Smoking on startup

[ElliotV]

1 hour ago, jakebson said:

I took the air cleaner housing back off and sprayed carb cleaner on all the linkages and worked them for awhile. Started it up and it was running well. I think the choke was stuck in the same position. I have cleaned the linkages recently and it was running fine so I am wondering if I may have had the vacuum line that is near the back of the carb hindering the linkage. After I buttoned everything back up it drove well on the highway and around town like it was before I messed with everything.

 

The last few days I have had this thing running at idle more than normal, but the mileage on the last tank was atrocious. 13 miles per gallon. This is the first time I have been able to calculate since the odometer quit working when I replaced the charge light bulb shortly after I got it.I had a feeling it was bad since I was filling up a lot. I mainly drive city miles with quite a bit of stop and go so I wasn't expecting great efficiency, but man that is brutal.

 

I am planning to do the valve lashes and valve seals soon when I can do them in a garage at a friends house, but besides that I feel like I am catching up on the maintenance. I read about adjusting the air/fuel ratio on here and I will work on that to see if it will help also. I am sure the carb is likely in need of a rebuild though.

That's very excessive fuel mileage. I'm assuming this is a 2wd truck? My 4x4 gets 18 avg maybe 60% highway. This is with the stock Hitachi running poorly..

[jakebson]

57 minutes ago, ElliotV said:

That's very excessive fuel mileage. I'm assuming this is a 2wd truck? My 4x4 gets 18 avg maybe 60% highway. This is with the stock Hitachi running poorly..

 

Yep, 2wd. Going to check it again on this tank after I have made some adjustments this morning. It is running really well right now. Smoother and quieter than it has been. Read several posts on here about adjusting the air/fuel mixture. Think I had it idling way too high beforehand also. Now the idle is slower (to the ear) but smoother. Hopefully I can just drive it for the next tank of gas and not have to do any work on it, that should help a little bit.

 

Here is a video of how it is sounding now here

Edited January 9, 2025 by jakebson

[datzenmike]

The Z24 carburetor idle mixture is set and sealed at the factory. You would have to remove the sealing plug to access the adjustment screw...

 

[datzenmike]

Poor MPG is likely the ECC feedback carb. It's designed to run extra rich if there is a failure in the system. This is because the running mixture is capable of a wide range of adjustment intended to be stochiometric but could go dangerously lean and damage an engine. It's assumed that the owner will notice the decrease in mileage and investigate. As you have just messed with the choke and said it may have been stuck, drive it some more and check MPG again.

[jakebson]

27 minutes ago, datzenmike said:

The Z24 carburetor idle mixture is set and sealed at the factory. You would have to remove the sealing plug to access the adjustment screw...

 

 

Yes, the plug was already removed so it has likely been adjusted by someone, at some point. I used the method that you had described in another thread about adjusting the throttle and the mixture screw to try and get the smoothest idle. I had previously not touched the idle mixture screw. I was if it was in the limp mode that runs rich that I have read about on here through searches. There are definitely several failure points that can cause issues on this setup.

[datzenmike]

Note that the engine must be thoroughly warmed up and the idle speed, eventually, around 700. Might not hurt to set the ignition timing.

[jakebson]

1 hour ago, datzenmike said:

Note that the engine must be thoroughly warmed up and the idle speed, eventually, around 700. Might not hurt to set the ignition timing.

 

Yes, I did it parked in the driveway after I had driven for around 30 minutes.

 

Is there a way to test the o2 senso, EGR and anything else that may be hindering the carb from functioning like it should?

 

Trying to borrow a timing light, if I can't that will be on my list of things to get. The ever growing list.

Edited January 9, 2025 by jakebson

[datzenmike]

It's a practice of removing symptoms. Drive it and see if mileage has increased first. Check that choke is on when cold and off when warmed up.

 

 

[jakebson]

[ElliotV]

57 minutes ago, jakebson said:

looks like someone is enjoying the snow. Was going to take mine out today but it decided to spring another cooling leak. I'm pretty sure mine is just afraid of the snow cause last year when it snowed it was so cold the gear oil in the trans turned into molasses haha. 

[jakebson]

1 hour ago, ElliotV said:

looks like someone is enjoying the snow. Was going to take mine out today but it decided to spring another cooling leak. I'm pretty sure mine is just afraid of the snow cause last year when it snowed it was so cold the gear oil in the trans turned into molasses haha. 

 

Ahh that's a bummer man. I had to put some cinder blocks in the back to add a little weight to drive it in the snow.

[ElliotV]

29 minutes ago, jakebson said:

 

Ahh that's a bummer man. I had to put some cinder blocks in the back to add a little weight to drive it in the snow.

yeah Im hoping I can fix it when I get off work tommorow if I can figure out where the damn leak is coming from. Ended up driving the 2wd manual dually to work and didn't have time to put any semi tires or railroad ties in the bed so it was fun driving to work and I found a couple empty lots when I got off. 

[Sephakrid]

On 1/9/2025 at 2:19 PM, jakebson said:

 

Yes, I did it parked in the driveway after I had driven for around 30 minutes.

 

Is there a way to test the o2 senso, EGR and anything else that may be hindering the carb from functioning like it should?

 

Trying to borrow a timing light, if I can't that will be on my list of things to get. The ever growing list.

If you get one, I'd highly suggest getting a "dial back" type that also displays RPM. They're a little more expensive but make setting idle and base timing super easy compared to my old basic light.

[adg]

Hi, I'm getting ready to do a head gasket on my 82' z22, since it blew I was thinking doin valve seals as well while I have it apart, I'm just curious what might be the best material for the head gasket and valve seals and whether or not it'd be good to take the timing cover off In the process as well just to maybe do that gasket too, I only have about 155000 miles on this truck so I'm not worried a whole lot about the major mechanical stuff more the seals and gaskets cause the truck sat for years. 

I'm also not too familiar with the timing setup on these and when to know it's on TDC cause of the 2 #1 plugs I just don't want to mess the timing up in the process of all this, thanks!

[NC85ST]

If the timing cover is not leaking, don’t mess with it if you don’t have to. You need to read up on replacing the head gasket if you’re not familiar with it. You may have to replace the timing cover gasket if the timing chain isn’t secured properly. As far as gaskets, Felpro works well. 

[ElliotV]

Top dead center is entirely based on the camshaft and pistons. The dual spark plugs has nothing to do with top dead center. TDC should be when the lobes are both not touch the rockers so I believe 8 and 4 o'clock. I highly recommend looking into making your own timing chain tool as none of the ones you can buy will fit. I actually made a post recently about doing mine if you look into my post history you should see it. Just take your time and do everything right like having the head decked and take very good care to clean out the bolt holes and the deck of the block. 

[datzenmike]

I never ever put weight in the back. Yes it helps on take off in snow and maybe climbing hills in a straight line, but that extra weight increases over steer and can mean the difference in stopping distance. Most of the time no problem but in an emergency and sliding, it all comes down to physics and inertia. Haven't you noticed getting stopped with a couple of fat chicks in the back takes longer?

[jakebson]

Glad someone replied to this thread, because I finally got around to replacing my valve seals. Took care of it last weekend and took me right around 2 hours. I used Fel Pro valve seals. I have driven it a little over a hundred miles since then and I am still getting a little bit of blue smoke on start up. It is less and going away quicker, but still there. I thought I got all of the seals seated well, but maybe not?

[datzenmike]

Push them all the way down the valve stem till they clip on the head. Oil them first? or grease so they don't start up dry.

 

Back in the '60s my slant six had 'umbrella style' seals. OK when new but age them and they split or harden and break apart. Pieces in the oil pan. Didn't have the spring around them either.

 

[jakebson]

7 minutes ago, datzenmike said:

Push them all the way down the valve stem till they clip on the head. Oil them first? or grease so they don't start up dry.

 

Back in the '60s my slant six had 'umbrella style' seals. OK when new but age them and they split or harden and break apart. Pieces in the oil pan. Didn't have the spring around them either.

 

 

Yes, I oiled them up. The old ones were definitely brittle and cracked as soon as I started to pull them off. I believe that all the new ones clipped onto the head.

[ElliotV]

1 hour ago, datzenmike said:

I never ever put weight in the back. Yes it helps on take off in snow and maybe climbing hills in a straight line, but that extra weight increases over steer and can mean the difference in stopping distance. Most of the time no problem but in an emergency and sliding, it all comes down to physics and inertia. Haven't you noticed getting stopped with a couple of fat chicks in the back takes longer?

I would argue its a matter of just the right amount of weight. If I can get enough traction to use all of my braking power then I would say that is the perfect amount of weight but if I were to say put my skid steer on my gooseneck with that truck then I definitly would have reduced stopping distance even with enough traction for full use of my brakes. No matter what during snow stuff has to be taken slower though especially around here due to black ice since our roads don't usually actually freeze before we get snow so it then melts and turns into ice. 

[datzenmike]

 Well when traction, say on ice or snow, and speed is the same, then inertial weight determines how far you slide. Agree that in bad conditions you go slower but what about something unexpected and not in your control? Say another oncoming vehicle spins out in front of you and you have to stop quickly. Faster than the room you allowed for on an empty road.  

 

I used to be pretty good at winter driving in Ontario, but now it's mostly PNW rain.

[ElliotV]

I would argue I am a pretty good driver but man some people around here shouldn't even have a license. I have never gotten in a accident yet but I have been close several times. 

[adg]

21 hours ago, ElliotV said:

Top dead center is entirely based on the camshaft and pistons. The dual spark plugs has nothing to do with top dead center. TDC should be when the lobes are both not touch the rockers so I believe 8 and 4 o'clock. I highly recommend looking into making your own timing chain tool as none of the ones you can buy will fit. I actually made a post recently about doing mine if you look into my post history you should see it. Just take your time and do everything right like having the head decked and take very good care to clean out the bolt holes and the deck of the block. 

I can't seem to find that post but I've had to make wedges before so hopefully I can get it, will wood work for that wedge? Is there any recommendations for shapin the wedge right? I'm not new to this stuff but I just want to make sure I'm the most informed I can be.

[ElliotV]

I made mine out of wood and used the blue one that pulls up for our trucks but doesn't reach deep enough and one for a l24 from zcars as a template.