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MG MGB GT V8 Factory Originals Technical - Lifter Drain Down.
Engine is late Rover SD1 fully rebuilt with new cam and lifters from Real Steel.
If the car has been left for more than a couple of days then, on start up, two of the lifters clatter loudly until oil pressure rises then they quieten down, but not completely. Oil pressure is fine at 45lb cold at fast tickover dropping to 25lb tickover hot to 55lb at 3000RPM hot.
The odd thing is that it appears to be two adjoining lifters on the left hand bank. The car didn't get much use last year due to health problems but I've improved considerably in the last few months and having had the car repainted am in the process of sorting out a few niggles.
I would prefer not to dismantle the top end of the engine, so any suggestions would be gratefully received,oh and the symptoms seem to have appeared after the last oil and filter change and from memory I think that put in 15w/40w whereas I would normally use 20/50
It's technically due for a change but the car has only done approx 100 miles since the oil change, and its so clean you can hardly see it on the dip stick.
|OK, here's what I would do - replace the oil filter with a new, successfully used brand. For makeup oil, use ATF and run this for about 100 miles. Change the oil and filter with your 20/50. My thinking is that the ATF should dissolve any varnish or gum that may have built up in the lifters. The 15w/40w really shouldn't have caused a problem, but it can allow lifters with a marginal preload to be noisier than the heavier oil.|
I do have a question, though. Do you know for sure that the cam was broken in properly? And how many miles are on the engine? Also, there has been a lot of discussion about the newer engine oils having less zinc additives for less pollution which seemingly is cause for premature wear of lifter to cam contact surfaces, which wear also reduces lifter preload.
|As far as I'm aware the cam break in procedure was carried out properly and there was no problem with the lifters within the first 500 miles on running in oil.|
Is it a feature of Hydraulic lifters that if there's not enough pre-load then it will allow the lifters to bleed down.
I have had one suggestion from Real steel and that was to insert a 25thou feeler guage between the valve and rockers of the problem lifters. I must admit I didn't fully understand what this could do but now realise that it would increase the preload and possibly cure the problem.
Is using ATF in an engine safe? or would it be better to try flushing oil if its an obstruction in the lifters.
The engine should be very clean internally as it was chemically cleaned prior to the rebuild, mileage now is only 650 Miles but I intend to drive it a lot more this year.
|How do the rockers and rocker shafts look. All the cleaning in the world will not make up for exesive clearance in the rockers.|
|if you are using a Fram filter, then try to replaqce it with a AC filter and see what happens.|
Also where is your oil filter located? some external filters are located where they drain back thus the engine has to re-prime the upper section of the engine.
Try this before you do anything drastic.
|Thanks for the reponses guys,|
The rocker shafts are in good condition and any worn rockers were replaced at time of rebuild.
The heads were milled 25thou and i used 16thou shims under the rocker pedestals to bring the preload back to original allowing for the 1.6/1 rocker ratio.
The oil filter is in the standard MGBV8 location.
A filter change would do no harm but if it is a filter drain back problem then i would have thought that all the lifters would drain down not just two on the left bank 4th & 5th from the front if I remember correctly.
I think I will try the Real Steel trick of putting a 25thou feeler guage between the noisy valves/rockers and see if it works it will only take 10 mins to find out.
Im going over to the car today as we are having some near summer weather but it's going to change tomorrow.
I'll report back later today.
|Heres some pics of the car just the interior trim to do. I have some grey leather piped green seats to install and am having some matching grey piped green door cards and side panels made up to match + consul lid and gear lever gaiter.|
|Nice looking GT.|
My low-mileage SD1 conversion sits in Arizona for several weeks at a time whilst I am in SoCal. When started, it does the death rattle with the lifters. This quiets significantly when oil pressure comes up but several continue until the motor completely warms up. Then all sound good. Things are then good for several days. I run a Wix filter (good anti-drain valve but obviously not perfect with the high remote filter location). I'm told this is all to be expected.
I'm running hot-wire EFI and its too damn efficient - starts right up. I'm thinking of installing a cut-off switch to leave the EFI off until the starter has cranked some oil into the system. I've seen pilots with WWII P-51 aircraft run electric pre-oilers for an hour to make sure everything is lubricated and warm before lighting up the 12 cylinders. If I had a RR Merlin I'd do the same.
I wish my wife would let me refurb the front crossmember in the front room. I was never forgiven for putting the rocker covers in the dishwasher.
Nice engine bay work though.
Whatever else you do, do not change the two lifters for new ones as that will destroy the cam. You are essentially stuck with the noise unless you are willing to change out cam and lifters. You can minimize it by using a heavier oil, but the real problem is the internal clearance in the lifters themselves. They are designed to constantly leak down slightly (otherwise the valves would never completely close) but the tolerances between proper leakdown and enough to clatter on startup are very tight. We had a run of intentionally loose lifters here in the states which were marketed as "anti pump up" or high rev lifters supposed to be good for an extra 500-1000rpm, but they clattered like a loose solid lifter cam on startup and often until the engine warmed up, and even sometimes afterwards.
The easy solution is to ignore it and run some heavier oil. It won't do any harm.
ATF will not harm your engine - it's just 10W engine oil with anti-foaming agents and detergents added, dyed red for indentification.
You could try taking the 16 thou shims away to try and put that much preload back into the lifters. Instead of the 25 thou feeler gauge, use 16 while the engine is running and see what happens first.
Not familiar with Real Steel camshafts, but if the lobe base circle is smaller than stock, then that will reduce the preload. Are these cams new or reground? This is one of the reasons that an adjustable valvetrain is so desireable.
Unless things have changed in the last few years, you could put new lifters on an old camshaft but not the other way around. You still have to run the cam/lifters in though.
|Buick V6 and V8 (early modles) have had problems with the leak down. some of the lofters have different tolerances than others and do leak down and other do not.|
Fram filters use a very cheap check valve in the filter, AC uses a much better check valve and avoids drain back problems. Also as the valves seats are cut when doing a valve job, some seats have to be cut down more than others and the clearance do change, yes hydraulic lifters are made to take the clearance as needed, but as mention before the lifters do drain a bit and strat-up clatter will occur.
It's only a possibility. Hope you find the correct problem.
|"Unless things have changed in the last few years, you could put new lifters on an old camshaft but not the other way around. You still have to run the cam/lifters in though."|
SOMETIMES you can get by with that. More often it destroys the case hardening on the cam lobe and destroys the cam.
|Thanks for the further comments, it seems that changing the noisy lifters is not an option if I don't want to risk wrecking the cam.|
I will check with Real steel what the specs of the cam are and who is the manufacturer of the Viper Hurricane cam, it may be Crane because it came with their cam lube.
The simplest things to do appears to be to change the oil and filter, what model no.is the AC filter and I will check to see if it is available here.
I can also remove the shims on the left hand bank if the oil and filter change doesn't work and see if that does the trick.
|Kevin, the store that you deal with will be albe to cross reference the Fram part # to the AC.|
We no longer use Fram filters. We use AC, Napa Gold.
Caterpillar. Yes they make a very good filter. More $$$
K&N, STP, and many others are manufacture by the same co that makes FRAM
This web page will give you an idea about filters.
I have stories to share.
Read the page and draw your own conclusions
the engine of my GT is a Rover SD1 from 1979. It came from a crashed low milage car and i did the conversion in the early 1980's. It was never put apart.
When only frequently using the car, the lifters are noysy for the first 30 seconds or so and have evrer done so.
With 20W50 it is not that dramatic than with 15W40 or even lighter oils i used. Within the years i've tried differnt qualities of engine oil up to syntetics and came back to 20W50.
With the filter, there have never been any regardable problems, althoug i allways pick them from Ford or from distributers that deliver the workshops. I never tried filters from discounters or low cost offers, seems to me not worth the little saving on this items.
With the Filter installed in the normal BGT V8 position, there should not be any drain down of the
I would do nothing on the engine but use it a little more often and change filter and oil at close intervals.
Seems that the oil change to 20/50 and the use of a quality filter may solve or reduce the problem.
If this does not solve it completely I can still increase the pre-load by either removing or fitting thinner shims under the pedestals.
The cars going in to have the coil over suspension and the reconned original rack fitted next tuesday so am looking forward to some improvements in driveability.
Don't currently have a wife so no problem with the crossmember being a fireside ornament. Don't have a dishwasher so have to do penance by manual washing up though. The crossmember was all clean and powder coated and the suspension components were all brand new, so no problem building it up in my living room, it was a sort of therapy whilst I was having health problems and kept my enthsiasm going.
|I am thinking about using an old ABS pump from the donor rangie to use as a pre oiler. Turn it on for 10 seconds and go. Anyone done this?|
|In my race car I use what is called Acusump.|
It works under pressure from the oiling system. When the engine needs oil for any reason, the system injects oil into the system while it's running.
By turning the system on before starting the engine, it pre-lubes the system and the excess oil return to the system.
I also use it to pre-lube new engines.
The unit can be mounted in the trunk and they come in different sizes by qts.
|here is the link for |
Accusump by Canton http://www.accusump.com/
There is a specific lifter treatment
Alternative would be Auto rx for cleaning lanolin ester
ATF is a 5W20 with no special cleaning abilities just thin.
Most oils only keep clean but ester oils will have some cleaning ability Redline Motul 300V Silkolene. UK oils do no have SM low ZDDP levels.
This thread was discussed between 26/03/2007 and 28/03/2007
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