yet another ticking m20 (long)

[Mops]

Hello.
I live in New Zealand and recently purchased 1985 325i, coupe, manual, UK import. It has m20 motronic engine with 122k miles on it. Once thing I noticed which is strange is that it does not have a cat (just mid and rear nufflers). It makes decent power and other people who know these cars complmented me on the power engine makes, however they did comment on excessive tapping.

Before I start let me assure you, I know that those engines tick and the injectors are noisy. I'm sure my ticking is head/valve related.

Here's what happened so far:

1. Bought the car, ticking loud, can hear inside the car at abouve 1500rpm, once engine is warm. On cold it does not tick a tall and sounds healty.
2. Adjusted the valves as per article to 0.25mm (0.1"). Some were loose, some were to spec. Did not make any difference in noise.
3. Inspected oil rail abouve the camshaft, and cleaned, seems ok to me, however i do not see oil dripping/spraying/comming out from it with engine idling (through the oil cap hole)
4. Inspected eccentrics, they all seem ok (i.e round, no deformations)
5. I'm not quite sure how to inspect the cam/rocker arms for wear, but i do not see any worn "trails" on the lobes
6. Readjusted the valves to 0.22mm (0.09"), it did quieten the noise, but not completly eliminated. Problem is that induced "clanking" valve sound at heavy acceleration across whole rpm range.
7. frustrated readjusted valves back to 0.25mm and ticking came back.
8. Fitted oil pressure gauge and oil pressure good (60psi at cold, no matter what rpm, once fully warmed up 20psi on idle and 60psi from 3k onwards). As well i got aftermarket oil temp and water temp, they read all ok.

Important facts:
(a) no ticking noice at cold engine, starts once the temp needle is just before 1/4. Ticking is loud, can be heard with bonnet open and inside the car. Volume incerases until engine is fully warmed up
(b) no oil spraying from oil rail (only checked on warm engine), even when mildly revving the engine (up to 2k rpm i tried)
(c) even while adjusted to spec have some claking noise under load across whole rpm range, not as bad when i tightened them, but definitely clanking noise is something i dont like
(d) i'm not a mechanic, but I owned few cars and I'm a DYI hard-out and that ticking does not sound right to me.
(e) I do not care about the annoying noise, but I dont want to wreck the engine
(f) maby it's my imagination, but when i was watching the oil rail, I think the camshaft was moving a bit foward/backwars (few milimeters)
(g) I do not know what oil grade is in the car - havent changed it yet. It's quite dirty, but very oily.
(h) oil and collant are both nice and clean, so I dont thing headgastet is stuffed.

Any suggestions welcome.
Questions:
1. How to check is my cam is worn ?
2. what else could I try or check ?
3. might it be cracked head ?
4. I concerned ablut that clonking valve sounds under load. what might be causing that ? (now thats separate from the ticking noise )

thanks in advance,
Mops.

[Demlotcrew]

IS the timing belt nice and tight?

andrew

[Mops]

IS the timing belt nice and tight?

andrew

havent checked... Since I dont know when it was last time changed, I might have a look at it. I had a brief look at it while doing valves and it looks undamaged.

[dobbey1]

I dont want to scare you but when i had my cylinder head removed and skimmed they took to much off the cylinder head so when the car was running from cold it was fine but when it warmed up you got this noise like you discribed and it was the valves just kissing the piston head due to the heat and expansion when warm. the cure remove head and measure thickness and then put an over sized head gasket from bmw on and this cured the noise. over than this noise the car run perfect

also is the timing correct.

[Mops]

I dont want to scare you but when i had my cylinder head removed and skimmed they took to much off the cylinder head so when the car was running from cold it was fine but when it warmed up you got this noise like you discribed and it was the valves just kissing the piston head due to the heat and expansion when warm. the cure remove head and measure thickness and then put an over sized head gasket from bmw on and this cured the noise. over than this noise the car run perfect

also is the timing correct.

I understand what you mean, But that tightening down valves below sactory spec (0.22mm in my case as abouve) would result in incerased noise, not lesser noise. Good post tho....

[Mops]

Allright.

Since no constructive suggestions, who about following scenario:

1. tighten intake valves to 0.20mm (0.08") - i know it's low, but it would compensate for work cam (if it is worn)

2. on some cars with manual valve adjustments, i heard that normally intake and exhaust valves run different gaps. can anyone comment on that ? normally intake r exhaust run larger gap ?

I'm wanting to prepare my m20 for turbo application, therefore head rebuild is not out of the question. what's involved in hear debuild ? so far i gathered that i'll need:
1. new camshaft
2. new rockers
3. new eccentrics
4. new seals (incl headgasket)

machining head, and valve seats.

is that correct ??
does anybody have a link to m20 head rebuild howto website ?

cheers.

[gcorky]

tech articles on here m8

[PeteE30Tourer]

I dont have any answers to this, but i'm registering my interest as i have a very similar problem. I haven't noticed if the ticking noise is worse or better at hot or cold, but it's so loud it's driving me nuts.

I've changed the head, cam, rockers and valves, set the tappets up twice and it's still there. This is leading me to think it's one or more of the injectors being seriously loud, though the senior technician at my local BMW garage swore that he'd never replaced an injector on one of these engines due to excessive noise. He believed it was my valve clearances.

Anyway, i dont mean to hi-jack your thread - keep us posted on anything you find.

[E30BeemerLad]

it's not the exhaust gasket is it?

[Turbo-Brown]

Cam belts can start to make a ticking noise as they near the end of their life. If you don't know how old it is, I'd start by replacing that

[MONSPORT42]

I'm with Beemerlad. A tiny leak in the exhaust gasket makes just the right ticking noise to think your top end is terminal. Also, have you checked the noise with the good old-fashioned screwdriver stethyscope (metal end to engine, plastic/wooden bit to ear). You can tell alot with a bit of practice!

[koos]

got the same prob on my mates 325, it's the camshaft. One lobe is worn, and when the rocker comes over it "slaps" the camshaft, we adjusted it to spec and then less, it wont compensate for the worn lobe end. Gonna try and replace the cam in place soon.

[Mops]

Some further progress this evening.

I removed the rocker cover and ran the engine while looking at the valvetrain.

That oil spray bar sprays, but pretty erraticly - I mean drips there and there and then from some holes and not others and then faster then slower then not at all. I already gave it good clean, I'll try the diesel trick in the sump

I'll check whether it the the exhaust seal tonight - I looked and around the 1st cylinder, there are black deposits around the exhaust gasket.

And yes, cabelt and waterpump (and cooling fan) are the next on the list.

I'll advise on my progress.

[Mops]

update on the situation.


While running the engine without cover, I noticed that when warm, heaps of oil is comming out from the rocker shaft plugs. As well I noticed that this does not happen on cold engine. These are rubber plugs and it's likely they lost their sealing properties after 20 years.

My theory is that due to those plugs not sealing peoperly, oil pressure in the valvetrain is lower than it should, therefore it's loud.

That would as well explain hy my engine it not taping/ticking while cold, but only as it reacher certain temp.

I'll replace them at the same time as i do cambelt.

Comments ?

[Brian28]

Sounds a good theory to me, well spotted mate

[Mops]

Just an update.
I did the cambelt and sorted out those rockershaft plugs. The ticking was better, but still present.

Then I came across the post where there was mentioned that engine noice somes through the hole in the steering column, which I blocked and that improved things alot.

Still yet, i have some ticking, but now it's much better than it was before.

It sounds like i have 1 or 2 valves doing all the noise.

I'll update as I progress.
I'm going to adjust the valves down to 0.22mm, and report back.