Jag! The Ghostly fleet thread

Talk about your cars etc here. Keep it sort of sensible and on topic please.
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by bub2006 »

Valve stem seals Im sure will not have a bearing on compression​. It's quoted 10% isn't it an ideal to be between across​the pots? That's how I've always gone by too. 150 is over the 10% from 175. Try some oil treatment maybe? It did help the reliant last year.
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by Junkman »

Well, that snake oil sure didn't help the Reliant this year now, did it?
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by SiC »

As they made so many of these things and so many rotted, if you ever need to do an engine replacement then it won't cost a lot. Plenty of info on how to do it too.
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by Uncle Albert »

Sounds like the perfect time to fit a 1UZ-FE. ;)
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by bub2006 »

Junkman wrote: Tue Jul 09, 2019 10:49 pm Well, that snake oil sure didn't help the Reliant this year now, did it?
No but it assisted it last year. Only used it twice Wynn's oil treatment. I found 20/50 oil was actually better to run the reliant on though
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by Hooli »

Valve stem seals have nothing to do with compression. Valve seats do however.
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by John F »

Yep. Valve heads / seats are likely to be the main culprits. Possibly also piston rings, but they usually just give you reduced power at high revs rather than a noticeable drop in compression.
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by DodgeRover »

Don't worry till it's down to less than 100 psi or only running on 3 cylinders.
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by Hooli »

Ghosty, did you repeat the compression test with a bit of oil down each bore?
If oil improves the readings then the rings are the issue, if not then it has to be valves (or a massive score in the bore but that'd smoke like a tank).
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Re: Reliable Mazda Engine: a spectral fleet thread

Post by ghosty »

Put oil down the 150 bore. Vague improvement.
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