250 engine water pressure test cylinder heads | FerrariChat

250 engine water pressure test cylinder heads

Discussion in 'Vintage (thru 365 GTC4)' started by christc, Mar 14, 2020.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. christc

    christc Formula Junior

    Mar 3, 2013
    444
    Germany
    #1 christc, Mar 14, 2020
    Dear All,

    here comes an engine question.

    I have mounted both heads on my Gte engine and want to pressure test the head gasket sealings.

    Two questions:
    1.) The 330 handbook says to test with 125 psi, thats about 8.5 bar. This is very high compared to the normal running conditions! What pressure do you use for testing?

    2.) I blanked of the side exit where the water coming from the water pump enter the block and use a warm water hose to feed water via the water rail running beside the block. I will use the y-piece in the V between the heads to a.) let air escape while filling the system and b.) apply pressure via a hand pump with manometer. See pictures. What do the experts think? Am I able to fill the block with water this way or are there better ways?

    Any comments on how you do it are very welcomed.

    Thanks a lot.
    Christopher

    View attachment 2907477 View attachment 2907478 View attachment 2907479 View attachment 2907480
     
  2. MiuraP400

    MiuraP400 Formula Junior

    Feb 3, 2008
    940
    Arizona
    Full Name:
    Jim
    #2 MiuraP400, Mar 16, 2020
    The way you have the test set up I would only go to 25 psig. That is about the max pressure you would see with the thermostat closed and at max rpm. Note this data is based on another engine I tested, not a Ferrari engine.

    If you want to test the fire ring, then I would fill the block with water and apply 400 psig to the cylinder with the Piston at TDC and on the firing stroke. Hold this pressure for 2 minutes. If the fire ring seal is good the water level should not rise significantly. I don't remember the amount but look for something less than 1/8 inch
     
  3. christc

    christc Formula Junior

    Mar 3, 2013
    444
    Germany
    #3 christc, Mar 17, 2020
    Dear Jim,

    Thanks a lot for the valuable input and the good tip of reversing the pressure for test of the firing ring!

    Thanks
    Christopher
     
  4. Ferrari_250tdf

    Ferrari_250tdf Formula Junior

    Mar 3, 2005
    462
    #4 Ferrari_250tdf, Mar 17, 2020
    Why would you like to pressure test your gasket sealings? Do you think you have a leak into the cooling system?
     
  5. christc

    christc Formula Junior

    Mar 3, 2013
    444
    Germany
    #5 christc, Mar 17, 2020
    No. Heads are freshly mounted and engine has new liners. Before commencing completion of engine, e.g. timing gear, it makes sense to test for water leakages. Hope this clarifies it.

    Christopher
     
    turbo-joe and Nembo1777 like this.
  6. Ferrari_250tdf

    Ferrari_250tdf Formula Junior

    Mar 3, 2005
    462
    #6 Ferrari_250tdf, Mar 17, 2020
    With all due respect I disagree.
    First of all because you have the risk of blowing a gasket with our test which wouldn't be blown during normal operation. Run the engine and if your cooling system doesn't show excessive pressure or any other sign of leaking coolant don't do anything but enjoy your engine.
    Second if if you do the pressure test like this and there is a leak you still don't know where exactly it is. So you have to take apart the engine again. Then you have to find out if it was just a gasket or if the head has a problem.

    If you have prepared and assembled your engine carefully there shouldn't be any problem with the gaskets.

    My two cents.
     
  7. christc

    christc Formula Junior

    Mar 3, 2013
    444
    Germany
    #7 christc, Mar 18, 2020
    Thanks for your input.
    Just to clarify:
    - at the moment just the heads are mounted, nothing else. So if there would be leaks it would be much easier to rectify now
    - engine so far has been carefully assembled, but I read a lot about 250 head gaskets not beeing up to the job
    - Inspection where leakage would come from would be much easier as I can look at liners from bottom (no oil pan) and bores with borescope as well as outside of engine around heads
    - my plan is to apply around 20 psi, not as recommended in 330 handbook 125 psi. So this would be conditions around normal engine running

    My reasoning is that if there would be leaks under this condition there will be leaks with the engine running. As I will use pressure around normal running conditions the system must be able to stand up to it.

    What do you think speaks technically against this test?

    Thanks
    Christopher
     
  8. Ferrari_250tdf

    Ferrari_250tdf Formula Junior

    Mar 3, 2005
    462
    #8 Ferrari_250tdf, Mar 18, 2020
    I understand, but keep in also in mind that a hot engine is something different then a cold engine. And all the gaskets are supposed to work under running conditions. I never had any problems with the gaskets as long as I used a modern quality product. If you have one of the earlier 250 engines which have the fire rings seperate from the gaskets it is of course a different situation. In this case you could consider to put new liners and use modern gaskets. If you want to know if your cylinderhead has any cracks or open shrinkhole you might consider to have the heads professionally pressure checked in a water tank.

    Good luck

    Matthias
     
  9. INRange

    INRange F1 World Champ
    Silver Subscribed

    Jan 27, 2014
    10,185
    Virginia/Florida/Caymans
    Full Name:
    JD
    #9 INRange, Mar 18, 2020
    You may want to reconsider doing this. I believe your combustion chamber compresses 125-135 psi on the piston stroke. The water system is maybe 15-20 psi so it if you are going to check for an issue.....a leak down test would be far more appropriate. It determines if there is a problem in the combustion chamber with the rings, valves and head gasket sealing. Most head gasket failures originate from the combustion chamber.

    Pressurizing the water system really won't tell what I believe you are looking for.
     
  10. christc

    christc Formula Junior

    Mar 3, 2013
    444
    Germany
    #10 christc, Mar 19, 2020
    To clarify further.

    - Heads have been pressure tested
    - I am less concerned about sealing to combustion chambers, if so I agree that a leak down test would be appropriate
    - I would like to check seal of head gasket around water ways under comparable conditions to running conditions
    - If possible I would like to ensure perfect sealing before going further with engine assembly
    - liners, pistons, etc are new
     
  11. MiuraP400

    MiuraP400 Formula Junior

    Feb 3, 2008
    940
    Arizona
    Full Name:
    Jim
    #11 MiuraP400, Mar 19, 2020
    Engines are cold when started.
    • The water pump raises the pressure above the radiator çap. Ads will not let me finish
     

Share This Page