Quote:
Originally Posted by andrewwynn
I did the chain guides job twice and I seem to recall I couldn't lift the chain off the intake sprocket even with the extra slack from missing chain guides. The problem was more that there was no sideways flex in the chain than lift. You'd likely have more luck at the bottom. No luck finding a YouTube video where somebody did what you are trying?
I'm trying to remember if there are any alignment sleeves etc that restrict the order of install of the chain covers. Since the lower cover goes around the crank if there are sleeves that lock to upper covers it may be impossible to slide it forward.
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Thanks for the reply. I found a really good write up on a Range Rover forum about removing the lower cover, but it was vague about if the uppers were still on the motor unfortunately. Everything else ive found is for a full timing chain guide job. It may be a booby trapped design for home mechanics, but i guess the system is pretty bulletproof or else YouTube would have plenty of videos and someone would make a master link chain, as they do for other bimmers.
The lack of sideways flex is a worry. I also was hopeful that there is a possibility there would be enough slack to simply slide the new oil pump chain between the crank and the timing chain. But that won’t work if it won’t come off the sprocket.
I bought an OEM oil pump chain and a master link timing chain for a 6 cy BMW and put my digital caliper on them. Very close, but not identical. My thinking is to break the timing chain to length and thread it on from the bottom, after cutting the old oil chain off.
The 6 cy chain has identical barrel diameter and pitch lengths, but is a tiny bit wider. The inside link widths are within 5 one thousandth of the same but the outside links are about 4 one hundredth wider on the timing chain. I think the pitch and barrel dimensions are the critical ones, but I’m no engineer. Could work great, could jump off at 80 mph on the highway!
So if I went with a new OEM chain, is it possible to replace the oil pump chain then without messing up the timing? Assuming there isn’t enough slack available in the timing chain?
Thanks again Andrew.