Rebuild N42 Head

[NC280z]

Good evening all,

 

I recently purchased a rebuild N42 cylinder head from "Go-Powertrain"  to prep for a larger cam and use on another build and noticed some things with this remanned unit. Cylinders number 5 and 6 have a bit of pitting, both in the chambers and on the deck of the head. I haven't measured the head yet, but I'm guessing it's been shaved a bit, as there's metal flakes all over the head, and some of the flakes are trapped under the valves along with bits of shop rags and other debris. Would these pits present much of an issue? I know that pitting is usually a sign of casting defects or of detonation damage, and that these pits can fill with carbon deposits and create hotspots that worsen preignition. I tend to be overthink things, and I don't know what to make of the pits on the cylinder head deck that are close to #5's combustion chamber. Run it or send it back?

 

[datzenmike]

I don't imagine this was cheap so send it back with a complaint. The pitting is right where the fire ring on the head gasket is supposed to seal. There's been some really crappy 'un-shrouding' around the valves done to it also. They should be smoothed and blended into the rest of the chamber like these with a nice radius curve near the valve...

 

 

I know that the 4 cylinder L heads are 4.248" thick from valve cover to head gasket if stock. I imagine that the six cylinder heads are the same.

[NC280z]

The pits on the deck were my biggest concern, that and one of the valve guides is so corroded that it looks like the upper portion of the guide is missing. Overall, it looks like they shaved the head, painted it and shipped it out. I don't know how you get so many metal shavings in the box it was shipped in, it's as though they took it off the mill and just chucked it into a box and sent it out. Not too happy, I've sent a polite request to return the item, so we'll see how it goes. As always, I appreciate your input (and sanity check!) datzenmike. I'm glad I wasn't over-thinking this one.  

[datzenmike]

BBB states that Go Powertrain has been in business for only 5 years and accredited for almost 3. There are 0 complaints..... there are no customer reviews either. Someone else may have 'worked' the head and they planed and painted it. It's still shoddy work unless it was free. 

[banzai510(hainz)]

rebuild  can vary a lot soemtimes

I had a 50$ rebuild L16 head, they cut the seats and put new seals  shaved it .010in and be honest it worked fine.

This is me,

since you on the east coast and harder to get parts and if you paid 300 just put the new cam in and try it

Edited May 6, 2020 by banzai510(hainz)

[Stoffregen Motorsports]

On 5/4/2020 at 8:09 PM, NC280z said:

Good evening all,

 

I recently purchased a rebuild N42 cylinder head from "Go-Powertrain"  to prep for a larger cam and use on another build and noticed some things with this remanned unit. Cylinders number 5 and 6 have a bit of pitting, both in the chambers and on the deck of the head. I haven't measured the head yet, but I'm guessing it's been shaved a bit, as there's metal flakes all over the head, and some of the flakes are trapped under the valves along with bits of shop rags and other debris. Would these pits present much of an issue? I know that pitting is usually a sign of casting defects or of detonation damage, and that these pits can fill with carbon deposits and create hotspots that worsen preignition. I tend to be overthink things, and I don't know what to make of the pits on the cylinder head deck that are close to #5's combustion chamber. Run it or send it back?

 

Notice all the water jackets are irregular shapes? See the combustion chamber shape? That head has had a lot of welding done on it. The pitting you see is from impurities in the welding. They did a poor job welding it up and it shows. I would recommend against using the head without having a head specialist have a look at it.

Edited May 6, 2020 by Stoffregen Motorsports

[NC280z]

Fortunately they sent a return label without any difficulties, I'm just waiting on it to arrive at the retailer for a full refund. Based on the box the head came in, it would seem that Go-Powertrain is a storefront for Allied Motor Parts from GA, and AMP does not have very good reviews. Oh well, on to the next project.