Saturday, May 28, 2016

Finally Solved the Starting Problem!

Well, so far, this engine has brought me nothing but problems... all of which were completely avoidable had I have known what I was doing! But hey-ho, that's all part of the learning journey. First time I built it, it started up perfectly, but I soon discovered that it was horribly imbalanced. So much so that it had to striped down again, sent off to a company to have the parts re-balanced, (twice!), before it could be rebuilt a second time. And now of course, it simply refuses to start, but I'm onto it and think I know what's wrong...


So far, I have checked for the presence of fuel and also checked for a spark and both were present, but while I was doing that I noted that there was a bit of petrol leaking from the head, so as a precaution, I swapped it over with another I had. All went well with the head swap, but it still refused to start.

Rotating the distributor as far to the right as it would go, I noticed a distinct difference in the engine's response. The lifeless cranking was replaced with a magnificent chorus of backfiring, with actual fire no less. Yes, it won't start, but it will fart fire!!





Hmmmm, I'm suspecting that I might just have put the distributor in the wrong way round. In this post here, I wax lyrical about how easy it is to put the dizzy in and go through the whole process in some detail, but right now, I'm starting to doubt my ability to perform these simple tasks!!

So how should the distributor be set, if we look at the post, it states that the engine needs to have piston one at TDC, but it's very important that it's the TDC just after the compression stroke and not the TDC just after the exhaust stroke. You have to remember that it's a four stroke engine and the crank goes round two times during those four strokes, while the distributor only goes round once.

Time to check... Thankfully, I have a little spy hole on my flywheel housing and as you can read here in this post, I marked the exact TDC point on the flywheel. Sometime I ain't so stupid after all!!!


So popping the little cover open, I rotated the engine and easily found the TDC position, but which one? - compression or exhaust? To solve this little conundrum, I simply removed the spark plug on piston one and stuffed an old rubber glove in the hole, like so.



Now I rotated the engine over by hand again and waited until the glove was fired out of the hole and bingo, the compression stroke was found!! It's surprising just how far it can catapult a glove!!



Now that the compression stroke was located, so was the correct TDC. Incidentally rotating the engine is made simple by jacking up one of the front wheels and putting the car in 4th gear. Then ensuring that all the spark plugs are out (to inhibit the engine from accidentally starting), the lifted front wheel can be rotated by hand in the direction of normal travel. This rotates the engine.

After popping the dizzy cap off... low and behold the problem was finally found. The rotor arm should be pointing at HT lead number one (between 1 and 2 o'clock), but look where it's pointing, the opposite direction!!!!



Yup, that's 180 degrees out - facepalm moment!!! When I installed the dizzy, I must have done it at the wrong TDC. That's TDC just after the exhaust stroke, hence the flames from the exhaust. The spark was hitting the cylinder while the exhaust valve was open and perfectly good fuel air mixture was being ignited and pumped out down the exhaust!!!! It looked good though!!

Thankfully it's an easy fix, as I'm now at the correct TDC, I just need to remove the dizzy and rotate the drive dog around a full 180 degrees.

Out
In
And Bob's your uncle!!!! It's now pointing at HT lead number one, just as it should.



Once everything was back together and checked over again, I sat back in the drivers seat with my key in the ignition and took a deep breath...
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Would it start?????
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I turned and waited...
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BOOM!!!!!!!! - No it didn't explode thankfully, but even with a depleted battery and the ignition timing a little off, it struggled along and but eventually started.

Here's the actual moment for your pleasure...




Oh joy of joys, as the engine chatted away, it was like the music of my people ringing out once more. And best of all, the engine feels beautifully balanced when it's revved up. I almost shed a little tear as finally my engine is reborn - again!

It's taken nearly 2 years and a great many number of failures and mistakes, but I'm finally one big step closer to my ambition of driving a car powered by an engine I re-built!!!

I'm hoping this time it manages more that 5 miles before the next rebuild though!!!!!! Fingers crossed.

Incidentally, it had pretty good oil pressure coming in at about 70psi at 2000 rpm, I'm pretty happy with that. When I test the engine further, I'll keep my eye on it and see what it reads after the engine has fully warmed up.



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