The Triumph Dolomite Club - Discussion Forum

No. 1 cylinder is nearest the fan. You have a bit too much variation in compression values. It could be a number of causes, a leak-down test would give more of a clue. But yes, head off time.

Thanks Martin, pardon my ignorance but what does a leak down test entail?
Rich

You buy a leak-down tester (you can make one, videos on youtube). You need a compressor as well. In layman's terms. You stick a tube in a spark plug hole with that cylinder at TDC. Turn on your compressed air. Watch the gauge to see if there is a leak. If there is you can usually hear it coming out somewhere. Either through the inlet manifold (valve not seated properly), out of the exhaust (same as inlet). From the block (rings). Bubbles in the coolant tank (head gasket).

https://www.youtube.com/watch?v=WgrfT0LFMhc

You could take it to your local garage. I wouldn't imagine it would cost much.

Mad Mart wrote:You buy a leak-down tester (you can make one, videos on youtube). You need a compressor as well. In layman's terms. You stick a tube in a spark plug hole with that cylinder at TDC. Turn on your compressed air. Watch the gauge to see if there is a leak. If there is you can usually hear it coming out somewhere. Either through the inlet manifold (valve not seated properly), out of the exhaust (same as inlet). From the block (rings). Bubbles in the coolant tank (head gasket).

https://www.youtube.com/watch?v=WgrfT0LFMhc

You could take it to your local garage. I wouldn't imagine it would cost much.

mmm looks a bit too much for my skills at the moment that one! Last thing I want to do is get head reconditioned then it turn out to be rings! She honestly drives like a dream, did another 60 miles today and didnt miss a beat.
Rich

RJF_70 wrote: mmm looks a bit too much for my skills at the moment that one! Last thing I want to do is get head reconditioned then it turn out to be rings! She honestly drives like a dream, did another 60 miles today and didnt miss a beat.
Rich

In that case just drive it. If there really is a problem there it'll get worse but have added nothing to the cost of any subsequent repair. OTOH you could get a year down the line and find you've near enough identical compression figures. I used to do a compression test at each plug change. Find a repeat interval that works for you, short initially I would suggest, and keep an eye on it. Plug changes for me were 12k miles, 9-12 months.
Also monitor your fuel consumption, she'll tell you via your wallet if she's unhappy.