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351M wonít rev past 1,000

  #31  
Old 10-24-2018, 07:00 PM
jtagge86
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Abandoned, thank you for all the insight, and thanks to everyone else also! I plan to reassemble the front cover and fire up again this weekend. I think Iíll use the idle screw idea to get me where I need to be.

The positive choke wire is connected to a switched 12v source and appears to function correctly but I will allow for everything to stay in key on engine off for a few minutes to see how that goes. Good idea on the throttle movement Iíll check that as well. Finally I will double check my air mixture, I have a feeling Iím too lean which may have attributed to the glowing exhaust. Either way if I can get everything properly broken in Iíll try to post a video of it running afterward. Hopefully I donít need to post any more help questions.
 
  #32  
Old 10-28-2018, 01:16 PM
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Well I finally got it figured out. After making a few adjustments the cam was broken in and now idle and initial timing is set. It runs pretty good! Thank you everyone for all the help and tips!!
 
  #33  
Old 10-28-2018, 01:17 PM
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Awesome! That's always a good feeling to get the cam broken in.
When you say, you "figured it out", what was it?
 
  #34  
Old 10-28-2018, 02:20 PM
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Glowing exhaust sounds a whole lot like retarded ignition timing. As soon as the cam is broken in it's time to get it out on the road, under load. Avoid idling. Excessive idling at this point will tend to glaze the cylinders over. The piston rings will not seat properly until they get some compression on them.
 
  #35  
Old 10-28-2018, 04:24 PM
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It all came to incorrect ignition timing, fuel trim too lean, and basically not trusting myself with the build. Since the last post I richened the fuel mixture and just trusted that everything was set up correctly. From there cam break in went well, coolant temp got a little hot but that was expected. I changed the oil and then fired up, adjusted idle to spec and set ignition timing (I was slightly retarded by about 2 degrees or so). If I could load a video I would, but it seems to be running pretty good at this point.

I can't take it down the road because I have also swapped out the 4 speed for a 5 speed overdrive ZF-5. I still need to set up a hydraulic clutch pedal system as well as complete the brake installation. I'm just happy the engine finally runs. Being my first build it was a little nerve wracking. This forum was a huge help and again I can't thank everyone enough!
 
  #36  
Old 10-28-2018, 04:40 PM
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Nicely done.

Yes, I finished my first build last year and that first fire up gets your heart pounding! I don't think it ever gets any easier.

I just swapped in a ZF5 into my Bronco. If you have any questions, let me know.
 
  #37  
Old 10-28-2018, 06:34 PM
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Originally Posted by jtagge86 View Post

I can't take it down the road because I have also swapped out the 4 speed for a 5 speed overdrive ZF-5. I still need to set up a hydraulic clutch pedal system as well as complete the brake installation.
Ok, but since the cam is broke in, don't mess with the engine anymore till it gets put under load. There was a guy here who was complaining about burning excessive oil and smoking out the exhaust on his new rebuild after several thousand miles.

Turns out he initially had it on a stand, and, since it wasn't getting installed for a while, liked to fire it up and listen to it run every now and then. He estimated eight or nine hours idle time in total or something like that till he got it on the road. Maybe an extreme example but it doesn't take long to cause trouble.

Cylinder glazing is a very hard smooth surface, and more or less permanent for all practical purposes. The cylinders would need to get hit with a ball hone again to re-establish the cross hatch pattern and allow rings to seat. Modern rings are better in this respect too, but I sure wouldn't want to risk it.
 
  #38  
Old 10-29-2018, 08:47 PM
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Thanks for the info, I plan to focus on the brakes and remaining driveline items so it can at least move. After that itíll be getting parked for a little while, my wife and I are about to begin some major house renovations on our new house.

Abandoned, I have the trans installed, I used the adapter from TMeyer and got the flywheel drilled. My question to you, how much did you have to modify the driveshafts? I havenít taken any measurements but Iím assuming the rear may need shortened and the front lengthened.
 
  #39  
Old 10-29-2018, 08:57 PM
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They were each changed about 3 - 4 inches.
Fortunately, for me, the 5 speeds came in the 80+ Bronco body style, so I was able to use the printed lengths online. I did measure with a straight edge, and they were nearly identical to the printed numbers.
Yours will probably need to be custom measured, since you're in a 79 body style. Also, it'll depend on which transfer case you have, since some are thicker than others.

Measuring is easy though.

Just measure yoke to yoke:





My rear driveshaft was 28.5" cruising/resting (which is what the driveline shop will want to know). Usually there's a few inches on each side for extra compression/extension when going over bumps, flexing, etc.
 


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