720 z24 motor... more power?

[Big Pip]

any ideas what can be done to get any more power out of my motor? I have the hardest time getting it to 70mph and as soon as I hit any kind of hill or bridge I lose 10mph. It is very slow also, any ideas what I can do to help?

I have changed the plugs (8) wires, cap & rotor.

[BEEBANI]

You still running the stock exhaust? Cat's probably clogged. Fuel system could be plugged also.

[Bleach]

ya, check your engine. fix vacuum leaks, check for good compression and correct timing. :)

 

if all else fails, swap in a KA24 ;)

[datzenmike]

My L20B was just like that till I blew the head gasket. Upon re-assembly I adjusted the timing chain stretch. WHAT a difference!!!! Better across the board, really noticeable at the bottom end.

[Big Pip]

Someone already took the muffler off so I was going to use the happy saws-all and cut the pipe off just before the cat, Tomorrow I am planning on going to the exhaust shop and having new pipe welded on to go to the back of the truck. One of my thoughts have been the cat could be cloged.

 

Timing chain, I just did a timing chain job on an Altima and decided that car was worth more to me in scrap, am I going to have that mushey feeling again with this motor?

[Icehouse]

You still running the stock exhaust? Cat's probably clogged. Fuel system could be plugged also.

 

 

I'm with Beebani do a new filter, I had that exact thing happen to my frist car (B2000 sundowner deluxe) after I put the new filter in it felt like a new car!!

[lynchfourtwenty]

timing chain on a datsun is easy actually, well it is too me anyways.. also hainz has dvd's and in one of them he shows you how to deal with that.. wel lfor the most part.. if u have the haines manual or chilton u should be able to figure it out.. if i could doit at 19 with no exp. u can doit!!!

[datzenmike]

Do the simple, inexpensive and easy things first. Set the valve lash and while valve cover is off check chain stretch. Set the idle and mixture. Set the timing. Inspect all eight plugs, looking for any fouling. Check the wires, cap and wires to both coils. They should be clean, in good shape, and firmly in place, no loose electrical wires. Replace if in doubt. Get a hose routing diagram or refer to the engine compartment sticker and assure that all hoses are correctly positioned, no vacuum leaks. Replace the fuel filter, it's located inside the frame above the left rear spring front shackle. It's hard to get at and has probably not been changed for some time. (I change mine twice a year, It's cheap insurance.) It's below the tank level so it will be messy to do. There is also a small fuel filter on the banjo fitting at the inlet pipe to the carburetor. The electric fuel pump also has an internal filter but do this one last only if necessary. Check for a clean air filter.

 

All this stuff should be done anyway to eliminate it from future diagnosis problems.

[tangent]

amen

[datzenmike]

amen? ................ verbose bastard!

[Big Pip]

You said basic tune up so I did- plugs, wires, cap, rotor, valve adjustment and oil change. Nothing!

You said timing chain so I- tore the engine apart and found out the chain has already been changed. It still looks Brand New, No Stretch and not out of adjustment or on the wrong tooth.

You said Cat. Conv. clogged, I- remove the cat, snapping 3 bolts in the process( so much for letting run and heating it up) just to find out it has already been hollowed out.

I say this is the biggest Piece Of $h1T I have ever owned!

 

Now, does anyone know anything about the vacume lines? Can I remove some lines? Please help...

[lynchfourtwenty]

the only vac lines mine has is the vacume advance and the brakebooster one other then that i have no lines.. altho i run a weber carb..

[lynchfourtwenty]

and i have an l20b

[Big Pip]

Ok, what about fuel mixture? I was taught to srew in the mixture screw all the way in, then loosen 2.5 turns. That was on chevy, and when I try to do that to this thing it doesn't run very well, so I loosen a little more and it gets better, then a little more, then a little more... by this time I am out like 6 full turns and it is way to rich and at an idle it floods itself...

So, what would I have to do to install a weber 40 dcoe on this thing?

[lynchfourtwenty]

is that what everyone else runs?? or the 32 36? mines 32/36 dgav and i adjust it like u were saying..

[datzenmike]

I went back and re read everything and no one said to replace the timing chain, only to check for stretch. This can easily be done when removing the valve cover to check the valve lash. As I said, do the simple, easy and cheap things first. Once you eliminate these things you can move on to the harder, expensive things. The last thing you want to do is start replacing things and find out later that it was a cracked distributor cap all along..$15 to fix.

 

Did you check/replace the fuel filter? If it's partially plugged it will not be able to supply the engines needs at high speeds. Less than $10

 

Did you set the ignition timing? This will seriously affect mileage and performance.

[banzai510(hainz)]

Is this eleltrically timed also.

Use a timming light???? Try this first. Wonder if the spindal was install off a tooth and your not electrically timed..

Me and Ray Stonhocker got a guys L motor running better by resplining the oil pump.

 

The guy timming the motor correctly however he had a mismatching distributor pedastal so when The moto was at 0deg on crank and the sondal was in the correct spot when installed the disdtributor and I find out the roto is right inbetween 1 & 3 plug wires so the timming plate would never get the correct timming.

http://www.guba.com/general/search?query=datsun&set=5

 

As for the Z24 I dont know muck about these and I kdont know how to adjust those head no actually seen one open inside as the cam rides in th head instead of cam towers. But I know the bottom half is pretty much the same and to time them is close to the same.

 

I guess alo maje sure the plug wires are on the correct spot and the 2nd coil fires later .so make sure the after plug wires are no in front or vise versa.

 

Datsunaholic would know more on these .

 

As for the vacuume line I think those vehicles has alot of hoses who knows go where.

 

Sorry If you redid the timming chain. Most just crank it to 0 deg then look where the adv timming marks on the cam sprocket.

 

 

The mixture idle waht your doing is correct. about 1.5-2.5 turns out it should be running ok then ck the timming again.

 

as for the flooding out you sure the float is OK????

[datzenmike]

Morning, hainz. Learning about the Z myself. The distributor is basically two EI matchboxes in one and both pair of plugs are fired by a single trigger at the same time. The intake and exhaust plugs are diferent heat ranges though.

 

The cam sprocket is a different diameter than the L series, so I guess the crank one is too. Other than that the Z and the L front end appear similar and are timed the same way.

[Big Pip]

Truck too weak, big POS... I sold it after only 3 weeks! Good luck all of you!

[lynchfourtwenty]

sorry to hear that, and i think u gave up to easy.. better luck to the next guy