Dead Hydraulic Lifter

[James_m 0]

Hi all, looking for some advice on a horrific tap my 1.9 Mi16 suffers from. Here is the story....

 

Right, its a rebuilt 1.9 Mi16 which had circa 100k on it before coming apart (dont they all ) On rebuild it recieved new bearings, rings, all the usual stuff as well as 8 new exhaust valves because the used valves were so heavily covered in carbon. Stupid waste of money im well aware.

The hydraulic lifters were taken apart and reset by my local machine shop when i had the head skimmed, to hopefully help acheive a nice quiet top end.....

So right from the word go its tapped, acceptably at first but now after 4k its a nasty CVH esque tap, as well as some other slightly dodgy noises from the top end, though im aware these engines are not the most refined.

So the thing is, im going to pull out the engine mid feb to change a few things im not totally happy with, and do something to get ready of this tap, but im not 100% sure of why its doing it, which is where the wealth of experience of Gtidrivers comes in!

 

My first thought is a dead Hydraulic lifter or 2. They've done highish mileage, so its not suprising one might fail no? Thing is ive never heard of one failing, either on here or elsewhere? i mean what can actually go wrong? bore wear excessively?

One thing which leads me to think a lifter is the cause is, i can be driving, tap is bad as ever. But then i stop for a few mins. Restart the engine and the tap is considerably worse for the next 2 mins or so. Im thinking the lifter drains, and it takes this amount of time for it to refill.

 

Another theory is maybe i wasnt especially careful when i removed/fitted the valves to the head, and ive scratched the lifter bores so the lifter cant hold any pressure.

I know i scratched one or two, but not massively and would this be enough to prevent the lifter from floating?

 

Or my third theory, and potentially worst case. At some point in the engines life, it has snapped a timing belt. I know this because piston 2 or 3 (cant remember which) has a nice valve shaped dent in it.

And a split collet was helpfully left in the sump (Maybe more than a timing belt and some kind of other valve train failiure?). I have no l history of this engine, so no idea of this is the original cylinder head, but assuming it is maybe ive got some bent valve guide(s) or Just bent head which ive read is common place on the Gti-6 heads from their forums.

But the head had so much carbon its clear its been on there for some considerable mileage. The headgasket was also quite old so all this probably happened quite early in the engines life.

 

The fact it appears to be gettting worse maybe points towards a lifter problem, Though i cant rule out myself imagining it to be worse because im so much more aware of it.

 

Thoughts on this would be much apreciated.

 

I really want to fix this problem in one go when i have the lump out, as i dont really want to be messing around with this when the engine is in car!

 

Cheers James.

[Mikey S 29 1 Cars]

it may sound funny but i think you may have a slightly bent camshaft, especially so if there are valve marks in the piston.

 

but, are you sure that the valve guides are ok? going by what happens when the gti 6 snaps its belt and the guides arent replaced they tend to tap a fair bit if they arent.

 

 

hth

 

 

mike

Edited January 2, 2008 by pugger

[James_m 0]

Cam could well be bent i guess! If some collets disappeared there must have been some serious forced flying around so its not inconcievable the cam was damaged assuming this is the original head. Im fairly sure there is no piston to valve contact now, as the dent was covered in carbon as opposed to carbon and im sure it would have gone bang by now!

Other than visually looking at the guides which all looked excellent, i cant say they are not bent.

 

Wish i could remember if it was exhaust or inlet side where the mark on the piston is. I have a reground inlet cam to go in so i hope it was inlet! though maybe i could use an inlet cam on the exhaust side anyway? assuming i actually have a bent cam of course!

 

Cheers James.

[gti_al 1]

I've got a noisy lifter as well, and i've stopped driving the car until it is sorted...

 

The people i have spoken to have suggested the a lifter failure is unlikely, and the camshaft is more likely responsible. Have you pulled the cam cover off to see what state the cam/lifters are in? Mine has done about 3-4000kms since a rebuild too, so i was really hoping to not have to worry about this stuff.

 

I'll be interested to see how you get on.

[tidypug 5 2 Cars]

I had a problem a bit like this. I rebuilt the head and put it back on the engine started it up and straight away it was tapping. I also thought (hoped) it was a duff lifter so i bought a new set. This didn't help, it turned out that 1 valve was ever so slightly bent. I never did figure out what bent it but got a new head and everything is nice a quiet again.

[James_m 0]

Well it would appear nobody has really had lifter failiure even on very high mileage.

 

To be honest i cant be arsed to mess around changing the lifters and cams to find it still taps. Think im going to bin this head and get hold of another, which is fustrating because it had new stem seals, the 8 new exhaust valves and hours of my time cleaning the bastard.

[James_m 0]

Forgot to say... Gti Al i have had the cam cover off, and there was nothing obviously amiss. I cant say i checked the cam for wear but the lifters were definetly flat.

[StuF215 1 1 Cars]

I had similar issues with my mi, was so so sure it was a follower. So I changed followers twice (2nd hand then new), cams, collets, valves (2nd hand then new) and head during the course of a year. And this did bugger all to stop the tap.

 

I changed a Rod and piston eventually and it stopped completly, im guessing it was the small end......... it had new bearing and i used the same ones with the 2nd hand rod n piston.

[James_m 0]

Gone an bought myself a mechanics stethscope from ebay Any tips on how to use the thing?

Annoyingly, the tap does'nt sound so bad with the bonnet up, just the usual mechanical thrash from the majority of 4 cylinder engines.

The inlet cam sounds noisier than the exhaust, but both make more of a heavy knock, which is less like the problem noise.

Putting the stethascope on the exhaust manifold make a noise more simular to the one heard when driving inside the car.

but i doubt its cracked, as it was a very nice condition manifold that went in, but would a poor seal from the head to manifold make a tapping noise? the confusion continues....

[boombang 2]

I had a tap which got louder at steady throttle between 3-4k rpm, otherwise wasn't very noticeable.

 

Turned out to be a worn exhaust valve guide, which was probably damaged when the cambelt went.

 

On my Corsa daily drive I have a horrible rattle but I don't actually want to know what it is, just for it not to fall to pieces!

[James_m 0]

Update: Took the head of today(usual catastrophe with broken Torx T55's and nobody stocking replacements) And im pretty sure all valves are straight which should be good news but i wanted an answer and i didnt get one I think i will get the head tested to make 100% the valves are not bent.

One thing that may hold a clue is that the exhaust manifold gaskets showed signs of heavy leakage on the lower sides woo!

So still not clear on what the problem was/is but i will carry on putting it back together and see what it sounds like!

Edited February 22, 2008 by James_m

[welshpug 1,626]

signs of exhaust leakage may be due to warpage or poor quality gaskets

[James_m 0]

Gaskets were O.E peugeot X2 because of the wedge at £15 each!!!! Going for that Loctite copper 5920 stuff this time. They probably leaked quite badly because i was using studs and nuts rather than the bolts you are supposed to use. Cant say it ever sounded like the manifold leaked either, apart from the tap of course which im still doubtfall ever came from the manifold.

[welshpug 1,626]

fact that they were studs not bolts wont matter, PeterT's kits use studs, as long as the tapered washers are there it should be fine, Peter recommends loctite on his site coincidentally.

[James_m 0]

fact that they were studs not bolts wont matter, PeterT's kits use studs, as long as the tapered washers are there it should be fine, Peter recommends loctite on his site coincidentally.

 

Yeah, tapered washers.....

[James_m 0]

Another update:

Bent valve

Ive had a piece of luck which i can only thank the gods for!

Did some checks over the weekend looking for bent valves, mainly checking that the valves were seating properly and making a good seal thus meaning the valves where straight.

 

Due to my incredible mechanical ineptitude and slight arrogance i decided if they sealed ok, then its all good and the problem MUST lie where else

All valves sealed fine, and filling the combustion chambers with parafin revealed no leakage.

The hardcore carbon that has build up over just 5k miles probably helped with this....

Slightly fustrated, im thinking everything is fine, and the problem probably lies with a rod

 

So it's all going back together, and im putting my new cam in, which out of luck happened to open the 2 inlets on cyl 3. WTF! one valve is considerably more open than the other!

Took the valve out, put it back in the guide and spun, and yes it was bent.

Never assume anything about anything!

Especially if your a crap mechanic/home bodger

 

RESULT!!!!

I was so close to throwing the toys out the pram and reassembling the head as it was. A lucky escape indeed.

Also lucky was that the engine didnt blow when i did a trackday in it with this problem

 

So the moral of the story is, if your engine taps, lifters rarely fail, and you probably have a bent valve.

 

Thanks for all the responses too

[pip470 61]

Well done mate. Propper result that.