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New 94runner

Discussion in '2nd Gen 4Runners (1990-1995)' started by jonasshole, Jan 7, 2021.

  1. Jan 16, 2021 at 4:25 AM
    #31
    atgparker

    atgparker Cal Poly, ETME 1988

    Joined:
    Jun 20, 2018
    Member:
    #6296
    Messages:
    328
    Gender:
    Male
    First Name:
    Andrew
    Mission Viejo, CA
    Vehicle:
    1991 White 4Runner 3.0 L
    Rebuilt Engine MLS and ARP on the heads, DT Header, 2-1/2" CARB compliant Flow-Master CAT with 2.0" Bosal CAT back Dayco 1-1/4" Spacers, SkyJacker M-Series Monotube Shocks, Ball Joint Spacers. 95-9006 K&N Air Cleaner, G-Plus Alum Radiator, ZIrgo 16" Fan, Derale Temp switch/relay
    Hey Toy4X4 thanks for acknowledging the 907. To be completely honest I am unsure of the wet liners actual alloy and/or manufacture. But they do come completely free from the block once the head is removed and the bottom end and pistons are out. All I do know is that before I put the block back together I thought that by painting the outside of the cylinder liners it would be a good idea in keeping the galvanic surface area insulated from any free ions in the ruddy coolant and causing any further potential corrosion. Hopefully the DI water and Redline wetter are keeping any free ions out of the equation. The inside edges of this Mk-2 block that I was using as a replacement was not perfect. The surface area where the head gasket sealed that blocks edges to the head were pretty badly eaten away by galvanic corrosion as best I could tell. So I used a bead of Right Stuff gasket maker on the perimeter of the blocks surface to seal up the head gasket to the head and block. Because the liners are quite proud of the aluminum blocks outer edges this makes sure the HG seals the combustion chamber on the cylinder liner when the head studs are torqued down. But the compression on the HG around the outside of the engine has slightly less compression as a result. The Mk-1 engine would weep coolant as it was coming up to temperature. But once the aluminum block, coolant and the liners had all heat soaked the greater CTE in the aluminum would expand and the weeping would stop. This phenomenon would reverse as it all cooled back down but the heat must have made this less apparent for the coolant to be visible although I suspect it was in part why the corrosion was occurring especially if an MLS HG had been in place on that Mk-2 block.
    WP_20150813_005.jpgIn the picture the front edge of the inner surface is very pitted from corrosion. Notice brass plug installed in the blocks oil feed to the head with a drilled hole in it to keep the oil pressure higher on the main journal bearings and less so in the heads and cam bearings. Been working a charm in keeping the oil pressure nice and consistent when pulling high cornering G's and high RPM.
     
    Toy4X4 likes this.
  2. Jan 16, 2021 at 4:42 AM
    #32
    Toy4X4

    Toy4X4 New Member

    Joined:
    Jul 18, 2020
    Member:
    #15580
    Messages:
    6,728
    Gender:
    Male
    First Name:
    Jeff
    Vehicle:
    2020 Offroad Prem. 4-runner
    RevTek 3" front- 2" rear leveling, JBA uca's, LED interior lights, Cooper 275-70-17 AT3 LT
    I see the brass plug(oil restriction to the cam) It's kind of the same thing Ford Cleveland engines had to do to keep the mains fed properly. So did you get the updated cam mounting heights as to try and eliminate the oil leaks that develop on the top end(cam cover)? If yours wasn't an issue it may become one depending on useage. The point I was trying to make about the aluminum radiator is: if proper precaution is taken, issues of longevity can be avoided. I've seen both 'arguments' as to have or not have one. Lots of people don't take precautionary steps to ensure longevity, it will come back to haunt in the future. Then there are those that do take their time, and in some cases 'overthink' the project sometimes good..... sometimes bad. Sounds like your taking a good approach to the radiator thing, good luck. It sure looks nice.
     
  3. Jan 16, 2021 at 5:44 AM
    #33
    atgparker

    atgparker Cal Poly, ETME 1988

    Joined:
    Jun 20, 2018
    Member:
    #6296
    Messages:
    328
    Gender:
    Male
    First Name:
    Andrew
    Mission Viejo, CA
    Vehicle:
    1991 White 4Runner 3.0 L
    Rebuilt Engine MLS and ARP on the heads, DT Header, 2-1/2" CARB compliant Flow-Master CAT with 2.0" Bosal CAT back Dayco 1-1/4" Spacers, SkyJacker M-Series Monotube Shocks, Ball Joint Spacers. 95-9006 K&N Air Cleaner, G-Plus Alum Radiator, ZIrgo 16" Fan, Derale Temp switch/relay
    The 907 is a slant 4 unlike the Lotus that was in the Cortina and Elan. It has 16 valves and a head with two cam towers that straddle the spark plugs. When I put the CAM towers on the head I pitched the paper gaskets and used Loctite 515 to seal them which required re-doing all of the valve shims to get the valve lash correct. The CAM covers are like a big "U" shaped cast aluminum affairs and are prone for leaking. Especially the exhaust CAM side as the cover is very horizontal and a lot of oil sits in this cover when the motor has been run for a bit. I use these orange colored Viton gasket panels and I laboriously and methodically torque down the six M6 fasteners to seat these covers so they draw down as evenly as possible. The addition of Halomar never hardening polyurethane gasket maker helps it slide together as the "u" shape has quite a large angle to it making the cover somewhat tapered as it meets with the sealing surfaces on the CAM tower.WP_20150815_001.jpg
    Mk-2 907 motor about to go back in after I had rebuilt it with massaged internals, ported the head and port matched the intake and header. It is awesome to own a street legal 1973 car with DCOE Weber's on it!
     

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