Timing Belt Snapped Rebuild. Bent Exhaust Valves, Broken rocker arm.

[tonyloban]

Starting a new thread to focus on the rebuild as the other one was getting stuffy with other people's car issues

Anyway, here's the big list I have so far of things I need and some questions that I really need answered from some of you smart guys out there. If some people can go over the stuff I have and let me know if I'm missing anything that would be so awesome because I'm stressing over this big time and I have no idea what I'm doing.

1. Do I need new head bolts and washers (the washers cost more...) or can I reuse them as long as I put the bolts back into the same spots?

2. Should I order a new rocker arm and valves or can I find some used ones and where would I find those (or i'll just ask on the forum) because I would really like to save some money on these (broke college student).

3. Should I bother with replacing all the valve stem seals or only for the bent valves? I've been reading up and it looks like quite a bit of work to actually do it right and carefully.

4. Is there ANYTHING else I need? The rocker arm broke and I don't know if I need to replace anything else with it like an eccentric or valve guide or plug (I don't know what any of this stuff does).

Currently totaling out to around $430 without coolant and oil that I'll have to change. I will be resurfacing the head.

Thanks for any help in advance.

[KIRIEIW]

I'd take the head off and inspect it for cracks before you go any further, including ordering parts. I think your at the point where it might be better buying a junkyard head and rebuilding that.

[tonyloban]

The head is the part right above where the piston cylinders and pistons sit, right? Because I have removed that already. Making sure I'm using the correct language here.

I'm starting to think it might be much easier to replace the whole engine and just do the timing essentials on that...

[Madhatter]

Yes. But from experience you can actually put a warp in the head if you hit the valves and break rocker arms. The other thing is the 2.5L heads are well known to crack (worse than the smaller 2.7L/2.3L/2.0L heads. I would suggest having it pressure tested by a machine shop that does cylinder head work to make sure you aren't putting a head back on that is cracked and will lead to overheating problems.

You also need to pay close attention to the rocker shafts and the journals these rocker shafts slide through. The shafts can bend and you can crack/break the journals.

[nrubenstein]

Yes. But from experience you can actually put a warp in the head if you hit the valves and break rocker arms. The other thing is the 2.5L heads are well known to crack (worse than the smaller 2.7L/2.3L/2.0L heads. I would suggest having it pressure tested by a machine shop that does cylinder head work to make sure you aren't putting a head back on that is cracked and will lead to overheating problems.

You also need to pay close attention to the rocker shafts and the journals these rocker shafts slide through. The shafts can bend and you can crack/break the journals.

I've got a head that has some pretty gnarly welding action going on. It's kind of amazing what people can fix. :) It's on the strongest stockfish M20 that I've driven, too.

But yes, I would have the head checked before buying any parts for it.

The bolts are torque to yield, so they need to be replaced. Get a few extra - technically, TTY requires one smooth motion, so you want a few spares around. I'd call the washers optional.

Also, get a Genuine BMW head gasket. You may find that Genuine parts are cheaper from one of the dealers.

[101]

+1 on getting the head checked before ordering any parts for it. A used head might be an overall cheaper option if you're already having to replace rocker arms and valves on yours.

You can reuse the 14 head bolt washers. No need to order those.

I don't see the rocker shaft plugs (x4), cam seal housing o-ring, rear heater pipe gasket, intake gasket set, exhaust manifold copper nuts (x12), breather "bitch" tube o-rings (x2) or thermostat housing gasket on your shopping list.

Always install a rebuilt head with fresh gaskets and seals all around. And if any of the heater hoses or the throttle body heater hoses look questionable, there's no better time to get at them.

[jeffnhiscars]

The washers are plain flat steel so, use them again and you do not need to replace the tension spring bolt.

Yes to all the other suggestions

[tonyloban]

I found a head in good condition for $100. Just going to get that instead of digging into valves and stuff.

[jeffnhiscars]

You still want to get it tested, decked, grind the valves and seats and replace the valve stem seals. Anything less is begging for a redo

[MR 325]

You still want to get it tested, decked, grind the valves and seats and replace the valve stem seals. Anything less is begging for a redo

Amen to that. Do this at the very minimum!

[tonyloban]

Ordered the parts. I went ahead and got the cylinder head gasket kit so I know for sure everything is in there (NOT THE REINZ, RELAX). Much thanks to everybody for helping me out. Now I gotta learn how to change valve stem seals.

[MR 325]

Now I gotta learn how to change valve stem seals.

Your machine shop will take care of this when you bring the head in for resurfacing and valve grinding.

[tonyloban]

Your machine shop will take care of this when you bring the head in for resurfacing and valve grinding.

On average, how much am I looking to spend on doing this?

[MR 325]

On average, how much am I looking to spend on doing this?

Usually from $300-$400 for a basic refresh without replacing any rockers, hardware, cam, etc.