Page 5 of 5 FirstFirst ... 345
Results 41 to 44 of 44

Thread: 2.25 petrol - poor running with Zenith

  1. #41
    Join Date
    Nov 2018
    Location
    Australia
    Posts
    33
    Quote Originally Posted by Busted Syncro View Post
    G'day Will,

    Start filing!. The thread is 3/16" x 32 UNS 60 degree Cheese Head Set Screw on a 29D. The centrifugal advance should spring back to zero. Maybe a broken spring? or jammed weight.

    The normal way to determine if the inlet manifold gasket is leaking is use a vacuum gauge. You have a rubber hose on the vacuum advance and just need a 3 way connector (like on windscreen washer setup) and some extra hose to connect the gauge in. You can pick one up on eBay for $25 that does vacuum and fuel pump pressure.

    Chris
    Thanks for that - I'll see if I can source some. (I can only really work on the car on weekends, so I don't mind waiting a bit for stuff to arrive.)

    Regarding the centrifugal advance, it springs back 90% of the way, it's just the last 10% or so that it can't do when stationary.

    I looked into using a vacuum gauge for the inlet manifold, but I wasn't able to figure something out - there's always going to be one cylinder with an exhaust valve at least part-way down, so how do I know the leak is coming from the manifold and not that cylinder? I've have thought the cylinder with the open inlet valve will always leak a bit due to piston rings not being a perfect seal.

  2. #42
    Join Date
    Nov 2014
    Location
    Sydney
    Posts
    186
    G'day Will,

    The vacuum gauge is used when the engine is running. (You are right about the valve/piston leakage when engine is not running.)

    If the vacuum gauge reads low when the engine is at idle you have a leak in the inlet side. The gauge can also diagnose a leaking/blown head gasket and ignition timing plus other faults. Very handy gauge and simple tool to use in the tool kit.

    The best way to cut a new slot in the screw is use a flat needle file with teeth all round.

    Chris

  3. #43
    Join Date
    Nov 2018
    Location
    Australia
    Posts
    33
    Thanks Chris! I thought I was missing something about the vacuum gauge. Unfortunately getting the thing running is a bit of a two-person job right now, so I think I'm better off just waiting until my air regulator gets here. Sounds like a handy tool in any case, I'll start dropping hints for Christmas ;-)

  4. #44
    Join Date
    Nov 2018
    Location
    Australia
    Posts
    33
    An update on this: all's well with the engine now, there turned out to be a pair of problems.

    The (brand new) carburettor was bad, and the second problem was that it was losing spark after running for a bit. So, when I was testing the quality of the spark earlier, it looked fine, but if I'd left it cranking over long enough it would have disappeared.

    Not sure what the deal is with the spark since I replaced the entire ignition setup (it was reasonably cheap to buy an entire aftermarket distributor and coil instead of messing around with the old-style screw-on leads on the old setup).

Page 5 of 5 FirstFirst ... 345

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Search AULRO.com ONLY!
Search All the Web!