Engine knock. Valves?

[motavated]

My truck ALWAYS has been making this clanking noise from the engine. From any rebuild and or motor. When I ROmp on it it clanks after a while. And it really clanks when going up a hill. I cant figure it out? Leaning out???? I placed the distributor at 8 degs and adjusted the valves. IT HELPED ALOT! But you can still hear it faintly and Greatly on the hills. I just want to smash on my engine with out worries...

 

L20b, weber 32/36, no smog crap, peanut head, dizzy...

 

Any one have the correct jet setting for a l20b with a weber 32/36 ?

 

Any one knows who can tune it for me in the LA area???

 

It sounds like this...

http://www.youtube.com/watch?v=Due7mkTHMlw&feature=related

[elmerfudpucker]

what octane are you using?

[motavated]

91

[hessianben]

does it sound like that vid clip? that 'bb's in a soda can sound?

if youre running a different timing pointer on the front cover.... with a different pulley...

maybe your getting a timing reading that's not accurate?

what happens when you back it down to zero? does it bog?

[datzenmike]

A rocker arm or any valve component doesn't change clearance because you are climbing a hill. If it is loose it will clack all the time.

[motavated]

does it sound like that vid clip? that 'bb's in a soda can sound?

if youre running a different timing pointer on the front cover.... with a different pulley...

maybe your getting a timing reading that's not accurate?

what happens when you back it down to zero? does it bog?

 

Yes, they are missed matched. I want to go to the yard and look for a l20b and take them off...

[hessianben]

I might have another timing cover in the garage here with a different style of timing arrow... I"ll look

what's yours look like?

[motavated]

from zero to 20 with teeth. If you have that. Then i will go look for the pulley then. Thanks!

[motavated]

My guess is this fucken carb. I know how to weld aluminum now..... HRH, efi conversion time.

 

I will also buy a new distributor vacuum advance..

[datzenmike]

Take the vacuum hose off the carb and suck on the end while looking at the dizzy with the cap off. The 'breaker plate' will turn. Hold the vacuum with your tongue over end of pipe. Vacuum advance unit should hold vacuum and plate not move until you release it.

 

Be sure vacuum advance tube is connected to a ported outlet on the carb. There should be NO vacuum at idle... there should be NO vacuum advance at idle. This is the way it was designed to work. If the vacuum advance is drawing manifold vacuum it will be on all the time and you will have trouble with idle/timing and getting full advance when revved up.

[motavated]

I checked the compression...

 

piston psi

#1 185

#2 190

#3 190

#4 185

 

 

That is why it is knocking BAD! Before my compression was at 160-150 psi So my engine didn't give a damn from the lack of gas. So it knocked less... But now it is knocking realllly bad. At least my gasket is still good...

[motavated]

Take the vacuum hose off the carb and suck on the end while looking at the dizzy with the cap off. The 'breaker plate' will turn. Hold the vacuum with your tongue over end of pipe. Vacuum advance unit should hold vacuum and plate not move until you release it.

 

Be sure vacuum advance tube is connected to a ported outlet on the carb. There should be NO vacuum at idle... there should be NO vacuum advance at idle. This is the way it was designed to work. If the vacuum advance is drawing manifold vacuum it will be on all the time and you will have trouble with idle/timing and getting full advance when revved up.

 

 

At times I would dial it in perfect! 12 degs... The drive it around and it would let it idle and then I would check the advance... It would be to HIGH or to LOW!!!! That is why I am thinking my vacuum is acting funky...

[mike]

When you adjust the idle air on your weber does the motor change RPMs and or smooth out? If not, check for a vacuum leak (carb spray around base, vac lines and linkage, change in RPM = vac leak)

 

If you have a leak around the base because of imperfections in either the manifold or carb run two gaskets on there. Sometimes thick paper (like a mac and cheese box) will work better than gasket material, double them up and get it wet first before you put it on, it will help it to conform better. ...Check your intake/exhaust manifold bolts too.

 

Ive also had shit partially block the primary on a weber... it would idle fine but it had a weird intermittent stumble and would lean out up top... Cleaned the piss out of it with carb cleaner and compressed air and it was good to go.

 

...I just read your last post, try disconnecting your vacuum and plugging the port on your carb, manually advance/adjust your timing and see if you still get detonation under hard acceleration under load.

[banzai510(hainz)]

a CLANK is different than detonation.

 

try soem high octane gas or race gas and see if it goes away after adj the timming.

 

I would have a clank when I turned left. it was a loose alternator mount!!!!!!!!!!

 

ck the dist if its really loose shaft. just cause timming errors or ck the vacuum adv plate for titeness

 

loose trans bolts/plate ect carrier bearing? owered to much causing a bind

[motavated]

I cleaned it once before. I still did it. I will buy some bigger jets just to be in the safe side and clean it. I had it idling in 500rpm. It would not stumble or die. But in cold weather is really hard to deal with it so its idling now at 650rpm. I don't think I have a leak really. I will by a new vacuum too and see what happens.

 

So clean/remove carb

new vaccum

and new bigger jets

 

that is my goal right now...

[motavated]

How do you check the vacuum advance plate? Just bolt down the bolts?

[banzai510(hainz)]

just make sure the dist plate has tention on there. No loose wiggle or anything. the shaft and the plate. should feel soemwhat solid.

 

I think your idle is alright maybe turn it up to 700-900

 

idle jet is between 50,55 60 should be fine.

 

maybe your senconday is on the weak side but I never fuck with those weber DGVs I just run them and seem to be fine.

 

dont use Arco gas

 

 

Does the motor has Run ON issues? If not then i would lean towards a lean condition or maybe swap out to another distributor since there are EZ to change. just put on TDC and assign the plug wires.

 

My 521 was cutting out on higher RPM when I raced a OLD MAN in Chevy luv. He beat me. I couldnt believe it. So I know soemthing was wrong. I pull the dizzy cap and shaft was loose. I have a Pertronix thingking this shouldnt matter as it dont knows its loose. But it did. I replace the dizzy and swaped ove the Pertronix and was like a new motor again. Wheres That old man now??It too late he bragging a whopped ass my Datsun so he thinks hes the big Pimp of the neihboorhood now

[Buzzbomb]

If your timing mark is moving around at idle, I'd bet Datzenmike is right. You might have the advance hooked to manifold vacuum. You might also have some crusty or weak advance springs that are not putting enough tension on the advance weights so the timing drops back to normal after they "fan out" at higher RPM's. I've had this problem on my Chevy. This is a total timing problem- initial + mechanical advance in distributor = total timing. Add in vacuum advance, and you could be getting too much timing along with the pinging that comes with it.

 

I'm not sure what is going on with the engine in that video. If you look real closely, you can see a puff of smoke right when that noise starts- like at 3 seconds. I don't think he has pinging, I think he has other issues.

[banzai510(hainz)]

You might have the advance hooked to manifold vacuum.

 

 

I hate when people do that!!!!!!!!!!!!!!!

 

spend 3 days trouble shooting then find out its this.

 

 

I had a guy same thing(fixing from the phone). he went and swap out a timming chain before I got involved and still car was running bad. then find out when he sent a photo to me the vaccuum hose was on manifold instead of carb.

[motavated]

The vaccum is connected to carb. I have a dizzy and it has not much play I think. If it did it would be hitting the metal tabs and stuff? But it looks good... I do use arco gas and shit. Maybe its watered down 91? LOL! So yeah... my truck is just sitting there until I get the supplies and time to work on it again. :P

[boxboy]

Just watched the vid. When I heard the noise, seemed to me that a puff of air came out of the #3 spark plug. I know little, but just an observation.

[elmerfudpucker]

Just watched the vid. When I heard the noise, seemed to me that a puff of air came out of the #3 spark plug. I know little, but just an observation.

 

 

Or an leak off the snail itself... :unsure:

[Buzzbomb]

You might have the advance hooked to manifold vacuum.

 

 

I hate when people do that!!!!!!!!!!!!!!!

 

spend 3 days trouble shooting then find out its this.

 

 

I had a guy same thing(fixing from the phone). he went and swap out a timming chain before I got involved and still car was running bad. then find out when he sent a photo to me the vaccuum hose was on manifold instead of carb.

 

I know it..I've done it in the past and it caused me some real issues :D. One of the best things I purchased for messing with cars is a vacuum gauge. It is foolproof to verify manifold or ported with that...I like the brainless no questions ways of checking stuff!

 

Which leads me to ask the OP, do you have a vacuum gauge? You CAN have manifold vacuum from the carb, not just from the manifold. You say vacuum connected to "carb". There are ports on your carb that are more than likely manifold vacuum. If you have a vacuum gauge, test it. Put the gauge on the port you are using. Vacuum at idle? You're using manifold vacuum. No? It's on ported, which with our cars is probably where it needs to be. If you have a car, and you work on that car, invest a few bucks in a vacuum gauge. It is REALLY worth it..Otherwise a general rule of thumb is posrt above throttle blades = ported, port located below throttle blades = manifold vacuum.