LZ23....good news...bad news

[Sealik]

Actually..... there is no good news.... :P

Other than just upgrading the retainers, springs and carb.....woot :huh:

 

For the last month or so....about 1800 kms on the LZ23...I've been trying to locate a miss in the engine.

Seemed like a vacuum leak initially....sooooo

 

.....I changed the IM gasket

Carb gaskets...eventually upgraded to a Weber 38, jetted for the Z24

Checked, confirmed, and or replaced spark plug wires (resistance) and dizzy(s)

Checked fuel pressure, PCV, vacuum connections ....eliminated brake booster.

'Blasted' IM/carb with WD...propane...no spikes in RPM....no leaks?

Lash is always spot on....8 and 10 hot.

Timing is at 15 degrees, vacuum advance is functional and ported to carb base

About 1 3/4 turns out on both Webers installed...but did run rich at idle....around 12.5 warm....11 +- cold.

Plugs look good....A/F ratios came up to desired levels when driving.

Uses 0 oil

Compression seems okay...little low....but...no variance across the board....175

Sprocket at No 3 position

Lower than normal vacuum readings...about 19lbs warm at idle, thought it might be the lift of the cam contributing to this.

 

But.....engine still has that odd miss.

 

WTF????????

 

Until... I do a 'leak down test'....sort of. I pressurized the cylinders to remove the springs.

Valves are leaking....on 1 to 3 pistons. No 4 seems to come from the cylinder. Can hear it through the top front TC cover.

I'll have a proper leak down test done...actually I'll get the machinist to do it

Not sure if the valves not seating could also compromise the rings....richer mixture?

Excellent....fuck

 

Obviously the machinist is incompetent.

Head was already returned 3 times prior to assembly...re and re valve guides (again) because the stem seals wouldn't sit hard up to the head, valve stems at random heights, wrong exhaust valves, striped cam tower bolt holes...etc.

 

I did notice some small hammer marks on the top of the valve stems when the head was returned last time.

Was concerned...so I took it to a local mechanic to get his opinion.

He said...not really conducive...but...okay.

They hammered the stem to set/seat the valve....?

Apparently....not 'good' enough.

 

Although....even with those leaks, the engine still runs pretty strong :D

 

 

Truck is parked in 6 weeks.....winter and all. I'll pull the engine and trannie...upgrade to the C trannie with the L bell

Have to be 'reassemble' the LZ.... :(

Not sure who will do it..????? The machinist should do it for free.....but

'Once' stung...thrice shy.......versa vise ;)

[datzenmike]

Doug when you get the valve spring and rocker off, try too wiggle side to side. If the stem to guide clearance is right it should only move less than 0.2mm (0.008") at the rocker end tip. Check parallel to the rocker arm, this is where most wear is.

[Sealik]

Doug when you get the valve spring and rocker off, try too wiggle side to side. If the stem to guide clearance is right it should only move less than 0.2mm (0.008") at the rocker end tip. Check parallel to the rocker arm, this is where most wear is.

 

Yup...I checked that a while back.

All the guides are new....suspect...but new :D

 

 

Got the taller retainers now.....gonna rev it.

Who knows.... something should get seated.

[Guest 510kamikazifreak]

:blink:

Hammered the valve stem...

Was this done to seat/set the retainers?

 

Time for a good blast in it and work it, see what gives after this.

[Sealik]

:blink:

Hammered the valve stem...

Was this done to seat/set the retainers?

 

Time for a good blast in it and work it, see what gives after this.

 

That's what the local mechanic said...

With the valve, springs and retainer installed.....they hammered the end of the valve stem so the valve comes in and out of the seat under pressure, takes any anomalies out of the fit....I guess :blink:

He also stated I might dump some fuel in the head and see if the valves leaked...(prior to install)

Should of heeded his advice.... :(

 

The head is somewhat of an 'easy' fix...and I'm not a automotive technician....but I would assume leaking valves might have compromised the rings.

 

Yes...shall go for a drive later today and take it up to 6000 RPM.. :D ..I've only had it to 5 so far.

Do another compression test on it...wet and dry.

Build a leak down tester

[banzai510(hainz)]

Compression seems okay...little low....but...no variance across the board....175

 

175 is really good

 

to me this is good!!!!!!!!!!!!!!!

 

i swap in a nother L series dizzy cause its EZ.

[HRH]

Hey Sealik,

 

You need to look these guys up: http://www.sunwestautomotiveengines.com/

 

The nice part is you could ship your head and have it shipped back. These are the guys I used to deliver to when I was working out at Airway Heights NAPA. They get all my machine work now. Right before I moved to Post Falls NAPA they got a new crank polishing machine. They're a smaller shop, only about 3 regular guys, but they give a shit regarding four cylinders. Don't let the fact that they build Toyota (crap!!!!:) ) 22Rs dissuade you. They did the work on the block in my truck, no issues. They'll be getting the rebuild of the bigger motor I'm planning for the 510.

 

If you do call them, tell them Datsun Matt previously of Airway Heights NAPA sent you their way. Doubt it will get you a discount but a little name dropping never hurts. Talk to Mike.

 

Their shop is in Medical Lake, WA.

[Sealik]

Compression seems okay...little low....but...no variance across the board....175

 

175 is really good

 

to me this is good!!!!!!!!!!!!!!!

 

i swap in a nother L series dizzy cause its EZ.

[Sealik]

Compression seems okay...little low....but...no variance across the board....175

 

175 is really good

 

to me this is good!!!!!!!!!!!!!!!

 

i swap in a nother L series dizzy cause its EZ.

 

I started with an L dizzy....was NFG...had no backup....0 available locally.

So...I changed the L TC cover to the Z22 TC cover....now I have many dizzys at my disposal.

The last dizzy I put in came from my other Z24 truck, which runs excellent...engine still misses.

Figured the compression should be a smidge higher....190s on a fresh engine????

 

Hey Sealik,

 

You need to look these guys up: http://www.sunwestautomotiveengines.com/

 

The nice part is you could ship your head and have it shipped back. These are the guys I used to deliver to when I was working out at Airway Heights NAPA. They get all my machine work now. Right before I moved to Post Falls NAPA they got a new crank polishing machine. They're a smaller shop, only about 3 regular guys, but they give a shit regarding four cylinders. Don't let the fact that they build Toyota (crap!!!!:) ) 22Rs dissuade you. They did the work on the block in my truck, no issues. They'll be getting the rebuild of the bigger motor I'm planning for the 510.

 

If you do call them, tell them Datsun Matt previously of Airway Heights NAPA sent you their way. Doubt it will get you a discount but a little name dropping never hurts. Talk to Mike.

 

Their shop is in Medical Lake, WA.

 

Thanks Matt...tempted...but shipping would be a bitch.

Might just have to lap the valves as Dmike suggested

[HRH]

Wait, which vehicle is this going in? Which head are you using? My thinking is if this is an L head LZ23, then the distributor for a NAPSZ motor is not going to work, unless it's a single plug version. The ignition box for it sees two coils, won't run right unless you put both together, and even then it's not that great. You probably know this, just thought I'd check.

[Sealik]

Wait, which vehicle is this going in? Which head are you using? My thinking is if this is an L head LZ23, then the distributor for a NAPSZ motor is not going to work, unless it's a single plug version. The ignition box for it sees two coils, won't run right unless you put both together, and even then it's not that great. You probably know this, just thought I'd check.

 

In theory it should work....

I'm running the intake coil...exhaust coil is removed

Also just using the 4 intakes on the 8 plug cap.

[banzai510(hainz)]

remember Spades had this prople with his dizzy using special gear ect to look for this proplem, Borrow a Dizzy and run it. 15min ck

[datzenmike]

Doug! I have a timing cover for a Z20E that takes a matchbox 4 plug dizzy. (should have two of 'em) The Z20 and Z22 are the same basically. Hell I get confused and thought this was for a taller Z24. You can have it.

 

Let me know and I'll go to the parts pile and (ugh shudder) have a dig through for it.

[HRH]

Ah hah, therein lies your problem! I've done this before. The system doesn't like working that way. You can make it work if you take both + and - coil wires from both coils and connect them, then run the single coil. The problem is you're fighting the ignition box, which is made to spark in a certain curve at the +3-3 firing of intake then exhaust for one big long spark basically.

 

If you switch to good matchbox unit, your problem will most likely be cured. (Bypassing the Z24 ignition control box) I ran my 720 in 4 plug version for a while and finally hooked it back up to dual plug. Worked ten times better.

 

You can also get the Z20 4 plug distributor and ignition box, which I think came in matchbox but may have also been the in the cab control unit too. Hard to find single plug Z series stuff though. At least you could probably get a 4 plug cap.

[Sealik]

Ah hah, therein lies your problem! I've done this before. The system doesn't like working that way. You can make it work if you take both + and - coil wires from both coils and connect them, then run the single coil. The problem is you're fighting the ignition box, which is made to spark in a certain curve at the +3-3 firing of intake then exhaust for one big long spark basically.

 

If you switch to good matchbox unit, your problem will most likely be cured. (Bypassing the Z24 ignition control box) I ran my 720 in 4 plug version for a while and finally hooked it back up to dual plug. Worked ten times better.

 

You can also get the Z20 4 plug distributor and ignition box, which I think came in matchbox but may have also been the in the cab control unit too. Hard to find single plug Z series stuff though. At least you could probably get a 4 plug cap.

 

I'll go try it......not gonna fry anything?

[merlin]

We should dig through my pile .. The z20s efi dizzy i got with that 200sx efi stuff i gave you should be in my stash somewhere... Anyong got a pic of a 200sx 4 plug unit?

[HRH]

As long as you connect the + with + and - with - you'll be fine. Your tach will work too if you have one.

[Sealik]

We should dig through my pile .. The z20s efi dizzy i got with that 200sx efi stuff i gave you should be in my stash somewhere... Anyong got a pic of a 200sx 4 plug unit?

 

 

Dmike has a pic...I know what it looks like though.

Thought you already got rid of it?

[Guest 510kamikazifreak]

The 4 plug Z20 in the Old ladys 200.

Need a better pic?

[Sealik]

 

The 4 plug Z20 in the Old ladys 200.

Need a better pic?

 

That's okay.....just ship it...I'll snap a better pic :D

[Guest 510kamikazifreak]

That's okay.....just ship it...I'll snap a better pic :D

:rofl:

Shed have my right one :o

She likes that damn funny looking car,too much :hyper:

[Sealik]

Doug! I have a timing cover for a Z20E that takes a matchbox 4 plug dizzy. (should have two of 'em) The Z20 and Z22 are the same basically. Hell I get confused and thought this was for a taller Z24. You can have it.

 

Let me know and I'll go to the parts pile and (ugh shudder) have a dig through for it.

 

 

Thanks Mike....gonna try to get that Z24 dizzy functional first.

I Think Matt has 'remedied' the issue

Update in an hour or so.

[datzenmike]

 

Top one is narrower but goes all the way through. Bottom one looks like a wider hole but with a lip near the bottom.

 

I assume the bottom one is the Z20E for use with the L20B type Matchbox dizzy.

[Sealik]

 

Top one is narrower but goes all the way through. Bottom one looks like a wider hole but with a lip near the bottom.

 

I assume the bottom one is the Z20E for use with the L20B type Matchbox dizzy.

 

 

Yup...top looks like the Z

Bottom....Z20E.......definitely not an L

 

Hooked those wires up to the coil....no diff...still has that miss

[merlin]

<br />Dmike has a pic...I know what it looks like though.<br />Thought you already got rid of it?<br />

<br /><br /><br />

I think i swapped an l perch and spindle onto it instead... But all the parts should be there to convert it back, just need to see what the right components are.