M42 360degree bearing upgrade

[appletree]

People may know that the m42 has a few faults from the factory which thankfully there are a fixes for, the oil pan fault and the thrust bearing wearing up being the main ones.

Well seen as i'm going to be running nearly double the intended power i though i'd buy some upgraded mains shells and rod shells.

i ordered them from metric merchanic in the US and they turned up today. so for anyone else who whats to know part numbers here they are.

they use two 180* standard thrust bearing shells BMW part number 11 21 1 706 829 and are fitted to loads of E30s and older BM's

the rest of the shells are standard so you could just buy a standard M42 shell kit and then two extra of the above part number to get the full 360* bearing shells.

I also bought upgraded trimetal conrod shells, these are made buy clevite NASCAR performance CB-1775HK-1 (rod half) and CB-1775HK (cap half)

Just a quick question, is it normal to have two part numbers for one pair of shells? one for the cap half and one for the rod half of the conrod?

At work we fit shells to large Engines but they come in pairs and must be fitted as a pair, which would make sence to me but is this the case with cars in genral to as these have come on a vacume sealed cardboard sheet four shells of each part number on each of the two cards.

cant wait to get the build going!

[GeoffBob]

Always come in pairs in my experience, although I guess there's always someone who does things differently. Can't imagine somone would ever buy one half shell to fix a buggered engine though

Did you come right with your headbolts Matt? You never responded to the info I sent you Was wondering what had happened to you ?

[appletree]

Sorry Geoff, ive been busy with work and buying and selling cars for the missus, i found out that you can use M50 ARP head studs as an M42 is basicaly an M50 with 2 cylinders lopped off you just dont use the whole set and you can torque them up the same as the M50 the lad with the turbo one in the US is using this set up and its been boosting up to 23Psi with no problems although that was when there was a problem with the boost control.


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[appletree]

Always come in pairs in my experience, although I guess there's always someone who does things differently. Can't imagine somone would ever buy one half shell to fix a buggered engine though

me neather geoff Guess thats why they have a different part number for each half , suppose with todays manufacturing techniecs theres no reason they cant make lots of halfs althe same an then mahe the other halfs the same way... like you say different people do things differently

[lloydp]

They're almost always sold as pairs, but there is rarely anything stopping you ordering just one half from a manufacturing point of view. Most presses will bang them out about one every second or two, and all the finishing (overlays, machining, boring, etc) is done on an equally massive scale, so one here or there makes very little difference. However, it is generally recommended to replace them as pairs because they do loose a bit of their clamping force with use and re-use.

Often the part numbers are different because the materials are different for rod (or block) and cap half. This is becoming much more common in newer engines as a cost-saving measure because the stronger/more resilient materials tend to be more expensive, and you can get away with a lesser-rated material for the half which isn't carrying all the load (cap-half for conrods, block-half for mains). As an example, you might have sputter-overlaid bronze trimetal rod-halves (££££) paired with aluminium alloy bimetal cap-halves (£).

NB: I work for a bearings manufacturer.

[GeoffBob]

Thanks Lloyd, very interesting. The fine print at the bottom of your post duly noted

[GeoffBob]

Sorry Geoff, ive been busy with work and buying and selling cars for the missus, i found out that you can use M50 ARP head studs as an M42 is basicaly an M50 with 2 cylinders lopped off you just dont use the whole set and you can torque them up the same as the M50

Glad to hear that you went for ARP's after all. May not be 100% necessary but I have never had any problems with ARP's, so I tend to stick with what I know works, instead of experimenting with that which may not work (not to say that HTS bolts won't work, its just that personally I don't have experience to back up that they do). Maybe one day if I have an engine to spare I fit a bog standard gasket with HTS bolts and see how how much boost it'll handle. On second thoughts, maybe not.

What head gasket will you be using?

[appletree]

Standard genuine bmw with wire 'o-ringf' block as recommeded by the engine builder.

When i build the engine up ill take some time and check with plasti gauge stuff for clearances to.

Rob with the above turbo m42 is running the same allbe it with slightly more displacement just re-bored to freshen the bores up.

I'm pleased to have sorted out the ARPs to i know i'd always have it in my mind that the HT were abit of a comprimise.

[rix313]

Glad everything is coming togethr for you bud, when are you getting the engine?