Fellow members

I have an issue with my 200B the plugs keep fouling and keeps breaking down. L20B, standard cam, 40mm side draft Weber, extractors. New rings, bearings, head refaced, compression is good. After reading the post from UTEBOY (L20B Rebuild Q) I have checked and replaced everything I can think of and I'm ready to set a match to it. If anyone has any Ideas to save my sanity you can have my first born...he's a bit old but house broken.

Thanks

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1980 Datsun 200B, Daily driver.

Did you just rebuild the engine?
Was it running ok before the rebuild?
Twins or single score?, and did you have the carbs running well before or are the carbs a new addition?
Are they jetted right? And have you tuned the idle mixture screws?

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When the sign says "don't feed the bears", man you better not feed the bears.

Jetting all wrong, running way to rich.

Plugs to cold , are they 6s or 7s. ????

Sorry fellas been away all week
Nad015
Yes it has just been rebuilt.
No it was doing the same thing prior to the change.
I had the standard carb on with the same issue.
Jetting is unknown and the mixture is a 1/4 turn out and idles.

Bluebird68
With the old carby and the motor doing the same thing i dont think jetting is an issue unless i need to down jet.
Plugs PB6ES and I tried BP5ES

I even changed out the dizzy, its got me stumped I might have to save some cash and call some one to have a look. Call out fees are a bitch.

Thanks for the help

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1980 Datsun 200B, Daily driver.

I bet this is a simple EZ fix. I think I seen on Natgeo Bushmen GoatHearders in Africa get these old L motors going.
Now if plugs are really really black then its a float issue/needle valve or maybe you have a electric fuel pump that's pushing to much gas(need a regulator) if you don't have a return line.

I was running a 38/38DGEV (from a LandCruiser FJ40 jetted)on a L16 it was so black that even inside the manifold was getting black, But still would run like a Raped Ape. Carb went bad and I went back to a 32/36 as a daily driver.

usually after a rebuild I use the same carb/ distributor ect.. to eliminate any induced proplems. A down draft carb is ez to get the mixture correct and start driving till motor is broke in.

I run 5 6 7 NGK plugs and don't really know a difference on my daily drivers. 510/ 521 truck


I will assume the motor is timed. cam timming then the distributor is in the middle of the timming rande and set to say 10. but you have the ability to get down to 0-25deg. this shows you installed the distribut correct. if dist is cranked to one side to run most likely your off when you installed it.

if a different type of Coil was installed you have to tell us. a Point coil(still running points with a ballast resisitor) or a EI type.

if sidedraft cheak to see if the jetblocks don't back out. My 40mm Mikunis do this all the time. It will load up


Hailmary but recheack the valve lash

Cam timing is correct and I'm still running points with a ballast resistor, which is new. The electrics are the same as prior to the refit. It has to be simple enough, just cant put a greasy finger on it.

Will take the Weber of and start from scratch again with the standard carb and manifold. I will look at getting a fuel pressure gauge to check the pressure. Maybe strip the Weber and check the jetting. A regulator may be in order - anyone know the pressure for a 40mm DCOE Weber?

I'll keep posting, but will have to wait till next week end.

Cheers

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1980 Datsun 200B, Daily driver.

A regulator may be in order - anyone know the pressure for a 40mm DCOE Weber?

Very low, 3 or maybe 4 psi.

Check valve clearances. Also what fuel are you running? I've fouled plugs before when running sh*t fuel. How does it run straight after you clean the plugs?

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Chris Thomas

1971 1600, mild L18, 5 speed

All I want is less to do, more time to do it and higher pay for not getting it done.

I assume your recharging fine.

I run the stock koyosan fuel pumps on 2 of my Datsun and never had a proplem with weber downdrafts and Mikunis sidedrafts stock pumps are under 4 pounds I believe.


let us know what you find.

Ok so I removed the fuel tank, and emptied it. Got some 98 octane and cleaned the plugs. Have good fuel pressure. Cleaned the old carby and manifold replaced the gaskets. I have been for a couple of short runs with better results. Its idling ok and runs but still breaks down at low revs but not as bad. The plugs haven't fouled as yet. I have to head to Bris vegas tonight so I'm going to give it a good run and see what happens.

Going to have the webber looked at. get the jets checked.

Going to get a sparky to check the electrics just in case.

Other than that I'm out of ideas. If any one else comes up with something I'd be glad to here it.

and I'll be back again next week end......never say die

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1980 Datsun 200B, Daily driver.

Im just guessing here now.

is this a crossover Lynx manifold? these are the best for a single 40mm

I assume you have new spark plug wires?

I really cant see why dropping the tank would change anything.

fuel float is not set right and loading up .

recheck the jet block if backed out

Hey guys,

So, I had someone look at the wiring and got that sorted, had a wire out of place on the coil, fixed.

Checked all the timing, plugs, leads and everything else, runs but still flat spots at low revs. At this stage only no3 is fouling but not as bad.

So Im of to the carby shop to get the carby looked at. The car is drive able and on the hwy cruises along. So I'll see what happens.

Thanks for all the help. If I get a result I'll post it up. cheers.

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1980 Datsun 200B, Daily driver.

# 3 see have tight valve lash maybe a ring or a valve is starting a crack or seat comming loose.

cant be carb as if would after another cylinder.

The rings are new so I would hope there OK. I'll check the compression again and when I had the head off I pulled the valves out and there were no visible cracks. The valve guides have been replaced and I'll recheck the Valve springs as well.

No retreat ...No surrender

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1980 Datsun 200B, Daily driver.