Hydraulic Lifters - maintenance free?

Clive · May 16, 2023

As one who spent years setting traditional tappets and is old enough to think the 961 onboard computer is a technological marvel I am a bit puzzled by the hydraulic lifters. Winding the tappet adjuster down from touching by 2.25 turns to 'preload' it seems very strange. My first odd experience was with my BMW Mini where one became extremely noisy after an oil change. I reluctantly tried some engine flush which, to my amazement, completely fixed it. This just compounded my lack of understanding. The workshop manual states that the 961 lifters are 'preset' at the factory - is this right? I am now using lash caps over my damaged valve stem - will this affect their 'setting'? Can they be inspected/replaced/flushed without lifting the head? I understand their purpose but not precisely how they work - can anyone illuminate me with their wisdom?

TonyA · May 16, 2023

2.25 turns should get the setting to about middle of lifter internal movement. This allows for increase and decrease of valve clearance distance . So essentially every time you start up your bike and lifters pump up they are meeting this new setting .
So yes , If factory sets them correctly , they are set . Of course it can't hurt to check and set if you are in there already . And the manual states if you are replacing/exchanging/reassembling they must be set again of course ! Are they 100% perfect ? Probably not , but I like them alot ! Ford use them in their OHC engines , I never have to set valve clearances in my F150 . Ford has a hydraulic stabilizer under the finger follower which set the clearance .

Clive · May 16, 2023

Thanks for this info so how do the factory 'preset' them? So if I have 1.5mm thick lash cap do you think I should need to change this setting? After I put my new rockers on I was disappointingly getting a lot of noise so I changed 3 things;
Took the lash caps off the exhaust valves
Ground the side of the rockers where they passed each other extremely closely
Shimmed the rockers so the side float was around 4thou

There is a massive improvement but still a bit more top end noise than there used to be so wondering where this is coming from. Hence my interest in the lifters.

TonyA · May 16, 2023

Clive said:
So if I have 1.5mm thick lash cap do you think I should need to change this setting?

I would suggest not to change the 2.25 turn pre-load but to verify that with the lash cap you have plenty of oil getting through the hole in the adjuster stud. The lash cap will change the positon of the adjuster stud . Why are you using lash caps ? Valve stem damage ? I have no lash caps in my engine .

TonyA · May 16, 2023

Clive said:
Can they be inspected/replaced/flushed without lifting the head? I

Definetly no , to remove the lifters head and barrel must be lifted . Can you check your oil pressure at 4000 rpm ? Do this from the drilling on the L/H side of the barrel . Look for the bolt with washer seal near the bottom of the cylinder at the l/h side. Don't remove the lifter keeper bolts which are close by. I seem to remember I had 40 psi at 3600 rpm cold .

City Garage · May 16, 2023

Clive said:
Thanks for this info so how do the factory 'preset' them? So if I have 1.5mm thick lash cap do you think I should need to change this setting? After I put my new rockers on I was disappointingly getting a lot of noise so I changed 3 things;
Took the lash caps off the exhaust valves
Ground the side of the rockers where they passed each other extremely closely
Shimmed the rockers so the side float was around 4thou

There is a massive improvement but still a bit more top end noise than there used to be so wondering where this is coming from. Hence my interest in the lifters.

You added lash caps for wear, so no need to change setting. A 1/4 out turn won't make that much difference anyways, whereas a 1/4 in could preload too much. Also it's always good to note where zero lash is.

When adjusting, make sure that you wait a minute to allow the lifter to level out when turning it over by hand, or you will not have a neutral lifter which could cause inaccurate adjustment

As Tony stated, oil pressure is your friend here. Take the reading where Tony stated and also at the oil switch.

Clive · May 17, 2023

Thanks for the info guys so I'll use the standard 2.25 turns and take notice of the lifter 'levelling' - Yes I fitted the lash caps due to the damage to the end of the stem on the inlet valve. And yes I have an adapter ready to screw in and a pressure gauge on order. Up to 4000rpm it sounds absolutely perfect but at the top end it actually sounds like a loose timing chain (which I have checked twice). I even went round hitting everything with a rubber mallet to make sure it wasn't some parasitic vibration.

City Garage · May 17, 2023

Clive said:
Thanks for the info guys so I'll use the standard 2.25 turns and take notice of the lifter 'levelling' - Yes I fitted the lash caps due to the damage to the end of the stem on the inlet valve. And yes I have an adapter ready to screw in and a pressure gauge on order. Up to 4000rpm it sounds absolutely perfect but at the top end it actually sounds like a loose timing chain (which I have checked twice). I even went round hitting everything with a rubber mallet to make sure it wasn't some parasitic vibration.

I know this doesn't help much, but some of them are just noisier than others. I have worked on a few that didn't make much noise, and they had more problems engine-wise, and then the louder ones had everything perfect. And on others, we switched to a heavier oil, and some of the noise came down.

Most of the noise we found was related to low oil flow and top-end pressure

Clive · May 18, 2023

Thanks - I'll check the oil pressure next week when my gauge arrives - it's just that I expected it to sound like it did before I had the problem with the rockers. There were a lot of small pieces of metal in the inline filter so I was wondering if some dirt had got into the hydraulic lifters. I checked the push rods and they were clear.

TonyA · May 18, 2023

Clive said:
Thanks - I'll check the oil pressure next week when my gauge arrives - it's just that I expected it to sound like it did before I had the problem with the rockers. There were a lot of small pieces of metal in the inline filter so I was wondering if some dirt had got into the hydraulic lifters. I checked the push rods and they were clear.

Have you considered lifting the barrels and replacing the lifters ? You can have a good look at the cam then . Can you remind us , this all happened because your rocker bushing came loose and migrated inward ? Then this caused the damage to the valve stem tip and the rocker tower . If you can pull the head you can replace the valve .

Clive · May 22, 2023

TonyA said:
If you can pull the head you can replace the valve .

Hi sorry about delay out of the country at the moment. Yes you are right about the bushes and lifting the head but the bike has been out of action for a while waiting for the parts and how my time is at the moment if I pull the head then it is going to be out of action for quite a while longer. For normal riding up to around 6k rpm it sounds absolutely fine so it is tempting to run it for the summer then do the job properly over the winter when it’s cold and wet. Which for us will probably be around August.

City Garage · May 22, 2023

Clive said:
Hi sorry about delay out of the country at the moment. Yes you are right about the bushes and lifting the head but the bike has been out of action for a while waiting for the parts and how my time is at the moment if I pull the head then it is going to be out of action for quite a while longer. For normal riding up to around 6k rpm it sounds absolutely fine so it is tempting to run it for the summer then do the job properly over the winter when it’s cold and wet. Which for us will probably be around August.

Thats a good plan! I would just replace the lifters while in there with something better(S&S or Fueling) and also the rings unless you leave the pistons in the barrel when you remove them. It will also be a good time to look around the bottom end. you can buy a really cheap snake cam from amazon for less than $40

TonyA · May 30, 2023

City Garage said:
You added lash caps for wear, so no need to change setting. A 1/4 out turn won't make that much difference anyways, whereas a 1/4 in could preload too much. Also it's always good to note where zero lash is.

When adjusting, make sure that you wait a minute to allow the lifter to level out when turning it over by hand, or you will not have a neutral lifter which could cause inaccurate adjustment

As Tony stated, oil pressure is your friend here. Take the reading where Tony stated and also at the oil switch.

Ok , Back to oil pressure . This is taken from the oil gallery on the l/h side bottom of barrels : oil is cold , 1000rpm , 19 PSI

At 3500 RPM , 45 PSI , I revved it to 5000 RPM momentarily , and I saw 48 PSI .

This is what you need to adapt the gauge : M8 x 1.25 is the gallery thread .

The other end depends on the guage you have , I used a M10 x 1.00 to M8 x 1.25 coupler in the photo :

TonyA · May 31, 2023

TonyA said:
Ok , Back to oil pressure . This is taken from the oil gallery on the l/h side bottom of barrels : oil is cold , 1000rpm , 19 PSI

At 3500 RPM , 45 PSI , I revved it to 5000 RPM momentarily , and I saw 48 PSI .

This is what you need to adapt the gauge : M8 x 1.25 is the gallery thread .

The other end depends on the guage you have , I used a M10 x 1.00 to M8 x 1.25 coupler in the photo :

Oil Pressure Measurement:
Relief valve opening pressure
400kPa (4 Bar)
Oil pump pressure @8000rpm with 130˚C 10W/40 oil
6L/min and 300kPa (3 Bar)
oil pump pressure @1000rpm with 130˚C 10W/40 oil
150kPa (1.5 Bar)
Note: From Service Manual

City Garage · May 31, 2023

TonyA said:
Ok , Back to oil pressure . This is taken from the oil gallery on the l/h side bottom of barrels : oil is cold , 1000rpm , 19 PSI

At 3500 RPM , 45 PSI , I revved it to 5000 RPM momentarily , and I saw 48 PSI .

This is what you need to adapt the gauge : M8 x 1.25 is the gallery thread .

The other end depends on the guage you have , I used a M10 x 1.00 to M8 x 1.25 coupler in the photo :

Great write up Tony! Thats what a proper working oil pump on a 961 looks like!

TonyA · May 31, 2023

City Garage said:
Great write up Tony! Thats what a proper working oil pump on a 961 looks like!

Thanks Lance , If it helps somebody great .

TonyA · Jun 10, 2023

Anybody do a careful check on how much oil you can put in to bring it to the middle of the hatch marks on a late new dip stick ? I am putting in 68 FL.OZ. , or 2 US Quarts + 4 OZ. . or 2011cc .. This is after a drain of oil tank , sump and oil cooler/ retuun side lines .

City Garage · Jun 11, 2023

TonyA said:
Anybody do a careful check on how much oil you can put in to bring it to the middle of the hatch marks on a late new dip stick ? I am putting in 68 FL.OZ. , or 2 US Quarts + 4 OZ. . or 2011cc .. This is after a drain of oil tank , sump and oil cooler/ retuun side lines .

I've tried to measure, but every time I get a different reading!!