Joined: Thursday December 21 2006 Location: Orange County Posts: 36
I'm sure this question has been asked before but I'll ask again. I've had one of my 'nationals sitting for a period of over three years and I'm currently doing a complete tune-up. The only problem is that the major autoparts store can no longer tell me what gaps the plugs and points for a 345 are. Apparently this information is not a frequently requested item so they longer feel the need to hold a record of it. If I had manual, then things would be different but I don't so henceforth why I come to the experts.
If my memory serves me correctly is the following true? Plugs - .032-.035 Points -.017-.019
Can some one help a brotha out?
Thank you!
Joe V. is my hero! - 77 Scout II & 76 Traveler -Semper Fi
Joined: Sunday May 15 2005 Location: San Diego Posts: 659
Not sure about points but Plugs are .035.
I have heard of people setting their points by placing a business card in there for the gap. William (Bill)- San Diego Chapter President 1978 Super Scout II SV 345, Holly 2300 2BBL, T19, Dana 300, SOA lift with 1.5" shackles, Dana 44s front and back with 3.73 gears, Detroit Locker in rear, 33x12.50 ProComp, On Board Air San Diego YouTube
Joined: Thursday December 21 2006 Location: Orange County Posts: 36
Thanks Bill for responding so quickly.
I too have heard that a business card can be used... actually I've also heard that a simple matchbook can also be used. I might just take one of my business cards and take a micrometer to it, gauge the thickness of it... I'll let you know my findings.
Thanks again! Joe V. is my hero! - 77 Scout II & 76 Traveler -Semper Fi
Joined: Thursday December 07 2006 Location: Garden Grove Posts: 1870
From what I have read your points should be gapped at 0.016 to 0.020 and from what I remember the book of matches is around 0.015. It will get you close in a pinch but a feeler gauge would be better of course.... Plugs can be from 0.035 all the way up to 0.045 with some of the aftermarket ignition systems, some might even go larger than that on gap, but they will tell you in the instructions.
Joined: Thursday December 21 2006 Location: Orange County Posts: 36
Thank you gents!
I really appreciate your assistance.
After doing some online research, I noticed that most numbers were from .016 to .019. I figured if I went with a .017 gap on the points that I should be fine. (Bill - I went out to the machine shop, here at work, and found that the business card is around .015)
In regards to the plug gap. I gapped it at .034 since the average numbers I pulled were around .032 through .035.
I'm pretty excited I recieved this much advise in such a quick manner. I really do appreciate it.
I should have her up and running again tonight. Thanks again Gents...
[ Edited Thursday July 29 2010 ] Joe V. is my hero! - 77 Scout II & 76 Traveler -Semper Fi
Joined: Monday January 29 2007 Location: the Netherregions Posts: 1576
The .016-.020 came directly from the FSM. The real deal on points gap is a little more complicated than we've discussed so far. As you probably know point gap will effect both dwell and timing. A larger point gap, say out at the end of the range at .020", although most V8's will run there, will decrease ignition dwell which in turn reduces coil saturation time. This can lead to misfire when the engine is under medium to heavy engine load. An increase in hydro carbons and an increase in fuel consumption will result. On the other hand you might not even notice this while cruising but the condition will still be present.
Timing will be advanced by in increased point gap. It would be worth while to check your base timing and total advance with a timing light to be sure you are in spec or better yet running best possible for your engine. You can find as much as 2-4 degrees difference in timing with in the FSM specified point gap range. While you can readjust the timing, the decreased dwell will still be there.
The correct setting for a brand new set of points is .018" and .016" for resetting points that have already been used. These should be set with a correct feeler guage not a matchbook cover. Not all matchbooks are the same thickness. It might be ok for a field fix but, why start out using one as your guage? Even if you had one that was .015", the gap wouldn't be in spec. With as much effect that point gap has on ignition system and engine performance, I'd argue that the proper settings done with the proper tools are worth while.
Joined: Saturday June 11 2005 Location: Very High Desert Posts: 527
Just a side note. When checking the points gap, also make sure there is some meat left on the points follower. When the follower wears down (usually due to lack of follower lubrication) this can cause the points to perform poorly and even become non-serviceable. Some better points sets have a felt pad to retain lube.
Joined: Wednesday May 18 2005 Location: Torrance, CA Posts: 150
The 'curved' point set with the 'felt pad' to lube the rubbing block is: IH4281XP. Add a coupe drops of clean motor oil to the pad. I get the points at the NAPA store. The 'straight' point set will have a different number - which I don't know.
Joined: Thursday December 07 2006 Location: Garden Grove Posts: 1870
Bill Bennett wrote ...
The 'curved' point set with the 'felt pad' to lube the rubbing block is: IH4281XP. Add a coupe drops of clean motor oil to the pad. I get the points at the NAPA store. The 'straight' point set will have a different number - which I don't know.
That's great to know the part number Bill, it's safe to say that these would be the longer lasting points also. I do remember having a set in my old Scout that I kept lubed and never had to change them in over two years.... Just checked them out every 4 to 6 months for wear.
Joined: Wednesday December 30 2009 Location: L.A. Posts: 595
Everyone that is quoting the FSM at .035 seems to be off... my FSM shows in 5 different areas the gap to be .030.
But whatever... =&%#@$*•=&%#@$*•=&%#@$*•=&%#@$*•=&%#@$*•=&%#@$*•=&%#@$*•=&%#@$*•=&%#@$*•
73 Scout II, 4x4, 318, mean... but currently still broken D30/44 3.73 77 Scout II, 4x4, 345, not mean... and has a little limp. (but at least not broken) D44/60 4.10 w/Detroit
NEW: 79 Scout II, 4x4, 345, Thermoquad, 4 sp, D44/D44 3.54, one owner, mint, roof never removed, zero rust.
Joined: Monday January 29 2007 Location: the Netherregions Posts: 1576
As long as you are talking about a Scout, pickup or Travelall. the correct spark plug gap for a stock SV engine in a light duty truck, with a stock distributor is .035" regardless of whether you are running a Holley points/gold box or Prestolite ignition system.
Some of the information available in the Factory Service Manual can at times be confusing or appear to be conflicting with itself. A lot of the time, the reason for this confusion is that the manual many times is not Scout specific. Since IH used the same engine and ignition systems in Scouts, Pickups, School Busses, Dump trucks and more, the basic specifications cover applications that a Scout owner would not be concerned with.
For instance, in this spec sheet, it might appear that the recommended spark plug for an SV 345, SV 392, MV 404, MV 446 and LV 539* (549?) is the Champion RJ-6 and, should be gapped .030. Upon closer inspection you will notice that "Optional for Light Service" indicates a Champion RJ-10 plug gapped to .035 for both the SV 345 and SV 392.
The reason for this difference is that the 345 and 392 were both used in medium/heavy duty applications such as busses and dump trucks and this spec sheet covers all applications for the same motors. The 345 was used in applications such as Scouts and Pickups while the 392 was used in Pickups and Travelalls. These are the "optional for light service" vehicles refereed to in the chart. You will also notice that the 196 and 304 both use the RJ-10 plug gapped to .035. Both these motors were only used in light applications therefore there is no "other" choice of plug or, gap specified.
The best thing to remember when referring to the FSM is that just because it says Scout on the front; that doesn't mean that it only covers Scouts. You've always got to keep the application in mind. This is particularly important in regards to tuneup specs, fuel system, emissions and, ignition systems .
Joined: Monday January 29 2007 Location: the Netherregions Posts: 1576
In a way you are right David. Just look at the various timing settings recommended in the two pictures I posted. You'll see everything from TDC to 9* sometimes dependent on engine size, sometimes on application. Initial timing gets set all over the place. As you can see in the top picture, according to the FSM, initial timing should be set at 7 1/2*BTDC if you have a 78-80 Scout/345 with a Prestolite distributor sold in California and per the bottom picture, timing should be TDC. So how would you know what is right?
When the vehicles came from the factory, there was a sticker on the cowel showing what the correct timing was for that particular vehicle, as equipped, where sold. If that sticker is gone, all you've got is base recommendations in the FSM. Even then, depending on where you are looking, you'll find conflicting information. This is one of the reasons that the FSM makes such great bathroom reading.
I don't usually pay too much attention to the book recommendations though because, timing is somewhat subjective. I've got a 345 that likes a lot of timing. Others, maybe not so much. Elevation effects timing. Higher elevations require more timing. Even the grade of fuel you use will effect timing. Advanced timing and low grade ARCO regular unleaded may not peacefully coexist. I go for overall timing of 34-36* because it's usually safe for a V8. A timing light and a vacuum guage are indispensable tools for this. More timing will increase manifold vacuum to a point. More manifold vacuum is better than less. The light will allow you to confirm your settings.
Even with the "usually safe" numbers, certain engines may not like that much timing. If you hear pinging under load, it's too advanced and, engine damage will occur. Rather than power gain, if the engine is pinging, you are actually experiencing power loss because the fuel/air mixture begins its burn too soon in the compression stroke. Now the piston is being forced up against the expanding gasses reducing power.
Power timing is only slightly different in that you advance the timing until the engine starts pinging under load then back it down a couple ticks. The idea being to give the engine all the timing it will take. I tend to shy away from this because I like the "safe" numbers and I like knowing what timing I'm running.
These full timing settings are usually not what you want for a smog test so, you'll have to back the timing off to book then reset it to run best after you pass.
What's needed here is a good campfire and a few beers. Ignition timing is one of those "lets talk about it" subjects. About on the same plane as engine oil and gasket sealers.
I got the beer , who's gonna get the fire going? BRD RACING
Joined: Thursday December 07 2006 Location: Garden Grove Posts: 1870
Tim Potter wrote ...
What's needed here is a good campfire and a few beers. Ignition timing is one of those "lets talk about it" subjects. About on the same plane as engine oil and gasket sealers.
I got the beer , who's gonna get the fire going?
I'm your huckleberry....been known to start a good campfire. I usually make the fires big enough for everyone to make the circle bigger and fit more people in, more beer = bigger fire. Maybe even having to move vehicles that are parked to close at 2am.
As Tim says timing can be a whole other topic and is sometimes really dependent on the specific vehicle....
, who's gonna get the fire going? 
