Billet SR20 machine shop disaster

Trigger warning for Andre if he sees this!

Having run my old SR20DET for 10+ years, which was originally built out of scavenged parts for minimal cost and had just started to exhibit signs of a leaking head gasket (again - turns out you can't torque ARP head studs more than a couple of times), I decided to build a new and much more capable engine with a VE head and better quality internal parts.

The rest of the car (180SX / Sil80 time attack car) was to get a major aero upgrade which requires major suspension and chassis changes, and as usual everything got way out of hand.

So, faced with the possibility of my basic engine build being a limiting factor on a serious car, the only option was to step up the engine specs to match.

I have a bit of a phobia of machine shops making a mess of things, so sleeving blocks and adding billet main caps etc always seems like a high risk activity and greatly increases the cost.

Engine machining is also basically the only job I need to outsource - with everything else being done myself.

Billet blocks started looking attractive (both in terms of bang for buck and general shinyness), so I made use of the project's slow progress to save more money and got hold of a Bullet billet SR20 block.

I had also tracked down a P12 cylinder head in extremely good condition.

One of my concerns was that the billet block uses 1/2" head studs, and the available head gaskets (including the Nitto gasket I had already bought) need the head stud and dowel holes enlarged.

The usual methods for this seem to involve clamping the gasket between bits of wood or metal and drilling through or grinding them out - which I was not keen on doing to a coated multi layer stainless gasket.

I decided to buy the Bullet fire ring head gasket setup which then meant having the fire ring grooves machined in the top of the sleeves.

The new billet blocks also need the sleeves set in place before deck surfacing etc.

I wanted to make sure this process was done properly so I asked around and was recommended APM in Sydney (by Bullet and some other people)

I discussed the project with Aaron at APM and made it clear that I cannot afford to do this twice and that I was happy to pay extra to have this job done with maximum care and accuracy.

I was told that the billet blocks are often well out of spec and that the deck surface would most likely need to be squared up with the crank centreline and that the main bearing tunnel would need to be honed to the correct size.

I had measured the main tunnel myself and concluded that it was basically right on factory spec. I was actually expecting slightly undersize based on Bullet's info as the bearings need to be fairly tight to allow for thermal expansion - but I had determined that I could get the target clearance using a sensible combination of bearings.

When the machining was done Aaron told me that the bearing tunnel was actually spot on and they didn't have to change it.

This was encouraging because it agreed with my measurements and reduced the chance of error, as well as the cost.

APM also installed my CHE valve guides in the head, cut the valve seats, and gave it a skim.

When I picked up the parts I was a bit shocked that one of the shop guys brought the block out on a 2 wheel moving dolley and then plonked it on the concrete driveway while I made space for it in the car!

While unloading it at home I noticed a lot of marks in the main bearing bores and thought they must have measured them many times with a bore gauge.

I ran my finger over it and the marks are actually fairly deep scratches. Deep enough to catch a fingernail on.

It looks like the block was dragged along a mounting bar with swarf or burrs on it. There are scratches top and bottom of all bearing bores, with the worst being at either end of the block.

With an large sinking feeling setting in I looked closer at the rest of the block and found pits and debris mashed into the deck surface.

Clearly a torque plate had been installed with swarf on it or the block. This would take quite a lot of machining to clean up, which would lose deck height and make the engine very second hand before it had even been assembled.

I then noticed a large amount of swarf mashed into the bottom of the head stud holes and threads. Clearly the head studs had been installed and torqued with debris in the holes. This is obviously not ideal and could easily result in deforming / weakening the threads in some areas.

The sleeve protrusion (0.1mm / 0.004") also seemed excessive, and is excessive according to Bullet's specs for the fire ring setup (they expect a flat deck).

There are also various other dings, scratches etc around the block from careless handling.

I put the block in the disaster category and figured I could get on with assembling the head in the meantime.

Step 1 is obviously to check the valve guide clearance. They immediately seemed very loose.

Nissan's factory wear limit spec is 0.2mm of radial play at the valve head with about 15mm of "lift".

The intake valves were at 0.2mm and the exhaust valves 0.4mm

I don't have a lot of experience with setting this up on a high powered engine, but my old engine was much tighter even after 10 years of use (with Supertech bronze guides).

I think there should not be a large amount of radial play, especially on a rocker actuated valve train.

The valves (supplied new in the box and indiviually packaged) were also returned to be loosely in the boxes rattling around against each other and at least one has a decent ding / nick in the stem.

I'm starting to understand why a lot of peoples engines have "unlucky" failures....

My view is that the damage done to the block is not acceptable for a brand new build, and that it cannot be fixed with compromising the condition / needing bandaid fixes.

To truly rectify the condition of the block to be as supplied would not be possible - thereforce replacement is the only solution.

With the cylinder head I am waiting to confirm the clearance measurements but I don't think it is fit for purpose. At least this can be fixed with a new set of guides, etc.

APM are saying they will not replace the block or refund any of the work but can rectify it with further machining while still being "in spec".

They don't think the cosmetic damage is worthy of concern, and as much as I'm a function over form guy - I don't think anyone expects to have their brand new $10k block dragged around carelessly and damaged.

It looks like I will need to take legal action to have it sorted out properly.

Am I over reacting to this damage?

Does anyone have a good feel for how much the bearing bores would need to be enlarged to clean up scratches like this?

Obviously if the clearance was correct before, honing the bearing tunnel is going to increase the clearance.

I think this has been the most stressful and disappointing experience of my life, and I have lost a lot of sleep over it.

I'm trying to build this engine to the best of my ability and resources to match the rest of the car and hopefully have a good balance of performance and reliability.

photo of some of the debris in the deck surface: