Exhausting times

Posted on June 30, 2013 by Dom

I picked up a 4-1 exhaust manifold at the Stoneleigh show this year – link here: http://parts-shop.westfield-sportscars.co.uk/index.php?route=product/product&product_id=174&search=manifold

Fitting it gave me a chance to investigate a rattle from the exhaust that had cropped up. Initial suspicions were that the catalytic converter was breaking up. With the misfires from the coils dying a couple of times I suspect the lifespan had been shortened a touch. Still surprised it’s this soon though. Took the silencer off and it sounded like it was full of lego. Gave it a little shake and was greeted by these:

OLYMPUS DIGITAL CAMERAInside standard silencer Inside standard silencer

Manifold insideIn the end I didn’t. I’m not chasing every last bhp and with it being brand new, I probably shouldn’t be attacking it with an angle grinder!

First impressions were good, it was a bit of a deeper sound at idle and took the edge off the raspy exhaust a touch.

A week or so later, I took it to the rolling road to see what kind of difference it had made.

Manifold before-afterI put the figures into excel to make a better comparison. As you can see, it’s largely up on the mid range but as the rev climbs the difference drops and then becomes negative. I think the dying cat is strangling the exhaust somewhat, not allowing the air to flow at high rpm. New silencer required, such a shame! Actually at the time of writing, a Wunoff repackable exhaust is in the garage awaiting the link pipe to be made…

edit: for those researching the manifold, I’ve since replaced the silencer and it drives much better – top end is really opened up. I’ll get it back on the rolling road soon.

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Leak plugged

Posted on May 4, 2013 by Dom

Finally, the coolant stays in the engine! Got the new plug in on Thursday, helped with a bit of sealant just in case.

New core plug

I filled the coolant on Friday, having given the sealant ample time to dry. Unfortunately, having had the core plug out I’d introduced the mother of all air locks. Fortunately, I was able to use the bleed screw fitted to the old thermostat housing on the front. I filled it up but it was too late to start it (there’s a flat above my garage with a small child).

So, today, I fired it up and lo and behold – no drips! Took it for a quick drive and still no drips.

Big test Monday – Stoneleigh…

 

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Coolant leak found?

Posted on May 1, 2013 by Dom

Well, if I haven’t found it I’ve certainly made a new one! With Stoneleigh looming every closer I’ve finally gotten around to commencing battle once again. I removed the inlet manifold and had a closer look at what I’d inadvertently photographed earlier.

Coolant leak Zooming in showed it was indeed likely to be the culprit

coreplugI think it would have been easier to see if I hadn’t painted it! I set about removing it and this is what was left:

Manky core plug

Ignore the big hole at the top, I made that. It is heavily corroded and there are a couple of pin holes in it. The inside of the head doesn’t look much better

Core plug outUrgh. I’ve cleaned out the rubbish as best I can and am now leaving it to dry before fitting the new core plug with sealant.

Thanks to Fraser at Blink for confirming the size of the plug! My local Mazda dealership didn’t have a clue

 

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Still chasing that leak

Posted on April 24, 2013 by Dom

Finally got the cooling system back together today. In the end, I only replaced the pipes to and from the oil cooler but obviously with all the rain the motivation wasn’t there hence why it’s taken so long. Fired the engine up, let it warm up to 80 degrees, check there’s no air leaks and job done. Come back half an hour later and there’s a small puddle under the oil cooler. Doh!

Unfortunately, or fortunately, I’ve made the leak worse. You can actually see it dripping now and it certainly wasn’t those pipes. It’s dripping onto the oil pressure switch, away from the block slightly. I got confused for quite a while and admitted defeat that I’d have to remove the head. It didn’t make sense though as if it were coming from the head/block surface it would trickle down the side of the block.

Then I stumbled across this photo, from the last post no less.

Coolant leak 2There, right above the oil pressure sender is a core plug. It does indeed look to be leaking!

Question is, can I get that replaced for Stoneleigh?

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Chasing the elusive coolant leak

Posted on February 24, 2013 by Dom

Ever since the car was built (and technically before whilst the engine was in the MX5) there’s always been a coolant leak of some sort. I fixed most of them whilst the engine was out during the build but one remained – just above the oil pressure sender. I’d originally caught this leak and ‘fixed’ it by replacing the head gasket. Here’s the leak from last time:

Another leak Head off

As we’re in a spell of cold weather with the roads once again salty, it seemed like a good time to strip it down and take a look. As opposed to the rest of the Winter, where I’ve done sweet FA …

The oil pressure sender definitely had coolant on it, and the oil cooler had marks too. I poked the camera down for a better look:

Coolant leak 1

There’s signs of coolant ‘spray’ all over the place, mostly to the left of the oil cooler. However, there wasn’t any tell tale marks above the oil cooler, which suggests the head gasket isn’t at fault. I needed a better look so I set about removing the inlet manifold. I think it would have been easier to remove the engine than faff about in there. I look like I’ve been self harming!

Still, several hours later, most of which spent wondering where I’ve put the spanner now and the inlet manifold was split from the head.

Coolant leak 2

Certainly doesn’t look like it’s coming from the head. However, there’s not a lot of coolant connections around there. I took off the oil cooler outlet pipe which looked a little worse for wear.

Dodgy pipe

It doesn’t look happy, but there’s no obvious cracks or splits. Back to the oil cooler:

Oil cooler areaMy suspicions are that there’s a tiny crack forming in that pipe. As the coolant heats up and the pressure increases it will open up and spray out towards the back of the engine. Once the coolant is up to temperature the thermostat will have opened and so the pressure in that area will reduce and so it won’t leak. That’s why it’s been difficult to catch and why it doesn’t leak much. It’s like you have to top it up every x journeys rather than x miles.

I’ve ordered replacement inlet and outlet hoses and new hose clips for good measure. Hopefully the solution is that simple!

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