Bent valve?

[Scrapson]

Yeah I know what your talking about I plugged it off with a cap but I can just switcch the cap to the intake spot and the hose to the carb

 

[banzai510(hainz)]

What?

this isn’t that hard

he has photos for you just plug it in to the distributor vacuum adv

Edited December 8, 2019 by banzai510(hainz)

[Scrapson]

No I understand it’s not difficult just I thought it’d have better vacuum in the manifold instead of off the carb but after being explained how it’s better off the carb I should just put it on the carb. 

[datzenmike]

At any RPM where full throttle is used the cylinder completely fills with gas and air mix. When compressed and lit it takes the same time to burn and the hot gasses expand. The ideal point is (give or take) about 15^o after TDC where it efficiently pushes down on the piston. Any later and the piston is accelerating away from the pressure, any sooner and the crank and rod are almost aligned vertically and can't be pushed down on effectively. As the engine speeds up, and as this burn time is set and can't be altered, the combustion must start sooner and sooner so that it arrives at the 15^o point. For this a mechanical advance is used which adds advance as the engine revs.

 

This is fine for full throttle but what about part throttle? Well, the combustion chamber is not filled and when compressed it burns slower. Think of the flame having to jump farther to each gas and air molecule than if they were tightly packed. Ignition needs to be advanced in relation to load or part throttle. Intake vacuum closely follows engine load being high at idle and dropping as the throttle is opened. At full throttle there is virtually no vacuum left and the vacuum canister is preset to only advance above 3-6 inches of vacuum. Until the mid/late '60 intake vacuum was used for vacuum advance. This is why you may read that it has to be disconnected to set the timing but later engines this is not mentioned. This is because the later vacuum advance is pulled from a port just above the throttle plate as mentioned before. Ported vacuum is only present above idle when the throttle plate rises up to and above the port. Effectively there is no vacuum advance at idle, and this was to effectively 'retard' the timing at idle and reduce emissions and nothing else. A retarded ignition at idle will run a hotter exhaust port and be rougher because much of the combustion energy is wasted. Next time you set your timing advance it to 14-16^o and it will rev up and smooth out because this is where it want's to be. Vacuum advance is purely for part throttle and more closely hits that 15^o sweet spot and vastly increases an engine's efficiency under part throttle conditions. 

 

Ported vacuum distributors are set up differently and running intake vacuum to them will advance them too much and they will ping at part throttle. If you retard your timing to reduce ping, your full throttle power will drop. To use intake vacuum the distributor must have a different vacuum advance canister that adds less advance

[banzai510(hainz)]

Scapsun

we are here to help but every time think your smarter than us on a simple 1960s technology motor let us know but it isn’t working for you.

Thia should have been fixed by page .

If Nissan wanted on the manifold it would have done it already

[banzai510(hainz)]

2days no hear.No update:

 

you must have took my advice and sold the truck

[Scrapson]

No not yet I’ve been busy with school shit since I’m failing algebra 2. So I need to hook it to the spot on the carb and then fix my manifold thing since the block plate is warped. 

[wayno]

Yes, put the vacuum advance line on the proper fitting on the carb, and fix any vacuum leaks the intake manifold my have.

[banzai510(hainz)]

Yea the EGR plate needs to be made

[Scrapson]

I’m gonna pull off the intake and double check there’s nothing else I missed and then just take the intake in and have someone maybe weld it. I’m gonna have someone use the CNC machine to cut one at school tomorrow. 

[datzenmike]

Weld what! The EGR??? If you weld the hole closed you won't need a block off plate!!!!

 

It's aluminum.... you'll need to have it TIG welded. What about the PCV valve???

 

I filled mine with JB weld years ago....

 

This...

 

to this...

 

 

This is the same '79 intake manifold but looks like the earlier L16 and I kept the PCV

[Scrapson]

Yeah that’s what I need to block I should’ve said a little more detail. JB weld? I was looking at the bottom one online to buy so I could use it instead of my stock one. 

[datzenmike]

Removing the EGR manifold is trouble. The block off plates look as bad as what they replace and many don't provide for the PCV valve, you have to keep that.

[Scrapson]

What do you mean by the PVC valve? Which hole is supposed to be?

[wayno]

See the thing fitting to the right of the fitting in in the center of Mikes photo, that is the PCV, that has a hose that goes to the crank case vent on the side of the block, the vent on the valve cover goes to the air filter housing, you need both of these to have everything work properly, the PCV helps keep the oil clean longer, it also helps keep the inside of the block clean.

 

[datzenmike]

Hell, if you have the old EGR manifold that bolts to the intake, put it back on. It won't work unless the hoses are connected. Quick way to solve this and get back to getting this on the road.

[Scrapson]

There wasn’t a hose from the crank case vent it’s always just been bent pipe that went next to the firewall. There wasn’t a hose off of it. I have old EGR thing I gotta cut off the loop thing that went onto the exhuast pinch it shut and sauter it but it should work. There’s also no hose that went to the carb from the valve cover never was when I bought it I just bought a breather filter for it and put it on there. 

Edited December 11, 2019 by Scrapson

[Scrapson]

Don’t mind the return spring it has to be replaced it’s too big for the new carb just temporary. 
https://drive.google.com/file/d/1Alpd9qAoGrzD5ue_dKlqS_X-SJiVmfme/view?usp=drivesdk

[datzenmike]

20 minutes ago, Scrapson said:

There wasn’t a hose from the crank case vent it’s always just been bent pipe that went next to the firewall. There wasn’t a hose off of it. I have old EGR thing I gotta cut off the loop thing that went onto the exhuast pinch it shut and sauter it but it should work. There’s also no hose that went to the carb from the valve cover never was when I bought it I just bought a breather filter for it and put it on there. 

 

You only need to close off the exhaust manifold end so no noise or exhaust leak into engine compartment. The intake end doesn't matter as I expect you wouldn't be using it. Just unscrew or cut off and leave it. 

 

Try to connect a hose from the block vent tube to the PCV valve. That will get it working. The block vent tube is larger than the PCV end so slide a smaller hose from the PCV into a larger hose from the block vent tube. 

[Scrapson]

Alright I’ll do that and pinch off the EGR shit or unbolt it from the thing. Hook up the PCV To the intake. 

[Stoffregen Motorsports]

Fuck the manifold. Go study so you don't fail out of school.

 

[Scrapson]

I appreciate the fatherly "fuck the manifold" comment. I did wonder is it important for me to hookup the PCV from the block for it to run correctly or no? It wasnt hooked up when I pulled it apart so I assumed it was just a random little breather like on the valve cover just wanted to put a breather filter on it for shits and gigs but Is it necessary. This single thing could've been like 8 different topics.

[Crashtd420]

PVC valve just helps keep the oil cleaner...

Best to hook it up if you can....

 

You can put a breather on the valve cover and the block vent but the intake itself should be sealed up if you do....

 

[wayno]

It's not necessary to have a working PCV system, but it is preferred, your not old enough to remember what the roads looked like when engines had no PCV valves but I am, the center of the road lanes were black and engine compartments were filthy dirty as the valve cover or somewhere on the block had a tube that vented towards the road, oil was spit out that tube onto the road, that makes the road slippery when it rains and that likely was the cause of a lot of wrecks way back then because one could not stop in time on them slippery roads, you can see evidence of oil on the road even today when your making a left hand turn just after a rain in an intersection and you give it the gas to make the left turn and instead of moving you start spinning out, but once it rains enough most the oil gets washed off the road and it not near as bad anymore.

I remember them lines being solid black.

 

Basically I would say if you have the hole for the PCV valve then use it, the block off plate could be drilled and threaded for the PCV valve, but you already likely have the hole in the manifold.

[Scrapson]

https://drive.google.com/file/d/1i34cxnIB_o-V_JGtV6TkCLOrCB1zV5z_/view?usp=drivesdk

I found the hookup for the PCV but the hose is clapped as hell but do I have to block the bottom port since exhuast went in the through the coiled thing. I assume the top one aswell and the side and stuff have to be capped?