fresh l20b not starting

[guillermofergu]

Hello all,

 

I'm having an issue with starting the new transplant. I used everything on my l16 including distributor on the l20b. I've got spark, I've got fuel, and my firing order is correct. Everything I've read indicates that the distributor is "180 degrees around". I have no idea what that means. All that I know about this stuff is the basic way it works. The shop I had rebuild the engine is the one who set the engine timing. I transferred the distributor to mimic the way it was on the l16. Before I took out the oil pump shaft to put in a shaft minus the gear, I marked on the front cover and the shaft so that I could put it in exactly as it was. I feel like I'm over thinking my issue a little bit and would like an outside viewer's opinion. 

 

tl;dr:

 

swapped l20b, used all accessory components from l16 that were in working order.

no starting...only backfires.

firing order, check

spark, check

fuel, check

 

Thanks!

[Eagle_Adam]

ill bet your 180 out and your firing order is wrong....

 

 

set thew motor to TDC

pull the dizzy

snap a pic of the orientation of the oil pump drive shaft

post said pic

[DAT510]

backfires from carb or tailpipe?

 

Remember Fire order. 1342. Counter clockwise.

Takefirst spark plug out, put engine on TDC, (Top dead center), check it its on TDC by putting screwdriver in the spark hole. Check dizzy. Bet thats your problem. Either that or the valve timing is off.

 

To check that, put engine on TDC, pop valve cover and look at the cam sprocket in relation to the cam tower. There should be a notch on the gear and it should be a little forward or in the middle of the mark on the tower.

That's if you've got a good gear. If not the intake and exaust lobe on #1 will be at 10 and 2.

[datzenmike]

Three things.

 

The #1 piston must be at Top Dead Center.

The cam must be positioned so that the #1 intake and exhaust valves are closed.

The dizzy must have the rotor pointing to the #1 wire on the cap. (or very close).

 

 

Additionally the rotor turns counter clockwise so the next wires are 3 4 2.

 

 

At TDC you can check the valves are closed by looking in the oil cap hole with a flashlight. The #1 intake and exhaust cam lobes will be in sight and upward at about 10 and 2 o'clock as viewed from the front. If they are, pop the dizzy cap off and the rotor should be pointing to the #1 plug wire.

[guillermofergu]

if the rotor isn't pointing towards #1, do I turn the rotor itself or do I pull of the dizzy, look at and adjust the oil pump shaft? 

[guillermofergu]

ps, it backfires out of both tailpipe and carb...just depended on what I was trying at the time. I went all the way around the dizzy trying to find where to start with #1 because the conventional placement wasn't working. It's looking like it'll be with the adjustment on the oil pump shaft / dizzy. I'll let ya'll know how it goes...

[Eagle_Adam]

the rotor only goes on one way, you have to adjust the dizzy 

[DAT510]

The wires can be rearranged, just make #1 where the rotor points. You don't want to move the dizzy to a plug because then it woudlnt allow you a range of motion.

 

If the rotor, with the engine at TDC, points in between two plugs then you need to drop and reclock the oil drive.I doubt it though

[DAT510]

pretty much, don't advance/retard the dizzy via the pedestal, unless its a bit off. Becaue when you go to time the car it won't allow you much adjustment. You can retard it a bit, since retarding too much is... retarded lol

[datzenmike]

If the rotor is below the wrong wire simply put the #1 there and go 3 4 2 counter clockwise.

 

If it's in between and not easy to adjust then yes drop the oil pump and the drive spindle, remove dizzy, check that you are TDC. Turn the spindle and insert it up inside so that the top looks like this...

 

 

Take note that the top has a small and large half moon shape. The small side goes to the front.

[Eagle_Adam]

Take note that the top has a small and large half moon shape. The small side goes to the front.

 

 

THIS!!!!!!!!! 

[banzai510(hainz)]

simple

http://www.youtube.com/watch?v=_aBTjhJMByo&list=PLEN4as7nBy8OT2ss_P2nc4xUgP6EAFu8Z

 

 

hopefully your wireing to the coil and ballst is still the same. since you didnt need to remove it.

[Eagle_Adam]

cant tell you how many times i watched those vids banzi......... 

[guillermofergu]

Checked everything out...still not working. Didn't have a lot of time to look at it much. With cam lobes at 10 and 2 and being able to see the piston engravings on #1, the oil pump shaft top end was at 1130 ish ...couldn't really tell. the smaller half circle was facing forward. I put the dizzy on, put the adjustments to the middle on both, then put the cap on (rotor faced the bottom forward position on the cap, so I put #1 on it)...instead of backfiring, it shot gas up out of the carb...

 

I don't know what to do anymore and I feel overwhelmed. I'll do more searching. Any ideas in the mean time?

[datzenmike]

Yes. Firing order is 1342 in a counter clockwise direction. Confirm the wires are right, usually 3 4 are wrong as people go clockwise by mistake.

 

Try retarding the dizzy (counter clockwise) slightly.

[guillermofergu]

It was in the right order. I'll try retarding it in the morn.

[datsunaholic]

Dumb question- which crank timing plate are you using, and which crank pulley?   L16s and L20Bs have different crank timing plates   L16s use a single pointer with multiple notches in the crank pulley, whereas L20Bs use a sawtooth plate with multiple marks on the plate, and a single notch on the crank pulley.

Using the wrong one (using both would be OK) would cause the zero timing mark to be significantly off.

[banzai510(hainz)]

set the valave lash

fire order correct

 

your ignition sparking????????????

 

 

as a last ditch pull the screw out of the dizzy and turn the distributor with your left hand and turn the key with your right thru the window. advand or retard the dizzy till it starts

[guillermofergu]

Not using any timing plate to reference anything...using cam lobe position to tell where tdc is. Hainz, the VL was supposedly set when it was rebuilt (had it rebuilt at a reputable place, but it was his first time working on a l20b - his usual is vg30/33), my firing order is correct, and my ignition is sparking. My current thinking is that I'm an idiot and can't see the cam lobes properly through the oil cap...gonna remove the valve cover today to make for sure that's what's going on. Once I do that, I'll try the last ditch stuff!

[datzenmike]

Valve lobe position isn't going to be close enough. We look at the lobes simply to know the motor is on the compression stroke, nothing more. True TDC is lining the timing scale and pointer up.

[Lee R]

My TDC method = Put your thumb over the #1 plug while turning the crank.  You should feel pressure pushing against your thumb....this is the compression stroke.  Once you feel that air, remove your finger and put a chop stick or wooden skewer (screwdriver can scratch) into the holel until it rests against the piston.  Turn the crank until the stick reaches the highest point. 

 

Voila.

[ggzilla]

It'll be up to 10 degrees off.

[datsunaholic]

The "chopstick" method gets you fairly close to true TDC but even then it's not exact.  The crank will move several degrees with no apparent movement of the piston at TDC.   Need to have something marked to "split the difference" between 2 known points to find true TDC.  That being said, it's probably close enough to get cam timing.  We use a TDC indicator and a dial wheel on old WWII engines, but that's because those engines don't have any direct access to the crankshaft.  No timing marks anywhere.

[DanielC]

On a four cylinder engine, you might be able to feel TDC.  Here is why.  At TDC, two pistons are well, at TDC, and the other two are at BDC.  There is a degree or two, of crankshaft rotation that the pistons are not really moving, and you can feel it.  If you do this without the rocker arms in the engine, you will not have valve train drag to mask the friction of the engine turning.

 

Find TDC, install the camshaft, at the right point.

Check the compression of the engine.  If you have good compression, set ignition timing, 10 to 12 drgrees before TDC.

The engine should fire just by pouring a little gas down in the intake manifold.

 

Compression, ignition, fuel.  Those three things are needed to make an engine run.  Give any engine those three things, at the proper time, and amount, and the engine will run.  Millions of engines prove that every day.

[guillermofergu]

...So, does that mean the engine can't be timed without that when building it?...It doesn't have the saw blade timer plate on it currently, but I have it in a box...thanks for the heads up. Definitely makes sense. So, I just line up the zero mark to the notch in the crank pulley?