M42 Rally engine

[welsh rally]

Hello
I have purchased a BMW compact  rally car with a M24 enging , steel crank , honda pistons , cat cams and a DTA management system ,the car needed some finishing , setting up ,rolling road etc however   after purchasing the car I saw the former owner /builder's  comments on another forum and seems he was having trouble with it in the sense that the rolling road tuner was reluctant to take the tune further due to some top end tappet noise , I then spoke to 2 m42 engine builders who said the cams have to have solid lifters , is there anyway to tell that without tearing the head down , I have tried moving the buckets under the lobes  and there is no movement .
please note I am not a engine builder , so please be as detailed as possible .
thank you in advance
regards

[bmwman91]

Are you using the car for actual rally racing where it will be spending significant time at very high RPM? Solid lifters really are not necessary unless you expect to be revving to >7500RPM and doing so frequently. The hydraulic lifters in my 2.1L M42 do just fine up to 7500RPM, although it is a street car and not used for prolonged hard driving.

You would not be able to tell if there was enough slop in the buckets to make noise just by using your hands. The spring force on those is easily 160lbs each.

Can you give any additional information about this "top end noise" that you hear or read about? Does it occur at all RPMs, does it get worse as RPM rises, etc?

[welsh rally]

Hi
Thanks for your reply .yes the car will be rallying and trackdays
All I can tell you is the tuner said it had a "top end" noise very tappety , the bmw engine specialists both said that the type of cams fitted have to have solid followers , I had a box of buckets  with the car which had cat cam followers written on it (see pic) but I am unsure due to my limited experience if they are the hydraulic or the solid type .

thank you

[jerseytim]

i believe you need solid followers with high lift cams, on mine there was quite a bit of work needed on the cam carrier as well

[bmwman91]

The ones in that pic look like solid lifters. Do they have a bunch of little shims with them?

And yeah, if it is a racecar with super high lift cams, you will need solid ones. If you have limited experience wrenching on engines, I would find a competent shop to do the installation. It is more than just popping them in. You need to select the proper shims to set clearances to the cam, and as jerseytim mentioned, some machine work may be needed depending on how extreme the cams are.

[welsh rally]

Hi
thanks for the response , no i did not have any shims with them , so  as I suspected I will need to take it somewhere that can sort it .
thanks for the advice
regards

[bmwman91]

Got any pics of the car and/or engine? It's always fun to see heavily built M42's since they are fairly rare! If / when you do get things apart and to a shop, I'd be interested to see the cams and any mods that need to be made to the carrier trays.

[welsh rally]

here you go , making enquiries as to where to take her for the work to be done , will report back on findings 

[bmwman91]

Nice car! I am sure it will be a load of fun once the last bits of mechanical work get sorted out.