Reviving an L26 - My 1st Engine Rebuild Ever ( log )

[Nite_Grind]

Hey Guys my names Joel. I've been on the forum for a few months, browsing and reading a lot. Skimming topics. I've barely scratched the surface on what I wish to learn and things I need to learn, but all in all, tons of good info. around here. Cool stuff in the archive I can't wait to apply to my Datsun as things progress. Clearly I'm a bit reserved posting my personal things but I do document nearly everything. One day I might make an interesting thread; one day. For now I just wanted to share with you all a little bit and maybe inspire someone as I've been inspired. This will be a log covering my first engine rebuild ever. You see, I decided when I bought my Datsun to avoid as many setbacks as possible due to outsourcing, that I'd try to do as much as I could by myself or under watch of a pro. Buying a non-running Z made my step easy and 1st priority....building a reliable heart. So from scrap to key-on here we go!!!!

 

Just a lil background. I bought my Z and it came with a L28 ( uninstalled ). Engine on a stand, with some quick pre-lim inspections I realized the motor was seized. "No Biggy" I thought to myself, because before I even bought the car I knew a 3.1L build was in the future and that would be the core. I set out on CL to find a replacement but the running engines were scarce and all seemed to be in norcal. The rest just had a sketchy w/ parts or rebuild w/ no receipts caption. I'll pass on those. Anyway, I ended up finding a local L26 w/ some extras for $140 I later when on to sell some spare parts for it netting me a positive $20. It was advertised as running, which I didn't believe that for a sec. but I figured at that price it was worth a gamble to me. Either way I needed an engine and I was prepared to rebuild an engine regardless of who I bought it from. 

 

 

 

 

 

Ready to get this thing underway and see where I stood, I hauled my newly found L26 down to our shop where my buddies and I wrench on Hondas to start my inspection. Off loaded and ready for teardown.

 

 

 

 

I've read a lot of people suggesting to begin with this book so I ordered one up.

 

 

[Nite_Grind]

Back to business, Just snapping some photos of components and condition of the longblock was in when I bought it. Due to time being of the essence, at least that is what I once though, I began to tear it down so I could inspect it asap and plan the next course of action.

 

1stly ripped off these flat tops

 

 

 

 

 

 

next the N36 Manifolds, which I later sold 

 

with those items out of the way, next was the exh. manifold. Remember I mentioned earlier the honda guy thing, it did not hot me conceptually until teardown that the exh. and intake were on the same side. #mindblown LOL

 

smog equipment? BWHAHAHA I scorn thee

 

 

More misc. goods I'm not sure I will reuse, also removed. They will be handy templates if I do not reuse them.

 

 

Then it was time to take the pan off. If the bearings are/were good I'd just do a bearing slap and install the engine in my car.

 

somewhere along the timeline I decided to remove the VC. Amongst all the sludge of poor maintenance I heard a hollow part drop...Hmmmm?

 

that's what it was. A pc. of the oil spray bar

 

 

Oil pan off, I began removing rod caps to check the bearings. I only have 5 pics but all the bearings looked good; this might be an actual running engine I said to myself. So I was content on just reinstalling them and torquing them a few ft.lbs extra. All I'd need now is a HG and re-assemble. Of course the conservative way out. How could I explain anything less to the mrs.

 

 

 

 

 

[Nite_Grind]

So with the bearings in good shape, I was in high hopes this would be easy, with just a gasket swap. So I pulled the head off. Quiet the carb build up.

 

 

 

 

Front engine components removed - a lot of sludge, not bad for 30/40yrs of being on the road I guess.

 

 

 

 

 

 

 

It was at this point, when removing carbon from the piston tops I realized, with my OCD I'd be digging a ditch. Yearning for a piece of mind would only mean one thing. REBUILD IT ALL.:cry:

 

 

 

Houston we have contact.  Piston to valve clearance was diminished for a moment in time. 

 

 

 

while I thought it out, I'd continue on to strip the block. I knew a proper rebuild would now be mandatory.

 

 

 

 

paused for a brief moment to inspect cylinders before I continued disassembly. 

 

 

 

 

 

 

 

bearings cast away like my dreams

 

 

 

fancy crank pose

 

 

 

replaced the mains. I Plan to send the block out to get hot tanked, and prep mentally, physically, financially for a rebuild.

 

 

[Nite_Grind]

Some updates: The building never ends. The more I stare at this machine the more extravagant I wish to be. A quick reality check, and back to earth, I press-on with the fundamentals. While the block is out for cleaning I decided I'd be sending the flywheel to be lightened and resurfaced, some before pics. Not into researching a performance clutch kit right now. Just stay within the realm of wholesome is what I'm after.

 

letting my boys in on some L6 lovin - poppin freeze plugs

 

 

 

 

 

sometimes when a man is lonely he gets a lil bit hone-y! 1st pass I ended up doing10fwd 10rev passes.

 

 

 

 

Fly being sent out for resurface & lightening 

 

 

adding these to the parts to be cleaned pile; w/ the others seen above

[datzenmike]

Did you have the cylinders measured for oval and taper? Are the cylinders worn past an acceptable hone and ring job?

 

 

Cylinder bore refinishing is extremely important in the engine rebuild process. There are some basic rules and facts that will prevent common problems incurred when deglazing or refinishing cylinders.

CROSS HATCH ANGLES

The correct angle for cross hatch lines to intersect is approximately 45 degrees. Too steep an angle promotes oil migration down the cylinder resulting in a thin oil film which can cause ring and cylinder scufflng.

Too flat a cross hatch angle can hold excess oil which conversely causes thicker oil films which the piston rings will ride up on or hydroplane. Excessive oil consumption will result.

The diagrams will illustrate cross hatch angles.

HONING METHODS

Two basic systems are used to refinish cylinder wall either rigid stones or a flexible brush.

Correct cylinder finishes can be achieved with either system if used correctly. In all cases the manufacturers instructions must be followed with respect to :

The vertical speed of the brush or hone in the cylinder Is what causes the cross hatch angle on the surface of the cylinder wall. Too slow a vertical speed causes too flat an angle, while too rapid up and down motion of the hone or brush causes too steep an intersecting angle. In the case of hand honing it will be necessary for the operator to experiment to learn the proper up and down movement in relation to the rotating speed of the one to produce proper cross hatch angle.

1. Stone grit

2. Honing oil

3. Stone pressure (Automatic equipment)

CYLINDER ROUGHNESS

Substantial controversy exists on the correct cylinder roughness for proper seating of piston rings, whether chrome, moly, or plain cast iron. It has been our experience that the use of 220-280 grit stones and achieving proper cross hatch angle produces a finish compatible to all three types of the above rings.

CYLINDER CLEANING

The single most critical factor of any cylinder refinishing job is the cleaning of that cylinder after the honing operation.

It can be stated, pistons, rings, and cylinder bores will forgive slight variations in roughness, cross hatch angle, etc. No engine component will tolerate dirt!

Honing cylinders leaves two types of "dirt" on the cylinder wall, honing stone residue, and cast iron dust. If not removed before the engine is reassembled, the world’s finest lapping compound is waiting to destroy all the hard work of assembly the instant the engine is started.

Proper cylinder cleaning consists of a thorough scrubbing of the block with hot, soapy water taking care to clean the surface under the cylinder facing the crankcase. Rinse with hot water, dry, and lightly oil to prevent rust.

For detailed honing questions it is wise to contact the manufacturer of your specific equipment. They are experts in metal finishing and of course completely understand their own equipment.

In general if the foregoing practices are used excellent engine performance will result.

[Nite_Grind]

SMH.... I bought this for a paper weight. Didn't follow a single measurement. Infact, I think it made just a great picture for my thread.

 

[Nite_Grind]

Onward, upward. 

 

so I had sent my block out to my friends shop to get hot tanked and cleaned, I guess he's a stickler for properly maintaing the fluids, because all my parts came back dingy. EHHHH! GRRR! Some may say that's what you get for being cheap, but I assure you I wasn't. My intensions were good; to support a friends. Should have went with my first instinct. So in the right hands, and some media blast later WALLLLLAHHH! 

 

 

 

 

 

my old tattered spray bar that's now in a better place

 

 

 

 

Block and crank return

 

 

 

 

 

while waiting for the head to come back ( apparently it has a bent valve so I will order one up ) I ordered the basics. Timing Components

 

 

 

Gasket Kit

 

 

 

freeze plugs. - note do not buy this kit, can be ordered cheaper at your local parts store.

 

 

 

When I bought my timing kit these were in it..... should have checked this part # 1st. :( set back #1 2.8L Rings.... ummm could have sworn I asked them for 2.6L! Grrr These will be going back for sure.

 

 

Turbo Oil pump to keep oil psi up, I drive aggressive-ish so might come in handy, while I attack fwy on ramps LOL

 

 

 

 

pistons and rods cleaned up as well

 

 

 

[datzenmike]

SMH.... I bought this for a paper weight. Didn't follow a single measurement. Infact, I think it made just a great picture for my thread.

 

 

Not following. Humor/sarcasm/irony is hard to express on the internet. Someone else may follow what you have done and rebuild an engine that has worn out cylinders in need of an over bore and over size pistons. With poor results.   

[Nite_Grind]

We are on two different planes and motives in regards to what you think you see and what's actually happening. I am choosing not to overbore, there's no reason for that. My clearances checked out: Taper, P2W, Ring gaps, I'm happy man! I am not building this engine as a guide, a powerhouse, or a how to build engines thread. I am building this motor solely to drive from point A to B. If I was building a high performance engine I think I'd care more about the stuff I think your focused on. This general rebuild....NCG.

 

and all that other stuff above about honing, degrees angles and finish are not concrete. Piston Ring material trumps all that info. Your hone grit should be based on what material ring(s) you will be using.

[datzenmike]

My point is that the cylinder needs to be accurately measured and I didn't read that this was done. If I missed it then stop reading further.

 

A worn out bore will not seal properly. Piston to wall clearance should be about 0.0009" to 0.0018"  No where did I say it needs to be done for 'high performance'. As far as a piston/ring/bore clearances and specs go there is no difference weather a rebuild or a performance rebuild. I've rebuilt before by simply honing and new rings and the results were less than ideal. Within 5k miles it was using oil again and compression was never like new.  If re-bored and properly honed a perfect cylinder can use harder chrome rings. A re-hone is likely to work best with softer cast rings.

 

 

 

 

SMH.... I bought this for a paper weight. Didn't follow a single measurement. Infact, I think it made just a great picture for my thread. 

 

 

 

Oil pan off, I began removing rod caps to check the bearings. I only have 5 pics but all the bearings looked good; this might be an actual running engine I said to myself. So I was content on just reinstalling them and torquing them a few ft.lbs extra.

 

Extra torque on the rod and main bolts will only stretch them, it won't reduce any clearances from wear.

 

 

If you have it apart, the bearings are cheap. If you are not going to measure the clearances at least put new ones in.

[datzenmike]

 

 

Turbo Oil pump to keep oil psi up, I drive aggressive-ish so might come in handy, while I attack fwy on ramps LOL

 

 

 

 

 

From the description on the box this is a Z24 720 and D21 oil pump. It will fit your L26 but what you want the high output oil pump only used on the '80.5 - '83 280zx turbo AUTOMATIC. The 5 speed engine did not get it and I doubt the parts supplier 'gets' it either. Better to order a KA24E or KA24DE oil pump from a Hardbody. They were all high output and will fit all L series engines. 

 

This is an ordinary L oil pump. Look down the oval inlet hole and you can just barely see the top of the internal rotor...

 

This is a high volume output from a KA24E. You can clearly see the top and edge of the rotor.

 

You paid for a tubo high volume oil pump.... make sure you get what you pay for.

[Nite_Grind]

Thanks for the oil pump info. I'll definitely get that sorted. As for the rest of my remarks ignore. They were snarly, apologies. Engine is being built to spec.