massive lack of power - Page 6
Have an account? Register

Forgot your password?

Forgot your username?

 
Likes Likes:  0
+ Reply to Thread
Page 6 of 7 FirstFirst ... 4 5 6 7 LastLast
Results 51 to 60 of 65
  1. #51
    Rods 'n' Sods Junkie TheWebDesignCompany's Avatar
    Join Date
    Jun 2016
    Location
    Southend on Sea
    Posts
    224
    Images
    3
    Post Thanks / Like
    TheWebDesignCompany is offline
    Had the propshaft checked this afternoon and found that there os a little bit of play at both ends.
    So I will need to get it done, the garage said they record the parts will be about £30 - £40 each
    end and an hour to and hour and a half work to fit, but they dont do it, they suggested
    Western Propshafts, anyone used them? Or is there anyone else near Southend you would recommend?

  2. Remove Advertisements
    RodsnSods.co.uk
    Advertisements
     

  3. #52
    Official RnS Addict Phunkie Hiboy's Avatar
    Join Date
    Apr 2009
    Location
    Lindford
    Posts
    1,014
    Images
    0
    Post Thanks / Like
    Phunkie Hiboy is offline
    J W Engineering, Barnehurst
    JW Engineering
    Built without compromise by the more luck than judgment method

  4. #53
    Official RnS Addict mygasser's Avatar
    Join Date
    Dec 2009
    Location
    faversham, kent
    Posts
    12,635
    Images
    514
    Post Thanks / Like
    mygasser is online now
    Quote Originally Posted by Phunkie Hiboy View Post
    J W Engineering, Barnehurst
    JW Engineering
    yep, used them several times. if you book in advance they can do them while you wait.
    need a job done on your project? i may be able to help.

  5. Remove Advertisements
    RodsnSods.co.uk
    Advertisements
     

  6. #54
    Official RnS Addict Stude Star's Avatar
    Join Date
    Oct 2012
    Location
    South London/NI
    Posts
    2,153
    Images
    721
    Post Thanks / Like
    Stude Star is offline
    I've read through a bit of this and i'l make a couple of points -

    1 - did you know your original deck clearance? i.e how far the piston sits at TDC below the deck? It's all well and good saying it has XYX CR ratio when CR ratio is a combo of

    - deck clearance
    - head CC
    - gasket thickness
    - piston CC

    Our vette and Stude both have 350's and have 10.5-1 and 10.3-1 achieved in totally different ways

    The vette deck height is 0.005, the stude 0.040
    The vette heads are 68cc, the Stude's are 58
    The Vette's gasket is 0.015, the Stude's 0.050
    Piston CC is -6 in the vette and can't remember in the Stude (stock GM '80 smog piston)

    All worked out on an online calc to get the vette's CR high enough and the Stude's low enough.

    You can change the CR by 1/2 a point with a different gasket, the only way to really know what you have is to know what you had and what has changed.

    CR is really a tad academic anyway as what you really want to know is the DCR (dynamic compression ratio), you put this in the calc once you know what cam to use as it'll tell you when you're going overboard on cylinder pressure

    Remember a bigger cam will bleed off pressure as the overlap is longer therefore you need more compression to offset it. Remember guys who put a big cam in a stock engine and it was slower than before? Yep that's because the overlap has bled so much pressure out of the cylinders you've effectively lowered the compression until you redline the thing...

    I appreciate this may seem a bit hardcore but this is how Vizard and co build fast cost effective engines, it's all in using the most compression you can for the cam timing and matching everything.

    It may help someone else in the CR department

    Oh also

    2 - how did he know they were hardened pushrods? I presume the original heads didn't have pushrod guide plates and wouldn't have needed hardened pushrods unless someone put them in as a bonus? Guide plates in conjunction with non aligning rockers need hardened pushrods as the pushrods rub on the guide plates.


    How's the car coming along?

  7. #55
    Rods 'n' Sods Junkie TheWebDesignCompany's Avatar
    Join Date
    Jun 2016
    Location
    Southend on Sea
    Posts
    224
    Images
    3
    Post Thanks / Like
    TheWebDesignCompany is offline
    Quote Originally Posted by Stude Star View Post
    I've read through a bit of this and i'l make a couple of points -

    1 - did you know your original deck clearance? i.e how far the piston sits at TDC below the deck? It's all well and good saying it has XYX CR ratio when CR ratio is a combo of

    - deck clearance
    - head CC
    - gasket thickness
    - piston CC

    Our vette and Stude both have 350's and have 10.5-1 and 10.3-1 achieved in totally different ways

    The vette deck height is 0.005, the stude 0.040
    The vette heads are 68cc, the Stude's are 58
    The Vette's gasket is 0.015, the Stude's 0.050
    Piston CC is -6 in the vette and can't remember in the Stude (stock GM '80 smog piston)

    All worked out on an online calc to get the vette's CR high enough and the Stude's low enough.

    You can change the CR by 1/2 a point with a different gasket, the only way to really know what you have is to know what you had and what has changed.

    CR is really a tad academic anyway as what you really want to know is the DCR (dynamic compression ratio), you put this in the calc once you know what cam to use as it'll tell you when you're going overboard on cylinder pressure

    Remember a bigger cam will bleed off pressure as the overlap is longer therefore you need more compression to offset it. Remember guys who put a big cam in a stock engine and it was slower than before? Yep that's because the overlap has bled so much pressure out of the cylinders you've effectively lowered the compression until you redline the thing...

    I appreciate this may seem a bit hardcore but this is how Vizard and co build fast cost effective engines, it's all in using the most compression you can for the cam timing and matching everything.

    It may help someone else in the CR department

    Oh also

    2 - how did he know they were hardened pushrods? I presume the original heads didn't have pushrod guide plates and wouldn't have needed hardened pushrods unless someone put them in as a bonus? Guide plates in conjunction with non aligning rockers need hardened pushrods as the pushrods rub on the guide plates.


    How's the car coming along?
    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 thick 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.
    Last edited by TheWebDesignCompany; 15-10-2017 at 08:29.

  8. #56
    Official RnS Addict Stude Star's Avatar
    Join Date
    Oct 2012
    Location
    South London/NI
    Posts
    2,153
    Images
    721
    Post Thanks / Like
    Stude Star is offline
    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
    Last edited by Stude Star; 15-10-2017 at 08:39.

  9. #57
    Official RnS Addict Stude Star's Avatar
    Join Date
    Oct 2012
    Location
    South London/NI
    Posts
    2,153
    Images
    721
    Post Thanks / Like
    Stude Star is offline
    https://www.lunatipower.com/CamSpec.aspx?p=00010
    COMP Cams® - 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.
    Last edited by Stude Star; 15-10-2017 at 08:51.

  10. #58
    Rods 'n' Sods Junkie
    Join Date
    Apr 2012
    Location
    Ystalyfera S. Wales
    Posts
    144
    Images
    0
    Post Thanks / Like
    daxcobra is offline
    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

  11. #59
    Carburation 'sucks' Roscobbc's Avatar
    Join Date
    Apr 2009
    Location
    South West Essex
    Posts
    4,071
    Images
    14
    Post Thanks / Like
    Roscobbc is online now
    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?

  12. #60
    Rods 'n' Sods Junkie TheWebDesignCompany's Avatar
    Join Date
    Jun 2016
    Location
    Southend on Sea
    Posts
    224
    Images
    3
    Post Thanks / Like
    TheWebDesignCompany is offline
    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.

+ Reply to Thread
Page 6 of 7 FirstFirst ... 4 5 6 7 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Where you live, Town\City\County etc.

Please enter your full name
This field cannot be edited once it has been completed other than via contacting the site admin. Please make sure the information is correct first time.

Log-in

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

    Similar Threads

    1. Lack of power under load
      By stevo1980 in forum Tech Discussion
      Replies: 19
      Last Post: 19-04-2016, 11:41
    2. Lack of power
      By plumcrazee in forum Tech Discussion
      Replies: 7
      Last Post: 18-04-2013, 16:39
    3. Power steering??
      By cabby in forum On Topic
      Replies: 12
      Last Post: 22-06-2009, 22:02
    4. A massive Happy Birthday to Mr Wal Barter
      By Battersea Boys in forum Chat
      Replies: 17
      Last Post: 05-05-2009, 12:36
    5. Power Meet Vasteras: Roll Call
      By Battersea Boys in forum On Topic
      Replies: 6
      Last Post: 28-04-2009, 10:19

    Bookmarks

    Posting Permissions

    • You may post new threads
    • You may post replies
    • You may not post attachments
    • You may not edit your posts
    •