See... Hang around here and learn something new every day. The 185 I'm running seems to have no adverse impact on the performance of the engine and provides sufficient heat for the comfort accessories year round, so unless it goes bad it will probably stay where it's at.
Let me clarify, a 351C runs best at 200-210 when your working it. The stat @192 prevents/reduces the build up of crap in the heads, but still ya gotta blow a Cleveland out once in awhile...
I'm not trying to railroad this thread but some of what is being discussed here follows along the line of what I'm also experiencing. Not sure of temp I'm running on my 351C, the gauge fluctuates whether I have the headlights on or not which is another problem I will have to deal with later. I don't remember which Shaw thermostat I purchased but it does run pretty warm, but not over warm. I plan to install another temp gauge to monitor real temp, at least until I can go out and purchase an entire aftermarket gauge set and build my own gauge cluster. Anyway, my question to all of you is, should I have the distributor connected to port vacuum or manifold vacuum? My motor is pretty radical but unfortunately it was built up before I purchased my Ranchero so I do not know what cam, pistons or valve train is in the motor. I'm currently running port vacuum and to keep it running, with the correct timing range setting, my idle speed screw is turned very tight to keep idle up enough to keep it running at idle. Based on what I think I'm reading I should be running manifold vacuum, as it would possibly allow me to turn my idle screw out and also help with my rich condition. I have already changed jets and adjusted idle mixture to just about leanest I can get and still keep it running, about 1 to 1-1/8 turn open. All good advice, which I have yet to not receive from all of you, is greatly appreciated. You all have been the greatest with your help and advice. Eric
Anyway, my question to all of you is, should I have the distributor connected to port vacuum or manifold vacuum? My motor is pretty radical but unfortunately it was built up before I purchased my Ranchero so I do not know what cam, pistons or valve train is in the motor. >ek59 +++++++++++++++ Well, the best answer is: try it both ways and see if you like one or the other better. Won't take much trouble to find out. The only situation in which the two differ is at idle. For my near stock motor, I prefer manifold vac. You said your motor is pretty radical -- which I suppose means the camshaft. Do you know how much vacuum it makes at idle? You might be a user who would be best served with mechanical only advance, no vac advance at all. If you have, or can borrow a vacuum gauge, connect it to manifold vacuum and tell us how much at idle.
Suggest you clean up your engine, firewall, dash, tail light and headlight ground connections. What base timing are you using now? If the cam is anything approaching a Q or R engine code cam your base timing could be as much as 16 degrees or more, and that could impact the internal settings on your distributor (distributor cam set at 18L or 13L).
If you've got the enginebuck$$$$ you might consider a mallory unilite all mechanical dizzy. You'll have to adjust the advance springs to your liking but the elimination of the vaccum line both cleans up the engine bay as well as allows your other parts to get a tad bit more vaccum, such as your brake booster.
I concure with the mechanical distributor, but I had alot of trouble with 3 differant Unilites and being hard headed, (3 times) I finally went with MSD and have not regreted it.
MSD makes good units. The vacuum advance will improve gas mileage while cruising on the freeway, and will improve engine braking at high speed. Even my engine with a crank trigger and full computer control has electronic "vacuum advance" as it is a valuable tuning tool even with high performance-high compression machines. Aside from eliminating a hose, there are only downsides to getting rid of vacuum advance. It may, superficially, appear that removing it simplifies tuning. But, in fact, it does the opposite. The Vacuum advance allows you to adjust timing based on engine load. Once you remove it, you have to make compromises in both fuel efficiency, power, and drivability. Total timing; Total timing is mech and vacuum combined. A quality distributer will allow for about 35 degrees plus your base timing setting. If you are getting 40+, you have a problem with the dizzy. If BB knows of a dist that operates otherwise (with vacuum advance) I would love to be educated. Base timing; Aside from small (5 or less degrees) changes, adjusting your base timing without changes to your distributer are only going to move you in a bad direction. Especially with a hot cam, moving the base timing up without moving the total down risks expensive damage. If anyone cares. On my 521 I run 15 initial, 7 cranking retard, 38 max with a 4 degree high speed retard and a 6 degree deceleration advance. And I can fire it up and floor it in a closed shop safely. All that comes out of the exhaust is CO2 and water.
If BB knows of a dist that operates otherwise (with vacuum advance) I would love to be educated. >ribald ++++++++++++++ Easily done; if you'll check post #14 in this thread you'll find 72gtva explaining how to get 6-base + 34-centrifugal = 40 degrees, BEFORE any vacuum advance. Any vac can worth having will add 10 - 15 degrees on top of that 40 when the motor is lightly loaded. The nearly stock Duraspark in my car [ex-'79 Montego 302] with vac can connected to manifold vacuum idles at around 28 btdc, with a base of 8 degrees, meaning my vac unit is adding 20 degrees. Stock Ford part. My only mod is putting in a couple lighter springs from Hubbards. There have been posts on this board speaking of seeing 50+ total on a timing light.
A lot of good information. If all works out I will try to put some of it to use this Friday, I will probably need to go in to work on my day off as usual but hopefully it won't be all day. I currently have an Accel distributor but have thought about getting a MSD distributor and a 6A, or something along those lines. I have always had good luck with MSD in the past. Anyway, I will check the vacuum and timing at the various RPMs suggested, using both manifold vacuum and spark port vacuum . I should have a little more info at that time and hopefully with all of your advice come up with a game plan. Thanks all, Eric
Show me the specs. The MSD for the 351 maxes out at 28 cent + vac, and the factory one does even less.
