Technical Fixing My 1.4 Bravo Engine Misfire

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Technical Fixing My 1.4 Bravo Engine Misfire

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I was getting lots of blue smoke out of the exhaust and my car destroyed two spark plugs in cylinder 2, creating a misfire. So ive decided to repair the car myself. I was getting blue smoke from cold and it would burn off after say 5miles, then sometimes you would get a puff of blue smoke on acceleration. I noticed oil being pushed through the oil breather into the SPI. Rocker cover was leaking oil uniformly all the way round.

Car Started misfiring.
Last week the plug in number 2 was naff.
Had a look at the plugs today and;

Today;
1-oily
2-oily
3-dry light brown
4-dry light brown

Last Week;
1-dry light brown
2-oily (and Broken)
3-dry light brown
4-dry light brown

Also you can smell exhaust under the oil cap.

compression test results, from cold with throttle fully open and dry (though some cylinders must be wet from the oil leak) I didn’t do a wet test.
1 153 psi
2 190
3 190
4 170

Not got the head of just yet. As expected im struggling with the exhaust manifold.

The rusted nuts have taken six of the eight studs out, probably would have been better if the other two studs came with it.

Taking the down pipe bracket off and the bolt sheared, not surprising really it is a rusted mess.



Everything under the rocker cover looks really good though. There was a very strong smell of exhaust under the rocker cover.

When I drained the water there was a very small amount of oil in the water but no water evident in the oil.

I took the air intake manifold of and the branch leading to cylinder-2 had oil.

look at all this (exhaust carbon presumably) on the inside of my rocker cover.


What do you make of this muck on my rocker cover? Im planning to unbolt my exhaust in front of the CAT and take it off in one part, any thoughts?
 
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Sounds like oil is getting in to the combustion chambers. There are several ways that can happen:
1. Worn valve guides.
2. worn or broken piston rings or worn cylinder bore.
3. head gasket gone between an oil way and the combustion chamber.
Head off and check it all is the only way.

The deposit on the inside of your cam cover is quite normal by the way.
 
lots of pictures.
Id love any advice.

Under the rocker cover.


Head Gasket, only thing i can pic out is the rusty bulge and the big missing chunk at the bottom.


Bores, Im worried about number 1 it has scoring 4 is almost as bad 2,3 are lighter. What do you think?


Valves,


Piston tops, look at all the pitting round the edge of 1. Again 4 has noticeable pitting round the edge, 2,3 have almost unoticeable pitting on the edge.



So what do you think about the gasket, scoring and pitted piston top?
Oh yeah there was no debris in any pistons.
 
I'd say straightforward worn engine, especially No. 1 pot. Damaged ring causes scraping of bore and low compression, exhaust blow-by. Marks on top of piston caused by something bouncing around, maybe a bit of ring, or maybe something that got in and caused the ring damage. Rebuild or replace the engine I reckon.

My old Tipo 1.4 has a low compression on one cylinder (can't remember which one), I never investigated further. It's the same engine as yours below the cylinder head...
 
Ive taken the valves out from cylinder 2. No bad/obvious damage but the two inlet valves are covered in carbon. Is this right? I would expect the inlet valves to be closed when the engine fires.

Valve guides are fine, valve oil seals are crispy and hard.

 
Nothing usefull but ive figured out where the pitting on piston 1 has come from. Look at this picture of piston one and the head.



There are two lips on the head with a little carbon flakes on them. Thats what has pitted the 1st piston.

Looks like a bad design.
 
cam wear is minimal, and with a good clean up and new set of valve oil seals you'll have a good head. that pitting is normal. a head gasket will seal it fine.

shame the bottom end isnt worthy of it. if you're thinking long term then a scrapyard engine is best bet, but since your head is so good just get the bottom end, allowing you to inspect it with head removed before you buy, ensuring you'll get a good un.
 
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Cheers jug.
Ill have to have a think Im doing all this on the street and I don’t have a engine hoist.

A bad bottom end was my worst fear. I suppose I could get a scrap yard block delivered build it up then hire a engine hoist to fit it.

What’s confusing me more than anything is piston 2 was always the one to oil up yet it looks the best and has the best compression, where as 1 has the worst compression and worst scoring.

Ill spend the rest of tonight cleaning my parts and have a think.
 
Cheers jug.
Ill have to have a think Im doing all this on the street and I don’t have a engine hoist.

A bad bottom end was my worst fear. I suppose I could get a scrap yard block delivered build it up then hire a engine hoist to fit it.

What’s confusing me more than anything is piston 2 was always the one to oil up yet it looks the best and has the best compression, where as 1 has the worst compression and worst scoring.

Ill spend the rest of tonight cleaning my parts and have a think.

oil in cyl2 probably due to leak in valve seal, and low compression on cyl1 due to piston ring leak. oil problem will be sorted with your head work, but compression on cyl1 wont improve. you could run it with low compression on cylinder 1, it isnt the end of the world, and tbh 153psi is plenty for good running. look at it this way, it wont run any worse than it did before the oil problem. how long until the ring fails? who knows, but i wouldn't expect it to happen too soon. maybe you should stick the head on and then sell it in the not too distant future ;)
 
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