Running in / Compression

Tagged: engine compression oil

This topic has 10 replies, 3 voices, and was last updated 1 year, 2 months ago by Steven Wright.

Viewing 11 posts - 1 through 11 (of 11 total)

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11th July 2023 at 10:06 am #33753
Steven Wright
Participant
I have finally got my BL back on the road after a long list of problems. I have done about a 150miles and when I checked the oil it had dropped from the top of the groove on the dipstick to the bottom of the dipstick. I have replenished the oil and now find that there is significant smoke coming out of the exhaust and I can feel definite pressure coming out of the engine breather.

I have complete a pressure check..

Cylinder 1 112 psi
Cylinder 2 130 psi
Cylinder 3 112 psi
Cylinder 4 122 Psi

The engine has had new liners pistons etc. Where do I go from here before I start looking at stripping the engine again.

Steve W
12th July 2023 at 9:14 pm #33761
Richard Larter
Participant
If you have used a modern high quality oil it may prevent the engine from bedding in but you have only done 150 miles. Best roads for running in should include plenty of hills for loading and unloading the engine.

Cheers

Richard
13th July 2023 at 11:10 am #33763
Steven Wright
Participant
Hi Richard,

I’m down to go to Newby Hall on Sunday, including going to Ripon its about 200 miles. The trip would be a mixture of main roads and some hills (Woodhead) – I’m now debating whether to go and put 5 Litres of oil in the boot and top it up as necessary. I have had a suggestion that I could use a borescope to look if the bores are scored.

I have only ever replaced pistons are relatively modern cars so this is my first running in on an older car.
13th July 2023 at 8:35 pm #33767
Richard Larter
Participant
Hi Steve

I recently rebuilt the engine of my Light 15 with new pistons and liners but living in Scotland there are plenty of hills to bed the engine in. I used cheap 20/50 oil for the running in, as far as I can tell it is not using oil but there is a persistent oil leak which I call rust proofing! Some possibilities, did you check the piston ring gaps and were the gaps at 120 degrees to each other, if there is a problem with the rings or bores try putting a small amount of oil down the bores and do a compression check, if there is a marked improvement then the problem lies with the rings or more running in is required. Modern car engines are made to much tighter tolerances so little running in is required.

Cheers

Richard
13th July 2023 at 8:36 pm #33769
Steven Wright
Participant
I’ve been out today up some significant hills and the smoke is not visible in the rear view mirror. The car is running well so I will going to Newby Hall on Sunday.
13th July 2023 at 8:56 pm #33771
Steven Wright
Participant
New pistons, liners, rings etc. I very carefully spaced the rings at 120 degrees and used a piston tool to reinsert the pistons. I must admit perhaps I should have done a compression check at the time but I didn’t. I am hoping that running it to Newby Hall will be all it needs. Failing that if the oil consumption isn’t too excessive i will use it until winter and then if remove the head.
14th July 2023 at 10:39 pm #33773
Richard Larter
Participant
Sounds like a good plan.

Cheers

Richrd
19th July 2023 at 11:29 pm #33777
Chris
Participant
Steve – let us know how it goes!

Chris
20th July 2023 at 8:11 am #33779
Steven Wright
Participant
Engine ran very well going up to Newby Hall apart from the oil consumption which was of the order of 3 pints over the 200 miles round trip. I will take the car out tomorrow – Royal Horticultural Gardens at Bridgewater. I will then check how much oil has been consumed and if it’s no better I will start to investigate further.

It is my intention to check the compression on all cylinders and compare them with my previous set of results. I have a borescope so I will look to see if there is any obvious damage to the cylinders. The next step will be head off and sump off – is it possible to get the sump off without engine removal as I will have access to a hoist.

I’m away for nine days at the end of July so it may well be after 6th August before I start.

Steve
8th August 2023 at 12:51 pm #33847
Steven Wright
Participant
I’m now back from London and have started to think about what to do next.

I’ve redone the compression tests (cold and hot) and have the following results

Cylinder 1 88 Cold / 92 Hot
Cylinder 2 84 Cold / 84 Hot
Cylinder 3 84 Cold / 84 Hot
Cylinder 4 90 Cold / 92 Hot

Engine has completed around 350 miles so probably still bedding in.

The spark plugs are as clean as a whistle see attached.

Although the engine has consumed or lost 3 pints of oil in 200 miles I would have expected to see huge clouds of blue smoke. If I leave the engine idling there isn’t anything on the ground apart from water vapour.

I am now wondering whether the car is leaking some oil – possibly from where the petrol pump is (I’ll redo the gasket).

Any Thoughts? – I have also asked for help from my motor club and lust waiting to hear back.
13th October 2023 at 12:08 pm #34095
Steven Wright
Participant
Well I now believe that I’ve found the oil leak. There appeared to be oil leaking from the petrol pump gasket. I removed the heat shield and redid the gasket. Drove to TOC meeting Sunday and there was oil everywhere including inside the wings. Got back and my brother in law spotted a threaded hole next to the petrol pump. This hole was threaded M7 and is not shown in the parts manual for th ID19. There has never been a bolt in the hole for the 12 years I’ve had the engine. Found and inserted bolt which should cure the problem.
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