1978 280z Engine Rebuild project

[txvepr]

So I am in the process of rebuilding my first engine and will post various pics and questions here.  Mileage at the time of purchase is unknown. I believe it was ordered and shipped from Japan recently.  I have already installed the 5 speed transmission in my Z and it works well.

 Here are a few from getting it in the garage.

Assistant is inspecting the situation...

Plugs seem to indicate fairly good mixture?

Dissassembly is coming along.

OFF WITH HER HEAD!!

Edited January 30, 2016 by txvepr

[txvepr]

Removed the front cover and head.

After taking off the front cover, I see that the crankshaft key is 'buggered'. Is this a show stopper? as is or is there anything that can be done to fix it if needed? It looks like the key only serves to hold the harmonic balancer in place, not like holding the cam chain gear or somesuch.

 

 

 

Is this a replacement level problem?

Edited January 30, 2016 by txvepr

[Patcon]

Somebody else can chime in but I would source another crank. The balancer is important and if it comes off at rpm, bad things happen

[Mark Maras]

 I'd replace it.  You shouldn't have much trouble sourcing another crankshaft. At the very least, you'll be using the marks on the balancer to set the ignition timing. Worst case scenario, Big, expensive problems at the front of the engine if anything breaks. Also, check your balancer to be sure the bond between the two pieces isn't compromised. They've been known to separate at speed with ugly results.

[Captain Obvious]

CAT scan!!

[Chickenman]

Good excuse to build a stroker now !!. If the key-way is damaged on the crank it's probably damaged the damper as well. Don't use either if damaged. I had a damper come loose while road racing. Bent the snout of the crank, ruined the key-way and destroyed the oil pump worm gear. Danged lucky it didn't come off completely.

Edit: BTW.. it would be a good idea to replace the oil pump drive gear on the crank as a precaution. A loose harmonic balancer can cause unusual wear patterns to develop on the worm gear and fatigue cracks to develop.

 

Edited January 31, 2016 by Chickenman

[txvepr]

So I took off the oil pan. Found some odd rails where also used.You can just see them on the back edge under all the oily grime. This seems to be an early 1978 block, it has the cam oiling bar instead of self oiling cam of the later ones.

They even have longer screws to reach into block than the ones on the front.

I couldn't find a reference to these existing in my manual. I found 1 reference to them on Ebay as oil pan keepers. 

I guess they were needed to better hold the pan to the block? There's over 20 screws used.

 

Edited February 4, 2016 by txvepr

[rossiz]

those "odd rails" are nothing new - i believe they help even out the torque on the oil pan lip to reduce dimpling and leaks.

[siteunseen]

I'm building a 2.4 myself, pretty much done.  Needs a little more work to get as close to perfect as I can, don't want to touch it again. 

I had a leaking oil pan gasket and it was suggested that I use those flat bars to help keep it from leaking on down the road.  My '72 240Z didn't have those but I had some from a junkyard ZX motor I had, so I am using them.  Not sure what year the engineers at Nissan decided the need for them but I'm positive they'll help.  

You need to look above the first 2 spark plugs and see what cylinder head you have, N42 or N47 most likely but who knows with an older car like ours.  I have a '77 280 that had a N47 head.  It was built in 9/'76 and had the oil bar and a oiling cam both, not too many of those from all I've read.  It was built during a changeover period.  The '75 and '76 had the oil bar with square exhaust ports, N42.  The '77 and '78 had a self oiling cam and round port exhaust, N47.  People often change the cylinder head for different reasons so it would be interesting to know what you have.  I'm gonna guess it's an N42 from an earlier year car.

I'm sure it has been suggested that you put all the nuts and bolts in ziplock bags?  The first motor I built I just marked the baggie with a Sharpie, most all of them smeared off.  Now I know better and write the description on a piece of paper and drop it in the bag.  The parts you take off, the front cover, water pump and the oil pump, thermostat housing etc., will have bolts of different lengths.  It's important to keep up with those and their locations.  I put the bolts back in the part and use some small wire to wrap around the threads.  That holds them in place.  Good luck with your project and have fun cleaning those old parts, lacquer thinner is a good cleaner.  You can get a five gallon bucket with a lid and all six piston will fit in the bottom, pour in some lacquer thinner and put the lid on tight or it'll evaporate.  Let them soak a couple of days, use a brass wire brush to clean them and all the aluminum parts.  They will look like new!

 

EDIT: I looked back at your pictures, you have an N42 head.  The square exhaust ports are desired by most folks.  The N47 that is original to your '78 had round ports with liners that people don't like because they restrict the flow, from what I've read.

[txvepr]

So, is SOS pad still good for some rust like this?  or coat everything with POR and then paint?

Interior of Pan shows no rust thru so I believe this is still usable, regardless of looks.

[gundee]

7 hours ago, txvepr said:

So, is SOS pad still good for some rust like this?  

I prefer sand paper and wire brush. Degrease with a paint prep solvent.

Then I use spray can self - etching primer. Use as directed.

Then spray pan with Rustoleum paint.

The automotive paint mix guy at the auto parts store told me

not to waste my money on that POR stuff. As he puts it.

Way too much work for mostly poor results.

[Mark Maras]

IMO, I would add one more thing to lumens' procedure. After wire brushing and sanding, I would treat the bare metal with Ospho before painting.