Typewriter spec M20

[Eddie25]

Ok so this has been bugging me since I rebuilt my head in 2010 but i finally got round to making a video.

Spec is as follows;

Cat cam
Refurbished Head with new OEM valve guides
New OEM Rockers and eccentrics
New OEM oil spray bar
BTB 3
Fritzs bits exhaust system
Speedtouch Mild Chip

But as you can hear in the link below it sounds like a typewriter.



Valve gaps are at BMW specification and oil is Mobil Race. 15w 50 (IIRC) was changed last year, went for thicker to try and quiet it down.

I've been told this could be caused by the stainless exhaust but it sounds more from the head itself. From cold it sounds fine but gets worse and worse. Possible tired oil pump? Car has done 110k.

Any ideas would be greatly appreciated as i'm sure it isn't right, I should add on WOT it sounds savage but the rest of the time

[Ajsingh]

That sounds like worn out injectors. My 2.7 M20 sounds like this yet my 325i that has refurbished injectors doesn't sound like that and is very quiet in comparison.

But i heard this many many times, if it doesn't tick, its not an M20!

[Eddie25]

That sounds like worn out injectors. My 2.7 M20 sounds like this yet my 325i that has refurbished injectors doesn't sound like that and is very quiet in comparison.

But i heard this many many times, if it doesn't tick, its not an M20!

So true but it seems way worse than before it was rebuilt

I should add the injectors were refurbished as well. Possibly a good excuse to go for MAF and M50 injectors?

[Speedtouch]

Defintely a tad on the tappetty side - as you say, it doesn't sound right. Is it because of the Cat cam, perhaps?

[Eddie25]

Defintely a tad on the tappetty side - as you say, it doesn't sound right. Is it because of the Cat cam, perhaps?

I wondered that perhaps more 'snap back' (not sure of the technical term) on the valves? But it's only a 274 so not too lary.

It's driving me mad as starting from cold it's lovely but as you drive down the road you hear it start to change in tone

[Ajsingh]

To eliminate the exhaust manifold, you could try heat wrap around the pipes. That could also act as a silencer maybe

[Eddie25]

To eliminate the exhaust manifold, you could try heat wrap around the pipes. That could also act as a silencer maybe

Definitely on the list of options mate, or ceramic coating but there are so many E30's on the zone with stainless manifolds and its not a problem that i've heard mentioned before.

I'm pretty lost with it.

[SGP]

They are just tappety engines I reckon. Inherent in the design, no hydraulic lifters buckets etc. There is a gap so it has to tap

[mcbonio]

Yeah shouldn't be that loud, I see you've replaced the oil spray bar.... Is oil being properly delivered through it?

[SGP]

It does sound like there is a fair bit of injector noise but this is how mine sounds it's a bit depressing sometimes

[SGP]

I prefer the sound from the other end

[Eddie25]

Yeah shouldn't be that loud, I see you've replaced the oil spray bar.... Is oil being properly delivered through it?

I wondered this too, which lead me to think about oil pressure. I should really get it tested. Not that i thrash it when its cold but if it sounded like that all the time I'd be very happy. Minimal clattering just a nice hum.

[Eddie25]

It does sound like there is a fair bit of injector noise but this is how mine sounds it's a bit depressing sometimes

Thanks for this SGP, i will have a look when i get home. Sadly work blocks youtube. Spoil sports.

[Eddie25]

Sorry one more thing i forgot to add; valve springs were also new OEM (double springs) at the time.

I only intended to fit the BTB3 initially but having found oil weaping from the head gasket and two snapped exhaust studs i set about starting again. All coolant hoses were replaced with new, thermostat, thermostat housing, waterpump, cambelt tensioner. Distributor. Needless to say the bill from BMW hurt and now it sounds like that.

[mcbonio]

Also you've put in 15w50 weight oil, might this be too viscous and flowing through the spray bar too slowly?

Only reason I'm thinking its a lubricant issue is that whenever I've done an oil change on either of my BMWs when you start the engine theres a good 5-10 seconds that the top end of the engine sounds just like yours, like the oil hasn't reached the valve case yet...

Try popping the rocker cover off and pouring some oil over the rockers and shaft, fasten it down and start it up, see if it quieten downs for a minute.. Worth a try?

[Eddie25]

Also you've put in 15w50 weight oil, might this be too viscous and flowing through the spray bar too slowly?

Only reason I'm thinking its a lubricant issue is that whenever I've done an oil change on either of my BMWs when you start the engine theres a good 5-10 seconds that the top end of the engine sounds just like yours, like the oil hasn't reached the valve case yet...

Try popping the rocker cover off and pouring some oil over the rockers and shaft, fasten it down and start it up, see if it quieten downs for a minute.. Worth a try?

Thanks mate definately worth a try. I went for the 15w 50 as the BTB heat soaks the engine bay something chronic. I should really get it coated, as around town the fan is going full chat pretty much continuously (presume the residual engine bay heat is engaging the viscous coupling).

It is also marketed as being ideal for older valve train designs. I did have 10W 40 in previously but it was possibly even worse.

I keep coming back to the cold running though. I wondered if again the BTB is getting things so hot the valve gaps are opening up more than they should be?

[Eddie25]

I remember hearing about a M30 oil spray bar modifcation? Or have I dreamt that?

What are the benefits if true? Is it bigger? Higher flow rate?

[Eddie25]

Sorry all I'm waffling here but i'm determined to sort it. Been reading some American forums on my lunch and they sway over to high zinc break in additives to increase oil filming;

http://www.lucasoil.ca/products/product ... =HeavyDuty

Any thoughts on this?

[Eddie25]

bump

[SGP]

It is possible to open up the holes in the spray bar a little to increase the flow as recommended in the e30 restoration bible, but remember the oil pours on to the camshaft lobes not the tappets so its not going to make any significant difference to the sound generated by the gap between the eccentric and the top of the valve stem.