Author Topic: Thinking about buying a M42 track car, questions!! (Read 3204 times)

JM35 · « **on:** July 11, 2014, 10:45:52 AM »

Hey guys,

New member here with just a couple questions about the M42. So I'm looking to pick up a track car, and I found a pretty sweet 1991 318is with a few mods here and there. One big issue is that it has some rod knock, and the bearings need to be replaced. I understand parts wise this is fairly cheap but it is a pretty heavy DIY from what I understand. Does anyone have any links to a great rod bearing replacement DIY? Pretty handy with cars, just usually need a DIY to help kick start it, especially when I'm only used to working on N54 engines.

Also the car has 270k miles on it, not sure if this is engine & chassis miles or just engine. I wouldnt really expect it to last much much longer than that but then again M42's arent my cup of tea.

Here is some details of whats been done on the car and what needs to be fixed:

�New Radiator & thermostat
　�All new front timing case gaskets (top & bottom)
　�New timing chain tensioner (new style m44)
　�New valve cover gasket
　�NGK spark plugs
　�New O2 sensor
　�New transmission fluid
　�New intake boot
　�New intake manifold gasket
　�New throttle cable
　�All new oil pan gaskets (upper & lower)
　�New fuse box cover
　�New fuel pump (in box) & pump relay
　�New Bosch Idle Air Control Valve

Upgrades:

　�M-Tech Rear Spoiler
　�Limited Slip Differential from 87 325is
　�Ebach Lowering Springs
　Tokico Blue Struts
　�E30 M3 Front & Rear Swaybars
　�Supersprint Magnum Exhaust (headers back)
　�Custom Intake
　�New BMW emblems (front & rear)
　�Alpine Speakers all around

Cons:

　�Engine has a rod knock (set of OEM bearings is $35)
　�Driver seat is a little torn due to previous owner
　�Dash is cracked (common in e30, it's a 1991)
　�Odometer doesn't work (gear set is $65)

Thoughts anyone? Thanks for the help!!

JM35 · « **Reply #1 on:** July 12, 2014, 11:07:24 AM »

Everyone has been warning about the rod knock saying that the engine will probably need to be replaced soon and that te gaskets will need to be changed, etc...

Any advice on here?

The owner says the bearings can be changed on jack stands in 2 hours but everyone is advising against it?

mabeer · « **Reply #2 on:** July 12, 2014, 06:54:04 PM »

I don't think you're looking at a quick, easy or cheap fix. The only way to know for sure to tear it down and see how much damage has been done. Sounds like rebuild time.

Ask yourself, if it just takes some bearings and a couple hours why hasn't the owner done it already? Your friends that are telling you you're in for more than a cheap, easy fix are right. If you buy this car and are not ready to swap in a solid motor or pull what you've got and rebuild it you'd be better off to pass. It is certainly going to be more than bearings and gaskets.

DesktopDave · « **Reply #3 on:** July 12, 2014, 07:41:40 PM »

They're nice cars, no doubt about it. I'd buy it as a chassis, the motor is just a bonus. Line up a good M42 from someone that's ruining their car with an S50 or whatnot...or a good used M42 from an E36 and use the E30 oil pan & intake to install it. I'd suspect it's not that hard to get at the bearings once you get the oil pan out. I haven't done it myself, so if there are any 'gotchas' someone else will have to advise you. You'll want to R&R the hydraulic engine mounts while you're in there...every 318iS has at least one bad mount.

It's odd that an M42 has a rod knock. Usually an M42 will crack a head or bend some valves...

Be sure to upgrade the stock half-shell thrust bearing to a full one from an M50. While you're at it, dig up an M47 crank and really do it right. Check out a few of Warsteiner's epic engine build posts. Excellent reading.

Considering the cars you're used to driving, you'd better get ready for a pokey-slow car. Even a brand-new M42 took around ten seconds to see 60mph. It is a lovely car to drive though...light and eminently tossable. Given the weight of modern safety systems (and the comfort-at-all-costs habit of the Baby Boomers) BMW will never build another car like it.

If you're doing some track time you'd need to tear that motor down anyway. He's just giving you the urge to do it right.

JM35 · « **Reply #4 on:** July 13, 2014, 01:04:45 PM »

The whole top half of the motor has been rebuilt, new gaskets and everything. The head gasket blew which is why all the top was rebuilt he said the rod bearings are the only thing that need to be done now.

Would love to do an M30 or S5X swap, just don't know if a swap is within my mechanical abilities yet at this time.

DesktopDave · « **Reply #5 on:** July 13, 2014, 03:19:59 PM »

Swaps are easy, if you have good documentation. You just need a decent set of tools and a cherry picker - it's all nuts and bolts.

I'd stick with the M42 though...read a few builds. I'd strongly suggest checking out the research we've been doing on the DTM S42. That's not a typo...check it out here:

Tell me this motor isn't the sexiest thing you've ever seen in a car. Errrr, I mean under the hood.

They ran as a BMW 320 STC. Here's a shop with spares, and here's a model register. Here's one on FB. Note the BMW model number - that car was the 8th in-house racing chassis built in 1997. These cars were never issued a VIN. Apparently they still run vintage races, hill climbs and other competitive events.

I was just at the Pittsburgh Vintage Grand Prix opening events, watched the BMWCCA race. Want to guess what the fastest car was? A 4-cyl. Someone built an E30 M3 that just demolished everyone else. I have no idea what work was done to that S14, but it lapped an E46 M3 during a twelve lap race. The newer car didn't have a chance; looked like it was sitting still.

JM35 · « **Reply #6 on:** August 12, 2014, 03:50:34 PM »

Thanks for the help and advice guys, decided to stay away from a project car for now and picked up a GSXR street bike instead haha

Author Topic: Thinking about buying a M42 track car, questions!! (Read 3204 times)

JM35

Thinking about buying a M42 track car, questions!!

JM35

Re: Thinking about buying a M42 track car, questions!!

mabeer

Re: Thinking about buying a M42 track car, questions!!

DesktopDave

Re: Thinking about buying a M42 track car, questions!!

JM35

Re: Thinking about buying a M42 track car, questions!!

DesktopDave

Re: Thinking about buying a M42 track car, questions!!

JM35

Re: Thinking about buying a M42 track car, questions!!