valves

Discussion in 'Mech Tech' started by wendygun, Feb 20, 2017.

  1. while I am waiting on some fubered parts to be exchanged I thought I would look at the heads that need building up, so in standard heads are the stainless inlet valves needed in a pretty much stock engine or just stick to standard, obviously they cost more than double the price but do they have any major advantages.
    any thoughts....
     
  2. EggBoxes

    EggBoxes Supporter

    The stainless are less bulky than the AA ones that came with the head so increased the CC volume by 0.8cc - not loads, small change on compression ratio.
     
  3. that reminds me to look for some plastic to make a disc for checking the head cc.
    if you say they are less bulky does that mean the valve head is slightly thinner..........
     
  4. EggBoxes

    EggBoxes Supporter

    They were slimmer than the ones that came with the AA heads, which made the valve head lighter - a plus for something that moves up and down quickly.
    It was my 1st engine build. Someone else will second this ?
     
    Last edited: Feb 20, 2017
    wendygun likes this.
  5. 77 Westy

    77 Westy Supporter

    A CD works well.
     
    V.R.M. and wendygun like this.
  6. 77 Westy

    77 Westy Supporter

    Stainless steel valves tend to be lighter, so put less strain on the valve train and lighter valve springs could be used reducing the load on the cam and followers etc. It doesn’t transmit heat particularly well but it does tolerate heat, so good in supercharged, turbocharged or NOS injected engines but in a standard engine that will seldom, if ever, be revved beyond 5,500 stainless steel valves are probably a waste of money.
     
    wendygun likes this.
  7. mikedjames

    mikedjames Supporter

    Also they tend to get hammered more than steel valves . I bought stainless valves ofor a stock head and the stems mushroomed fter bei g hammmered by the adjusters to the point they will not come out without filing the ends of the stem or using the valve as an oversize reamer in the valve guide .

    From this I suspect that lash caps or elephant foot adjusters may be needed for long life.
    Despite that my stainless valves are still going 35000 miles after fitting.
     
  8. 77 Westy

    77 Westy Supporter

    Yes, if the valves don’t have a hardened stem tip it’s really essential to fit lash caps.
     
  9. Stainless valves have a stem shape where they meet the valve head that is better for flow
     
  10. Or cut a circle out of an old plastic number plate
     
    wendygun likes this.

Share This Page