Swapping a 304 in place of a 345

Discussion in 'General IH Tech' started by David Banner, Oct 18, 2015.


  1. David Banner

    David Banner High Wheeler

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    I'm sure it's been asked and answered before but my searching the forums has proved fruitless...
    The new knowledge base seems to be missing a lot of stuff the ol' FAQ contained about the SV motors too...

    Anyway--I'm picking up a 304 next week to replace my 345 (which probably needs a new crank and two con rods...)
    http://www.binderplanet.com/forums/index.php?threads/sad-scout-death-rattle.130046/

    Any issues with swapping the flex plate from my current 345 onto the 304?

    Are there any issues with the automatic "kick down lever" hooking up to the carb/intake because the intake sits about an inch lower?

    I have duel exhaust--is that gonna be okay with the 304?

    I have a motorcraft 2100 carb, it's a 1.21 venturi size--is this gonna be too big for the 304? I've got a 1.08 venturi I can build up if I need to...

    I need new engine mounts (I see metal on metal when I look up from below). IH mounts are stupid expensive. Any reason why these mounts won't work fine with an additional spacer to bring them up to IH height?
    http://www.amazon.com/Anchor-2710-Front-Left-Mount/dp/compatibility-chart/B000CRER8M

    I'm sure to have more questions when I start wrestling the SV monsters into place...
     
  2. Dennis Bernth

    Dennis Bernth Moderator Staff Member Moderator

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    In order, the flexplate won't know the difference, the V8's are balanced the same. I've done it many time, both 304 to 345 and vice versa, no issues there.
    Dual exhaust is cake, if you had a single with a Y pipe it would be a possible issue due to the slight difference in width of the engine. With duals you're golden.
    I'd try the Motorcraft that you have and see how it works for you. Jets are the main thing, if it's rich you can always jet it down a little, but you might be surprised how well it runs as is.
    I have no idea whether those engine mounts will work or not, but if you buy them and figure out how to make them work you'll be an IH legend, those are much cheaper than any alternative I've seen.
    All in all, it's an easy swap especially with the dual exhaust. I think you'll be happy with the 304 too, I've liked the ones I've had just fine.
     
  3. jawsplace

    jawsplace Farmall Cub

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    Out of curiosity, why are you downsizing to the 304 from the 345?
     
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  4. David Banner

    David Banner High Wheeler

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    Thanks Dennis,
    Still wondering if the 304 used a taller bracket to mount the throttle linkage/kickdown lever (throttle control rod) for the 727 or used a different length/bend actuating rod for the kickdown lever. I guess this is where a factory parts manual would come in handy...

    I will document the adaption of the mount (if it works!) and take lots of pix along the way. This won't be a rush job so I'll have time to document.
     
  5. David Banner

    David Banner High Wheeler

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    Cost. The 304 is said to be an "ok runner" and the cost is my labor for helping to pull it!
    I'll inspect it before installing it in my Scout but if it needs any machining it goes in the same "scrap pile" as my current 345!
    He!!, if I can't find a work around to $200 worth of IH engine mounts I'll be buying these engine mounts instead...
    http://www.advanceadapters.com/products/713007--chevy-v8--43l-v6-engine-mount-kit/
     
  6. kevingweq

    kevingweq Y-Block King

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    One of my favorite fuel pump parts supplier/rebuilders "Then and Now Automotive" also rebuilds motor mounts , Personally I have never
    used this facet of their service ,But have heard many satisfied customers recommend them .
    http://www.picturetrail.com/sfx/album/view/1195994

    Apparently the process requires 50 + tons of pressure at 300 deg for an hour to properly bond or
    vulcanize the rubber , Has anyone heard of another company rebuilding mounts ??
     
    Last edited: Oct 19, 2015
  7. David Banner

    David Banner High Wheeler

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    Got the 'new' 304 home last night.
    1020051700.jpg

    It appears that the throttle linkage bracket is the same part, but the kick-down-lever is slightly different. It has a different angle bend at the engine end. You could probably turn one into the other with a propane torch heating the bend to a dull red.

    Now, does anyone have the height (thickness) spec for a new engine mount?
     
    Last edited: Oct 24, 2015
  8. David Banner

    David Banner High Wheeler

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    Started doing a little inspecting of my 'new' 304A.
    compression #'s aren't great but then I realize I'm used to higher compression duel overhead cam 4 cyl engines. So...
    Engine cold, on a stand, carb removed. Engine hasn't run since last spring.
    Dry: 8) 100 6) 120 4) 99 2) 100 1) 107 3) 99 5) 95 7) 99
    Wet: 8) 140 6) 165 4) 145 2) 140 1) 125 3) 115 5) 110 7) 115

    These numbers indicate some ring wear. I'll do a leak down test as soon as I borrow the tool.
    But are these numbers reasonable for an old/cold engine? Are those compression numbers worth installing or do I already know I need to at least re-ring the pistons. What is the minimum acceptable compression psi? The FSM doesn't say anything about this?
    Considering the factory sticker on the valve cover I'm assuming this engines never been apart. There's evidence of the rear main seal leaking and at the valley pan so I'll wanna replace those for sure.
     
    Last edited: Oct 24, 2015
  9. Erik VanRenselaar

    Erik VanRenselaar Y-Block King

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    I would recommend going with something like the RPT engine mounts from IH Parts America, or the similar item from Anything Scout.
    The compression spec for the IH 304 (IIRC) is 155 psi. I think a hot compression test is better. All plugs out and throttle plates wide-open. Then do the oil squirt in each cylinder to temporarily seal the rings and test again.
     
  10. BinderBookie

    BinderBookie High Wheeler

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    I'm with Erik. A dry test on an engine that has been sitting produces generally unreliable. readings. On top of that, a cold test produces low readings in and of itself. My suggestion would be to install the engine, get it running, run a for a while after an oil change, THEN do a compression test as Erik outlined. By then thing rings would have reseated after scrubbing off whatever rust is on the cylinder and if they were a little sticky, they will have been freed.
     
  11. David Banner

    David Banner High Wheeler

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    Pulled the oil pan off today--two ½ a-dime sized non-metallic bits of what I guess are cam bearing...
    The main and rod bearings look good. Pulled a couple caps off--the bearings are IH with a 5 77 std install date.
    Looks like this motors never been rebuilt--never been professionally damaged--that's a good thing.
    Won't need to do anything with the crank, and hopefully nothing with the heads...
    I'll have the cam out tomorrow and see if that's where the metal flake came from...
     
  12. David Banner

    David Banner High Wheeler

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    Delaminating on the #1 and the #5 cam bearings--guess I'm glad I didn't just install the "runs okay" motor...
    Not complaining--for the price, this motor will still be cheaper to rebuild/refresh than my old one.
    The cam doesn't seem damaged--neighbor will clean up the #1 bearing surface with crocus cloth on the lathe at work...
    IMG_0032.JPG

    The block is stamped 304A and the bearings indicate a build date of 1977 which is the year of Scout this motor came from.
    I thought the rockers would be of the 5 stand and not the 9 stand variety. Should I care?
    IMG_0028.JPG
    The rod & main bearings all look good. Could be reused if I had to but since I think I'm going for new rings I'll renew all the bearings. They're all standard IH.
    IMG_0048.JPG IMG_0050.JPG

    The pistons slid out pretty easily--I didn't knock any ridge off before removal like the manual suggested...
    IMG_0029.JPG IMG_0035.JPG IMG_0038.JPG
    There's still some cross-hatching visible all around. There's also some vertical scuffing here and there...
    Should I try a ductle moly ring pack or go with a stock iron rings figuring there's some taper in the bores the rings will have to conform to?

    It looks like changing the cam bearings will be easier with the crank out--should be able to see what I'm doing...

    Since the idea here is to avoid the machine shop. Lets see what we can do with a "back yard rebuild" kinda thing...
    What DIY machine work is still worth doing to make this a better motor?
    I will do a light hone crosshatch on the cylinder walls.
    Replace front and rear seals and casting plugs. The casting plugs look great but I can see the best way to clean the block is to get them outa the way.
    Clean up the sharp corners of the intake plenum?
    Basic gasket matching of the ports?
    Definitely do Bill-USN's oil passage drain-back cleanup and umbrella valve seals.
    Probably install new valve springs. I may have one bad lifter--I'll know better after clean-up.
    Rebuild oil pump. Any other tips for the oiling system?
    Anything else I should consider or reconsider while it's all apart...?
     
  13. BinderBookie

    BinderBookie High Wheeler

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    Did you buy an installer to replace the cam bearings or are you having those professionally installed? They aren't brain surgery to do DIY if you have the right sized drivers but they are easy to mung up.

    I would recommend iron rings for the reason you specified and buy a hone that delivers the correct surface for them. Yes, there are different hones for different ring types and if you want the best results (e.g. quick ring seating), I suggest you do a little googling before you buy the hone.

    If you have the manual, it will tell you how to mike and measure everything, including the oil pump. Do that and buy parts accordingly. Absolutely nothing wrong with an overhaul vs a rebuild with a basically good engine like this one, where by to reuse what's good and only replace what's bad.

    One major tip is cleanliness. Even during overhauls, I wash all the parts in clean solvent and after that, the block in hot water and a good degreaser, blowing out all the oil passages with compressed air and pressurized hot water (I rigged up a hose to a hot water tap).

    Here was my latest overhaul, my old 6.9L diesel. That is not a hone, just a big bore-cleaning brush. I had already honed the cylinders at that point and a good hot, soapy scrub afterwards is the best way to get the honing debris out. Use hot water, which helps the block dry quickly, but blow it out quickly with dry air to prevent surface rust. I then sprayed the bores and bearing surfaces with StaBil fogging oil to prevent rust. I am anal about the cleanup and my anality was demonstrated by oil analysis with particle count about 1000 mile later. It was clean enough to leave the oil in and, in fact, the break in oil was run nearly 8000 miles (after I installed a bypass filter @ 1200 miles) and it could have run longer but I wanted to switch to synthetic.

    The main reason for a "break in oil change" is to get rid of contaminants. Some of those come from the break in of the parts but the vast majority, some sources list about 80%, is dirt and debris introduced during the machining and assembly and not properly clean out. In the case of an overhaul vs a full blown rebuild, where everything is machined to minimum tolerance, there will be little contamination from the break in of new parts on the overhaul. Most your contamination will be dirt, dust and junk from the engine sitting apart, still left in the lube system from the bearing failure and stuff you may introduce from honing etc. That's why you do the super cleanup after you have honed and done all the other work.
     

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  14. David Banner

    David Banner High Wheeler

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    Thanks BinderBookie. Great idea to hone the cylinders and such before I take the block to the steam cleaners
    I'll be using the neighbors hone which is very likely for iron rings (he's an early ford lover)
    Matt76 has a very nice cam bearing installer so I'll borrow that :beer:

    Any recommendations on the best cam bearings to buy? I'd like ones that can handle sitting for 8 months at a time with out farking up at startup the way the oem IH bearings are rumored too...

    The timing gears are R2's. Would finding a set of R1's really make a noticeable difference? Should I concern myself with degree-ing the cam if I'm using the stock cam?
    Safe to assume a "fresh" 304 will make more hp/torque than a worn 345?
     
  15. BinderBookie

    BinderBookie High Wheeler

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    I'm no expert on the IH V8 (though I have rebuilt hundreds of engines over the years) but I would theorize the bearing issue as much a lubrication/lubricant issue as anything. Use an API SL rated motor oil that has sufficient ZDDP (zinc) and one that has significant amount of moly. (molybdenum). The ZDDP protection kicks in mostly with warm oil but the Moly works well with cold oil and that aids wear on cold starts. It could be an operational issue also. Truck sits. Driver starts it up and burns rubber. Akkkk! Start it up, let the oil pressure stabilize at idle, drive easy until the engine and oil warms up. Don't use excessively heavy oil that doesn't flow on a cold start... e.g. no 20W50. A high ZDDP 10W40 or 10W30 is optimal IMO.

    As to bearing brands, I like Clevite but you may not find any IH applications in that brand. Don't know. You check ( : < ) Federal Mogul I like too (only because I worked with them on a story and got a lot of inside info from one of their engineers).

    I honestly don't know what the diff between the R1 and R2 gears... I vaguely remember it has some to do with the angle of the teeth but???

    It can be worthwhile to degree a cam if they are known to be off. I worked as a factory (England) trained Land Rover tech. In the late '80s and relay '90s I wondered why some 3.5 and 3.9L V8s were dogs and some raped apes. In tearing many engines down for warranty work (I have some stories there, boys), I started throwing my degree wheel on every time I had the front cover off. Very wide difference in the spot the keyway was cut on the cam gear. About a 10 degree range IIRC. The ones that were a couple degrees advanced or dead on were the raped apes. The retarded ones were, well, retarded and the obvious dogs. A degree or two either side of "zero" don't amount to much that the driver can feel but more than a degree or two retarded, you can start to feel it. In a few cases, retarding the cam timing is beneficial but it goes along with other specific mods. Generally you want zero or a couple advanced on an otherwise stock engine. Unless the IH V8s have a "rep" for cam timing being off, it may not be worth the time from a strictly practical POV, but it's fun to do and then you know. Offset keyways are the only way to change the timing on a gear driven cam unless you have a keyway recut on a blank gear.

    Going back to the Rovers, I could roughly check them from the box and pick out a factory replacement that was better. Most often, if it was a customer pay job, I'd recommend a Cloyes roller set.

    FWIW, I checked the gears on my 6.9L diesel, also an IH Indy Engine plant product, and it was dead-nuts on.
     
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  16. 76-scout-MATT

    76-scout-MATT High Wheeler

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    gasket matching the ports .... have to research that one .... I think matching exhaust port is recommended but intake has no real gain .... or the other way around ... I will poke around on that one .... Matt
     
  17. David Banner

    David Banner High Wheeler

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    Okay, thanks to ebay, rockauto closeouts and summitracing I've managed to keep all the parts under $450 to do the overall meeting my goal of not breaking a $500 build budget to overhaul a 304A.
    Time to plunge down the rabbit hole--2 nice weather days so I can do the gasket match port/polish work outside--I don't want all that metal dust in the garage! (I'm also in the middle of a woodworking project...)
    1) Any reason not to use the oem metal gaskets as a guide for the porting?
    (My Sealed Power gasket set 2601075 hasn't arrived yet)

    I won't be changing compression (I have oem metal head gaskets), I'll be using new sealed power oem rate valve springs.
    2) Can I get some opinions on using this cam http://www.summitracing.com/parts/cca-83-200-4 compared to a stock replacement cam?
    I'm thinking I don't want to use "more cam" on a stock 304... I want to maintain/improve low end torque while still being easily street/hwy driven. Mild wheeling and highway to get there are the main uses with occasional towing of 3000lb camper/trailer. Snowplow days are currently over but that could possibly change...

    3) Any other recommendations for oil passage way mods or other improvements while I'm in there?
    (I'll be following Bill's advice from the KB on head cleanup here http://www.binderplanet.com/forums/index.php?resources/ih-cylinder-head-valvetrain-problems-and-cures.31/ )
     
    Last edited: Nov 23, 2015
  18. BinderBookie

    BinderBookie High Wheeler

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    Pretty mild cam and probably the best for the 304 (as the Summit specs say). Looks like it has a little less duration on the intake than stock and a little less lift as well. Exhaust has a little more lift and about the same duration as stock. Haven't calculated the LSA for the stock cam. Given they apparently used the same cam for 304 thru 392, I'd say your choice is probably a good one for a 304 where too much cam could be counter productive
     
  19. David Banner

    David Banner High Wheeler

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    And after pouring over old threads it seems there's disagreement on the value of spending any time porting the intake if I'm not building a high rpm motor. Any new thoughts on this? The intake valves are smaller on the 304...
     
    Last edited: Nov 23, 2015
  20. Tom Mandera

    Tom Mandera Dreams of Cub Cadets

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    Just to confirm - the relay linkage for the kick-down is different between a 304 and 345 to make up for the deck height difference.
     

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