The Triumph Dolomite Club - EzBoard Archive

Posted on behalf of Mike Taylor:-<br>
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“ I have discovered where all my oil was going!! Whilst on my way to watch Santana in the Wembley Arena in mid May in the Sprint I pulled into Reading East services on the way up for a break. The engine stalled just as I was turning into one of the parking bays (it needed quite nifty footwork on the throttle to keep the revs up and the engine running whilst moving at car park speeds) and it would not run at all after that although it was trying to fire up when turning the ignition. Oh well, call the breakdown company! 3 hours later I was comfortably in my hotel in Wembley getting ready to watch this great band – sod the car !!!. The next morning (Sunday) after egg and bacon, I tried to sort the problem out – still no joy so a second call to the breakdown company had the car once again on the back of a low loader and we were taken all the way back to Plymouth. <br>
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After the exams period had finished end of May and I had a weekend clear I spoke to a learned colleague of mine who, while trying to fire the car up discovered during our checks an alarming amount of smoke coming from under the dizzy cap (up through the dizzy shaft and out under the loose fitting cap). I removed one of the spark plugs and there was enough smoke to create a smoke screen for the next WW2 movie at sea!!! He was of the opinion that I had suffered some sort of piston ring problem and further investigation was required. After removing the head of my Sprint as you can see from the pics of # 3 piston, the piston wall has disintegrated in a pretty big way, breaking up both the scraper and the oil rings in the process. As the piston metal is softer than the rings, the piston wall has been chewed up and as a result the oil has been burnt off and has been allowed to burn and blow out of any point it can find! # 4 piston was showing signs of beginning to follow the same route – the piston was complete in itself although one of the oil scraper rings had broken up and was just laying loose in its groove!!. #’s 1 and 2 pistons were fine. Surprisingly and I don’t know how, neither of the cylinder walls of #3 & 4 were damaged or scored in any way!! The main bearings and the bottom end con rod bearings are all fine as well. The general view was that either the rear carburettor is running too lean allowing #3 & 4 pistons to run too hot or there was a compression problem (unless the compression problem came about as a result of the rings beginning to fail as reported in my first thread on “no oil!”<br>
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Although I have a set of very good Koehler & Schmidt pistons in my spares box, and these will be fitted with new rings and small end bearings as well as replacement bottom end and main bearings all round, I still have to decide what caused the problem before I start rebuilding the engine. <br>
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What is the general view out there? What do you think may have started this process? My engine does tend to run on the hot side – particularly as I have mentioned before when travelling up Holden Hill which causes the engine to create the “spit, spit “ sound and does pink quite a bit. Should I change the plugs I use which are the Champion BN9Y to a cooler plug? If so to what plug? When taking the plugs out, they were not indicative of too lean a mixture. Should I fit an oil cooler kit? (Does anyone have one they want to sell?) <br>
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Any thoughts on this would be keenly received !!<br>
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Mike Taylor “<br>
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<p>Martin<br>
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This is the fourth such failure I have seen/heard of. Steve Wilkes, Dave Waker (from memory) and an engine I took to bits that wouldn't start due to very low compressions.<br>
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The only answer so far suggested was the use of unleaded fuel. I started a thread ages ago on this vey issue asking for research examples of similar problems to try to get some correlation, but no-one answered save for some immediate post digression...<br>
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I suspect we will be seeing more of this as time goes on...

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Didn' tMike have some problems with pre-ignition (pinking) and could there be a link ?

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ITS Det <br>
get the afr checked out <br>
and put some octain booster in until you do or try backing the ign off a tad<br>
You will only destroy the new rebuild if you dont<br>
It needs to run richer mid and topend <!--EZCODE EMOTICON START ;) --><img src=http://www.ezboard.com/images/emoticons/wink.gif ALT=";)"><!--EZCODE EMOTICON END-->

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It isnt unleaded.<br>
I saw a few failures like this on TR7's in the olden days.<br>
I put it down to just running too lean at the top end. If you are genuinely running hot and it isnt just the stabiliser causing the guage to misread, that wont help either. Suggest a rad recore/upgrade, check of water pump for loose impellor and then adress the carburation and ignition advance curve. Best to gor for a rolling road tune on this to make sure you arent weak under load, which is suggested by the pinking. I find it hard if not impossible to get my Sprints to pink and they are set up as per the book.<br>
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Jonners<br>
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Might be useful to know what needles, air filter, and exhaust set up you have. Also compression ratio and cam if different from standard at all.<br>
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David

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Hi guys, sorry I've not been up for a while, had a mountain of things to do. Thanks for the replies. I didn't get chance to check the compression before taking the head off, but I have a standard air filter (clean) and cam. I can find the needle details in a day or so. I had been suffering from pinking - as you may have seen from earlier notes from me, it was more of a spitting sound (as if you were to drop water onto a hot iron - it tends to "spit off" - oh ok, nobody uses an iron anymore then!) with occasional pinking in the background at lower revs/speeds uphill. The rad I think is fine - but as I have this out at the mo, I can always get it checked out. Unfortunately, I sold a bloody good 90 core (I think) uprated rad when I god rid of NLJ194M at the sodit at Duxford. On the question of running unleaded, I tended not to put any additive in - well, only now and again and when I did I put in the Superblend zero lead 800 as sold me by Wineke in Holland a few years back. I suppose there could be a link in this area. Is there a more common brand used by anybody out there and if so how much is it?

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I've been running my sprint for years no additive, and at one time was doing 12,000 miles a year and 90moh or so and no problems, unleaded should only affect the valves.<br>
I reckon some of your engine may run a bit hot, personally I run a 74oC stat, a little cold in winter maybe.

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