L26 Engine

Mr Ex Jnr

Club Member
eyup Russel
coudnt tell you weather it works on element as i dunno what he had it for think just a spare as we had a family daily z 2+2 when was a kid
left in garage doing nothing been there 20+ years tho
 

Farmer42

Club Member
So, picked up the engine a few weeks back and have started the strip down ready for de-greasing and repainting the block which I am going to do before removing the head and sump.

It looks a bit of a mess but most of that is on the cam cover and ancillary items which I am not going to use anyway.
 

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Farmer42

Club Member
It looks as though I have been lucky in that it looks as though a new clutch was fitted which has very little wear & the flywheel if fine with no scoring. Will do my bit for the environment and re-use it.

Drained the oil that was in there and looked a reasonable colour despite having been sat for quite a few years. The crank turns over fine with no graunchy sounds or feeling and there were no nasty bits in the old oil so reasonably optimistic that the bottom end is ok.

Unfortunately, most of the exhaust manifold studs and thermostat housing bolts sheared off so they will need to be removed when I send the head off for a refurb at a local engineering company.

Took the cam cover off and found some wear on some of the cam lobes so will probably need regrinding or replacing.

Water pump seems ok so will clean that up and re-use it but will get the pulley and crank pulley sand blasted and powder coated along with the air filter box.

Next job - clean the block & repaint it followed by removal of the head, front cover & sump pan & remainder of ancillaries (oil filter, sender, oil pump etc.).
 

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tel240z

Club Member
I see you have an externally oiled camshaft there quite rare now i think be sure to use the same cam or if you use another cam that's internally oiled a better oil pump should be used,as for re- using the water pump seems a bit of risk to me, the seal is probably dry and old, hate to see it leak going along the motorway and you cook your nice fresh built engine

TT
 

richiep

Club Member
Water pumps are cheap too - check eBay for example.

If you change the cam and go for an internally oiled one, let me know - I've got a set of cam towers for an internally-oiling cam (no spray bar) that I'd swap for your externally-oiled towers and spray bar... ;)
 

Albrecht

Well-Known Forum User
...will get the pulley and crank pulley sand blasted and powder coated...

STOP! Please treat the crank pulley/damper with care. Blasting will kill it, powder coating will kill it. When the rubber bond deteriorates and fails it can be catastrophic, and can cause collateral damage if not being downright dangerous.

I recommend a gentle clean-up and - at the most - a light coat of paint from a rattle-can. No blasting, no powder coating.
 

Farmer42

Club Member
Thanks for the advice everyone. Good stuff especially as this is the first time I have attempted anything like this and it's going to be a steep learning curve.

Had a look at e-bay and water pumps seem fairly reasonably priced and relatively easy to get hold of so I will definitely go with a new one. Was trying to do my bit for the environment and recycle as much as possible but note the possibilities of a perished seal so will avoid that like the plague. I presume that if they are listed for 240, 260 & 280Z then they will fit all the relevant L-series engines from those cars. Listings seem to include Laurels, Cedrics & various others alongside Zeds and more buying options seem to appear when searching against those models as opposed to the Zeds. Anyway, easily sorted.

Didn't realise the effect on the crank pulley from blasting so thanks for that one:bow:. It is absolutely covered in rust including in the 'V' so not sure how to get over that one. I know that any kind of rust or lack of smoothe surface in the V will strip a belt in no time so I need to be careful. Time to get the thinking cap on!!

Not sure what I will do about the cam yet. Will wait for advice from the machine shop.
 

Albrecht

Well-Known Forum User
Didn't realise the effect on the crank pulley from blasting so thanks for that one:bow:. It is absolutely covered in rust including in the 'V' so not sure how to get over that one. I know that any kind of rust or lack of smoothe surface in the V will strip a belt in no time so I need to be careful. Time to get the thinking cap on!!

Try not to get any chemicals on the bonded rubber section, as they will invariably weaken it. Hopefully it will still be good enough to use, and I would recommend hand sanding the rust off (it works inside the 'V' too). Nasty job, but worth avoiding damage.

Ideally the crank pulley/damper would be a replaceable long-term service item, or at least 'lifed'.
 

grolls

Well-Known Forum User
TBH,

If it was mine, I would replace the pump and core plugs. Gently lift each big end and main cap off one by one to check for wear as there is no point putting it all back together in the car and then having to take the lot out again. The same applies to the pistons, if they have covered lots of miles a quick hone, a new set of rings will do it a world of good.

AS for the clutch, if its been out in the damp, I would also bin that. Worse case scenario you'd be looking at £500 ish all in.
 
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Farmer42

Club Member
Managed to borrow a stand and hired a crane and have been carefully stripping down the engine over the last few weeks and the block is all nice & clean thanks to some good degreaser & a good scrub. Most of the bits that bolt on the outside of the block & Head are unusable so I will have to hope I dont break anything when swapping from my L20 engine later.

Invested in a copy of 'How to rebuild Your Nissan & Datsun OHC Engine' which is really good and a lot more detailed than the Haynes Manuals (thanks for the tip Huw).Took the head off starting with removing the timing chain & cam sprocket, noting the position (athough I have now lost the post it with it on - should have taken a photo:().

Took the cam and towers off the head and having looked at the lobes a bit more carefully, it seems as though my concerns about wear were unfounded to I am going to leave that alone and reuse it. The head will go off to be refurbished shortly as I managed to snap off most of the exhaust manifold bolts and the valves look a bit messy. Will get the machine shop to replace valve guides and seals, skim the head and refurbish the valves & seats if necessary.

Then started on the bottom end. The water pump was removed but was really corroded inside so I bought a new one ready to go on. Removed the oil pump and will probably invest in a new one of those as well.

The internals of the block look really good. There is no wear, scoring or ridges on the bores and there is no piston slap. Removed a couple of bearing caps from the big end and main bearings and the shells looked like new The crank is also in good shape. It looks like this has had a previous refurb and not so long ago. I don't think it has done many miles before the car it was in was taken off the road because of rust.

The next step for the block is to remove the rest of the bearing caps, drop the pistons out and make an assessment. If all is well, my initial feeling is to put it all back together as it is. Probably not to the liking of some but my budget has become limited and I there is no point in my mind in spending money when not needed. I think in this case the risk is worth taking.

Here are some pics I have taken on the way so far.
 

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Rob Gaskin

Treasurer
Staff member
Site Administrator
Two things:

I didn't know 260Z's had dished pistons.

The bores have been 'relieved' at the top for the inlet valve.

Both seem strange to me so if correct then 'every day is a school day' - as they say.
 

Farmer42

Club Member
Yes, someone else has mentioned both points which is why it was concluded that it has had some previous work done. I don't know enough about these engines to say whether it is normal or not.

I haven't dropped the pistons out yet but having looked down the con rods to the gudgeon pins it all looks very shiny & new but then again I don't know if it stays that way after use. My theory is that the previous owner had the bottom end done and then run out of money or put it all back together and the car failed an MOT big-time so they left it.

Not sure what having dished pistons and larger inlet valves would do to the smoothe running of the engine. What impact would it have over 'normal' bits? Not even sure now that it is a 2.6 litre or whether it has been bored out to a larger size so I suppose I need to do some measurements. Are there any other ways I could tell?
 

jonbills

Membership Secretary
Site Administrator
If the bores have been relieved, I don' think it'll be an L28 - it'll be an 83mm bore from L24/L26.
(the 86mm + bores don't need notching for 44mm inlet valves)
 
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Farmer42

Club Member
It'd be worth putting some flat top pistons in if its feasable?

Why? Are you saying that dished pistons are no good? I presume it is something to do with compression and power but bearing in mind I have a L20A engine at the moment, even an L26 engine with a slightly reduced power output from normal has to be an improvement on what I have. I would be happy with that & I would rather not go to the expense of new pistons unless I really had to. In fact I don't think my budget would stretch to it:(
 

Farmer42

Club Member
So, 2 months on and the engine has now been almost fully re-assembled. Had a few issues along the way but none that were insurmountable.

Had the head refurbished by Country Engineering at Oldbury-on-Severn which involved skimming, and cutting the valves & seats although most weren't in that bad a condition. The good news is that it confirmed that it is ready to run on unleaded as I wasn't sure before. One of the valves was badly pitted on the face and I managed to get hold of a used replacement. Valve guides were ok so just fitted new oil seals which cam as part of the head gasket set anyway.

Torqued the head down with no problems and assembled the cam towers ok. Assembling the rockers was a real time consuming process as it wasn't as simple as just installing the arms and then setting the valve clearances. You have to check for lash pad wear and possible offset due to any valve seat cutting. The rub area where the cam lobe hits the rocker arm is quite precise and according to the book, you would have to change the lash pads on the top of the valves if it was outside tolerance. It means you have to install the arm with some dye or marker pen on the rub pad, turn it over, take it back out and check how much of the dye had been removed and if it was equal from each edge, re-install the arm and set the clearance. Given that there are 12 rockers, this took the best part of a day to complete. Luckily all were ok and didn't need new lash pads.

The next problem I had was with the valve timing when I installed the new timing chain. Unfortunately the new Cam sprocket didn't come with all the same timing marks as the old one so lining it all up was a bit of a nightmare. I got piston 1 to TDC and got all the marks etc in what I thought was the the right position by using the old sprocket and then swapping them over making sure I was very careful not to move anything. Went to crank it over and found that I was 180 degrees out on the cam position so the valves would hit the pistons . Having already torqued the head down this was a bit of a problem so I ended up having to remove the rocker arms again and set the cam to the right position. All the clearances had to be re-set so another day gone!:(

Eventually got all the timing gear and cam parts back together and put the timing chain front cover on. Went to tighten the last bolt on the cover and heard a crack sound. It wasn't completely obvious at first but closer examination showed that I had cracked the cover just to the side of the water pump. Luckily it wasnt near any water or oil channels and it was only a small crack so rather than take off the cover again which would need a new gasket and a new cover which isn't easy to get hold of, I ran some solder into the crack as a sort of weld/seal and then covered it with some gasket sealant. I know it's a bodge but hopefully it won't get any worse or leak when I get the engine running. If it does, then I will have to use the one off the other engine when I swap them.

Got hold of all new manifold studs, nuts and bolts and refurbished the set of round top SU carbs I managed to get hold of a few months back. All manifolds bolted together without a hitch although getting to a couple of the nuts and bolts under the manifold wasn't easy.

Cleaned up the fan and crank pulleys with a lot of elbow grease and a wire wheel on a drill running at slow speed. Got hold of a new inlet pipe, heater pipe elbow and Thermostat housing and bolted those on using some new bolts. It all looks nice and shiny. Just the Alternator, starter motor, rocker cover and oil pressure sender to be fitted when I transplant the motor as they need to come off the other engine. New clutch also ready to go on when I take the block off the engine stand.

Will get some pics of the finished engine downloaded when I get the time and weather to be able to wheel it out the garage. All in, I reckon this has probably cost in the region of £900 not including the initial cost of the engine and cost of the carbs. Would have been a whole lot more if I had had to change piston rings, bearing shells, cam etc and machine the bores so I (and my wallet) are grateful for that.

It has been good experience and quite enjoyable given that I am not that mechanically minded. Wouldn't have thought that given the mess it was in when I picked it up, it would turn out so good but the best is yet to come if and when it fires up in the car and I feel the increased power when I drive it. That will probably be in the Spring now unless I find somewhere indoors where I can swap the engine over a few days. Trouble is, I am itching to do it and find out if all this has been worthwhile.:driving:
 
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