Leaky Auto Engine after conversion.

[Zebbysebby]

Hello all,

It’s been nearly two years since my last post, lot of health issues and glad to say I survived the Vaccine. All this means nothing has been done to my MK1 until now.

In a previous post I wrote about my replacement front main seal which simply slid in with no tapping. It continued to leak and started to worsen when put on the road after Winter. I replaced the seal again and success, no leak however it’s leaking from somewhere else and I cannot see where. Cam seals have been replaced and are OK but I had forget to dab silicone in the corners before fitting the rocker first time around.

It seems to be both sides, above the sump and below the head gasket but not the head gasket. I wonder if its the housing around the crank which I think contains the oil pump. What I can’t understand is why the oil is above this. I’m wondering if the water pump fitted by the previous owner has a leak that’s mixing with oil??? I have no idea.

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I’ve attached a photo of my spare dry engine for clarity. This plate around the crank sits on top of the sump. Autozone do an O ring seal for the pump.

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I wanted to put my MK2 1.8 engine but I haven’t obtained the parts required for mating up to the MK1 so I’m swapping in my spare 69K miles 1.6 engine.

I can’t recall how many flushes this engine has had, but this is the red antifreeze after 40 miles use. No signs of water mixing in the Oil.

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I noticed that the clutch master cylinder fitted during the auto conversion is also leaking and split after just 2K miles.

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Any ideas on the likely hood of the front crank housing leaking. I will need to strip this engine and repair. I used a locking tool that fits to this plate to tighten the crank bolt. I’m wondering if the pressure disturbed the seal or maybe after 32 years it’s just failed. Thanks.

[Mazda Mender]

Recheck the cam seals, and the slave will be a cheap copy replacement, swap the boot only.
Did the last owner have the sump off for any reason? Did you clean everything down again after the crank seals final replacement.?have you checked the cam belt now for contamination?
M-m

[Zebbysebby]

Thanks for the reply M-m

Yes, I removed the rocker to check and dry up there. I can see behind the plate from the passenger side shining a torch in and again nothing. It was a brand new gasket as well and sealed this time.

Can’t imagine the last owner doing anything too involved like taking the sump off. Surprised he did the belt and pump, the belt being a screw up as previously covered.

Everything was cleaned down well after the repair because I wanted to be able to see any issue. Belt wasn’t too contaminated and being a non interference engine doing relative low miles and plans to replace it I wanted to make do and re-used it.

Even found oil on the air pipe from the air filter/ meter to the inlet manifold, the square lower section was covered in oil on the inner face with a pool on the bottom as though it was being sprayed on but nothing on the drive belts.

Slave cylinder was from MX5 business on ebay but obviously poor quality.

So much oil and I cannot work out where from.

I suppose I could re-do the water pump seal and what appears to be the oil pump housing seal but it’s likely the sump needs doing so it’s an engine out job whatever I do.

[Mazda Mender]

By the sounds of it ,I would have no faith the the last owners work also , personally i would remove the engine covers and follow the trail taking into account the timing belt flicking it also.
M-m

[Zebbysebby]

I’ve spent so many days trying to figure out where this oil is coming from, drying it off, short run, torch…over and over…I gave up and pulled it out.

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I can also clean the engine bay and deal with a few rust spots.

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Looks like the Gearbox is also leaking.

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Still struggling to see where it’s coming from.

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I will tear into it and try and work out what has failed then post back to finish this off.

[Zebbysebby]

I’ve mostly stripped the front down but I suspect the oil pump won’t come off without removing the Sump.

It looks like the Cam seals could be leaking but this doesn’t run down bad enough to explain the amount of oil leaking. Another ‘MX5 Parts’ purchase off ebay. I need to start using genuine parts only.

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It looks like the issue is the top of the oil pump. I have a new gasket and as can be seen from the replacement dry engine, the gasket is still visible whilst on the leaky engine its disintegrated.

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Oil has pooled below the front crank but the seal isn’t leaking.

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I’ve started to prepare the new engine but will re-use some parts of the old engine with less rust on them.

One issue is the woodruff key which seems to be shorter and no longer has the pronounced chamfer. It does not locate as well as the original. Purchased from Autolink who think it’s an update part and are checking further into this.

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New version.

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Original version

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I may update this in the future when the sump is removed, it may be helpful to someone in time.

[Mazda Mender]

It is an updated part now, as there was no chamfer on the later roadsters, it will be fine, the later roadsters run on them with no issues, but if you are not comfortable with it, the original looks all good to re-use again.
M-m

[Zebbysebby]

Excellent, thank you.