Noisy top end - 4.2

[Hawkeye1922]

Hi all,
just fired the 4.2 for the first time in 18 months - it's been out due to chassis refurb. It fired and idled OK - oil pressure within 5 seconds no probs, BUT:

it's very noisy on the LH bank top end - I ran it for no more than a minute - just enough to ascertain that the loud tapping noise is coming from the front end of the left hand bank. While the engine was out I took cam covers and front cover off and replaced both crank seals, but did no other work at all. All I can think of is:
- have i somehow blocked an oil way in the LH valve train?
- I wired up the timing chain when taking the covers off so as not to disturb the cam timing, so it shouldn't be this
- have I over-tensioned the chain (had to slacken it to get the front cover off)?

planning to take the cam covers off and bar it over carefully this weekend. Any thoughts / suggestions?

cheers

Paul

[scotty_d]

How tight did you make the chain tension? Might be worth backing it off a touch and listen to it again. But I would double check all of the above first before starting again.

[Luckyone]

Did you take the cams out? If not I can’t see how you could possibly have blocked an oil way as the feed comes up to the front bearing then the oil runs through the cam, then out of it to the other bearings, then as far as I can tell with what sprays out from the bearings being the lube for everything else. It will have got quite dry up in the head being sat for so long, mine did. Did you add any extra oil in there before putting the cover back on? Still, once up to pressure it should fill with oil very quickly I’d have thought. I’d take both covers back off & compare the amount of oil in the heads then you can tell if there’s a problem with supply.

If there was any sludge inside the cam it may have moved to block the oil outlets on start up (that’s a total guess by the way). But I’m going to try to take the end cover of my cams tomorrow to wash them out inside before putting them back in.

I guess there is a slight chance you have a stick valve / guide. My engine was running very well with only 40k on it but when I took the heads off I found the exhaust guides were knackered.

[Luckyone]

By the way congrats on getting it fired up, must have felt good for all of half a second (till you head the noise). Can’t wait to get mine back together, hoping I won’t have any odd noises form anywhere, but not holding my breath

[Hawkeye1922]

Luckyone said:

By the way congrats on getting it fired up, must have felt good for all of half a second (till you head the noise). Can’t wait to get mine back together, hoping I won’t have any odd noises form anywhere, but not holding my breath

cheers Luckyone. Incidentally, this is partly your fault because if it weren't for your body lift guide I might not have had the confidence to do it!

taking both covers off and comparing oil levels: good idea - i'll give it a go on Saturday...

[Hawkeye1922]

scotty_d said:

How tight did you make the chain tension? Might be worth backing it off a touch and listen to it again. But I would double check all of the above first before starting again.

The build manual is pretty vague - "tension so that the tensioner arm can just be lifted from the tensioner pin with a 12 inch screwdriver". So I did that as best I could and also looked at a photo of number of exposed tensioner bolt threads which I took prior to dismantling. Will definitely try backing it off.

[Trtj]

Will a slight drop/gain in chain tension affect valve timing? Albeit acutely?

[Tanguero]

The slack is taken up after the chain has driven the cams so the tensioner will have no effect at all on timing.

[Trtj]

Tanguero said:

The slack is taken up after the chain has driven the cams so the tensioner will have no effect at all on timing.

got you

[Hawkeye1922]

Thanks everyone for the advice. Whipped the cam covers off on Saturday - no issue at all with oil supply, which is a relief. Barred it over and tightened the timing chain - seemed much quieter on the bar. Unfortunately didn't have enough battery power to fire it

I was probably a bit timid with the tensioner the first time. Touch wood it'll be fine when I fire it later this week...