11-06-2021, 05:12 PM
An update:
I had covered nearly 500 miles of running in, gradually refining various aspects, retightened the head, adjusted the tappets, etc. I found the engine to by rather harsh on pick-up and accelerating, at around 35 mph however it seemed to gain power and smooth out, running quite nicely at 40 (true speed by sat nav)
On Wednesday I called on Ivor while adding some more miles, his observation of the engine while the car was stationery, was the same "a bit hard". We discussed possible causes and while relating the history and what I had done, we came to the conclusion that it might have a slightly lumpy cam and that my fitting an HC head in place of the LC fitted might have not suited the purpose of Dave Orange.
I thought about it overnight and on Thursday bit the bullet and refitted the LC head. The engine was immediately softer in sound and a test drive of 20 miles or so revealed that the harshness had been much reduced and there was no appreciable loss of performance, indeed it still seems to pick up its heels and is happy at 40+ (I am keeping the reins in a bit until the 500 mile oil change tomorrow.
My conclusion is that the tappet profile might be a bit fierce, it may have a modified cam, it was built with larger inlet valves and intended to run well on an LC head.
On Sunday we set off for the Dales (200 miles) intend to cover about 80 miles a day for 4 days and then 200 miles home. I shall be happy if it continues to run as it did after the head change.
Thanks Ivor for the suggestion and providing the nudge to actually do it!
I had covered nearly 500 miles of running in, gradually refining various aspects, retightened the head, adjusted the tappets, etc. I found the engine to by rather harsh on pick-up and accelerating, at around 35 mph however it seemed to gain power and smooth out, running quite nicely at 40 (true speed by sat nav)
On Wednesday I called on Ivor while adding some more miles, his observation of the engine while the car was stationery, was the same "a bit hard". We discussed possible causes and while relating the history and what I had done, we came to the conclusion that it might have a slightly lumpy cam and that my fitting an HC head in place of the LC fitted might have not suited the purpose of Dave Orange.
I thought about it overnight and on Thursday bit the bullet and refitted the LC head. The engine was immediately softer in sound and a test drive of 20 miles or so revealed that the harshness had been much reduced and there was no appreciable loss of performance, indeed it still seems to pick up its heels and is happy at 40+ (I am keeping the reins in a bit until the 500 mile oil change tomorrow.
My conclusion is that the tappet profile might be a bit fierce, it may have a modified cam, it was built with larger inlet valves and intended to run well on an LC head.
On Sunday we set off for the Dales (200 miles) intend to cover about 80 miles a day for 4 days and then 200 miles home. I shall be happy if it continues to run as it did after the head change.
Thanks Ivor for the suggestion and providing the nudge to actually do it!