 928M. I understand they do quite a few blocks for Carl so they have the specs.