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Posted

I have a recon 5k motor and have recently had it Dyno'd which was running perfect after. I stupidly washed the engine down without covering anything. It was miss firing so I cleaned out bay and changed plug then it ran fine, know its dropped cylinder 2 again. I thought sticky valve so gave it engine flush but nothing.

 

Please help I'm stuck.

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Posted
I have a recon 5k motor and have recently had it Dyno'd which was running perfect after. I stupidly washed the engine down without covering anything. It was miss firing so I cleaned out bay and changed plug then it ran fine, know its dropped cylinder 2 again. I thought sticky valve so gave it engine flush but nothing.

 

Please help I'm stuck.

 

 

Check your points gap

Posted

Make sure there isnt any water sitting in the spark plug tubes.

 

Definitely sounds like there is water somewhere in the electrical system and the dizzy is the only other place that it could be, which has already been mentioned.

 

A few other things to look at:

 

- Check for corrosion on your cap where the leads plug into and on the posts inside.

 

- Also give your rotor button a clean with some fine sandpaper along the edge where the spark jumps to the post.

Posted
Well checked everything and cylinder 2 ain't coming back up so I think it may be something internal ie valve or valve springs

 

I've bent a pushrod before revving the ring out of an old 3K motor.

 

Unhook you accelerator/choke cables, undo the two nuts on top of the rocker cover and remove it and check to see if a pushrod is just sitting there doing nothing.

Posted

Tappet gap will tell you... big gap for bent valve or pushrod.

 

But if it ran fine with a new plug for a while it won't be either of those. You'd have more chance of a broken oil ring shitting up that particular cylinder.

 

The lead shouldn't give you a shock either, so they aren't much good. I occasionally look at night, especially a foggy or wet night and check for green sparks jumping around the leads in the dark.

 

If you're lucky, the water destroyed the lead's insulation on number 2, a new plug had lower resistance so it fired for a while, but now that plug is harder to work so the lead can't hack it anymore.

 

Swap leads and see if the miss moves. It may sort itself out when it dries out completely.

Posted

check for water/ corrosion in the coil output. i had so much rust in there it ran like poo. cleaned it out and weeeeeee

Posted

Yep swapped lead and plug over just to make sure last night but no difference. Swapped them naack left the plug in the lead put it near some metal and there was plenty of spark. I was touching the metal on the internal of the coil.

 

Checked for water everywhere so I thinking it may have been coincidence, I have just have it dyno tuned so u may have been testing its abilities so I'm guessing that may of caused some problems.

Posted (edited)

Ok, so you have swapped the lead over, and the plug over and the miss stayed on number 2?

 

Check the tappet gaps and if you have a compression guage do a comp test. A bent valve or bent pushrod will show as a bigger tappet gap, and a burnt valve will show as low compression in that cyl.

 

Is the misfire constant from startup to warmup?? No problems with water vanishing or condensation under the oil cap?? Bubbles in the radiator when cold??

 

The dyno run may have blown the head gasket slightly between 2 and 3 and you have water getting into #2, which will make the plug misfire when cold or until you change the plug.

Edited by altezzaclub
Posted (edited)

Yeah swapped lead and plug over but nothing, just had RAA out here to check on my work but he said the same thing. Need to get a compression tester and check the cylinders that make sure, obviously if that fails then start pulling apart and checking to see what the problem is. It is under warranty for parts only but I suppose the company I bough the motor off are going to want a mechanics report saying what the problem is.

 

If it is valves are they something a NOVICE (and yes that was meant to be in capitals) could do?

Edited by Scott_87

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