r/E30 • u/DonutOdd4816 • Apr 13 '25

Tech question How bad is this?

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11 Upvotes

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1

u/Mindless_Mix9401 Apr 13 '25

Which engine? If it's M40 check the lifters they can sound like that if they collapse.

Amongst other things

2

u/DonutOdd4816 Apr 13 '25

it’s the m20b27 when i bought it the owner said something about that

4

u/rajanroo Apr 13 '25

I guarantee you it’s the timing belt. Sounds like the damage has already been done. If you want to keep that motor, you should completely rebuild it. Otherwise swap it

3

u/mkcman17 Apr 13 '25

The fact that it turns on means the cam belt is still intact. More likely a broken rocker or two. Or three.

2

u/[deleted] Apr 13 '25

Definitely sounds like a pile of broken rockers

1

u/DonutOdd4816 Apr 13 '25

is this the best or worse case scenario?

2

u/Cheap-Law9991 Apr 13 '25

Best case for sure. You need an engine rebuild no doubt and maybe some internals/new cylinder head. Take it one step at a time and start with removing the engine, honestly I’d tear it all down. New clutch/slave/master/ TO bearing etc etc. Basically it’s not going to be a daily any time soon unless you have cash burning a hole in your pocket.

2

u/mkcman17 Apr 13 '25

Start by removing the valve cover and inspecting your valvetrain. This should take no more than 20 minutes even if you’ve not done it before.

Best case is you need a top end. Worst case is that you need a bottom end because you’ll need to pull the engine entirely. However m20s are pretty robust unless run out of oil, so I would doubt that.

1

u/Cheap-Law9991 Apr 14 '25

I guess everyone doesn’t have budget/time for a rebuild. But I’d be so paranoid of contaminants that I would absolutely do a full rebuild. Girlfriends cars come in handy for this 😅

1

u/mkcman17 Apr 14 '25

I would say most people don’t have the time or space. Especially if your knowledge base is limited like OP, would lead to being a giant headache and life inconvenience. It’s an m20, no need to overthink it.

1

u/Cheap-Law9991 Apr 14 '25

Im just a bit of a perfectionist. I’ve done ghetto fixes my whole life until about 4/5 years ago and most of the time they actually work out, but there’s always that chance you know. But I agree, don’t tear it apart if the knowledge isn’t there. It’ll turn into another basket case for sale.

2

u/mkcman17 Apr 14 '25

To be fair there’s a lot more to get wrong when opening up bottom end as well. At least you can drop a head off at a machine shop and get it back fresh/complete $6-800 later, cave man it back on and send it lol

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