Engine wear

[sujitroy]

On a Triumph club run this weekend, I was following a TR4 and then a Stag. I could smell burnt oil from the exhausts. Is there a way to isolate weather you have worn valve guides or worn piston rings?
Not on this occasion, but I've noticed when cars change gears, you can see blue smoke from the exhaust, but appears normal otherwise. What causes this?

Sujit

[StagJonno]

Whip the plugs out and do a compression test. squirt some oil down the plug holes and repeat the compression test. If the second set of results is significantly better, this indicates worn rings/ bores. If no difference (assuming compressions are down) indicating that valve sealing is not as good as it should be.

Think blue smoke after changing gear is caused by worn valve guides/ seals - throttle is shut, so manifold depression is high sucking oil via the valve stems, which then burns off. Blue smoke when running can be excessive crankcase pressure (ref Wheeler Dealers Mk2 Jag episode, where sorting a blocked oil breather filter and gunged up oil catch can eliminated fairly severe blue smoke pretty much all the time).

[sujitroy]

Thx. I had my head rebuilt and the machine shop said the guides were worn. I had him put in new bronze guides, but the machine shop said regular steel guides should have been sufficient.

[jbuckl]

Thx. I had my head rebuilt and the machine shop said the guides were worn. I had him put in new bronze guides, but the machine shop said regular steel guides should have been sufficient.

I thought the original guides were iron.

modern guides are usually sintered.

I think original triumph valves had a chrome stem plating though , which may not suit a bronze guide.

[richardthestag]

why dismiss what the machine shop told you? standard guides on many tens of thousands of triumph 4 and 8 cylinder engines are proof surely. Then you can start counting the saab installations as well..

[sujitroy]

For clarification, initially, I took the heads to the mechanic for rework with new valves only. He subsequently rang me and said it needs new guides. I consulted this forum and the consensus was to rebuild it with bronze valve guides. When I took the bronze guides to him, he said these guides were a bit of an overkill and regular ones would have been fine.
These are the guides I got:

https://rimmerbros.com/Item--i-142476BR

Sujit