Replacing 250 Distributor

Discussion in 'General Maverick/Comet' started by fullcm, Mar 25, 2021.

  1. fullcm

    fullcm Doug

    Joined:
    Jun 10, 2017
    Messages:
    262
    Likes Received:
    39
    Trophy Points:
    61
    Location:
    Michigan
    Vehicle:
    74 maverick
    I found a NOS distributor complete with a new Vacuum Advance for my 250 I6. The chiltons manual says a to remove and replace a distributor I just need to mark the distributor location with respect to the engine and also mark the rotor location to the distributor before removal. Will this also work with changing the distributor if I set the new one to the same spots then just reset the timing if needed? I don't want to go through the trouble of setting the engine at TDC compression stroke.
     
  2. RMiller

    RMiller My name is Rick

    Joined:
    Dec 12, 2009
    Messages:
    4,124
    Likes Received:
    1,154
    Trophy Points:
    523
    Garage:
    1
    Location:
    Kennewick, WA
    Vehicle:
    1971 Maverick Grabber
    Trying to shortcut a step to save time has always cost me more time and headache in the end! It really doesn't take that long to line it up at TDC. That said, you are on the right track and might get away with it if your marks are perfect. Good luck!
     
  3. fullcm

    fullcm Doug

    Joined:
    Jun 10, 2017
    Messages:
    262
    Likes Received:
    39
    Trophy Points:
    61
    Location:
    Michigan
    Vehicle:
    74 maverick
    Thanks Rick, your probably right, better to have things lined up first. This is a new procedure to me. Here is what I saw on youtube.
    Pull all 6 spark plugs so engine can rotate easier.
    Put a compression gage in #1 spark plug hole to make sure its coming up on the compression stroke.
    Put a pencil or dowel rod in the #1 hole to see when cylinder is nearing TDC then fine tune with the timing mark.
    Does this all sound right? Also, how hard is it to turn the motor over with spark plugs removed and car in neutral? Would I need a second person?
    Initially I thought if I messed up doing this I could cause severe engine damage but it sounds like the worst that could happen is it just would not start/run.
     
    Last edited: Mar 25, 2021
  4. Krazy Comet

    Krazy Comet Tom

    Joined:
    Sep 13, 2012
    Messages:
    7,561
    Likes Received:
    2,319
    Trophy Points:
    531
    Garage:
    1
    Location:
    Chesapeake VA
    Vehicle:
    1972 Comet GT clone 306 . 1969 Fairlane Cobra 428CJ 1988 T-Bird awaiting 331 ..
    If original position of dist is known, there is no reason chase after TDC. If unknown, TDC on compression stroke is the logical start point. Could just as easily use TDC on exhaust stroke & point rotor at #4(or #6 if V8).

    Carefully mark dist setting, note exactly where vacuum canister in pointing, take a picture. Mark location on dist housing where rotor points. Only one correct location, if off a tooth on reinstall, will be at least the width of rotor contact from mark. Pull & try again. Should run with no issue, always check timing.

    Eons ago I marked location of dist on my 428, used chisel to make light mark on both intake & dist(FE dist insert through intake). Also a mark on dist housing for correct location when engine is at TDC.
     
    Ronald Hopkins likes this.
  5. fullcm

    fullcm Doug

    Joined:
    Jun 10, 2017
    Messages:
    262
    Likes Received:
    39
    Trophy Points:
    61
    Location:
    Michigan
    Vehicle:
    74 maverick
    Ok Thank you. I figured even with transposing my location mark onto the new dist. I should be able to get it close enough to start up then just retime it. I found a nice deal on this complete new old stock distributor. I want to go to with a restored original look engine compartment.
     
  6. Powerband

    Powerband Member

    Joined:
    Nov 6, 2014
    Messages:
    430
    Likes Received:
    178
    Trophy Points:
    128
    Garage:
    1
    Location:
    NY's \H/
    Vehicle:
    ---- 1976 Comet --- 1974 Maverick- - '61 Comet T'Bolt Six ---- 'quite a few projects ...
    another $ .02 :

    Important - as distributor is removed the 5/16 hex drive from oil pump (@ 2" long) will either stay in bottom of dist. or stay down in the engine's oil pump. It is not attached to either and can easily fall into the oil pan if dislodged !.

    Distrib' swap:

    > turn engine with fan to near balancer TDC timing mark with rotor pointing away from block (towards #1 as marked on dist cap or #1 wire ) Remove dist. cap out of way.

    > note approximate position of the dist related to block, remove dist lock clamp and gently pull up on dist. - * * as dist comes up, the rotor will follow drive gear and rotate a bit, these are positions new dist. and rotor need to be in to re-install. Hex drive must be engaged in oil pump for re-install, and may have to 'jiggle' rotor to engage hex shaft as dist. is inserted.

    > button up cap, start engine and adjust timing to your preference.

    IF the engine spits and back fires it's off time - line up balancer TDC and repeat installation more carefully until dist. is close to original distrib position ....

    IF the oil pump hex drive should ever inadvertently falls into oil pan - it can easily be fished out by removing fuel pump for access to using a stick magnet into pan - (ask me how I know... :))

    [​IMG]

    hav efun


     
  7. RMiller

    RMiller My name is Rick

    Joined:
    Dec 12, 2009
    Messages:
    4,124
    Likes Received:
    1,154
    Trophy Points:
    523
    Garage:
    1
    Location:
    Kennewick, WA
    Vehicle:
    1971 Maverick Grabber
    If I were going to line up TDC I would just line up the timing tab and make sure the rotor is pointing at #1 on the distributor, that will get you close enough.
     
    mojo and Krazy Comet like this.
  8. fullcm

    fullcm Doug

    Joined:
    Jun 10, 2017
    Messages:
    262
    Likes Received:
    39
    Trophy Points:
    61
    Location:
    Michigan
    Vehicle:
    74 maverick
    Thanks for that advice on how to retrieve the oil pump shaft!!!! That sounds exactly like something that would happen to me!
     
  9. fullcm

    fullcm Doug

    Joined:
    Jun 10, 2017
    Messages:
    262
    Likes Received:
    39
    Trophy Points:
    61
    Location:
    Michigan
    Vehicle:
    74 maverick
    That's a good point (no pun intended) if the timing mark is aligned and the rotor is pointed at #1 its gotta be at the compression stroke, right?
     
  10. Constable

    Constable You have the right to remain silent....or not!

    Joined:
    Feb 15, 2021
    Messages:
    186
    Likes Received:
    112
    Trophy Points:
    90
    Garage:
    1
    Location:
    Portersville, PA
    Vehicle:
    1975 Maverick 4 door, 1994 Mustang GT convertible
    The good thing is that the 250 is pretty much bulletproof and if you do go out a tooth or so, you shouldn't do any real damage (especially if you don't run it long) like an interference engine. Personally, I'd go with the advice to take the extra precautions then just lining up the distributor. Always better safe than sorry and the extra work setting up the engine may just save you aggravation and more time on the back end.
     
  11. RMiller

    RMiller My name is Rick

    Joined:
    Dec 12, 2009
    Messages:
    4,124
    Likes Received:
    1,154
    Trophy Points:
    523
    Garage:
    1
    Location:
    Kennewick, WA
    Vehicle:
    1971 Maverick Grabber
    A tooth off on the distributor won't hurt anything, just causes a few challenges. Reached a point where I would just move wires when I put it in 180 out (happened more often than I care to admit). It really doesn't care about orientation of the housing and shaft so long as the rotor points to the correct wire when that cylinder needs the spark. The cam however, it's very finicky about which teeth line up!
     
  12. Krazy Comet

    Krazy Comet Tom

    Joined:
    Sep 13, 2012
    Messages:
    7,561
    Likes Received:
    2,319
    Trophy Points:
    531
    Garage:
    1
    Location:
    Chesapeake VA
    Vehicle:
    1972 Comet GT clone 306 . 1969 Fairlane Cobra 428CJ 1988 T-Bird awaiting 331 ..
    Makes no difference if engine is interference, distributor timing has zero effect. Problem occurs when/if valve timing shifts due to slipped/broken belt or chain.
     
    71gold likes this.
  13. Constable

    Constable You have the right to remain silent....or not!

    Joined:
    Feb 15, 2021
    Messages:
    186
    Likes Received:
    112
    Trophy Points:
    90
    Garage:
    1
    Location:
    Portersville, PA
    Vehicle:
    1975 Maverick 4 door, 1994 Mustang GT convertible
    Very true but the point being that you still have to be careful with an interference engine regarding timing period.
     
  14. Powerband

    Powerband Member

    Joined:
    Nov 6, 2014
    Messages:
    430
    Likes Received:
    178
    Trophy Points:
    128
    Garage:
    1
    Location:
    NY's \H/
    Vehicle:
    ---- 1976 Comet --- 1974 Maverick- - '61 Comet T'Bolt Six ---- 'quite a few projects ...
    Makes no difference if engine is interference, distributor timing has zero effect. Problem occurs when/if valve timing shifts due to slipped/broken belt or chain.

    and:


    ... if the dist. gear is off it will only shift the position of the dist. housing but may make the vac. diaphragm interfere with block.
     
  15. 71gold

    71gold Frank Cooper Supporting Member

    Joined:
    Apr 9, 2002
    Messages:
    26,456
    Likes Received:
    2,835
    Trophy Points:
    978
    Garage:
    1
    Location:
    MACON,GA.
    Vehicle:
    '73 Grabber
    that's how I ran the wires on my 347...
     

    Attached Files:

Share This Page