Barefootdan's 280z Build

[Barefootdan]

13 hours ago, Captain Obvious said:

I take it back. Other than the valve dents and occasional other minor blemishes, those pistons don't look bad at all. If you don't have a really good condition other option, I'd run those. Must have been a trick of the camera. I was really expecting serious destruction.

And you can see the sizing numbers now. Not cylinder number. It was just luck that the only one you could see before was #3.     

Same! I think I will run them with some fresh rings and a deglaze. Overall compression was averaging around 90psi so I think its safe to do rings while im here.

13 hours ago, Zed Head said:

One of your pictures, and the damage you've found, made me wonder about the camshaft.  Might be a performance, high lift cam.  A picture will tell, look for new stamps on the ends.  The lobes will have a smaller base circle if it's a regrind.

Detonation causes damage that looks like foreign object damage.  Might be that somebody built a "race" engine.  Check your head also  to see if it's been shaved.

You got my hopes up 😄 I dont think it is base on the pictures. I did front, lobes, and rear.

 

[Captain Obvious]

10 hours ago, Barefootdan said:

Same! I think I will run them with some fresh rings and a deglaze. Overall compression was averaging around 90psi so I think its safe to do rings while im here.

Well you've got two obviously bent valves, and marks on other pistons as well. That makes the whole top end suspect to me. The point is, the compression numbers may be more related to issues in the top end than the rings. However... You're this far in and it would suck to do a bunch of work on the top end and put it back together with a tired lower end.

Who would ever do such a thing.             

 

[Barefootdan]

2 hours ago, Captain Obvious said:

However... You're this far in and it would suck to do a bunch of work on the top end and put it back together with a tired lower end.

Who would ever do such a thing.             

 

Exactly! I would be so bummed putting a fresh head on only to find out that the rings were also bad....Well since we're this far I may as well pull the block! It could use a deep clean anyway 🙂 

Started tearing the head apart more today. Got the rockers and cam out. I'll need to get a spring compression tool to move forward. 

Planning to send off the cam for a stage 1 grind as well as the rockers to refinish. Darn EFI limits me on the cams!

Also was able to start cutting some rust out of the floor pans. I think I'll get the big chunks out, weld in new plates, then POR15 the entire floor pan to tackle the deeper surface rust. 

I may also work on cleaning the intake manifold:

• Charcoal canister
• EGR
• BCDD
• Cold Star Valve

I think we should still retain decent idle even with the above gone. Phoenix never gets cold. Main goal here is just to make everything look better.

[Captain Obvious]

About the spring compression tool... You won't be able to use the "hooks on the cam" version if the cam is removed. (Duh.)

Here's some pics of my latest valve spring took contraption. A little faster to use than my previous contraption since there's less wrench turning:

 

[Captain Obvious]

9 hours ago, Barefootdan said:

• Charcoal canister
• EGR
• BCDD
• Cold Star Valve

I think we should still retain decent idle even with the above gone. Phoenix never gets cold. Main goal here is just to make everything look better.

Well lets see... If adjusted properly and working as designed, absolutely none of those items should have any effect at all at idle.

Charcoal can - Disabled at idle
EGR - Disabled at idle
BCDD - Disabled at idle
Cold star valve - Only active while cranking the engine, so disabled at idle

[Barefootdan]

2 hours ago, Captain Obvious said:

Well lets see... If adjusted properly and working as designed, absolutely none of those items should have any effect at all at idle.

Charcoal can - Disabled at idle
EGR - Disabled at idle
BCDD - Disabled at idle
Cold star valve - Only active while cranking the engine, so disabled at idle

Oops, i guess a better term is just overall running of the engine. Trying to remove as much unneeded stuff as possible while still retaining whats *needed* for a smooth experience. 

I read that you can also take out the TPS and AAR but it start to have negative impacts. Is that right?

[Zed Head]

How much are you planning to spend?  Your engine seems to have seen a lot more abuse than most.  You might want to do a thorough inspection before buying parts.  That $450 combo might be a deal once you add up the cost of parts to fix what you have.  Cam + rocker arms + pistons + bore + >>>  

[siteunseen]

I removed the egr and thermal switch plus the warming plate on my '77.

I think the bcdd and tps, cold start valve would be best left on the motor. They serve a good purpose in my reading and I've read so much now I forget. Too much too soon before my rebuild of the efi motor.

 

[Barefootdan]

26 minutes ago, Zed Head said:

How much are you planning to spend?  Your engine seems to have seen a lot more abuse than most.  You might want to do a thorough inspection before buying parts.  That $450 combo might be a deal once you add up the cost of parts to fix what you have.  Cam + rocker arms + pistons + bore + >>>  

Eh, not a ton. But I dont mind spending more to know it is done right. Rather than picking up the $450 combo, see it also needs a rebuild 😅 As you can tell, I am not a betting man.
Id be happy if I could freshen up mine for under $800. Rings, deglaze (bore/hone if needed), regrind the cam and refinish rockers, new seals throughout, misc block off plates, new timing kit and waterpump, new head bolts.

[Barefootdan]

31 minutes ago, siteunseen said:

I removed the egr and thermal switch plus the warming plate on my '77.

I think the bcdd and tps, cold start valve would be best left on the motor. They serve a good purpose in my reading and I've read so much now I forget. Too much too soon before my rebuild of the efi motor.

 

Ill check out the thermal switch and warming plate removal. thank you! I agree, tps is better left on. Is BCDD pretty mandatory? To be honest, that is a bit of a wizard device to me (like carbs!). 

[Zed Head]

7 minutes ago, Barefootdan said:

Eh, not a ton. But I dont mind spending more to know it is done right.

That was my point.  I'm just saying do the math first.  That motor looks beat upon.  Good luck.

Take a picture of the side of the head where "N42" is cast in.  You can tell if the head has already been shaved/skimmed by the distance from the bottom.  While you're there you might as well check flatness.  If it's been overheated (likely) it might be warped.

[Barefootdan]

It looks like there is about a 1/16th of an inch. Head is definitely not flat. I was able to slide a .3mm feeler, granted my straight edge is not super precise, but it (straight edge) felt flat on the block. On the head, it rocked on the 4/5 cylinder wall regularly. I different angles and positions of the straight edge to try to rule that out. Is this too much to shave?