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Thread: Questions about 345 rebuild

  1. #1
    Join Date
    May 2009
    Posts
    9

    Default Questions about 345 rebuild

    Hi all,

    I have a 1975 Scout II XLC project. I want to rebuild the motor. It has the 345 in it. I will break it all the way down so I know that it will be reliable for a long time. I read in some post during my search that people "deck" the block before putting it back together. Can someone shed some light as to the reasoning behind this? I know the 345 IH motors are hard but is it a necassary thing to do? I have a couple of friends that will be helping me and with some luck and if we have all the right parts on hand we think we can get this motor out rebuilt and back in the truck in a 3 day weekend. Oh and the truck has 94,000 on the odometer. Is there anything else I need to do when rebuilding this motor?

    Second question:

    I have a dual speed electric fan out of a late model ford Taurus. I believe it came out of one with the 3.8ltr engine. Would this fan be enough to cool the 345? I am not sure of the CFM's but I can find that out. Just wondering if anybody here would know. Thanks.

    Brian

  2. #2
    Join Date
    Jun 2009
    Location
    Erie PA
    Posts
    2

    Default

    If you want to do a proper rebuild the engine should be disassembled, and sent to a machine shop for cleaning, either a hot tank, or baked and blasted. Then magnafluxed. You need to measure all of your critical tolerances- Bore, Crankshaft journals, the main and rod sizes as well. The machine shop will also check your deck for warpage, along with the heads.

    A quickie re-ring and bearing is a far cry from an actual rebuild. I've done it myself quite a few times, but your taking slot some chances and could be wasting alot of time.

  3. #3
    Join Date
    Feb 2009
    Location
    Aiken, SC
    Posts
    2,423

    Default

    Some issues come up.

    Why a rebuild is necessary after 94K, for starters. These engines normally last 3 times that long.

    This brings up the next question. If it needs a rebuild after 94K, why would you think you could solve the problem in a weekend? As was already mentioned, those oil passages have to be cleaned.

    The reason the blocks are decked is that the aftermarket composite head gaskets are .043, and compress to .025, compared to the .018 original steel gaskets. In addition, many of the aftermarket pistons are .020 destroked. You may end up needing .030 just to break even. This is a decision that should be discussed with your machinist, and that takes more than a 3 day in-and-out.

    With the SV block, when you pull it apart and clean it, you also must bore clean the oil passages. I use a small rifle brush.

    Prior to reassembly, the machinist will then temporarily assemble the engine and measure exactly how much the block should be decked. This would be after the cylinders are bored true, which may not be needed after only 94K. Then the engine is disassembled again and the work done. The decision on which cam to use is also part of this equation.

    Lining up the cam bearings is critical on these engines. The oiling system for the lifters goes THROUGH the rear cam bearing, and the oiling system for the rockers depends on this oil as well. If you fail in either of these steps, the engine is toast. Some people even install them as perfectly as they can, then drill the oil passages right through the cam bearing to make sure there is good flow.

    The balance must then be checked.

    By the way, if you need a new crankshaft, get one out of a dump truck or school bus or something. They harden them better. Valves, same thing. The loadstar valves are induction hardened.

    There are several things that must be done that simply take time. Also, this is not a small block. This engine is HARD. It is designed to pull around dump trucks and school busses up to 30,000 lbs. In a scout, the top end can be reworked for more peak horsepower, and you end up moving the power band up at the same time.

    An example of this with which we are all familiar is the 350 chevy that was used in corvettes. It makes less power below 2000 rpms than the same engine configured for an old station wagon, but because the corvette is so light, it's not needed there. It's needed at much higher rpm. A little of that is possible with the SV series to make it more of a light vehicle (compared to a dump truck) engine. I prefer the stock setup, and when it's fresh, the 345 is a pretty strong, very smooth engine.
    Allan E.
    Curmudgeon Extraordinaire
    Charter Member, Old Hippie IH Club
    Old fashioned binder freak

  4. #4
    Join Date
    May 2009
    Posts
    9

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    Very good info thanks, I guess I should re-think exactly what I am doing. I want to do a rebuild but like you said Allen why do one at only 94K. I just got the truck and do not know what kind of abuse it has taken. I know the rear main leaks. Basically I was planning on taking it out tearing it down replacing all the seals and gaskets, using a hotsy to clean the block then re-assemble. I dont want to have to spend a ton of money at the machinist because like I said before this is a project. So alot of things need attention. I guess my error was thinking the engine was like a 350 chevy where you can tear it down put it back together within a couple of hours. I will see what I have the funds to do at the time. The scout will be used occasionally to commute to work when the snow is bad up here in Craig CO. Other than that she will be an off-road machine. Please keep the info coming as it is apparent that I do not know much about these scouts. Thank you

    Brian

  5. #5
    Join Date
    Feb 2009
    Location
    Aiken, SC
    Posts
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    About 3 1/2 hours from you in Fairplay will be the RMIHR (Rocky Mountain IH Rendezvous) at the end of July/ first of August. I strongly suggest you attend.

    http://www.rmihr.org/

    I've had to miss the last one and will miss this one. Too far from where I was going to be that weekend.

    Chances are your engine is okay if it just runs and leaks. It really is an industrial grade engine.

    Also, be very sure it's the rear main leaking before you make a bad mistake. These engines leak from the valve covers and other places, and it LOOKS like a rear main seal leak. The valley pan can leak, the PCV grommet can leak, and if your PCV is clogged, you can blow oil back out the dipstick. All of these will look like a rear main seal leak.

    If you have done this already, great, but if not clean the engine really well and replace the valve cover gaskets. Take your time, flatten the holes, use The Right Stuff, and do not over torque. Then look again. 9 times out of 10, the leak is in the valve cover gaskets, usually from sitting.

    After the engine has been run a while, do a compression test.

    Use any brand oil filter except FRAM. They are terrible. Wix or Baldwin or Hastings. Everybody else's are made by those brands, like NAPA is a Wix, and so forth. Carquest has the right filter. It is NOT the crossover to the PH8A Fram, but those will work.

    You have a lot of work to do. I very strongly recommend that you buy a factory manual for your scout. They are available through any light line dealer or direct from www.binderbooks.com on line.
    Allan E.
    Curmudgeon Extraordinaire
    Charter Member, Old Hippie IH Club
    Old fashioned binder freak

  6. #6
    Join Date
    May 2009
    Posts
    9

    Default

    Thanks Allen, I will try to attend the IH rendevous. It might be hard as i work at a power plant and we will be in an "outage" but we will see. Your right I have alot of work to do. The body needs rust attention, I want to change all fluids and do a complete assesment of the brakes. I was told the axle was changed up front for a D44 but have not been able to find any way to identify it. It has drums all the way around. I was told it was running just before this past winter but I doubt it as the last time it was tagged was in 1999. I have been looking to get a manual for a while but they seem pretty expensive. I'll bite the bullet and go ahead and get one since I need to re-wire the ignition and some other odds and ends. Thanks again for the advice. I will clean the engine up good and look for leaks. I just have not had much time to do anything with it except kill the bee's nest that was in it!

  7. #7
    Join Date
    Feb 2009
    Location
    Aiken, SC
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    Quote Originally Posted by zonianbrat View Post
    Thanks Allen, I will try to attend the IH rendevous. It might be hard as i work at a power plant and we will be in an "outage" but we will see. Your right I have alot of work to do. The body needs rust attention, I want to change all fluids and do a complete assesment of the brakes. I was told the axle was changed up front for a D44 but have not been able to find any way to identify it. It has drums all the way around. I was told it was running just before this past winter but I doubt it as the last time it was tagged was in 1999. I have been looking to get a manual for a while but they seem pretty expensive. I'll bite the bullet and go ahead and get one since I need to re-wire the ignition and some other odds and ends. Thanks again for the advice. I will clean the engine up good and look for leaks. I just have not had much time to do anything with it except kill the bee's nest that was in it!
    The 75 came with D44 front w/disc brakes. There were no other options on the XLC (Extra Load Capacity, it's a smog thing) in 75 and later. 74 was the last year for drum brakes, which was a transition year. Could have had drum or disc, D44 or D30. If you have drum brakes, somebody swapped them on. Chances are they just swapped the whole axle, so you may have a D30 from a 71-74 scout. The 73 and 74 had open knuckles, which makes the disc swap easier.

    Coonrod's in Grant, (near fairplay) Colorado will most likely have the front axle if you need it.

    Rocky Mountain Binders has a Denver area chapter. Nice bunch of folks.
    Allan E.
    Curmudgeon Extraordinaire
    Charter Member, Old Hippie IH Club
    Old fashioned binder freak

  8. #8
    Join Date
    May 2009
    Posts
    9

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    Any other easy way to see if it is indeed a D44 up front.

  9. #9
    Join Date
    Feb 2009
    Location
    Aiken, SC
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    Quote Originally Posted by zonianbrat View Post
    Any other easy way to see if it is indeed a D44 up front.
    Look at the diff cover. If it's the same as the rear, it's a 44. If it's more rounded, it's a 30. In the lower right corner of the housing, as you're looking at the cover, is a number, like 44-1, or 30, or something. That tells you which axle also.
    Allan E.
    Curmudgeon Extraordinaire
    Charter Member, Old Hippie IH Club
    Old fashioned binder freak

  10. #10
    Join Date
    Jun 2009
    Posts
    5

    Default

    why shouldn't you use fram on a IH I do and it seems to be fine?

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