340 build up

Discussion in 'Small Block Tech' started by Jim Blackwood, Aug 20, 2008.

  1. Jim Blackwood

    Jim Blackwood Well-Known Member

    That's a real judgement call on these blocks Wes, and should be based on a competent sonic check. On my block the thinnest thrust wall was .144" at a .030" overbore. We went to .050" on the fresh reman block to clean and square the bores, shifting a bit to minimize thinning that wall further, so it probably ended up between .140 and .135". That's a little thin for a real high powered build up and about 3/16" would be pretty much ideal but I think it'll be fine and that put us at the standard 350 bore size. I wouldn't have wanted to go any further, which probably means that is the last rebuild for this block. It's possible to go thinner, but can be risky. The problem is core shift of course. The #2 cylinder was perfect, right at .220 all the way around. But by the time we got back to #7 there was a core shift of about 1/16". If you had perfect wall thicknesses all the way around you could get by with a .110" overbore which would be .060" over 350 pistons and still have a 3/16" wall, but that isn't likely to ever happen. So in practical terms a .030" overbore is nearly always going to be safe and anything more is going to depend on the particular block and your own risk tolerance. It doesn't help any that the 340's are getting a little harder to find, but otoh they do tend to be cheap when you do find them.

    Jim
     
  2. Jim Blackwood

    Jim Blackwood Well-Known Member

    Here's some eye candy for you guys. The lower section is done. It needs a thermostat housing, bypass nipple, and a couple of flow dividers but it's ready for the intercooler enclosure to be added. I'm getting better on the welds as I go, it's been a long time since I welded aluminum but since almost all of these welds will be hidden I don't feel too bad about them. I think I'm about up to speed by now and should be able to get a good cosmetic job on the outside welds, or at least good enough to grind and polish. Time to buy more parts.

    Jim
     

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  3. sean Buick 76

    sean Buick 76 Buick Nut

    Amazing work!!!
     
  4. Jim Blackwood

    Jim Blackwood Well-Known Member

    Haven't gotten much done on the intake lately but I've made some progress on the damper. It didn't want to slide off the crank snout easily after I added the speedy sleeve so I smacked it lightly with a deadblow hammer and the inertia ring moved. Time for a replacement. Looks like fluid dampers are all the rage but since I didn't see one for SBB and didn't have the big bucks for one anyway I found a real nice one for a Jeep on ebay and bought that. It has a removable hub so I can adapt it to the center of the stock damper, it is zero balanced so I'll have to remove some weight from the adapter on one side, and it has a 7 groove serp pulley cut into the outer edge. I can cut an 8th groove to match the blower pulley. So next on my to-do list is to make a bearing suspended balancing jig to use in matching the new to the old. Then I'll probably still ship it off to Dale Spooner for him to check it.

    I can't actually cut metal on the adapter until I get an A/C compressor though. I found a stock compressor mount on the shelf, and it turns out that the old A6 Frigidaire compressor that GM used by the millions has a displacement over 12 cu.in, making it the largest readily available compressor, and I want the biggest compressor I can get to run the intercooler. Some of them apparently came with an 8 groove pulley, so the combination of the stock mount and that pulley will establish the belt position. The damper and the blower will have to line up to that.

    Jim
     

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  5. 87GN@Tahoe

    87GN@Tahoe Well-Known Member

    thats gunna be an awesome setup Jim...

    I wish fluidampner made dampners for Buicks:error:
     
  6. roverman

    roverman Well-Known Member

    I think they still make one for the V6. I'm not shure if it's ext. bal. I use the sbc.(sorry), and bore/ hone it to fit. No problems to-date, being steel billet hub,:Smarty: roverman.
     
  7. Jim Blackwood

    Jim Blackwood Well-Known Member

    Good tip, but without knowing the sbc bore size, keyway specs, seal diameter, nose length, and bobweight size and location relative to the keyway, I reasoned making an adapter might be easier than cutting poly-v grooves on the periphery and taking a chance of going too deep. Plus the existing bobweight on the hub of the stock damper helps by setting the location and decreasing the weight needed. Since I also need a trigger wheel that is another place I can play with the weight.

    Jim
     
  8. 67Rag

    67Rag Well-Known Member

    Jim,

    It looks really cool! I'm just starting on my 340. I do have a quick question for you, where did you get the valve covers?

    Andy
     
  9. Jim Blackwood

    Jim Blackwood Well-Known Member

    Those are Rover. Bought 'em off ebay for $40, bead blasted and painted them with clear. They come with a real ugly plastic covered oil filler cap but the plastic comes off. There are quite a few different varieties, and the thing you need to pay attention to is your pcv plumbing since the Brits did it differently.
    http://www.britishv8.org/Articles/Positive-Crankcase-Ventilation-PCV.htm

    Jim
     
  10. Jim Blackwood

    Jim Blackwood Well-Known Member

    Been a lot going on since I last posted. First off, the A/C based IC system has real questionable viability. No real surprise there since Ford had to use a thermal accumulator to make theirs work. The problem is that the heat of evaporation of freon is very low, something like 1/20th of water's. Various other fluids were investigated in terms of phase change temperature, latent heat, freezing point and compatibility with the system materials and after considerable calculation and testing it has been decided that plain old gasoline at atmospheric pressure and 2 gpm flow through the evaporator is the best choice. This means that a good fuel pump will handle circulation and no draw-down and purging will be necessary. OK, that's the good news. Calculations are being checked as we speak but it looks like a workable plan and other details of the system will be described later. Cabin air will be a separate system.

    Next, the damper has to be mounted before anything else can be done. So, in the following photo you'll see a balancing tool I made up from bits lying around the shop.

    [​IMG]

    Assembled it looks like this:

    [​IMG]

    But needs more room to rotate completely so:

    [​IMG]

    Here it's mounted in the bench vise. It turns out to be very sensitive and will detect less than 1/8 turn of the screw and very minute angular changes so once dialed in I marked the keyway, drilled and inserted a pin to lock the position. The slight position error that resulted meant that I had to screw a couple of bolts into the damper hub to get back to center. I dare say that when I send the finished part to Dale for checking it should be within grams of proper balance.

    So next I'll knock off the inertia ring and begin to turn the adapter out of the large blank of 1018 steel seen above the stock damper in the first shot. That's over $80 worth of round stock, just one example of why custom parts cost so much. Most of it will be whittled away to make an adaptor that will precisely fit the fluid damper to the original hub, and it will also have a ring of holes drilled in the rim of it to trigger the Ford EDIS ignition system and Megasquirt EFI. Quite a bit of work before we're at that point though.

    <table border="0" cellspacing="0"><tbody><tr valign="top"><td class="read_left_column" width="150">
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    I got the blank chucked up in the lathe, rough turned, faced, drilled, and cut one counterbore on the back side for the trigger ring. Tomorrow I will try to do some more work on it, the bore for the damper hub and the one for the pilot ring on the face of the hub. First I need to measure the amount of offset weight that is needed. This can be done by placing weights on the threaded rod at the correct distance from center until it is balanced (with the outer balance ring now removed) and then finding the mass of that weight in a common sized material such as round stock. That will tell me how much material will have to be removed to balance the adapter, which in turn will tell me how much material I will have to leave in an area where it can be selectively machined away. It would be far too easy at this point to leave excess metal in the part, but this increases rotating mass and reduces the responsiveness of the engine. Conversely it would make it idle smoother but I'm not after a smooth idle. So light weight is the goal. When completed the adapter should be as light as I can make it and still do it's job. After the bores are cut and all surfaces turned to finish size I will flip the part and turn the pilot for the fluid damper, at which point the lathe work should be done. Then comes drilling the hole patterns for the damper and hub, then trigger holes and balance/lightening holes, and final assembly and fitting. Then it goes to Dale for a final balance. By then I hope to have the pump for the IC ordered and can get back to welding.

    </td></tr></tbody></table>
     

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  11. bob k. mando

    bob k. mando Guest

  12. Jim Blackwood

    Jim Blackwood Well-Known Member

    Thanks Bob. It was late, I got in a hurry. I'll do better I promise.

    So how's this for a start? More motor porn! The attaching holes, crank trigger holes, and balancing holes have not been drilled yet, and I have to cut a few belt grooves plus paint also but a pretty good look at it.

    Jim
     

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  13. bob k. mando

    bob k. mando Guest

    I'll do better I promise.


    oh fer ... i'm not ridin yer butt. i'ze just lettin ya know that the pics ain't coming up.

    if'n i hadda known you was such a wee delicate flower, i woulda tried to be more gentle. :af:



    :bla:
     
  14. D-Con

    D-Con Kills Rats and Mice

    http://www.killerchiller.com/ Jim don't know if you've studied this, some of the mustang cobra guys have used them, a bit of controversy if they are worth it.
     
  15. Jim Blackwood

    Jim Blackwood Well-Known Member

    Yeah Bob, that's me, Delicate Flower. Guess I'd better change my log-in name. So how'd you like the dampener? It'll look even cooler with the trigger holes and the extra poly-v grooves.

    I hadn't really thought about those thermo modules for intercooling. Maybe the cost has come down a bunch on them. By my reckoning it'd take a boat load of them though to move enough heat that you could tell they were there. Consider the coolers that use them. Yeah, they work but they aren't fast. Not nearly as fast as regular refrigeration. So if an A/C based system is going to struggle..... that's why I didn't look into it.

    Right now I'm trying to decide whether it'd be better to use two pumps or one. Combine the IC and EFI circuit or separate them. Pros and cons each way and it's not an easy choice. 2gpm is not such a large volume that it worries me, but it's still the entire contents of the tank in 6 minutes. So I'm leaning towards separate, which also allows me to only run the IC side under boost. That does mean more complicated plumbing, but it also allows me to consider a recirculating system that uses the return of the EFI circuit to top it off, eliminating extra lines to the rear. That seems the most practical at this point, but I may have to redesign the EFI side of the system anyway, and I'm not sure that the stock Ford external pump can supply adequate fuel for this motor. For now maybe I'll stick with less vexing matters, like making mechanical parts.

    Later,

    Wee Delicate Flower
     
  16. Jim Blackwood

    Jim Blackwood Well-Known Member

    Some new photos for you guys, the first one is the set-up I used to mill the timing slot and holes in the rim of the damper coupler. Next is the billet mount for the pick-up which bolts to the fuel pump location on the front cover. Last is the whole thing assembled. Lines up well and looks good. I'll be boxing it up to send out to Dale Spooner at Motion Machine for balancing to match the crank, and while that's gone will probably do a little more work on the mount for aesthetics.

    JB
     

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  17. sean Buick 76

    sean Buick 76 Buick Nut

    Nice progress!
     
  18. Jim Blackwood

    Jim Blackwood Well-Known Member

    A little more work on the intake:

    JB
     

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  19. Jim Blackwood

    Jim Blackwood Well-Known Member

    The intake/IC is completed and installed on the engine. Need to make fuel rails, install a filter on the IAC and build a throttle body/air scoop. A pancake alternator was needed to fit in front of the cylinder head so I cut down a Delcotron and made a new rear cover for it. Presently working on the pan spacer.

    There was a good bit of talk on here about what it would take to make a crank girdle, and as far as I can tell that's just about as far as it ever went. Which is fine, but it doesn't get the job done. Here's something that works and is simple. It's the template cut out of posterboard and transferred with spray paint to 1/4" CR. Needs 2 spacers for the rear cap studs and will otherwise bolt up and work. Final layout will be with digital calipers and straight edge and cut out will be done with a portaband held in a vise. No blanchard grinding or any other frills. It will space the pan down 1/4" and secure the free ends of the cap studs to eliminate cap walk. No estimates of what horsepower levels it will handle but it'll be better than stock.

    JB
     

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  20. Jim Blackwood

    Jim Blackwood Well-Known Member

    Done. Just need to make some spacers and washers.

    JB
     

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