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Topic Review (Newest First)

  • 16-10-2017, 23:29
    TheWebDesignCompany
    They received really good reviews on YouTube by a port and polisher in America. With higher than advertised numbers when measured.
    The problem is of course that one of my camel hump heads was cracked. So I bought new heads that I though would increase the power...
  • 16-10-2017, 19:49
    TECHNICALTOM
    Some interesting reading and plenty of good advice too.Let me state right off I could not make SBC alloy cylinder head if my life depended on it , so I am very slow to bring the Quantico cylinder heads country of origin up,but I am curious. will a relatively unknown V8 Cylinder head manufacturer ,produce a cylinder head as good as say "Made in USA " Brodix or AFR Dart, ETC ETC,The old Camel hump heads Ported by the right hands were well able to produce good power.
  • 15-10-2017, 22:29
    blackpopracing
    Big valve heads, not really required for street use as power from them is only realised at top end rpm. Smaller valves give more low end torque.
    You need to start at the beginning and set the timing correctly. Then start tuning the carb.

    A trip the rolling road in Essex will get the full potential of your setup and save you weeks of fiddling around while not getting the results you want.
  • 15-10-2017, 14:04
    68roadrunner
    I know of a "500 MOPAR with B1 heads that has only a "484/500 hydraulic cam in it, .....as opposed to a "600-"750 solid or roller cam that "B1 heads need"...and it works great as a street driven car.

    64-68cc comb chamber difference will not matter for a 13sec street engine..i.e., IT wont even know its been changed.....would in a race engine though, so dont overthink here.
    Good luck fella.
    Sounds like there is a load of "specialist mechanic" BS going on IMO.
  • 15-10-2017, 12:54
    TheWebDesignCompany
    Quote Originally Posted by mygasser View Post
    yep, used them several times. if you book in advance they can do them while you wait.
    I was hoping to find a good place this side of the Dartford Crossing...
    Has anyone ever used Western Propshafts in Benfleet? Any feedback on them?
  • 15-10-2017, 12:51
    TheWebDesignCompany
    Quote Originally Posted by Roscobbc View Post
    Trying to 'sit on the fence' here and look at all the information that's been provided to date. Parameters not fully discussed so far (unless I missed it earlier in the thread) - rear axle ratio (and effect that may have on auto transmission with this engine combo) and whilst we learn that timing may have been way too far advanced - do we know what its currently at - we don't know the timing curve set in the distributor - I'm sure all will agree than an engine with either of these cams will want far more initial 'advance' than a 'stockish' 6 or 8 degrees initial. What is the vehicle? - what is the weight? We may be presuming that a 'performance' curve suitable for one of these cams (i.e plenty of 'initial' timing) was already 'set' in the distributor before the engine work - but are we sure? Whilst comment is being made about these cam being 'mild' - they may not be 'mild' in the wrong vehicle. There has been no mention anywhere about where torque peak is likely to be - and surely with a stock auto transmission/low numerical axle ratio etc this is a more important goal in terms of drive-ability for street use than looking for HP peak figures?

    Im afraid I don't have all the details being requested here.

    The car is a steel bodied 1928 Model A, it is on a purpose build drag race chasis.
    It has a Ford 9 inch rear Axel with limited slip diff. (It was originally built as a drag racer in the 1990s in America, then sold to a collector here in the UK.
    Sadly I dont have the build specs or the contact details for the builder, so I've had to learn what I can as the car has been worked on.

    What I do know is that it used to shred the tyres, and you couldn't pull away without wheel spinning before.
    However it had an issue with overheating, which after a blown head gasket turned out to be due to a cracked head.
    The heads that were removed were camel hump heads with the small valves. I replaced them with a set of Aluminium Quantico Racing heads with high flow and big valves.

    The old Lunati camshaft was replaced with a Comp Cams Extreme Energy Cam (an EX268 Cam) which although slightly less cam than I had previously, is only 200 rpm out on the top end, and actually should kick in earlier than the old cam. It isn't a big Heavy car and should be absolutely flying. I guess after getting my PropShaft done, I will need to fork out for a Rolling Road tune up.
  • 15-10-2017, 10:05
    Roscobbc
    Trying to 'sit on the fence' here and look at all the information that's been provided to date. Parameters not fully discussed so far (unless I missed it earlier in the thread) - rear axle ratio (and effect that may have on auto transmission with this engine combo) and whilst we learn that timing may have been way too far advanced - do we know what its currently at - we don't know the timing curve set in the distributor - I'm sure all will agree than an engine with either of these cams will want far more initial 'advance' than a 'stockish' 6 or 8 degrees initial. What is the vehicle? - what is the weight? We may be presuming that a 'performance' curve suitable for one of these cams (i.e plenty of 'initial' timing) was already 'set' in the distributor before the engine work - but are we sure? Whilst comment is being made about these cam being 'mild' - they may not be 'mild' in the wrong vehicle. There has been no mention anywhere about where torque peak is likely to be - and surely with a stock auto transmission/low numerical axle ratio etc this is a more important goal in terms of drive-ability for street use than looking for HP peak figures?
  • 15-10-2017, 09:33
    daxcobra
    I too feel for the op ref the expected outcome and the real world, we all make mistakes, go down a route, spend hard earned And end up disappointed, machine work in U.K. Is stupidly expensive so simple bolt on is often used, you will get there, fundamental issues need to be addressed, and with help from the forum problems solved. Dave
  • 15-10-2017, 08:47
    Stude Star
    https://www.lunatipower.com/CamSpec.aspx?p=00010
    COMP CamsŪ - Xtreme Energy 268 Hydraulic Flat Tappet Camshaft, Part # 12-242-2 Dyno Sheet

    Peak power with the comp cam is 5000, quite low, but it should still be quick up till there. The Lunati cam is a bit bigger but not much, maybe 5500 peak.
    Sounds like you needed the 274 cam?

    Anyhow the engine shouldn't be as lame as you're saying so further tuning investigating required.
  • 15-10-2017, 08:37
    Stude Star
    Quote Originally Posted by TheWebDesignCompany View Post
    Great post very interesting.

    No I haven't measured the distance that the piston sits at tdc below the deck, and as the heads are on now I can't measure it either.
    I seem to remember the mechanic telling me to get a tick Fel Pro gasket as it would make the best possible seal between the block
    and the heads and prevent another head gasket failure, so that may have lowered the compression a touch.


    The mechanic told me the original pushrods were hardened so I assume he know what he was talking about, and no it didnt have
    guide plates on the old heads, I had to buy a set for the new heads. (although the cam isn't as big as the one it replaced...

    The car is running better than it was, but it isn't quite right and it still lacks power compared to how it ran before I paid a fortune for all the new stuff.
    I appreciate it must be very annoying, you're at the mercy of other people and their opinions/talent.

    Most CR's quoted are not accurate, I measured a late 70's smog engine for a mate that was stock and had 8.5-1 from the factory, I measured 7.6-1 in real life.

    A 268 cam is quite mild, I was going to go for a 274, but the car still should be quick, the fact you have domed pistons means you should have quite high CR regardless of the other measurements. Usually only see domed pistons in racing engines, I've always used flat tops or - pistons and still got CR in the 10-1 area.

    I've used 0.015" head gaskets a lot to raise up compression, these are super thin and never had any issues, I suspect he used a thicker gasket due to the domed pistons and trying to make sure CR wasn't too high? That's if he knew what he was doing? The dial indicator should have used to verify measurements to pick a suitable head gasket.

    Im not in any way slagging off your mechanic, just trying to help you figure out what's up.

    Anyway it would appear you have good compression

    Can you get the specs of both cams?

    The stude with quite a lame cam (around 470 lift runs low 13's and will go sideways when you hit 2nd gear), that's with a shift kit th700., 3000b car and an LSD
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