240Z Cam Spray Bar on L20B

[D52E]

I was at the junkyard yesterday and came up on an almost complete L24 or L28 engine from an S30 Z-Car. I recalled that there was talk of using the cam spray bar from this engine on a L series 4 cylinder. I figured that it couldn’t hurt to remove the valve cover and pull the spray bar/cam-towers. So, about $14 later I have the parts and consider using them on the L20B engine I want to build.

I have several questions that I could not find clear answers to after searching this forum:

1) Do I just use the 2 front and 2 rear cam towers from the L24?

2) Do I cut the center joint of the spray bar and join the front and rear ends together (red square in attached picture)?

3) I read that it is necessary to change the size of the engine block oil hole that feeds the head. Can someone tell me what size?

4) Is it necessary to run a L28ET oil pump (KA24E is an option)?


The car will be a mostly street driven 510 with ocasional local SCCA or driving events.
The engine is an L20B with the following specs:
W53 Head with intake side ported 1.5"
Calculated compression ratio of 10.3:1
Weber DCOE 45's with 36mm Chokes
Cam is about 0.501" lift (unknown duration)
Rear gears 3.70:1
Transmission is dogleg 5 spd

[datzenmike]

The high volume oil pump is found in the D-21 Hardbody from '86.5 and on. It's used on the Z24i, the KA24E and the KA24DE motors used in it. It is also found in the S13 240sx with the single cam KA24E engine only. A similar higher volume pump is used on the early 280zx turbo automatics with oil coolers and maybe on the later 5 speeds. It is also used on the Maxima diesel engines and L20B forklift motors and rumored to be on the JDM Z18ET motors.

There is no way to tell from the outside so if buying one don't take someone's word for it or the label on a box. Don't forget any engine could have been rebuilt and the pump replaced with the wrong one.

Here's two pumps, which is the high volume one???



Here's what to look for:
This pump below is a normal regular pump used on all L series engines and is from an L18. If you look in the 'oval' inlet hole you can just barely see the top of the trichoid rotors way down inside.



This is the high volume pump from a 240sx KA24E. Here you can clearly see the much taller rotors inside




The high volume oil pump will not give you more pressure, that is set by the relief valve spring and is in the 50-60 PSI range. Oil pressure is always lower at idle because there is less volume available to replace the oil that 'bleeds' past all the bearing surfaces at a set rate. A 'tight' engine may have a 30 PSI idle but worn engines (or ones with spray bars) will loose more oil than the pump can replace and the pressure will drop. My 300,000Km L20B hot idled at 17 PSI. I replaced the stock with a KA high volume pump and with no other change the hot idle jumped to 29 PSI!

For higher pressure output the relief spring can be stiffened or shims used. Use caution and check carefully when revved up. I had a relief jam with a stray piece of casting and the over pressure split the oil filter off its base!!

[D52E]

Wow, THANKS for the valuable information datzenmike.

I am under the impression that I should source a high volume pump. Should I buy a new one or can a junkyard part be trusted. Are aftermarket KA24E pumps ok to use or should I try to get an OE Nissan?

Also, when adjusting the oil pressure, do I just add/remove washers behind the spring (more or less of the three small washers in item #4 in the picture attached)?

Edit: Changed KA24DE to KA24E

[defdes]

I would always buy new when dealing with the "heart" of your motor. You can add shims, or stiffer springs from Nissan Comp, bu with the addition of the hi volume pump you probably wont need to. As to your first question about the spray bar, someone correct me if I am wrong, but I would think you would need to line bore the head if you were swapping around cam towers. There might be a way to retro fit that part w/out doing that, though I don't know the solution.

[Byron510]

I agree with John; the cam towers are a matched set. If you are lucky, you may get your I-6 towers to fit your I-4 head - it's a "try it and see" scenario. Do not mix and match the cam towers, the likely hood of the cam rotating freely is very low.

I know that this external spray bar method was done in the early years of the 510; however the existence of the Nissan Comp external spray bar kit proves that there was an issue with the S30 swap. I have not done this myself, however I do (like John) run the Nissan Comp parts. It's fairly easy to install, the conversion come absolutely compete and there is no guess work at all.

I do like the idea of using the S30 unit, and if you have the time to try to bolt it up to you head to see if the cam rotated freely - why not. However in my experience with swapping of cam towers in the past, or even trying to salvage a warped head is in y indication, I think the degree of success will be low. Keep us posted at any rate - at $14, your investment is minimal. And some S30 purist out there is just boiling! Don't get me wrong, I owned a hot rod 1969 S30, #000548 (cam, header, big exhaust and low gears) and it was a blast. But I still love the 510 better from a driver’s point of view.

Byron

[bertvorgon]

WHATEVER you do..make sure that you do a TEST of the spray pattern, as it relates to the flow to the camshaft!!!!!! If you cut, weld , it could slightly change where it sprays. I lost a cam because of a similar problem. As Mike said, pressure will drop slightly, so you may want to put a thin shim in there, to get pressure back to that 60-70 range when hot.

[okayfine]

FWIW: DQ Volume 3 Issue 3 - Installing a spraybar - How to install a spraybar to improved camshaft lubrication.

[hang_510]

So, about $14 later I have the parts and consider using them on the L20B engine I want to build.

$100 new. simple to install.



does not mount to the towers.

[D52E]

I like that Design products racing unit and it would be much simpler to instal (no messing with cam towers). I do see one concern so far...

How can I check the spray pattern on that one?

With the S30 setup its possible to pull the valve cover, spark plugs and crank the engine over to visually inspect the oil spray.

[hang_510]

How can I check the spray pattern on that one?

good question.

ill let you know what i find this weekend (beside follow the install instructions) to verify.
i am gonna check flow from each port during the priming, then w/the "710" cap off, confirm #1 is there, the others should be right.



i will be selling the old set up from the LZ24 and the "datsun OHC" VC its on (everything in the pic, installed)

[S15DET]

I guess you could cut the top off of an old valve cover to inspect the spray pattern?

[bertvorgon]

Here is what we do to check the pattern.

What we have seen in the past, is that occasionally, the holes get drilled at a slight angle, instead of straight on, and/or, have a small bur on them. This then causes the oil to spray out at a slight angle, which will either miss the rocker/cam interface, or not hit it square on. So, with CLEAN solvent in the parts cleaner, we just put the parts cleaner nozzle into the spray bar oil entry point. You can quickly see if the oil is coming out with no issues at all, or, there is a problem. It only take a few minutes to do this, and most parts washers have enough pressure and volume to demonstrate the flow out of all 4 holes, AT THE SAME TIME. As I mentioned, I lost a cam on my new motor, 9 years ago, when we put the NEW spray bar in ( I won't say where it was made, came out of the States), so the assumption was...well..it was NEW right?! The thing must have been drilled by a 5 year old! Holy crap, the oil was spraying everywhere but onto the critical area. Andy welded up the holes, and re-drilled the damn thing, and I had to put a new cam in, and one or two rockers if I remember correctly.

[510rob]

"new" only means the item may not have been proven to work...

[Tedman]

For the L24 spraybar mod, see "How to Modfiy..." cam section, pages 80-81:
http://www.datsun510.com/modules.php?na ... page&id=82

[James]

"new" only means the item may not have been proven to work...

SO TRUE - especially with electrical parts.....