Discussion
Following much useful advice from those in this forum better informed than me on the possible causes of my apparent cam failure, I though it incumbent on me to inform all interested parties of the outcome.
I first noticed a lack of power when l could only beat Andy at Santa Pod by disconnecting his drive shafts (laugh? we nearly died), but on checking the compression I found a zero reading on cylinder no. 5 so took off the rocker covers and exhaust. There was about 4mm of movement on the push rod and none on the rocker as the push rod could be pushed down by hand. The exhaust was fouled by carbon deposits so something was wrong.
Gail at AS was very helpful despite the fact that the engine is well out of warranty (2 years old) and assisted with the spec for replacement parts, even though I bought them elsewhere.
It turned out that the cam lobe was almost worn away and the follower had worn right through leaving a hole and losing any chance of oil pressure. A few of the other lobes were slightly worn but nothing too serious on its own.
Apparently this just happens on these engines sometimes and often it is never noticed as they have enough power for the average Joe in a yank tank.
Replacement parts were bought from Roadcroft in Worthing (brian@roadcraftuk.co.uk) who advised on upgrade parts. They build ford and chevy engines for Cobras so could be another source of engines for Ultima having built a few. Certainly a useful contact for Chevy parts and advice. I even met a new GTR kit owner there whilst collecting the new cam and other shiny bits.
If anyone knows how to post a photo on the site l can do that. X rated for any with mechanical sympathy.
I first noticed a lack of power when l could only beat Andy at Santa Pod by disconnecting his drive shafts (laugh? we nearly died), but on checking the compression I found a zero reading on cylinder no. 5 so took off the rocker covers and exhaust. There was about 4mm of movement on the push rod and none on the rocker as the push rod could be pushed down by hand. The exhaust was fouled by carbon deposits so something was wrong.
Gail at AS was very helpful despite the fact that the engine is well out of warranty (2 years old) and assisted with the spec for replacement parts, even though I bought them elsewhere.
It turned out that the cam lobe was almost worn away and the follower had worn right through leaving a hole and losing any chance of oil pressure. A few of the other lobes were slightly worn but nothing too serious on its own.
Apparently this just happens on these engines sometimes and often it is never noticed as they have enough power for the average Joe in a yank tank.
Replacement parts were bought from Roadcroft in Worthing (brian@roadcraftuk.co.uk) who advised on upgrade parts. They build ford and chevy engines for Cobras so could be another source of engines for Ultima having built a few. Certainly a useful contact for Chevy parts and advice. I even met a new GTR kit owner there whilst collecting the new cam and other shiny bits.
If anyone knows how to post a photo on the site l can do that. X rated for any with mechanical sympathy.
. Jeff, wise words. l too have opted for a roller cam set up. The result is an engine that feels very different to what l had (ie 7 cylinders) but l have yet to give it some stick as l am running it in carefully. My other concern is that the worn cam must have found its way into the oil in the past so l am wary of excessive wear in other parts of the engine. l removed the cylinder head of the affected valve and all looked OK, just a bit of carbon. The adjacent exhaust valve stem was caked in carbon but this was softened in the dish washer and should burn off. The other point of note is that the circlip on the damaged cam follower was missing. l wonder where it is?
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