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Posted: Sun Sep 20, 2009 3:44 pm
by crayefish
Rule of thumb is about 10psi per 1000rpm according to the Ligenfelter... should be similar for a Rover.
Oil pressure seems a bit high, especially for 10W40... not sure why that would contribute to a tapping sound though...
Posted: Sun Sep 20, 2009 6:04 pm
by smoker
CastleMGBV8 wrote:Smoker,
I would suggest checking that you have a good oil supply to the valve gear, as you have had the heads off it is quite possible that when they were re-fitted that they were switched from one bank of cylinders to the other, this is perfectly ok as oil ways are drilled in the heads so that they can be fitted either way.
Only one pair of oilways feed the rocker gear that being the front pair and what happens is the redundant oilways tend to get blocked so if you switch heads from one bank to the other you have no oil to the rocker gear causing extreme wear.
If you cant see oil ousing out from the rockers it would suggest a blockage, take the valve gear off and check the cups that the pushrods fit into, they are prone to wear in high mileage engines anyway and the steel inserts can wear away completely in extreme cases.
If no oil supply the oilways will have to be cleaned/drilled out and then turn the engine over to push out any residue,
Also check that if you have fitted shims that you have not accidently blocked the oilways from the front oil feeds.
Blocked oilways to the rocker gear may also explain the very high oil pressure but it also may be a sticking releaf valve in the oil pump.
Kevin.
Thanks all for the suggestions, much appreciated. I checked the position of the shims and the oil supply - seems to be plenty of oil flow out of every rocker. I can't see any sign of wear in the rocker cups but i might order new rockers and shafts as I can't think what else it could be.
Oil pressure is now 40 psi @ 2000 rpm with the 20w/50 oil and about 13psi at tickover. It goes off the scale when the engine is cold 60 psi so i'm wondering if the oil pressure relief valve is sticking.....Engine is as tappy as ever. The thermostat is 88 deg. one so im wondering if a cooler stat would help?. I also tried 0.8mm shims under the rocker posts instead of the 1.5mm fitted but that hasn't made any difference to the tapping either.
annoying..i've spent a fortune on this engine and it sounds like it's clapped out at tickover!
Posted: Sun Sep 20, 2009 6:27 pm
by ged
Hi Smoker,
If you set the preload correctly with 1.5 shims I'd put them back in. As for the oil pressure being 60psi cold, if this is at revs don't worry about it. Just let it warm up before you give it stick. As for the rattle could it possibly be the timing chain? With SD1's I used an 82c thermo in the Summer & an 88c in the Winter.
Regards Ged
Posted: Sun Sep 20, 2009 9:03 pm
by crayefish
One more thought.... I know rhoads lifters can be noisey as hell due to the high bleed down rate....
Maybe your lifters are bleeding down very quickly?
Posted: Mon Sep 21, 2009 7:53 pm
by smoker
crayefish wrote:One more thought.... I know rhoads lifters can be noisey as hell due to the high bleed down rate....
Maybe your lifters are bleeding down very quickly?
Thanks for those suggestions chaps
It seems like it's oil pressure related as the noise only gets bad when the engine is idling and the oil pressure drops to around 15 - 20 psi.
I'm on my second set of tappets,...the set I have in now are genuine boxed land rover items.
All the preloads were 1 - 1.5mm with a 1.5mm pedestal shim fitted. I tried it with no shims (wouldnt start) and now i have 1mm shims in there.
The timing chain and sprockets are new all steel items. The only thing i didnt change were the rocker gear and cam bearings but they all looked fine to me so i'm baffled why it's so noisy. It's definitely getting worse I can hear the tap tap tap in the cab now when the radio is turned off.
Before I took the engine apart it was much much quieter but had a flickering oil pressure warning lamp, a worn crank needing a regrind, visibly worn cam and a loose gudgeon pin that was eating a hole into the cylinder liner....
Posted: Mon Sep 21, 2009 8:57 pm
by mgbv8
Where do you live smoker??
I'd be happy to have a look at it for you if you are not far away!!
Perry
Posted: Sun Sep 27, 2009 12:10 am
by smoker
mgbv8 wrote:Where do you live smoker??
I'd be happy to have a look at it for you if you are not far away!!
Perry
Thanks for that kind offer, I'm in Northampton if your ever in that neck of the woods!