Mixed Up Hydraulic Lifters After Refitting Head

[Alan_M 66 1 Cars]

Some of you may know that a few weeks ago I snapped a cambelt and bent all exhaust valves and 4 inlets. All due to a random bolt that wedged itself between the belt and crank pulley!

 

Anyways, got the head refurbed with some spare valves I had kicking about. No hassles in refitting apart from getting mixed up with where each lifter went in relation to the camshafts. I 'had' noted it down, but used the diagram from another head when rebuilding my Mi and now the lifters are in the wrong place. Thats what you get for having 3 head rebuilds on the go.

 

The Mi16 is all together bar the exhaust manifold and I thought it would be a good idea to crank over on the starter in an attempt to build oil pressure up, and test the compression too. It was only when I got 165, 165, 165 then 150 that made me think.

 

Have I rogered my cams/lifters or shall I just box it all up and use a 'bedding-in' procedure?

 

I'm a wee bit concerned on the compression results too......Completed on a stone cold engine not run in weeks with throttle open and all spark plugs out. Could un-primed lifters cause a change in the compression?

 

Thanks

Edited June 15, 2010 by Alan_M

[woodsy 0]

I would say you should be ok mate as when the lifters are full they will take any difference in tolerance out when full.If any lifters arent fully primed you will get a lower compression reading so get it running and let the hydraulics quieten down properly and do a compression test again and check

[Cameron 16]

Did you drain all the lifters? If so it doesn't matter so much what order they go back in. If not, you may have some valves open a crack but hopefully not enough to damage anything.

[Alan_M 66 1 Cars]

I would say you should be ok mate as when the lifters are full they will take any difference in tolerance out when full.If any lifters arent fully primed you will get a lower compression reading so get it running and let the hydraulics quieten down properly and do a compression test again and check

 

 

Did you drain all the lifters? If so it doesn't matter so much what order they go back in. If not, you may have some valves open a crack but hopefully not enough to damage anything.

 

No, I didn't. In fact, I primed them (or tried to) before refitting. I was always under the assumption that when refitting lifters, they should go back where they came from in the head.

 

I'll just get it running and go from there.

[Cameron 16]

You should, because the cam lobes and lifters will be worn to match each other, or that's what I've always thought.

 

It's a good idea to refurbish all of your lifters whenever you remove them, especially if you're swapping cams or replacing valves as the clearances will be different. If the lifters were all drained then it may take longer for the compression test to reach the maximum as the valves may not open fully, but it should still give the same result. If you have lifters that are pumped up though, you may have valves that stay open a tiny amount and that will affect your results.

[Alan_M 66 1 Cars]

I'm in two minds as to what to do now.....Just fit the exhaust back on and fire it up, or fit the lifters in there 'proper' places. I'd imagine that as I've cranked the engine over for a compression test, the damage/wear to the cam lobes & lifters has already been done.

 

May as well just fire it up.

[hcmini1989 16]

I'm in two minds as to what to do now.....Just fit the exhaust back on and fire it up, or fit the lifters in there 'proper' places. I'd imagine that as I've cranked the engine over for a compression test, the damage/wear to the cam lobes & lifters has already been done.

 

May as well just fire it up.

Ive always just stuck them back in any order never had any problems but it does make sense what cameron is saying ,just try it mate,Did you unplug injectors when doing this comprssion test as if theres fuel in there it will effect the compression to how much i dont know though

Edited June 15, 2010 by hcmini1989

[Alan_M 66 1 Cars]

All back together now and running nicely. Took ages for the lifters to shut up (about 15mins) but pretty smooth now. Only thing is the cambelt is a touch too tight as it's whining a little, so will slacken off.

 

What a nightmare, not so much the head refit but all the other little things that can go wrong. Broken studs, snapped covers and a manifold that refused to line-up

 

Thanks

[C_W 3 1 Cars]

It's just best practice to refit them i nthe same position, but it can't be that critical as you could replace them with brand news ones that have never seen the engine before. Probably best to do a few miles run in and change the oil just incase they do need to bed in or something.

[Beastie 1]

I wouldn't worry about it now it's done: I've seen plenty of more modern engines (particularly Jaguar and Volvo) which have been run on unsuitable oil and which have lost compressions due to lifters pumping up. When you change to the correct grade of oil the lifters nearly always drain down and restore to a correct working clearance. If the disparity with your compressions is due to the lifters then they will sort themselves out after the first drive.

 

As already said, keeping the lifters in the same positions is because the cams and the lifters wear together. This is less of an issue with hydraulic lifters than it is with solid ones: Eventually over a considerable milage the friction surfaces will wear into each other - hydraulic ones will automatically compensate for this whereas solid ones will become noisy and need re-shimming.

[Cameron 16]

Something I've always wondered is whether the lifters ever "go down" when the engine is running. Say if you fitted a lifter from the wrong place and it was pumped up more than it should be, would it go back down again in time or would the one-way valve hold all the pressure in there? I always thought that once they're pumped up, that's it. But thinking about it maybe it's possible that when the valve closes and the pressure inside and outside the lifter equalises, the valve may let some excess oil out. Any thoughts on this?

[Beastie 1]

I've come to the same hypothesis as you on this one: I've come across a number of relatively modern cars - VW and Volvo diesel and Jaguar petrol being examples which can pump up the lifters when driven with unsuitable oil. In all but one case driving them for a short distance with a fresh sump of Mobil fully synth restores full compression to all cylinders and there is no further trouble. The last case was a 2005 VW TDI which had dropped onto 3 cylinders just after a full service at a garage. It took about 5 minutes of driving with suitable oil before the 4th cylinder regained its compression.

[Cameron 16]

Sounds good to me. I reckon I'll carry on draining the lifters whenever I have them out though, just for peace of mind.

[pugman211 0]

what does it mean though if the lifter doesn't pump up if you get me??? Does that mean the lifter is buggered or just needs draining and cleaning and reassembling?? (this is on a crummy vauxhall btw, but same principle)

 

Thanks Baz

[Cameron 16]

Could be that the one-way valve is either blocked or broken? I'm not sure on how to disassemble the Vauxhall ones though, never had any experience with them.

[pugman211 0]

nice one thanks for the reply

[hcmini1989 16]

Did a cam on a k series the other day swapped both cams in case they were difrent allso swapped the lifters .Put it all back together it started but was running rough .It sounded like one of the valves was touching a piston every now and again.I then did a compression test to see if it had bent a valve and there was no compression on cyl1.So i ran it up to temp on idle had it running for about 2hours until it quitend down then redone the compression and it had 160 psi across the board.

 

So i guess the answer to your question is they can go down once pumped up when fitted

Edited June 19, 2010 by hcmini1989