Problem with Compression or Timing on High Compression L20b causing pinging

[toylet]

Go on ebay and buy a wide band o2 sensor with gauge. Than tune your carb off the wideband. Its way easy to do

[datzenmike]

Side drafts... It won't pinpoint which cylinder or which carb though. It will just say rich or lean. You could look at the plugs for that.

[DISLEXICDIME]

You could get a gunson color tune and a wide band

[510SSS]

Ya that's prolly a good idea, I think I will get an o2 sensor wideband, I just welded in a bung to my exhaust, so it should make it easier to get some good readings, ill post it up once I get the proper tuning setup going. Thanks for everything you guys, I am going to make this run properly no matter what.

[docbainey]

If you really want to know what's going on in each jug, and since your running side drafts, get  EGT probes. You can tune each cylinder optimally individually.

 

Pegasus Racing can fix you up.

[datzenmike]

We may run out of bandwidth :lol:

[510SSS]

Oh sweet man, ya I have dealt with Pegasus before, they seem too be a lot more reputable then what i hear from Wolf Creek, I asked Futofab if they would go through them since they took over the assets of the company and they said that they would not cover it :ninja: even though it should have been under warranty, lame. Wish I had bought my carbs from Pegasus lol.

[510SSS]

Btw, how does the EGT probe work exactly? Seems cheaper than the wideband, but the one's I am seeing appear to need to insert into the header? Are their different types of EGT probes? Those are the only one's im seeing on Pegasus.

[Stoffregen Motorsports]

There are different types of probes, but they all poke into the exhaust header. Some have weld in threaded bungs, others use a hose clamp. For a street driven car, use the ones with threaded bungs.

 

There is no wiring though. The probes use capillary tubes, like on a mechanical water temp gauge. They can't be cut to length and they are a bit on the fragile side. If you bend them too much or too sharply, they will break.

[datzenmike]

Couple of pages ago it was a 're-curved distributor' now EGT probes.

 

 

If you want to narrow it down you will need one for every cylinder or run it separately on each one at a time. But so what??? At best it will say something is wrong... you already know that!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
This isn't fixing anything. Take the carbs off if you think that's it and look for something obvious. Go online or get a book on them and go through it. Learn something about them. Maybe wrong jets or mixed up or plugged air bleeds or emulsion tubes.
 

Two pages ago...

 

A picture might show a plug wire off  :lol:  or something not mentioned or seen by you that could be the problem.
 
You say pre ignition problem, so we have to take your word that this is your problem. I take into account that you or your mechanic could be mistaken and carefully ask other questions and read all replies for clues. We're on page 7!!!!!!!! and no closer really. Diagnosing means eliminating causes of illness or problems and moving on to the next. Go back and look up all questions and offered suggestions and put an answer after them. If nothing, say nothing was done so there are no assumptions. Elimination is the name of the game.
 
Borrow an E12-80 module. The improvement will be immediate or not at all.
 
Valve lash? Tight intake valve???

 
 

22100-????? is all I need for ID what the distributor was off of originally, but it's an L20B dizzy if it has the matchbox. It will run. The module is another story. There were two numbers. You need E12-80.

[Stoffregen Motorsports]

Right.

 

Find a problem. Fix it. Repeat.

[john510]

Im starting to think this guy is trolling.All the advice that's been given and no evidence he took any of it.

[510SSS]

Hey guys not trolling like some people who posted in my thread, just trying to fix an automobile and trying to learn. So my friend who has raced Datto's for year's was able to look at the carbs with me and open them up, after checking inside we were able to discover that the main jets on both the 3rd and 4th cylinder had almost completely backed this was causing the pinging so we used loctite to keep them in place, on top of that the needle valves turned out to be 2 sizes too large on both carbs causing the misfire and the constantly dropping cylinders because of rich condition and fuel flooding and washing down the cylinders, now that I leaned it up a bit it has gained a ton of power and the pinging has disappeared completely, thanks everyone for their help, finally diagnosed the problem, just have to rebuild my alternator now, because one of my diodes went out and I'll be back on the road, great thanks really to Ratsun, without you guy's I wouldn't have been able to eventually realize that it was the jetting and needle valves in the Carbs the whole time. :thumbup:

[Stoffregen Motorsports]

Awesome. Glad to hear that you're out having fun with it.

 

One thing though, did you say you loctited the jets?

[racerx]

go back to thread where Doc510 said not to use Loctite.

[510SSS]

Oh whoops I will tell my mechanic not to use Loctite, but to use fishing line instead, any reason not to use the Loctite will it clog up the carb or something?

[Stoffregen Motorsports]

Besides the possibility that you'd never get the jets out, there's the probability that if you did, the bits of loctite that fall off whenever it's broken free, would fall into the carb and make quite a mess. A mess that would have to be cleaned before the car could be run again.

[john510]

Theres also the possibility that gasoline will melt monofilament fishing line which is made of nylon.

[datzenmike]

Gas does not affect nylon.

[KoHeartsGPA]

This thread lacks pics BIGTIME

[john510]

Gas does not affect nylon.

You are correct.I put a piece of fishing line in some gas last night,its still fishing line this morning.

[datzenmike]

Im starting to think this guy is trolling.All the advice that's been given and no evidence he took any of it.

 

Endgame.