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Barefootdan's 280z Build


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Been a bit since my last update. The head was dropped off at a local machine shop who is familiar with the L28. Head needed shaving, 3 new valves and some new bronze valve seats. Among other work such as full cleaning, shimming of the towers, and seals. I came out just under $700 for the work. More than I was planning (originally tried to stay under $500) but I am glad that they were familiar with the head and knew what to do. Well worth it in my opinion. The head should be done this week and then I will start planning on pulling the block to do the ring job. In my spare time I have pulled mostly everything from the engine bay in prep for painting. I will be getting new master cylinders for both the clutch, brake, and then a new brake booster. One thing I am curious on is the lines. Generally is it okay to reuse the hardlines? For reference the clutch line was connected while the brake lines were open while it sat. 

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3 hours ago, Barefootdan said:

Generally is it okay to reuse the hardlines?

Usually it's okay, clean them with some brake cleaner and compressed air, some guys have had success with replating  them, these days I just replace them all with new copper/nickle hardlines because I can't stand the thought of the possibility of rust inside.

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Wow....I am DEFINITELY going to need to pull the bottom end now. There is no way I can put this crispy clean head on that grimy block....anyways enjoy the pictures! Check out that pitting in Cyl #6 though 😲 Would it be worth it to grind these smooth or is it more hassle than need be for a stock build? 3 new valves, shaving of 8 thousands, and a DEEP clean later:

Clean Head 2.jpgCyl 6.jpgClean Head 3.jpg,.;Clean Head 4.jpgClean Head 1.jpg

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You have done a wonderfull job bringing the engine literally back from the dead.

The workmanship looks good and he shimed the towers, so he knows what needs to be done when you shave the head. I would still have a few questions for the head shop. He replaced three valves (inlets on 5 & 6 and exhaust on 6) with a completly different aftermarket vavle. The form could change your compression ratio. The originals cost $20 each through nissan. Why did he use those after market vavles?

Are you sure he used brons seats? Maybe brons guides? Brons seats don't work well with todays fuel. The L28 changed over to steal alloy seats in the N47 to run unleaded fuel. The lead "lubricated" the valve seats and helped transfer the head. The brons P/N:11098-N4200 and steal alloy P/N:11098-N4210 seats are interchangable. It could be a cost factor that made him just replace what was needed with brons (3x $22) as to replacing all seats (12x $18).

I would not grind the scratches away. Grinding them away will could alter your compression ratio and with the different valve head shape? You can use a scraper to remove the burs, I wouldn't do any more than that.

Looking forward to seeing this project progress.

 

 

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Thanks for the kind words @siteunseen & @EuroDat!!

I noticed the difference in valves too, but not until I left. I may give him a ring on monday to see why he chose those. I know it was $10 per valve so its not like I much overall. Maybe he had them in stock already.

I dont believe he used bronze seats. If I recall correctly, the old bronze seats fell out when he was doing the cleaning? I probably took that as "replacing the bronze seats with new bronze seats". But they all definitely look uniform throughout now. The receipt says "SBI SEATS" as parts and "6 INTAKE SEATS" as labor.

I'll leave the pitting as is 🙂 

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SBI is  a well known valve seat supplier. I think you would have to special order brass inserts. More than likely he used steel alloy, but would be good to check.

If you have braas inserts, you should use an additive to extend the seat life.

Sorry if it sounds like I'm nitpicking, but now he knows exactly what he did. If you call him over a year, it could be a best guess response.

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Check the rock arm wipe pattern before installing.  If he didn't dress the valve stem tips you might need new lash pads. 

Those three odd valves might cause an imbalance between cylinders.  Combustion chamber volume, as mentioned.  They look more massive also, and might hold heat, or not handle high RPM as well.  

Might be fine, but for $60 it might be worth swapping to stock valves.  I don't have any experience building engines, I just absorb a lot.  They look like lawnmower engine valves to me.  No offense.  Can't find anything similar on the old internet either.

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Another thing to ask when you contact the head rebuilder. Ask him which model the valves are designed for. If he is a Datsun head specilist he should know the difference in valve stem lengths and probably not an issue. 

The L28 was used over a period of 8 years in the Z & ZX, but with different head combination. The N42 and N47 heads had valves with 2mm longer valve stems. These valves are often used when people shave 2mm of the later P79, P90 or P90a heads. These valves eliminate the need to shim the cam towers.

280Z 75 - 78 & 280ZX 79 to Jun 80 with NA engine had the longer correct valve stems.

280ZX Jul 80 to 83 NA and all torbo engine had shorter valve stems and will need larger lash pads.

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  • 4 weeks later...

Bought a bunch o parts from Zcardepot to get the engine refresh going. They should arrive today. Also picked up an engine stand, hoist, and leveler. 

Preparing to pull the block tomorrow and trying to decide where to hook up the chains as my head is already off. I plan to use the driver side bell housing bolt then unsure for the front passenger side. Any recommendations since my head is already removed?

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56 minutes ago, grannyknot said:

I have used the head bolt holes and old head bolts to pull the block out, never had a problem.

Oh DUH. I don’t know why that never crossed my mind. Thank you! 

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Big milestone for me today! My first engine removal. Took about 2 hours solo. Zero issues along the way which was awesome. No seized bolts, no rounded bolts, nothing broke! I ended up using two water pump bolts for the front as I didnt have a short enough bolt for the head bolt holes. I cant wait to start cleaning this up and refreshing. Check out the spider nest in the bell housing 😨

Almost there.jpg

Out.jpg

Transmission.jpg

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Surprisingly well in comparison to the rod bearings. I haven’t undone the main caps yet though. 
 

there is a very slight score in one of the journals but I’m optimistic it came be polished out. 

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Does Nissan stamp numbers on their rods and caps?  Or does it look like somebody has been in there before?  The bearing wear seems odd, but I'm not an expert.  Haven't seen many.

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  • 3 weeks later...

Been slowly making more progress. the crank is fully out and the journals look surprisingly well in comparison to the rod bearings. I was worried for a bit...Next step is to drop the block off at a machine shop for a thorough cleaning. Unfortunately I will be out of town for the next month for summer so the build is on pause for now. AZ summers dont make it fun to work in the garage! It was 117 out yesterday

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  • 1 month later...
On 6/16/2021 at 2:55 PM, ETI4K said:

Two words for you my friend- mini split.

That would be a joy. Even to keep it at like 90 degrees would make it so much nicer. 

This passed week I finally was able to get around to dropping the block at the machine shop. Deck, Hone, and Clean. In the mean time I sprayed the engine bay satin black (Please dont hate me!). I'll have to grab some photos once everything is cleaned up. I am more and more tempted to do a light sand and clear coat the patina look for the time being. I dont see myself being able to give the car a full paint job anytime soon so I may as well embrace it. Do people usually clear with a matte/satin or is gloss used?

 

Lastly, the block is scheduled to take 5 weeks to finish. I need to order bearings and rings to finish my build check list. Progress is slow but its coming along 🙂

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I just finally found bearings for mine (.25 oversize).  Had to order from Australia - anywhere from 2 days to 6 weeks for delivery.  My engine build has obviously come to an abrupt halt.  Hopefully, you'll have much better luck!

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13 hours ago, ETI4K said:

I just finally found bearings for mine (.25 oversize).  Had to order from Australia - anywhere from 2 days to 6 weeks for delivery.  My engine build has obviously come to an abrupt halt.  Hopefully, you'll have much better luck!

Dang thats brutal! What is the reasoning for the oversize? I planned on going with factory specs

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