Welcome to the Connecticut Z Car Club Forums




Username:  
Password:  
Log me on automatically each visit
Register 
It is currently Thu Mar 28, 2024 9:48 am
Welcome to the Connecticut Z Car Club Discussion Forums   
If you have trouble logging in or encounter any issues, please send an email to webmaster@ctzcc.com.

All times are UTC - 5 hours





Post new topic Reply to topic  [ 31 posts ]  Go to page 1, 2, 3  Next
  Print view Previous topic | Next topic 
Author Message
PostPosted: Fri Jun 14, 2013 12:18 pm 
Offline

Joined: Thu Oct 11, 2012 6:48 pm
Posts: 387
Location: Stamford, CT
Car started having some trouble a while back and ive gone through nearly the entire ignition system trying to find it. Attempting to retard my timing from its fully advanced position rewarded me with a nice big intake backfire from the Holley and now my plugs are black and wet with gas when I try and start it.

Soooooo~ Im looking to buy a set of round tops (that I actually know how to work!) and a 260-280ZX electric distributor. Let me know if youve got one or both that youre trying to unload!

_________________
71' 240Z: HLS3040666


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 14, 2013 5:07 pm 
Offline

Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
Something is set wrong. Your ignition should never require a full-advance setting. When the vacuum advance adds degrees to a full-advance setting, your ignition would be off the chart.

You need to throw a timing light on that bear and find out where it's sparking at idle. That will give you a place to start.

Do you know who put that engine together, and whether they knew how to set the camshaft timing or not?

_________________
1970 240Z


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 14, 2013 6:20 pm 
Offline

Joined: Thu Oct 11, 2012 6:48 pm
Posts: 387
Location: Stamford, CT
No idea if the PO or PPO knew what he was doing. It was running as well as the day I got it (not sure if that was full potential or how it shouldve been running) up until a few weeks ago when I noticed a loss of power and then stuttering that kept getting worse until now. The car barely made it back up my driveway and now it wont idle at all. Borrowed some new NKG spark plug wires, put on new plugs and a new ignition coil but the problem actually got worse! The car ran much better with the MSD blaster 3, but when I pulled it off I noticed that the positive terminal was broken and leaking oil. The vacuum advance moves freely and does not leak but the car will only run with the distributor fully advanced.

Im hoping the stuttering issue will be solved by changing out the carb and the dizzy (as I had been planning before I started having problems). About how long does it take to set the camshaft timing?

_________________
71' 240Z: HLS3040666


Top
 Profile  
 
 Post subject:
PostPosted: Fri Jun 14, 2013 8:33 pm 
Offline

Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
Once you have all the gaskets and tools you need to do the job, it's only a single afternoon. You might get away with just removing the cam cover and confirming that the sprockets are set properly. If the timing chain has slipped or the lower sprocket spun on the crankshaft (either of which might have been what you experienced a week ago), you would of course have to buy a new chain and pull the radiator and front case off the engine. If the lower sprocket spun, you'd have to put in a new keyway and probably a new sprocket. Phrog had his sprocket spin a few years ago and it drove him nuts trying to set his timing. I think he actually wound up replacing his crankshaft.

I would recommend against "guessing" and replacing things until it's fixed. That's an expensive method and you never really learn what fixed the problem.

If you don't want to buy a cheap timing light, you can rent them from many auto parts stores. That would be the first thing I would do. Check the basics first (timing, compression check), before you start spending money replacing the fuel system. It's also pretty common with these cars to find that someone put the distributor back in the car 180* backwards. It's not supposed to be possible but it happens. That makes life VERY complicated when you try to set the timing. There are enough people in here to tell you their own horror stories about that happening to them.

You only need a few basics to make your engine run well:
1. Proper air/fuel mixture
2. Proper compression
3. Proper valve timing
4. Good spark at the proper time (ignition timing)

When I met you your cam sounded so 'lumpy' (radical) it was hard to determine if things were set the way they needed to be. Your idle was well over 1,000rpm and the car didn't want to run below that. That's common for race cars, but almost unlivable for street cars. If you have a full-race cam in your car, you might have to learn to live with irritable response until you change it. If the cam is set wrong (or if something has slipped), the resulting timing disruption would require a fast idle just to keep the engine running. If it's a vacuum leak (another possibility) you could find it by spraying a can of starting fluid around a COLD, idling engine until the rpms jump up.

http://www.ehow.com/how_4793417_use-timing-lights.html

_________________
1970 240Z


Top
 Profile  
 
 Post subject:
PostPosted: Sat Jun 15, 2013 12:49 am 
Offline

Joined: Thu Oct 11, 2012 6:48 pm
Posts: 387
Location: Stamford, CT
Ill probably pull the cam cover to see what I find but ill wait until I get my camera back this weekend. I dont mind buying a cheap timing light but right now the car cant even idle whereas before it would run and drive fine and the stuttering would eventually come in as I drove more. On my distributor the #1 plug is the rearmost closest to the driver and #6 is closest to the radiator (not sure if that means its orientated properly but thats how I got it and how every other distributor is wired up in pictures).

I have a feeling the cam is set wrong since I did buy it from a guy who sold the car to me with only 3 lugs on each wheel and told me thats how they were supposed to be run. I still think my issue is caused by the distributor but the car hates if the timing is changed at all from its fully advanced state so I wouldnt be surprised if the cam was set wrong also (though im notoriously bad at pinpointing problems).

My friend stopped by to give me a lift to Zorros to borrow the new wires and recorded this video of me trying to make it back up my driveway. When I met with you the car ran alright since I didnt have to drive very far, but the stuttering would start after a few minutes of driving which is why I ran into some trouble when I tried to go for a drive. You can hear the car trying to die when I try to clutch in and a very wrong sounding exhaust compared to this:
Healthy: http://www.youtube.com/watch?v=ms8ch30kIzM
Sick: http://www.youtube.com/watch?v=Ii9HIvUyf0A

_________________
71' 240Z: HLS3040666


Top
 Profile  
 
 Post subject:
PostPosted: Sat Jun 15, 2013 9:05 am 
Offline

Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
['On my distributor the #1 plug is the rearmost closest to the driver and #6 is closest to the radiator"]

:D AHA! You sir, have found your problem. Your dizzy has been installed 180* backwards.

Here's how it is supposed to look:

Firing order is 1-5-3-6-2-4, counterclockwiZe rotation. (Remember "15 is too young, 36 is too old, but 24 is just right").

No wonder you can't make it run well. All the tuning in the world won't overcome a bass-ackwards distributor. (Believe me ~ many of us have tried) :roll:


Attachments:
File comment: #1 sparkplug is closest to the radiator, #6 is closest to the firewall.
240Z firing order.jpg
240Z firing order.jpg [ 134.44 KiB | Viewed 8684 times ]

_________________
1970 240Z


Last edited by Frank T on Sat Jun 15, 2013 7:03 pm, edited 2 times in total.
Top
 Profile  
 
 Post subject:
PostPosted: Sat Jun 15, 2013 9:32 am 
Offline

Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
To be sure, look at your dizzy and tell us where the vacuum dashpot is located? Is it at 7-O'clock, where it belongs, or is it on the back side of the distributor?

(Sorry if this should be in the Tech Talk forum instead of Marketplace, but we could move there if you prefer).

_________________
1970 240Z


Top
 Profile  
 
 Post subject:
PostPosted: Sat Jun 15, 2013 10:01 am 
Offline

Joined: Thu Oct 11, 2012 6:48 pm
Posts: 387
Location: Stamford, CT
Could the difference be the cap? My vacuum advance is the in the same spot and every other Z engine bay that Ive found on google images has been wired the same way (sometimes easiest to just look for 5 and 6). I think I tried that a few days ago and it wouldnt even start.

I do still think its the distributor since the engine seems to be running fine until it starts missing/giving off a weak spark. The stuttering reminds me of the one time I got points bounce at high RPMs, lots of noise but no more power.

_________________
71' 240Z: HLS3040666


Top
 Profile  
 
 Post subject:
PostPosted: Sat Jun 15, 2013 1:02 pm 
Offline

Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
Yes, if the vacuum dashpot is in the right place, your wires are in the wrong holes or the cap is on backwards.

The reason it's important for the plug wires to be set in the manner shown in the photo, is that the rotor under the cap is timed to the position of the pistons. When #1 piston reaches TDC on the compression stroke, the rotor will be pointing to the #1 terminal on the cap (or certainly should be).


Altho you can arrange the wires in the proper sequence around the cap, if you don't start with #1 cap position at the front of the cap, the rotor will arrive at the distributor pins either later or sooner than TDC for that cylinder's compression stroke. THAT will require you to advance or retard the distributor timing all the way (like you have now) just to make the thing run. That deprives you of proper advance/retard while the engine is running at different speeds.

Pull the wires off. Replace them one at a time, using the proper length wire for each plug. Start with #1 pin to #1 plug, then follow in the proper firing order as listed above, counting counter-clockwise. (#1 cylinder is at the front of the engine, #6 is at the rear). Because your dizzy has been advanced all the way, loosen the cap screw and return your timing marks to the center before starting it. Leave it slightly loose enough so you can twist the dizzy to find the best idle when you've corrected the plug wires, then tighten it down when you're happy. You'll have to re-gap your breaker points to make it all work, since you're changing everything else.

I think you'll be amaZed at the difference when you're finished with this simple 10 minute step.

Does anybody disagree with this analysis? I welcome second opinions!

I'm sorry to have muddied up your Wanted to Buy post with a Tech Talk issue. I have opened a new thread in the Tech Talk about this matter

http://forums.ctzcc.com/viewtopic.php?t=7583

Webmaster, please feel free to remove all this chatter to Tech Talk if you feel it's appropriate.



Frank

_________________
1970 240Z


Top
 Profile  
 
 Post subject:
PostPosted: Sat Jun 15, 2013 6:59 pm 
Offline

Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
Any luck with this today?

_________________
1970 240Z


Top
 Profile  
 
 Post subject:
PostPosted: Sun Jun 16, 2013 12:01 am 
Offline

Joined: Thu Oct 11, 2012 6:48 pm
Posts: 387
Location: Stamford, CT
Frank T wrote:
...if you don't start with #1 cap position at the front of the cap, the rotor will arrive at the distributor pins either later or sooner than TDC for that cylinder's compression stroke. THAT will require you to advance or retard the distributor timing all the way (like you have now) just to make the thing run.

That makes a whole lot of sense. I didnt adjust the timing at all when I tried moving the plugs around so its no wonder it wouldnt start. Was able to test it today because I already pulled the Holley and the intake off to prep them for sale and to make way for a set of round tops that im looking at :oops:. Waiting to hear back from some other people regarding the dizzy, coil, and wires.

_________________
71' 240Z: HLS3040666


Top
 Profile  
 
 Post subject:
PostPosted: Sun Jun 16, 2013 8:52 am 
Offline

Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
OK, you're going back to SUs. I noticed you no longer have SU throttle linkage on your car ~ should you also ask to buy that, or do you have it stowed someplace?

_________________
1970 240Z


Top
 Profile  
 
 Post subject:
PostPosted: Sun Jun 16, 2013 11:10 am 
Offline

Joined: Thu Oct 11, 2012 6:48 pm
Posts: 387
Location: Stamford, CT
I have the linkages laying around in my garage. Folks over at Zcar seem to positive that properly set up SU's will beat the Holley any day but ill just be glad to get better gas mileage and a set of carbs I am very familiar with.

_________________
71' 240Z: HLS3040666


Top
 Profile  
 
 Post subject:
PostPosted: Sun Jun 16, 2013 12:41 pm 
Offline

Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
Well then, they've never seen both setups running at their maximum potential. That Holley 4Bbl effectively doubles the intake of the twin SUs and adds far snappier acceleration than the SUs are capable of. When properly set up, the Holley unit will make a 240Z run away like a scalded cat.
If fuel economy is a concern, you can *either* keep your foot out of the Holley (so you only run on the primary throttles), *or* switch back to the SUs. You can actually get better mileage from the 4Bbl if you never open the secondary throttles (because the primaries are smaller than the SUs), but then what's the sense of having a 4Bbl?

_________________
1970 240Z


Top
 Profile  
 
 Post subject:
PostPosted: Sun Jun 16, 2013 1:16 pm 
Offline
User avatar

Joined: Sun Dec 02, 2012 9:26 am
Posts: 219
Location: Jamestown, RI
Hi Porkbun,

I just removed a complete great running l24 from my 71 240z yesterday. Putting in a v8 shortly. It has the round top carbs with all linkage and emission equipment still installed. It has the air cleaner with a K&N filter. The carbs were rebuilt by ztherapy about 12 years ago and still work great. These are set up to run on a stock setup and are dialed in perfectly for that setup. I haven't needed to adjust them in a couple years. Aesthetically they are dirty on the outside and would look great cleaned up. I'm in the middle of putting together a for sale thread here for all the parts I am selling and just saw this ad. If your other deal falls through and you are interested let me know. To make things as easy as possible I could include everything from intake to air cleaner all still assembled if you want.

I also have the original 240z distributer that has been converted to electronic ignition with an almost new coil.

Thanks,
Rob


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 31 posts ]  Go to page 1, 2, 3  Next

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 9 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron









Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
mile200 v1.0.1 designed by Team -Programming forum- .