Old school diesel question

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20th Century Pug
Posts: 15
Joined: 07 Apr 2022, 03:58
x 5

Re: Old school diesel question

Post by 20th Century Pug »

By skimming the head and replacing the gasket, you have probably increased the compression slightly. I know it's a flat head, but presumably the volume of the swirl chamber has been reduced? Gaskets come in different thicknesses, identified by semi circular cutouts on a protruding tab that is visible at the flywheel end with the engine assembled. Depending on which gasket you used, the compression may have altered. Also, the skim has effectively moved the camshaft and pump sprockets closer together - very slight valve timing change. Did you check the valve clearances are still within tolerance?

I have noticed when replacing the XUD timing belt that the engine sometimes sounds a bit different. No change to the timing setting, but my theory is that an old belt may have stretched, so there will be a very slight change in the injection timing.

I suspect that your timing is correct if you havn't disturbed the pump and the belt is correctly tensioned. Certainly worth rechecking the belt tension and that the pins still line up. However, if the perceived sound change is only during cold start and warm up, I would be inclined to follow Old Pug's 'old school' advice. You have most likely restored the engine to more like it should be. Presumably it is easier to start now? It's performance on the road with the engine at normal temperature that matters.
20th Century Pug
Posts: 15
Joined: 07 Apr 2022, 03:58
x 5

Re: Old school diesel question

Post by 20th Century Pug »

Apologies, I hadn't noticed there was a second page. I now see most of my points have already been covered. Do let us know what it drives like now you have retarded the injection.
aerodynamica
Donor 2021
Posts: 1098
Joined: 26 Dec 2007, 19:10
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Re: Old school diesel question

Post by aerodynamica »

20th Century Pug wrote:
11 Apr 2022, 00:28
Apologies, I hadn't noticed there was a second page. I now see most of my points have already been covered. Do let us know what it drives like now you have retarded the injection.
Hiya, thanks for the advice. Yes it starts very quickly indeed - half a turn on the crank from cold after 8sec on the glowplugs. I've marked the timing and it's 1mm retarded so can be returned to the original position if it proves to be limited in performance. Have to confess I've only driven it 50m up the road and back since ....