Our Tomahawk refresh

Discussion in 'Race 400/430/455' started by slimfromnz, Jan 20, 2016.

  1. gmcgruther

    gmcgruther Well-Known Member

    That there should tell you, its not fuel wash, that there is almost too lean. You are completely burning fuel. Your tune is awesome. Good luck my friend.
     
  2. speedtigger

    speedtigger 9 Second Club

    The popular dynamic compression formula is irrelevant and useless in a race engine as it does not take volumetric efficiency into account.

    Tremendous engine OP. That thing is a beast!
     
    Last edited: Jan 22, 2016
  3. gmcgruther

    gmcgruther Well-Known Member

    Please tell that to Reher-Morrison, Moran Motorsports, Nelson racing engines, Sonny's racing engine's and so and so on. They all follow a very specific cam regiment and that deals with the very detailed build of an engine their working on, not some S.W.A.G. Simple Wild Ass Guess. Damn, even the guys in NHRA do this. I didn't think so at first but once you get a cam that is specific to your vehicle, not just engine , but also to engine functionality, you will notice a huge difference in power.
     
  4. slimfromnz

    slimfromnz Kiwi Abroad

    Thanks Speedtigger. Cant wait to drive it again!
    Cheers
     
  5. gmcgruther

    gmcgruther Well-Known Member

    Royden, Go to Reher-Morrison.com go over to "Tech-Talk" click it, go find "Tech-Talk #8" and this is way Reher-Morrison is a very well established "Custom Building Engine Company" and someone that is not. Known your Cylinder head information " C.F.M., Port velocity in its interiority, Wet Flow capability, and so much more." YOU CAN USE THE "DYNAMIC COMPRESSION CALCULATOR TO YOUR ADVANTAGE." Don't be fooled. On race engines, you want the Dynamic Compression close to Static Compression because your engine builder found out how to make you heads breath very efficiently. Now, if someone wants static compression in lets say "11.5:1 " but can have a Dynamic Compression of 8.5:1 - 9.5:1 for running pump gas. But dont get me wrong, the knowing of your cylinder heads is the ticket to getting the best of your engine.
     
  6. slimfromnz

    slimfromnz Kiwi Abroad

    Well its back home again after repairing the rear main leak.
    We changed from a 2 piece seal to a 1 piece, and it seems to have fixed the issue.
    The trans is in the shop getting a once over, and also going to put a race converter in it to see what we can do.
    [​IMG]
    Cheers
     
  7. Cellguy

    Cellguy 86 Somerset Screamer

    Royden,
    Looking good! What is the sending unit looking thing you have tapped into the 4th port on the back of the engine?
     
  8. Smokey15

    Smokey15 So old that I use AARP bolts.

    Saw that as well. Looks like a 'hobbs' switch That would be used to kill nitrous should the oil pressure drop. Or, like my wife's Z, it's set up to run both a gauge and an oil pressure light. I could be wrong. Been wrong before. I have an ex wife.
     
  9. slimfromnz

    slimfromnz Kiwi Abroad

    Hi Guys,
    One runs my VDO oil pressure gauge, and the other is for an oil pressure light that comes on under 15psi. It is just laying there at the moment. Once back in the car it will be fixed in position.
    Cheers
     
  10. Tom Righter

    Tom Righter Well-Known Member

    If you could give some more info on using a one piece rear main seal ,this is the second time I've heard of leaking rear seals in the tomahawk block. what seal is used on the 3"main deal. I'm building a 565 twin turbo motor and want to make sure i don't have any seal issues. Thanks TOM
     
  11. capsgs

    capsgs Well-Known Member

  12. Tom Righter

    Tom Righter Well-Known Member

    Thanks Chris, Wow thats a little disappointing that the block wasn't machined for a more common ,better designed seal especially after all the seal issues with the stock block.
     
  13. Jim Weise

    Jim Weise 1000+HP

    Knock on wood, but I have built 3 of them now, and no leak issues, with the Fel Pro Performance seal.. for the 460.. none of them have had vacuum pumps.

    First motor went 3 years and 435 passes and never leaked a drop.

    Although, the one piece seal looks interesting, have a 'hawk on the stand right now, am going to order one and do some test fitting.

    I believe TA is selling a one piece seal, and Mike has used it.. might want to chat with him on it.

    JW
     
  14. Tom Righter

    Tom Righter Well-Known Member

    Ok thanks Jim
     
  15. Jim Rodgers

    Jim Rodgers Well-Known Member

    No leaks on mine either. 2 piece seal. Big compression and no pump.
     
  16. sailbrd

    sailbrd Well-Known Member

    This is not the cheap solution but it is how we are going to set up our GN to run E85 street gas. One, you need to run a FAST ECU. Then get a GM fuel sensing unit, they are common in junkyards now. FAST will interface with the GM unit and adjust tune to the fuel. Since we already have the FI and FAST in the GN the last step is not much money. But the first two are a bit of a hit, especially if you are not already FI.

    Probably a lot cheaper just to get good fuel.
     
  17. capsgs

    capsgs Well-Known Member

    So as not to cause any confusion, the Butler seal has to be split to use. To my knowledge it is the only double lip seal out there and works very well with a vacuum pump. I know of a couple guys that while the Viton seal from TA didn't leak oil, it would not hold vacuum.
     
  18. Tom Righter

    Tom Righter Well-Known Member

    Well I guess thats what I'll be using. thanks again for the info. Also if T/A would do another block run it would be nice to O ring pan rail and timing cover, just a thought.
     
  19. slimfromnz

    slimfromnz Kiwi Abroad

    O rings would be good.
    I got my one piece seal from Mike at TA. You just cut it at the dimple mark and feed it over the crank and drop the crank in with the seal attached.
    Cheers
     

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