Engine problems

[zimm]

I have a 1976 Datsun king cab my truck started missing  i rebuild it about a year-and-a-half ago I put new plugs new Coil new  distributor.cant figure out what is going on with the engine now it seems like it's out of time but I tore it down and all the timing marks are lined up has anyone have any ideas what the problem might be I would appreciate some info thanks and have a blessed day

[datzenmike]

If it runs but has a (seemingly) random miss then it won't be the coil because it obviously is working. 

 

I hope you kept the old parts because this didn't fix it, so they were not the cause. Old stock parts are usually better than the parts that replace them.

 

 

Is this miss at idle only? Could be a lean mixture miss. Try turning the idle mix screw out 1/4 or 1/2 a turn to richen it up.

 

Has the valve lash been checked lately? A tight valve can cause a random miss. If an exhaust valve and not fixed an allowed to continue it can end up burnt. Lash is 0.010" intake and 0.012" exhaust, set while the engine is hot.

 

The points should be set while on the high part of the distributor can lobe and should be 0.020" give or take a couple of thousandths either way. If too tight the timing will be advanced, if too wide it will be retarded.

 

Ignition timing should be 12⁰ before TDC

 

 

[zimm]

Thanks for the info i pulled the old distributor out and put a new one in the same way the old one came out but when I tried to get it to run it back fired I thought I got it out of time so I took it apart to check the timing and every thing seems to be in order just wondering what I should do next

[datzenmike]

I don't think it's possible to exactly swap a distributor and keep the timing correct. Get a timing light and set the timing.

[zimm]

The only thing I can't even get it to run sent I changed the distributor.really don't know what happened could it be in the wiring. I really appreciate you trying to help me.... 

[datzenmike]

The distributor has an adjustment for setting the timing. It can be twisted clockwise or counter clockwise. Even if it doesn't start, the timing can be set close.

 

I would but the old one back in and try it.

[wayno]

Since you replaced the distributor I expect you changed the dist cap also, are you sure you got the firing order correct, 1, 3, 4, 2 counter clockwise, also when you put the distributor in was the rotor pointed the same direction, you need to put it at TDC with the cam lobes on number one cylinder pointed approximately 10am and 2pm, but it might be closer to 11am and 3pm, that will be the TDC you want, what ever post the rotor is pointed at on the distributor cap is where number one plug wire goes, again 1, 3, 4, 2 counter clock wise.

Edited September 3, 2019 by wayno

[zimm]

Okie dokie thanks will check tomorrow 😊 I would put the old distributor back but they took it for a core .

[banzai510(hainz)]

cheack the valve lash or for a Lash cap to fall out above the valve.

 

line the dist back up and use the correct coil with the distributor. ex.. EI with EI coil. If point dist use a ballast and point coil.

[zimm]

On 9/2/2019 at 10:20 PM, wayno said:

Since you replaced the distributor I expect you changed the dist cap also, are you sure you got the firing order correct, 1, 3, 4, 2 counter clockwise, also when you put the distributor in was the rotor pointed the same direction, you need to put it at TDC with the cam lobes on number one cylinder pointed approximately 10am and 2pm, but it might be closer to 11am and 3pm, that will be the TDC you want, what ever post the rotor is pointed at on the distributor cap is where number one plug wire goes, again 1, 3, 4, 2 counter clock wise.

I have a question about the distributor I have all the marks lined up on the crank and the cam and the oil pump  have It at top Dead center i know the little inn of the oil pump shaft has to go to the front but can't get the distributor on number one Piston the distribute  will only go one way have any ideas on what I am doing wrong.

[banzai510(hainz)]

look into the dist hole from the top. If the spindal looks like its in the 11.28 position that should be correct. then instgall the dist till it locks down and that should be close enough to start the truck given with in the timming slot on the dist.  Now unless you got mismatched parts then it may be off and you have to move the spindal to get it right.  start at about 11min into the video

 

 

[wayno]

If you cannot get the rotor to point directly at one of the spark plug wire posts on the distributor then something is not put together correctly.

It needs to be at TDC with the cam lobes on number one cylinder close to 10am and 2pm, when you drop the distributor in the rotor should be pointing towards either the driver side hood hinge or the upper radiator hose connection, if it is pointed anywhere else something is not likely put together correctly.

 

I had something weird happen a while back, I use "regular" pump gas in my 521 work truck, the damned thing knocked something awful unless I had it timed at 0 degrees(TDC), I had a matchbox distributor in it, I had another matchbox distributor I was not using so I tore it part and welded up one of the oblong holes that the weights move in 1/16th inch to stop it from advancing so far, it worked great as I now have it timed at 8 degrees BTDC, it's like a different engine, anyway when I put the modified distributor in the engine it would not run, what happened was either I put the distributor back together 180 out or not all matchbox distributors are the same.

 

Will your engine start, or after you start it it sounds weird?

 

[Stoffregen Motorsports]

When faced with any amount of unknowns, I always try to get back to a known value before proceeding. Is the TDC pointer accurate? Start there and work forward.

[zimm]

Don't know what else to do to my Datsun 620  put new voltage regulator new fuel pump new wiring harness new distributor got it back in time it run great for about a week then it started missing again it has a whining in the engine could anybody give me any ideas what to do

[datzenmike]

What was the reason for the new regulator and fuel pump????? Often replacements are much worse than the originals and sometimes even bad in the box. Did you keep the originals?

[zimm]

There something going on in the engine thought it was not getting in fuel

[banzai510(hainz)]

so it’s been running last few days since this is a old post.

You check the valve lash?

new fuel filter?

 

im not getting why you keep swapping parts in here.

if you cycle the carb you see gas squirting in then the fuel pump is good

A point coil needs the stock point type and the ballast otherwise points will burn up 

 

I say check the valve lash

 

what does it mean you got new wiring harness? whole truck?

Edited November 16, 2019 by banzai510(hainz)

[datzenmike]

YOU know what YOU mean but you have to be CLEAR when describing what you have and what you've done.

 

If you changed to another distributor and it wouldn't run, seems to me you should put your old distributor back in. Oh, you exchanged it for the new one?

 

Changed the wiring harness????? Do you mean new spark plug wires??? this a perfect example of lack of clarity.

 

It was suggested the valve lash be checked and adjusted.... you never confirmed this. One at a time things need to be eliminated. Replacing the fuel pump and distributor is the worst way to try to fix a running problem... it's expensive, it's like trying to win the lottery and you never know it you are putting a bad part in which compounds the original problem which may turn out to be a simple adjustment.

[Stoffregen Motorsports]

1 hour ago, datzenmike said:

 One at a time things need to be eliminated. Replacing the fuel pump and distributor is the worst way to try to fix a running problem... it's expensive, it's like trying to win the lottery and you never know it you are putting a bad part in which compounds the original problem which may turn out to be a simple adjustment.

It's like me trying to teach my kids that exhausting your resources is the only way to fix a problem with their PS4 or laptop. Don't just push a bunch of buttons and expect it to work. And my son tells me this morning that he always skips the updates, which is why we're now waiting 4.5 hours to let it update.

 

Go through the steps. Listen to advice. Report back in clear engrish.