idle is still rough.

[Stupid_fast]

Hey all, I'll try to include as much information here as I can remember and think of.

 

I've had my car running for a few months, over that time vastly improved how it runs. Its a rebuilt L20b(hard break-in), weber 32/36 w/ L16 intake/ no smog, dual point dizzy modded to pertronix with ignitor coil no ballast, headers and full 2.5" exhaust(sounds mean... I doubt the muffler is doing much), NGK iridium IV plugs(replaced twice, these have about 200 miles on them) with bosche wires, pretty much every accessory is new ... everything has been bought and installed by me... I got the car with longblock motor, trans, and rolling shell. Has about 3k miles since I first started it. Comp was 170-170-175-175 last I checked.

The PCV system is hooked up with the upper one filtered, the one out the block goes back into the intake manifold with a PCV valve. Dunno if that's useful.

 

It runs strong, makes really nice torque even low rpm like 2000 up hills it does better than I expected (I live in oakland hills, some really steep stuff) and even runs pretty strong in the high end, pushes it along as fast as 100hp will go.

 

I've run it the hard break in(theres an article online I followed.) Oil and K&N filter changes at 20 miles(30w), 150 miles(changed to 10w30), 1000 miles using valvoline VR-1 non-synthetic racing oil. I've changed the fuel filter about 200 miles ago, valve lash has been done about 5 times since it first ran, fixed some low voltage coil problems, fouled plugs, ect, tuned carb countless times.(to weber recommended lean best idle)

I have checked over and over again for vacuum leaks, since it is so likely yet I have found nothing. Tried spraying carb cleaner around all the gaskets, no change in the idle.

 

 

Now for my best description of the problems...

The idle is rough, it will have troubles stalling around corners, ect if idle is much under 800rpm's, I've adjusted and readjusted the carburetor over and over again blasted it out with carb cleaner, adjusted the float, checked the ignition countless times and everything has made it a little better but never solved it. The idle is most smooth at 900-1000rpm, which would be OK but its not optimal I would rather have it running right.

 

Something odd I noticed, if I unplug the idle cutoff solenoid(anti dieseling) nothing happens, I pulled off the jet and applied power watching it work. It definitely works but makes no change to idle? Going to replace it.

Since I'm getting a new one anyway, if I remove the jet and cut the needle to bypass it would this be a good test if that is in fact the issue?

 

When driving, if I get on the throttle hard sometimes it will cut out for half a second and then the power will come on, but half the time it will respond immediately. Sometimes it will do it when shifting, I have to be really gentle on the throttle to avoid it. when running, if I gradually increase throttle and into the 2nd progressive barrel it will run strong at WOT. If I get to WOT too fast, really onto the 2nd barrel it will bog a bit, that's normal of course just needs rejeted.

 

I notice if idle I hold the throttle about 15-20% open, there is a spot where it runs really rough. This is probably related, seems to run pretty smooth through the rest of the throttle range. Responds well from idle to lots of throttle, revs right up.

 

There is a lot of water coming out of the exhaust, I notice it while idling in my driveway tuning in... Its odorless and is not slimy like coolant, just condensation?

 

I pulled the plugs and they are a nice tan, indicates the fuel ratio is running nicely?

 

The motor is timed to 12btdc, valve lash is set I spend an hour on it getting the valves perfectly adjusted, again improved the problem but never made it go away.

If I advance the timing to like 25btdc it will run a bit more smooth, but not much.

 

 

Thanks for any advice or ideas. I've tried almost everything I can think of and have gathered from extensive online searching. Nothing has helped by much so far!

 

I can get a video of it if it would be helpful.

 

 

TL;DR, L20b, Y U NO SMOOTH?!?!!!1!!!!

[DatDoug]

What are your idle jets? All your problems sound like they are happening before 2000 rpm which is your carbs idle curcuit. Prolly needs bigger idle jets. Where is your air-fuel mixture screw set @? Optimum is 1.5 to 2 turns out. If it is further out then you need bigger idle kets. If it furthe in then you need smaller. More than likely you need bigger ones. Both primary & secondary.

 

Also with a weber its best to set your timing a lil more advanced. Say 15ish. If you run Hi-Octane gas then you can go a lil more. Up to 19.

[DISLEXICDIME]

Is your vacum advance good ? What fuel pump do you have ? What cam is in it ? Is the pertronix gapped right?

[racerx]

Did you spray carb cleaner around intake area, vacuum hose...are all of unuse vacuum plugged?

[Stupid_fast]

What are your idle jets? All your problems sound like they are happening before 2000 rpm which is your carbs idle curcuit. Prolly needs bigger idle jets. Where is your air-fuel mixture screw set @? Optimum is 1.5 to 2 turns out. If it is further out then you need bigger idle kets. If it furthe in then you need smaller. More than likely you need bigger ones. Both primary & secondary.

 

Also with a weber its best to set your timing a lil more advanced. Say 15ish. If you run Hi-Octane gas then you can go a lil more. Up to 19.

 

Lets see, primary idle is 60, secondary 50, main's are 140-140, air correctors are 170-160 Mixture screw is best at about 3/4 turns out.

 

I dunno about the speed screw, have not checked how far in it is. idle is about 800rpm's it wavers by about 30rpm's.(timing light has a tach on it)

 

The stuttering/hesitation problem happens anywhere 2000rpm-3000rpm. It is less harsh at higher RPM, and is pretty much gone around 3500+, but my tach isnt hooked up at the moment.

 

 

What about that idle cut? Isn't it strange nothing happens when I unplug it from 12v??

 

Is your vacum advance good ? What fuel pump do you have ? What cam is in it ? Is the pertronix gapped right?

Vacuume advance looks good, reman dizzy, new hoses on everything and CLAMPED. cam is stock AFAIk, does not feel like an aftermarket one though I could measure it.Pertronix gap?! its about 1mm from the pickup, how much is it suppose to be gapped!? I had to mod the mounting plate for it to work correctly in the dual point dizzy, maybe this is a problem? I fixed the problem of the rotor being loose on the shaft, so that's not the problem.

 

Did you spray carb cleaner around intake area, vacuum hose...are all of unuse vacuum plugged?

 

yes.

 

 

 

One thing I could think of was blown gaskets... blown head gasket? But no other symptoms of it. I did run it hard ... ?

 

It does run cold... I have an aftermarket autometer gauge. water temps about 150 on freeway 3500-4000rpm's 70-80mph, never hits over 180 in traffic ... Backroads keeps around 150-160 3000-3500rpm's. If temps under 180 w/ 180 deg tstat, the rad isnt even kicking in is it?

 

 

Thanks.

[banzai510(hainz)]

I would swap another dizzy and a carb.if you have them.

 

 

What about that idle cut? Isn't it strange nothing happens when I unplug it from 12v??

 

is there even a idlejet on the end of it? Have you seen if the needle moves in/out with the 12volts?

 

I seen where people use the speed screw to have it cranked all the way in to get it to idle as they are bypassesing the idle jet.

 

 

make sure the carb vac adv for from the base of carb not the intake manifold

[SHRALP_GNAR]

have you checked the throttle plate? it should fit tight right over the first progression hole. as soon as you crack the throttle the hole should be revealed. if you can see a gap at all when the plate is fully closed your progression circuit is always on a little bit.

[datzenmike]

If your idle speed is too high the idle cut will have no effect simply because the throttle plate is above the idle port and not being used. It's getting enough fuel from the venturi. OR there is no fuel available at the idle port and therefore a higher idle speed needs to be set. Chicken or the egg... which came first?

[banzai510(hainz)]

I have also seen if the nut holding the trottleplae/linkage is too tight cause a off idle stumble. I guess it can cause a BIND

[racerx]

Did you do compression check..if you think your gasket is blown.

[Stupid_fast]

 

 

I would swap another dizzy and a carb.if you have them.

 

 

What about that idle cut? Isn't it strange nothing happens when I unplug it from 12v??

 

is there even a idlejet on the end of it? Have you seen if the needle moves in/out with the 12volts?

 

I seen where people use the speed screw to have it cranked all the way in to get it to idle as they are bypassesing the idle jet.

 

 

make sure the carb vac adv for from the base of carb not the intake manifold

I don't have a spare carb or dizzy... Maybe should just ditch it and go to sidedrafts?

Yeah, the idle jet is a 60. Speed screw is barely turned in. advance is plugged in correctly.

 

 

have you checked the throttle plate? it should fit tight right over the first progression hole. as soon as you crack the throttle the hole should be revealed. if you can see a gap at all when the plate is fully closed your progression circuit is always on a little bit.

Eh? There is a little gap (idle speed???) but not even 1mm wide...

If your idle speed is too high the idle cut will have no effect simply because the throttle plate is above the idle port and not being used. It's getting enough fuel from the venturi. OR there is no fuel available at the idle port and therefore a higher idle speed needs to be set. Chicken or the egg... which came first?

 

I checked it today.. idle speed screw is barely in.

 

I also ruined my idle cut solenoid today, cut out the needle to bypass it... no effect.

 

I have also seen if the nut holding the trottleplae/linkage is too tight cause a off idle stumble. I guess it can cause a BIND

I tried loosening it again today, no difference I already had it adjusted right.

Did you do compression check..if you think your gasket is blown.

 

Yeah as I said in 1st post, 170-170-175-175.... comp test I did at like 50 miles was 170 on all 4.

 

 

Not sure what to do at this point I played around with the pertronix mounting, seemed OK. Nothing I can really do there.

 

It does run better if I advance to like 25-30 btdc, but then it likes to stall when I clutch in ...

 

 

More fiddling with the carb and nothing really has changed.

 

I will try to get a video of it running in a day or two.

[DISLEXICDIME]

The pertronix should have had a little plastic feeler gauge to set it in the kit

[banzai510(hainz)]

go back to swap carb or another dizzy.

Thats all I can say.

If motor is timed and you get 170 I say motor mechanics are good

 

 

what I find questionable is the dizzy 25deg-30deg part to me.

 

re ck the dizzy install maybe

[Stupid_fast]

The pertronix kit 1741 I got did not come with a feeler gauge.

 

@hainz, I did pull out the dizzy shaft when I primed the oil pump.... Maybe I did not put it in at the right 11 28 that I thought I did.

 

I will check that again, its the only thing I can think of.

 

 

Maybe I can buy another dist off a member here, or convert this one back to points.. at least to test it.

 

As for the carb I could get a used one, but I just don't like spending cash on a setup I don't think I'm going to keep for a long time. I'm thinking a single sidedraft would be nice.

[banzai510(hainz)]

I'm thinking a single sidedraft would be nice. ?????

 

I havent seen one in person I liked!!!!!!!!!!

 

 

every L motor guy should have a spare weber and a L series dizzy set up?

Putting points in there might still not find the proplem if its a bad vacuum adv or spring popped.

[Stupid_fast]

I'm thinking a single sidedraft would be nice. ?????

 

I havent seen one in person I liked!!!!!!!!!!

 

 

every L motor guy should have a spare weber and a L series dizzy set up?

Putting points in there might still not find the proplem if its a bad vacuum adv or spring popped.

 

You would not recommend a single sidedraft setup?

 

 

Yeah, yeah... I am just annoyed it will delay me getting new wheels.

 

You really think its worth it $255 for new weber 32/36 spare carb? There is also a twin 40mm setup in the for sale section for 600... Tempted but cant afford it yet.

 

Maybe a twin SU setup? There is a set on the for sale section for 250... I am not experienced with carbs, I just want something that will give nice torque, smooth acceleration, reliability and fun. Also its gotta sound nice, the weber I have has a good sound to it ...

 

I pulled apart the pertronix yesterday, I checked the dizzy... its still as nice as it looked when I put it in. It was a remanufactured one from napa.

 

Anyone got a single point dizzy laying around they want to send me?

 

 

Chicken or the egg... which came first?

 

Oh and Datzenmike,

http://notch.tumblr....ickens-and-eggs

 

(Its about a videogame, fyi)

[banzai510(hainz)]

I like that $600 Mikuni set up. But 450 would be a better price as I got mine for 250 and was well worth it.

those SUs? you know they good and from a running car? then mayeb get them otherwise I dont care for them and if they were so good the other owner would keep them.

 

But throwing money at it just isnt going to fix it just yet.

Ck the dizzy install FIRST

 

 

This is How I trouble shoot a motor.

esp if its soembodyelses.

 

Put motor at TDC. ck the cam timming marks

ck the valve lash to make sure rockers are loose when lobe it pointing up.

ck the dizzy timming. 11.28 position and dizzy is soemwhat centered on timming plate(mean sit has the full adjustability)should be pointing right at sparkplug #1, ck for loosness of dizzy shaft.

Visual ck the coil and ballast if it has them.

Ck the carb if accell pump works Nice squirting action.

usaully motor will run.

 

Your motor runs just has a few quirks.

 

I figure somebody near you could just bolt on a carb or another distributor. So you dont have to spend money.

 

If i had to guess. I would think its more CARB as you put a Pertronix on there ans they are reliable. However you have a dual point conversion job which I never heard of so I cant totally rule that out either

[Stupid_fast]

I like that $600 Mikuni set up. But 450 would be a better price as I got mine for 250 and was well worth it.

those SUs? you know they good and from a running car? then mayeb get them otherwise I dont care for them and if they were so good the other owner would keep them.

 

But throwing money at it just isnt going to fix it just yet.

Ck the dizzy install FIRST

 

 

This is How I trouble shoot a motor.

esp if its soembodyelses.

 

Put motor at TDC. ck the cam timming marks

ck the valve lash to make sure rockers are loose when lobe it pointing up.

ck the dizzy timming. 11.28 position and dizzy is soemwhat centered on timming plate(mean sit has the full adjustability)should be pointing right at sparkplug #1, ck for loosness of dizzy shaft.

Visual ck the coil and ballast if it has them.

Ck the carb if accell pump works Nice squirting action.

usaully motor will run.

 

Your motor runs just has a few quirks.

 

I figure somebody near you could just bolt on a carb or another distributor. So you dont have to spend money.

 

If i had to guess. I would think its more CARB as you put a Pertronix on there ans they are reliable. However you have a dual point conversion job which I never heard of so I cant totally rule that out either

 

Yeah 600 is a bit much for me. Where did you get mikuni's for 250?? with manifold? I'd buy that instantly if I saw them at that price.

 

I will check the dizzy tonight hopefully, I'm hoping I can fix it and verify 11:28's.

 

 

I agree its not good to just throw money at it, but I've exhausted almost every other option at this point.

I don't mind spending money if its worth it, but I already have thrown way too much at this project now and frustrated by the results.

 

 

Tomorrow night I'm going to the santa clara monthly meet, maybe someone there can help me out.

 

 

For the pertronix I'll get a pic of my install but I did as best a job as any as far as I can tell.. engine timed 12btdc the adjustment bracket on the dizzy is at 0 .

 

I will try some more stuff and get back with more info tonight or tomorrow.

 

 

Thanks for all the help.

[DatDoug]

That prteonix kit is made for the sigle point distributor. Im sure if you put an ad in the "Parts Wanted" section somewone will have one local. I have about 10 of them if you cant find a local. Let me know.

[Stupid_fast]

That prteonix kit is made for the sigle point distributor. Im sure if you put an ad in the "Parts Wanted" section somewone will have one local. I have about 10 of them if you cant find a local. Let me know.

 

Yeah I did mod the plate to fit in.. maybe that can cause problems.

 

Something else I thought of I heard the magnets can be 1/2 deg off, could this cause my problem? Is there anywhere I can get a replacement rotor for the pertronix?

 

Its strange though, it does it every rotation like its a single cylinder that is off slightly.

 

I'm going to santa clara monthly tomorrow, I'll definitely ask around.

 

Thanks.

[banzai510(hainz)]

Something else I thought of I heard the magnets can be 1/2 deg off, could this cause my problem? Is there anywhere I can get a replacement rotor for the pertronix?

 

But you can dial it out using the timming plate

 

Its strange though, it does it every rotation like its a single cylinder that is off slightly. ????

 

yes you can get new magnets 17413 is the partnumber if I remeber right.

 

 

somoebody has a stack of dizzys. try that first but i think its carb.

[Stupid_fast]

Something else I thought of I heard the magnets can be 1/2 deg off, could this cause my problem? Is there anywhere I can get a replacement rotor for the pertronix?

 

But you can dial it out using the timming plate

 

Its strange though, it does it every rotation like its a single cylinder that is off slightly. ????

 

yes you can get new magnets 17413 is the partnumber if I remeber right.

 

 

somoebody has a stack of dizzys. try that first but i think its carb.

 

 

Yeah, if the pertronix or anything is positioned off it can be dialed out... I stuck some screws onto the magnet and looked like they where pretty straight 90* from eachother.

 

Yes, it does it every rotation ... if you listen to the exhaust can hear a slight consistant "pop"(not loud!) like its a harley... Like bad wires or spark .. or comp is off on a cyl(but i tested that).

 

Bad wires maybe?!

 

I'm not going to have more time to work on it until the weekend... I will dig into it more then.

 

The valves have always been noisy... I thought this was normal cause they where even when I adjusted them several times. I got the adjustments so they smoothly slide in the gap but not loosely. Maybe try to perfect it more? What could cause that?

 

 

KADET510 says he has a single point distributor, so I'll be able to pick one up in santa clara tomorrow.

 

 

At 11:28, verified... motor at TDC.

 

Pertronix install, I tired to make it more even against the magnet with a single screw to test, it made no difference in how it ran.

[banzai510(hainz)]

Pertronix install looks good.

Since you have a l16 dual point you better be using another l16 dizzy so the mount timming plate come out right unless the other dizzy comes as a set with mount and timming plate set up(L20 set up)

 

put to TDC and make sure rotor points to #1 or make it to #1.

 

Im thinking its carb. But you say it sounds like a single cylinder. But you cked the compression.

 

 

Icehouse had a buddy you had proplems and I looked at the car and adjust the carb best i could and said to him try another carb . he had 175 in 2 pistons and 2 with higher. I said well maybe they stuck flattops in 2 cyl. well just so happens later they find 2 of the lower had holes in the pistons so I was really off.

But Can I assume you cked this motor and assembled it?

 

170 sounds about right for a L20. Most L16 is about 140 I think.

 

If the car runs fine at the higher speeds on the hiway I think your ignition is most likely fine

[racerx]

When you adjusted the valves, you said it was loosely, it should have some drag to it..did you adjust cold or hot..hot I heard is better.

[Stupid_fast]

T-T-T-TRIPPLE POST!!!

 

 

@KEWL510, I have checked the timing... at TDC the cam/crank timing is correct.

 

The car runs fine at steady RPM, I cruised from long beach at 80MPH 4000RPM no problems!!

 

 

 

Pertronix install looks good.

Since you have a l16 dual point you better be using another l16 dizzy so the mount timming plate come out right unless the other dizzy comes as a set with mount and timming plate set up(L20 set up)

 

put to TDC and make sure rotor points to #1 or make it to #1.

 

Im thinking its carb. But you say it sounds like a single cylinder. But you cked the compression.

 

 

Icehouse had a buddy you had proplems and I looked at the car and adjust the carb best i could and said to him try another carb . he had 175 in 2 pistons and 2 with higher. I said well maybe they stuck flattops in 2 cyl. well just so happens later they find 2 of the lower had holes in the pistons so I was really off.

But Can I assume you cked this motor and assembled it?

 

170 sounds about right for a L20. Most L16 is about 140 I think.

 

If the car runs fine at the higher speeds on the hiway I think your ignition is most likely fine

Could not get the dizzy.. Got stuck in traffic didn't make it to the meet. :( I did not assemble this motor, the previous owner of the car bought it rebuilt and never dropped it in until he sold it to me.The furthest checking I've done is pulling out the plugs and making sure engine was TDC...I can pull off the head if I have to but rather not. 171 comp on L20b according to olddatsuns. It does it consistently... Same time difference between shakes of the motor. It is very slight but noticeable. Yeah... runs good at higher RPM and nice power 3500-4000. Up the grapevine from LA(mountain pass) doing 80mph uphill was no problem at no more than 1/2 throttle(32mm open).

When you adjusted the valves, you said it was loosely, it should have some drag to it..did you adjust cold or hot..hot I heard is better.

 

Eh? What part loosely? Which part should have drag to it? the feeler gauge? I adjusted it cold this time... Perfectly to cold specs.

 

I will warm it up tomorrow and adjust it hot, see if there is a difference.