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Thread: Valve stem seals replacement on a m70

  1. #1
    Join Date
    Nov 2012
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    Little Rock, Ar, USA
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    '98 M3 '79 635csi '74cs

    Valve stem seals replacement on a m70

    IMG_0080.JPGHi
    I'm battling rough idle/oil consumption issues. Since the piston rings were fairly new when i got the car i'm thinking of reconditioning the air intake manifold gaskets and replacing the valve stem seals. Anybody familiar in how to use the tool in the pics?
    Thanks!
    Last edited by aeronotix; 12-10-2018 at 02:08 AM.

  2. #2
    Join Date
    Jan 2005
    Location
    Japan
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    54,654
    My Cars
    11/88 E32 750iL+98 E36M3
    see my website below, click fixes >>>engine general>>>>>>top end overhaul

    but I did not use the same tool as you show , we used this one, more pics about M70 valve stem seal replacement http://e32b12.blogspot.com/search/label/Stemseal
    Last edited by shogun; 12-10-2018 at 03:08 AM.
    Shogun tricks and tips for the E32 series are HERE!

  3. #3
    Join Date
    Nov 2012
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    Little Rock, Ar, USA
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    '98 M3 '79 635csi '74cs
    Thanks Shogun, this is super helpful. I guess i don't have the right valve compressor tool so i'll need to do some research to locate one. Do you remember where you got yours?

  4. #4
    Join Date
    Jan 2005
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    Japan
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    11/88 E32 750iL+98 E36M3
    I bought them from the U.K., but shipping was expensive, plenty available from Ebay, they are anyway all made in China, here $32 incl. economy shipping
    https://www.ebay.com/itm/Valve-Sprin...68ok:rk:1:pf:0
    plenty in the auction house, search for: Valve Spring Compressor Lever Type OHV/OHC Engine Seal Keeper Removal Tool Kit

    I bought 2 sets to make it faster, as the settings are different on the tool depending on the valves, as you can see from our Japanese site. One will do also, just takes a bit more time.
    Shogun tricks and tips for the E32 series are HERE!

  5. #5
    Join Date
    Jan 2017
    Location
    The Netherlands
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    153
    My Cars
    850i
    Hi aeronotix, I just did this repair myself. Also because of a high oil consumption (engine smoking light grey when idling).
    Although I can call myself a well experienced DIY car mechanic, this was one of the most difficult repairs I ever did.
    Hardest parts:
    - compressing the valves: you need a Midlock type of tool (cheap imitations available); needed to change the settings of the tool many times depending on the location
    - removing the valve collets / keepers and thrust adapters: use a little magnet on a stick, otherwise you will definitely loose some (actually I had one broken thrust adapter)
    - pulling off of the old seals, virtually impossible without proper valve stem seal pliers I found out
    - reinstalling the valve collets and the rocker arms with thrust adapters: absolute nightmare, but after a while I managed this in half an hour per valve... (best to use a pincet for the collets while compressing the springs)
    - reinstalling the intake manifolds due to the hard fuel return line (next time I'l throw this pipe out and replace with a hose I think)
    The old seals were rock hard, with a much larger hole than the new ones. Also I noticed some compression loss with the can lobes pointing up: it appeared that the hydraulic lifters kept some valves slightly open -> installed 24 new lifters also.
    I kept the valves from falling into the cylinders using compressed air in the spark plug holes, this worked fine and safe (1 bar is OK). Easy to perform a leak down test this way: found 5-15% which is fine I believe (leakage via some intake valve seats).
    In other posts, members talk about 30 wrenching hours, and I can confirm this. Note that probably all of our M70 engines will need this treatment sooner or later...
    Have fun, Albert

    - - - Updated - - -

    IMG_6481 (1).jpgIMG_6462.jpgIMG_6452.jpg
    Attached Images Attached Images
    Last edited by Albert850i; 12-16-2018 at 02:22 PM.

  6. #6
    Join Date
    Sep 2018
    Location
    Belgium
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    My Cars
    1990 850i and 1970 2800C
    good point on the fuel return line.... i soon will mount the manifolds and are already looking how to change that line.... i think we can route it above the valve cover out of the way so all nuts can be placed with direct reach , ok , with extensions , but no magic swivels .....

  7. #7
    Join Date
    Nov 2012
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    Little Rock, Ar, USA
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    '98 M3 '79 635csi '74cs
    Hi
    update (a few...) hours down in the project.
    the messages above summarize very well the challenges:
    - find the right tool. I found a cheap tool of Ebay that ended up working well. The right tool has two hooks that loop around the camshaft.
    - fuel rail return is on the way for manifold removal so was a nightmare
    - my valve seals are definitely shown worn as described by other comments
    - i will follow a two step approach for valve retainers installation: i’m installing only 1 half by myself then will have a helper to help installing the other halves (a set of hands to correctly place the tool / another set to juggle with the retainers)
    - there is a lack of clearance between the valve pressing tool handle and water hoses/harness at cyl 12 & 6. Plan for removal of the hoses (so replacement with new ones).
    harness on Passenger side: not sure yet, probably remove the harness on that side.
    - the rope method did not work. I fed as much nylon rope as possible at bdc, felt resistance moving piston up yet valve still moved. I used the compressed air way so far.
    - the air method gives you an assessment of the engine health by hearing air leaks. So far no valve leak (knock on wood..). Only hissing that i hear is on the timing chain area so thru piston rings. Since engine is dead cold i guess it’s normal to have some air loss at this point.
    - place pistons at BDC for removing the camshaft rocker arms. Close to tdc to work on the seals (in case you have issue with air compressor, no risk to drop a valve)
    To maintain tdc put the transmission in gear otherwise engine will rotate with piston under pressure.
    - the air intakes are caked of oil residue and completely gummed up. A radiator shop may clean for $60. Worth it to same time and lungs (brake cleaner is nasty)
    - i got an ultrasonic cleaner from Harbor Freight ($60) to clean the hydraulic lifters. I used a solution of marvel mystery oil and degreaser as cleaning solution.
    That’s it for my remarks. Will report back once further progress done

    Quote Originally Posted by Belgiumbarry View Post
    good point on the fuel return line.... i soon will mount the manifolds and are already looking how to change that line.... i think we can route it above the valve cover out of the way so all nuts can be placed with direct reach , ok , with extensions , but no magic swivels .....

  8. #8
    Join Date
    Jan 2017
    Location
    The Netherlands
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    My Cars
    850i
    Some comments:
    - At the end I used only one of the 2 camshaft hooks of the tool, which gives some more space to reinstall the followers
    - The fuel rail is a big problem for reinstalling the bank 1-6 manifold, so next time I will replace it with an insulated hose or something
    - My new seals definitely solved my oil burning problem at idle, no more white-grey smoke (idling warm engine)
    - For the retainers I used following trick: on top of the compressed springs, I put a thick washer fitting around the retainers, with a slot cut in for the tip of the follower: one man job now
    - Using air: easy to do a cylinder leak down test this way, which gives a good impression of piston ring and valve seat leakage (my results: 5-15% which is good)
    - During this leak down test, I noted intake valves leaking as they were not completely closed: hence I renewed all 24 hydraulic lifters (around 5 Euro each)

  9. #9
    Join Date
    Nov 2012
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    Little Rock, Ar, USA
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    '98 M3 '79 635csi '74cs
    C71FDED8-5F06-4D8B-A1D9-6871295E0111.pngTool i used (as reference)

  10. #10
    Join Date
    Sep 2018
    Location
    Belgium
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    My Cars
    1990 850i and 1970 2800C
    after rerouting that fuel line i could install the manifolds easy in one hour , i'm sure i can demount them now in 1/2 hour ! All nuts are in sight , reachable with just straight extensions, no magic swivels needed. Ok, were the horizontals are in the manifolds , one needs a grind down socket on wobble extension.
    Here is my idea, but i had to forget that extra front support to give clearance for the oem support under the manifold pipes , they must be "there" loose ,ready for placing them in position after fastening the manifold nuts . I used the oem steel fuel return pipes , just some flat bending and adjusting to the hose in the rear .

    SAM_2643.jpg

    PS i don't use the vacuum hoses anymore for the fuel tank vent valves … as it's a FI... OEM will demand another solution. (perhaps connected above on the DK motors instead of below) . Mine are just pugged . Below that would interfere with the fuel hoses.

    SAM_2644.jpg
    Last edited by Belgiumbarry; 01-19-2019 at 08:42 PM.

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