Results 1 to 9 of 9

Thread: 136.5mm valves to be replaced with 130mm valves

  1. #1

    Array
    Status
    Offline
    Join Date
    11-29-2011
    Posts
    50
    Location

    Philippines
    Vehicle

    1986 Mitsubishi Mighty Max
    Engine

    4D56-T

    136.5mm valves to be replaced with 130mm valves

    is it possible to change a cylinder head equipped with 136mm long valves with shorter valves (130mm)? if ever, what hardware needs to be done also? valve springs, camshaft, etc? in short, i'll be using the same head. only the valves needs to be done if ever. whats the effect on compression ratio, hp & torque band, starting (hot & cold), etc? btw, it's a mitsy 4d56 turbodiesel. i know you guys can shed light on this. thanks

  2. #2



    Array
    Status
    Offline
    Join Date
    03-16-2011
    Posts
    3,814
    Location

    Sacramento, CA
    Vehicle

    1979 Dodge D-50
    Engine

    Chevy V6
    I don't see why you couldn't do it. It's only 0.0065" shorter. You might need to cut the head for the springs just slightly to keep the same rate. And shorten the valve guide. Other then that they should open the same amount once adjusted. Does it have hydraulic adjusters or mechanical? Call a machine shop and ask what there thought is. I'm unsure on the diesels. But it can't be much different then any other engine. Why are you looking to go with a shorter valve?
    Members come and members go, But the board keeps track of them.
    Find me on FaceBook
    clicking HERE.

    Or look on YouTube Click Here.
    http://mobilemillwright.com

  3. #3

    Array
    Status
    Offline
    Join Date
    11-29-2011
    Posts
    50
    Location

    Philippines
    Vehicle

    1986 Mitsubishi Mighty Max
    Engine

    4D56-T
    Quote Originally Posted by camoit View Post
    I don't see why you couldn't do it. It's only 0.0065" shorter. You might need to cut the head for the springs just slightly to keep the same rate. And shorten the valve guide. Other then that they should open the same amount once adjusted. Does it have hydraulic adjusters or mechanical? Call a machine shop and ask what there thought is. I'm unsure on the diesels. But it can't be much different then any other engine. Why are you looking to go with a shorter valve?
    mechanical valve adjuster .....how about changing the valvesprings designed for 130mm valves? the primary reason i'm thinking of going to a shorter one is to lower the compression ratio. but still debating myself on this one. don't know yet what will happen with the power band? how would the hp and torque behave with a lower cr?

  4. #4



    Array
    Status
    Offline
    Join Date
    03-16-2011
    Posts
    3,814
    Location

    Sacramento, CA
    Vehicle

    1979 Dodge D-50
    Engine

    Chevy V6
    A shorter valve won't change the compression ratio. You are not physically changing the amount of air that is compressed in the combustion chamber. To lower the compression ratio you would need to change the pistons to a dished piston. The HP and torque will go down a little if you lower the compression ratio. But it will run a tad cooler. From what I here the best thing is oil squirter's for the diesel engines. Thats the trick set up.
    Members come and members go, But the board keeps track of them.
    Find me on FaceBook
    clicking HERE.

    Or look on YouTube Click Here.
    http://mobilemillwright.com

  5. #5

    Array
    Status
    Offline
    Join Date
    11-29-2011
    Posts
    50
    Location

    Philippines
    Vehicle

    1986 Mitsubishi Mighty Max
    Engine

    4D56-T
    Quote Originally Posted by camoit View Post
    A shorter valve won't change the compression ratio. You are not physically changing the amount of air that is compressed in the combustion chamber. To lower the compression ratio you would need to change the pistons to a dished piston. The HP and torque will go down a little if you lower the compression ratio. But it will run a tad cooler. From what I here the best thing is oil squirter's for the diesel engines. Thats the trick set up.
    i'll cancel my plan then.....but do you mind explaining that oil squirter thing for me. i'm curious. thanks again camoit

  6. #6



    Array
    Status
    Offline
    Join Date
    03-16-2011
    Posts
    3,814
    Location

    Sacramento, CA
    Vehicle

    1979 Dodge D-50
    Engine

    Chevy V6
    If you look through some of the other posts they talk about adding in the oil squirter's. It sprays oil up at the pistons. It helps to cool the engine and adds lots of lube in the cylinders. I know some of the engines had them stock but IDK just what ones. I would guess the later blocks have them. They just thread in to the oil galley. But I did here there are kits out there. Ask 4d55preformance. Thats his area of expertise.
    Members come and members go, But the board keeps track of them.
    Find me on FaceBook
    clicking HERE.

    Or look on YouTube Click Here.
    http://mobilemillwright.com

  7. #7




    Array
    Status
    Offline
    Join Date
    03-20-2011
    Posts
    4,857
    Location

    Pittsburgh, PA
    Vehicle

    1980 Dodge D-50
    Engine

    G54B
    The oil squirters were in the 2.6 conquest turbo motors - to add them you have to drill and tap the runner in the block where they are installed on the turbo block. Not sure if the 4d55 ever had them though.
    Pennyman1
    The best Dodge that Dodge never made
    Living the D-50 lifestyle since 1980

  8. #8



    Array
    Status
    Offline
    Join Date
    03-26-2011
    Posts
    1,507
    Location

    Vacaville, CA
    Vehicle

    1989 Mitsubishi Mighty Max
    Engine

    4G63-T
    Oil squirters are also found in the turbo 4g63's from Eclipses/Talons/Lasers.
    Josh
    09 BMW 335i E92 Twin turbo
    89 Macrocab 4g63 Turbo swapped & Bagged: Build Thread

  9. #9



    Array
    Status
    Offline
    Join Date
    03-20-2011
    Posts
    69
    Location

    Laporte, IN
    Vehicle

    1989 Dodge Power Ram 50
    Engine

    Please Select Your Engine Type
    yep the oil squirters are stock on the 4d55......and the 4d56. if you shorten the valves that will bump your seat pressure up. which is a good thing. just make sure you get turbo valves....... there is a difference!

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
  •