Low Compression

Discussion in 'Mazdaspeed 3/6 Engine' started by chrisgrissle, Aug 12, 2020.

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  1. chrisgrissle

    chrisgrissle Greenie N00B Member

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    Had a compression test done today at a shop numbers dont look so good, guy said he did it on the cooler side of temp, 110-105-80-110

    car has 162k miles on it.. it sat for about 2 years with minimal driving as i was getting alot of oil loss and didnt have the funds to find out how or why.. i want to keep the car, its gonna be a weekend driver mainly. i want to put some power to it maybe mid 300. looking for advice if i should rebuild, or get a used engine and drop it in there?
    i had the shop do it as i just havent had time to get around to it. i can go about most repairs my self but the engine seems a bit out of my league to be honest. mainly looking on insight of where i should get a used motor, or if someone knows anyone in the midwest region to get an engine rebuild on the cheaper end?
     
  2. jsilva

    jsilva Silver Member

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    A couple of thoughts which may or may not help:

    1. You could try Engine Restore on a couple of oil changes and see how much that boosts your compression. How well it works probably depends on several factors, but it does work. I don’t think you’d get those numbers back up to 180 but it’d be an interesting and cheap experiment at least.

    2. When I started working on my Speed6 engine last Dec it was way above my ability and knowledge. But I forced myself to work on it anyway and in the process learned a lot and developed a lot of confidence. Now I wouldn’t hesitate to do just about anything with it. Perhaps you are more able to do the work yourself than you think?
     
    jsilva, via an iPhone, Aug 14, 2020
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  3. chrisgrissle

    chrisgrissle Greenie N00B Member

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    So i actually felt uneasy after they gave me the numbers, i warmed the engine and did it myself hitting about 170-175 each cylinder.

    it sat for awhile changed brakes rotors, oil/filter, ran it for a bit but now i got a p0012, i removed the valve cover timing chain seems tight still. replaced the OCV solenoid as i had it open. Anything else i can check? i cant find much on this code besides in most cases its a VVT replacment. just seeing if theres anything that you guys might think is worth troubleshooting or checking before going into a VVT replacement?
     
  4. The_big_dill

    The_big_dill Greenie Member

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    The engine position is an important factor when checking the chain tension.

    From what I have read, when the VVT fails, the little cap on the barrel wall of the VVT gear is missing, the VVT actuator has play and a rattling noise is audible on cold start.

    Personally, I have seen 2 VVTs with the cap missing. Both engines failed with a burnt valve - at which point I bought them.

    There is a TSB on this. Do your research, diagnose it and fix it before you are left stranded.
     
  5. chrisgrissle

    chrisgrissle Greenie N00B Member

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    appreciate the response, I haven't been driving really besides changing the oil filter, took it on a ride then got an engine code. removed the cover replaced the OCV/VVT Solenoid, ran 6-7 more miles lightly to see if the code returned which it did, its been sitting since havent had a chance to open the cover back up and look for alignment or the cap.
     
  6. The_big_dill

    The_big_dill Greenie Member

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    Do you hear anything on cold start from the valve cover? Do a google search to see what people are talking about.
     
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