1977 zcar L28 6 cylinder low power, smoking

[datzenmike]

You don't need to remove the cam for this. Remove the mouse trap springs. Slip a large screwdriver diagonally under the cam and over the valve spring beside the rocker arm, being careful not to pry against the cam lobe. Pry down, compressing the valve spring enough to slip the rocker off the pivot ball on the other side and remove it.

 

Keep the rockers in order so they go back in the same place

[4zcar crazy]

ahh.  That sounds like something we can do with a little practice.  And I like not having to remove the cam.  I assume I still have to support the valves?  Thanks.

[datzenmike]

Yeah I use nylon rope with a big knot in the end so there's no chance of it falling in. Use the crank pulley bolt to rotate the engine over.

[4zcar crazy]

For the first time since starting to help kid on this project 9+ months ago (off and on), I feel like this motor, electrical, fuel, etc will work.  There have been many hurdles not mentioned.  It finally ran pretty good yesterday, and while it still smokes (even a small amount at idle), it seems to be much less and maybe tolerable until we can start the valve seal project (thanks a ton for the advice on it) and exhaust leak (exhaust manifold bolt broken).  I am going to pretend that the adjustments suggested and the lucas/? miracle oil/gas additives helped LOL.

 

 

We will continue to try driving often rather than letting it sit until it is licensed to be on the road.  We drive it on our little country gravel road now.  

 

It has more power than ever and stays running.....yeahhhhhhh!   Now we can get back to the other suggestions on some fine tuning too.  And go over brakes and coolant again to finish.  Thanks so much everyone.  

[4zcar crazy]

As for the 1/4" nylon rope into each cylinder.  I do this at top dead center for each cylinder and I stuff the rope in until it's tight and cannot get anymore in?  

 

Then pull it out and move to next cylinder?

 

I can totally see the reason for the big knot.  So you basically do one cylinder at a time remove old seal, replace with new one, put springs rockers and etc back together?

 

Oh! the cold start valve must be working correctly because if i unplug it, it is hard to start especially when the motor is cold.  

 

I also picked up some NGK BP7ES plugs when it was having the rich running problems.  I have BP6ES in the motor now.  I will try them after driving it more and getting the motor cleaned out some.   Sound ok?    

[datzenmike]

The knot is so the end can't fall inside. I stuff several feet of rope in and turn the motor by hand toward TDC until tight. Do NOT use the starter motor. Replace seals, back the motor up and retrieve rope.

[4zcar crazy]

Thanks.  I start putting the rope in just a tiny bit before TDC and then fill cylinder as much as I can with the rope.  Then turn the motor by hand to tighten the rope in the cylinder so the valves are tight.  That makes sense.  We can do that.

 

By the way, we have driven it a few more times for 15 to 25 minutes at a time.  The motor is definitely not smoking as much.  It looks much better.  Still smokes but in a tolerable range now.  So, hopefully replacing the valve seals will help more.  Sounds like an interesting repair.

[4zcar crazy]

Hi again.  

 

Another strange problem while driving the car.... the rpms go up to about 3000 and idle stays there until the car is slowed to about 5 mph or so.  Its not the accelerator as far as we can tell.  Putting the brake on or the E brake does not change the problem.  Once we slow down to about 5 mph or so, the idle drops from 3000 to 1000.  Its really weird.   ANY help on that one.

 

 

The car seems to be running well.  I still need to make the idle or mixture spring adjustments and a few other fine tune items.  But, we did adjust all valves and bumped the spark plugs up from a  6 to a 7.  That seemed to help the motor b more responsive (quicker under acceleration) and seemed to have a little bit better power (not much).  It is running well. 

 

Still have to replace the valve seals.  Will try that as soon as we can. 

 

Seems to be tolerable on the smoke, much better than after we first got it running (and after the fuel pressure fix).

 

[TFM1066]

check for any devise on the throttle linkage that could raise the idle "IE" A/C idle solinod etc, more throttle return spring?

[4zcar crazy]

I sat on the car fender with hood open while someone drove (slowly).  Once the car speeds up past 10 mph, the RPM's would go up to about 4000-5000 RPM's, and then as soon as the clutch was pushed in the idle drops down but only to around 3000 RPM's. The throttle linkage was still at idle position, which I checked manually while the car was moving.  Then when we slowed to below 5 mph, idle RPM's dropped back to normal (1000ish).  It almost feels as though the car is trying to keep itself moving, if you put the car in second gear and speed up to around 35mph and let off the gas the car doesn't slow down but will continue to drive at the same speed, sometimes it will even speed up. It's possessed.