XJR tensioners - advice please!

[slippery]

I am currently having the head gasket done on my 1999 XJR. While it's being done, I told the garage to upgrade the timing chain tensioners if they were the old plastic type as I've heard they are a problem. I have just been told by the garage that they were the plastic type and had actually started to disintegrate. What worries me is where the pieces will have gone and what effect this may have? Sorry if this is a silly question! I was told they were probably laying in the bottom of the sump and if I was worried about it they could drop the sump. Should I pay the extra and have them do this? I'm trying to do everything right while it's in bits, including new water pump and 4 new timing chains, but don't want to spend money for the sake of it! Your thoughts would be appreciated.

[drummerboyXJR]

Hi, yes, its only a half hour extra labour surely?

[NormanD]

It would be silly not to have them done at the same time

As the previouse post you are half way there already

[a8hex]

Even forgetting the "where are the bits of tensioner now?" question.
I guess that if you are that far into an engine it is always useful to be able to see is there anything else in the sump we don't know about.
It is better to know when it is already in pieces.

Remember it's not paranoia when the world is out to get you!

[slippery]

But I can't forget the "where are the bits of tensioner now" question! If the sump was checked and cleared, could those missing bits cause any future problems?

[a8hex]

I assume they've drained the sump (I'm guessing here) so unless they sieved it the most like place is in their waste oil drum.

Bits of engine that end up in the sump can end up being sucked up by the oil pump. Hopefully there is some filtering arrangement on the pick up. I've seen bits of engine that have been chewed up by the pump. I've no idea what the V8s oil pumps are like, the one in an old straight 6 XK engine the blades look pretty tough.

Once bits of swarf have passed through the oil pump then they can end up logged in all sorts of bits of the engine. Full engine rebuilds tend to need to go though all the oil ways to make sure everything is clear.

Hopefully someone who's rebuilt one of these AJ26 engines will come along and put your mind at rest. I'm sure things have moved on since 1948 :-)

[6speedmanual]

Quote: "Once bits of swarf have passed through the oil pump then they can end up logged in all sorts of bits of the engine"

May I just ammend that - Once bits of swarf have passed through the oil pump, they end up in the oil filter.

Unless the filter is blocked and it has a bypass arrangement, any bits picked up from the sump will get caught. The oil pump rotors and pressure relief valve are vulnerable to damage from picked up bits. The strainer on the pick up is intended to stop anything large going through the pump which would cause a catastrophic failure.

If the sump has been drained and refilled, I wouldn't worry too much. Teh next step of precaution would be to remove the sump and clean it and Teh pick-up strainer. Other than that, if you have oil pressure, just keep going!

Regards
Peter

[slippery]

Thanks Peter, that all makes good sense.

[slippery]

Thanks Peter, that all makes good sense.

[a8hex]

6speedmanual said:

Quote: "Once bits of swarf have passed through the oil pump then they can end up logged in all sorts of bits of the engine"

May I just ammend that - Once bits of swarf have passed through the oil pump, they end up in the oil filter.


Regards
Peter

Duh,,, sorry being brain dead there. Can't think what I was thinking of.
Thanks