L20B Rebuild

[deadmonkey]

Well... I'll look at it again when I get home, but following the '78 manual trouble shooting it says transistor modual or high-tension wire... :(

Is there any difference between stock coil and say one from Smucks?

[banzai510(hainz)]

if using a 78 or newer you would use a .7ohm coil designed for that rig usinf EI ignition(dizzy)

 

point car/trucks use a 1.6 ohm coil with a 1.6 ohm ballast resisitor(this is 510s but will assume the rest 620s ect are the same or close to it.)

 

 

Is there any difference between stock coil and say one from Smucks??????????

what does this mean? they sell alot of coils different types ect.

wht is the ohm reading and whats it used for .im sure you read the ignition section of Jason gray's

http://olddatsuns.com/620tech.htm

 

also here in the HOW TO section

[datsunaholic]

I'd change the plug wires. If they were old, the new EI, which should have had a hotter spark than the points setup, might have burned open the wires. Especially if they are carbon-core wires (very common). Oh, and make sure the rotor is turning. It's not common but I've seen the dist drive spindle break when assembled wrong.

[deadmonkey]

Holy Fing crazy shit!

 

So I figured it out... Testing the sparkplug by taking it out and visibly watched it spark.

My heart sunk as I knew it was mechanical.

I thought it through for a second...duh, no fuel (but I know the carps are working) so I took the valve cover off and turned it over.

Sure enough, the cam was not moving!

I'm thinking that little pin sheared because something seized up...

Nope, the pin wiggled out of the hole in the cam! It was in the Cam sprocket, just chillin' out. Nothing was stuck, nothing was sheared and the Cam was in the "10 and 2" position.

 

I'm thinking that little pin never got pressed in properly?

I clamped onto the pin, 1/2 way down w/ the vise grips as hard as I could as to deform it a little bit pressed it into the cam 1/2 way in. Boy, its in there now!

 

So, luckily, the timing never changed. I won't be able to verify this unless I take off the timing chain cover, but I don't see HOW this is possible. Is there a way to verify there are 44 links between #2 dimple on the the cam sprocket and the dimple on the Crank sprocket w/ out taking off the timing chain cover?

 

I'm doing a leak down test now... at this point I'm more worried about the pistons having touched the valves. If the cam is at "10 and 2", is it possible for the valves to hit the pistons?

 

Whew!

~DM

[banzai510(hainz)]

First off you had sprk the whole time then. If you pull the center wire off the dizzy an place near ground, it should have sparked. we went by what you said.

 

 

Remeber the first part of my vid.

 

YOu could always try to put a breaker arm on the crank and turn it by hand. if it dont lock up then its not hitting a valve.

 

I dial the crank to ZEO exactly, then I look up at the marks on the cam plate. If it lines up then your good to go.another common thing is if people do head gasket swaps w motor still in car. Some people including me have a HARD TIME pulling up the chain. thus cocking the cam sprocket thinking its ON.

On a new motor I assumed you have the cam/head assembled/spocket prior to putting the chain ON.

 

 

Ok by chance your offa tooth you dont need to remove the timming cover but it will be a tial and error effort on your part to get it lined up. Hopefull you have a timming chain tool to keep the tensioner from falling out

 

I'm doing a leak down test now... at this point I'm more worried about the pistons having touched the valves. If the cam is at "10 and 2", is it possible for the valves to hit the pistons?

 

Its very possible you hit something as the starter motor turn the lower end and the cam stayed intack.

 

when I set up my cams I also spin it with my hand a few times just to make sure the cam is not binding before I put the rockers ON

[deadmonkey]

well of course it means it was sparking the whole time...

 

but when I was testing it, it was turning over the bottom end the entire time.

 

So if the cam was at 'top dead center' (lobes at 10 and 2) then all intake/exhaust valves should not touch any of the pistons if the bottom end was free to rotate free of the top end? That's all I'm worried about at this point.

 

If nothing touches then I was lucky as hell.

===

 

What's even crazier is I think the machinist GAVE me the cam unless it came with the timing kit...because it isn't mine and it came with all rebuild kit stuff in a little box. It isn't a new cam, but just looks refurbished maybe. Its a stock U20 stamped cam, but I didn't think my kit came with a cam. Chances are they just didn't press in the damn pin!

 

I think I just dodged a bullet on this one!

[Wide14u]

no valve are open i am lost

[Wide14u]

ok so if the cam is at 10 and 2 where you said is any valves open if so i think it could hit

[banzai510(hainz)]

deadmonkey

Just because the valves are in the 10 & 2 position on #1. I cant confirm that one valve is open or slightly open else where in the back like # 4 cylinder. I would think if the cam stopped moving you still have the pistons going via the starter or just momentum that kept it going.

Maybe you got lucky.

 

as for the sparking.

The botom end controls the spindal so it shold have still rotated the rotor in the dizzy to make a spark if Key IGN was ON.

 

 

I have been lucky a pin has never come out

[deadmonkey]

Well I visually inspected the piston heads as best I could through the sparkplug holes. I saw the sharpi writing and the "0.75" stamped on the top, but saw no nicks or anything. I think I'm good.

 

I buttoned 'er up and she turned over with out a problem. I may have a small exhaust leak but not really worried about that. Its timed and ready for driving!

 

Worst case, I have to get a few new valves.

Compression tests are good but I'll do it again later when hot.

[Wide14u]

alright lucky bastard lol

[Javin]

I am on the edge of my seat for this. I need to know how this tuns out!

 

EDIT: Did I just read it was working!? YAY!

[deadmonkey]

I blame chester for the exhaust leak! :) J/K

I probably didn't seat the pipe in that flange deal properly. Kit didn't come w/ a seal, isn't there a seal replacement for those?

 

but yeah... Its running I just need to time it after I take it out and warm it up. I'll probably do that tomorrow. I did a rough time for now and it was right at 10deg BTD with the dizzy right in the center (notches lined up). That and It kind of stammers at idle and with the timing light (harbor freight crap special) the notch seems to light up in two spots. Its hard to time w/ that light in the daytime though.

[Wide14u]

good job

[chester]

thanks just throw me under the bus <_<

[Wide14u]

he didn't throw you under the bus. he pushed lol

[chester]

thats worse :blink: if it was just a friendly push it could have been an accident

[greengo]

Either way the best time over the build will be when u drive it for the frist time..

[deadmonkey]

Either way the best time over the build will be when u drive it for the frist time..

Did that today...

I found two things; one, the clutch is slipping, so I wonder if it got oil on it? The clutch is brand new (when I put swapped engines this summer).

If I put any amount of power it seems to slip or increase RPMs with out noticeable power. I adjusted the clutch out a bit farther but the pedal was nearly at the end of its range already. I believe it should have been fully disengaged at with the pedal out. I'm driving it tomorrow so I'll see if the adjustment I made today does anything.

 

Two, That exhaust leak is really annoying. I got looking and I think the pipe is touching oil pan too.

 

Other than that she sounds great. I probably won't have time tomorrow, but I want to do another leak down test while it is still warm.

Here are the results of a cold leak down test after I fixed it but before I let it run/warm up for the first time:

.... | PSI | PSI 15min later

#1 | 142.5| 140.0

#2 | 135.0| 131.0

#3 | 145.0| 140.0

#4 | 144.0| 140.0

 

#2 is the oddball in all this, but We'll see once its had time to break in a bit.

I'll be takin' her to work and back tomorrow.

One thing I know... man does the heater get hot now! I put in a hotter thermostat :)

[banzai510(hainz)]

a new motor might run hotter as everything is tite.

 

Bleed the clutch.so the slave cylinder pushes itsself all the way back in.

 

adjusting the pedal inside doesnt do as much. if everything is new it dont take that much movement to to push the slave to push the fingers on the pressure plate

 

If you used the same trans and flywheel I assume you used the same TO bearing sleeve.

[deadmonkey]

yup, everything was new with the clutch kit when the engine was swapped this summer.

I adjusted it all the way to the end and it was enough to disengage it.

Guess I have a bleed job ahead of me. yet another thing to add to the list :)

[greengo]

Gravity bleed then pump with hand tell u see slave starts to really move... Then when u get pressure pump with foot..

[deadmonkey]

Story time:

So coming back from work Tuesday I turned on the heat and shortly after noticed the temp gauge kept going up and up and up. I pulled over into a gas station parking lot with steam coming out. I knew what happened because when I put the engine back in and hooked the heater hose I noticed it should have been replaced. I thought it had longer than it did though!

 

So there I am, stranded because I left my cell at home charging and not enough change to make a pay phone call. I was going to have to limp it home some how.

 

With my years of McGyver watching as a kid I knew I could put something together.

After searching the truck I gathered up some extra wiring harness wire and my bag of Christmas red and green MnM's.

Since there was still like 1/3 of a bag I didn't nom them all but thought about it.

After the split hose stopped squirting coolant all over I wrapped it with the MnM bag then wound the wire around and around for about 4 inches with the wire nearly touching eachother all the way.

 

Upon starting her up there was no more leak and I continued on.

Not a block down I saw the temp go back up and realized I forgot to put nearly a gallon of water back in to replace what spilled all over the parking lot.

Pulling over again near Arby's parking lot I went in and asked if they had a large container I could put water in, they said no... but I think they were lying. I went to the Sharis across the street and asked for the same. The nice lady there brought out a few gallon bucket full of water. Thankfully I took it and waited for the truck to cool down a little.

Knowing it would take for ever for the coolant to cool off I used my coat to CAREFULLY and ever so slowly crack the radiator cap. Thankfully (as I suspected) steam slowly came out and not coolant. With the truck running I filled it up until and ran it for a bit watching for leaks while it purged any bubbles.

 

Watching the temp the whole way, it never went below half way like it is supposed to.

I made it home safe and sound.

Confident of my McGyver patch job I blasted the heater and looked for any leaks. Still none. I probably could have went 100's of miles with that patch.

Mental note for the future...wire and MnMs wrapper will save your bacon in a pinch!

[chester]

is there anyway to get some pics of this nice repair job. Glad you were able to get it home.

[deadmonkey]

is there anyway to get some pics of this nice repair job. Glad you were able to get it home.

Nah... I was gonna but figured a story would be better :)