Author Topic: Somethings wrong. (Read 18889 times)

elementskater_xx · « **Reply #15 on:** May 12, 2008, 03:57:02 PM »

Ok so i bent up 3 exhaust valves. It's back in the shop. Only $150 this time. But i also think i need some new pistons. I should just do a complete rebuild. I will keep everyone updated as i go along. I live in ct by the way.

peerless · « **Reply #16 on:** May 12, 2008, 04:17:50 PM »

Pistons are pretty strong. I am sure it left some minor ding marks, but you should be able to clean the tops off and be good to go.

So I take it you got your timing off?

My question is how you had good compression when you started and lost compression afterwards?

The chain shouldn't slip and if you had good compression then it should have stayed that way. Sounds like you had the cam out of time from the beginning?

Well good luck with it. I just got back from the machine shop and the head I am having done for a customer has all 8 exhaust valves bent.

elementskater_xx · « **Reply #17 on:** May 12, 2008, 05:49:53 PM »

Yeah when the guy gave me the head back he said thatthe timming was all set. I should of checked it tho. The cams were off by quit a bit. It looked fine when i put it back togethor. I have some markes in my pistons. Not like the ones that are supposed to be there. But more it's like they hit right outside of the old grooves and made some new marks. I will try and get a pic up for ya. Ths problem strted when my chain broke and i bent a total of ten valves. Thanks to nomad tho i got a great hook up on some valves.

Cobra Jet · « **Reply #18 on:** May 12, 2008, 05:55:00 PM »

Man, if you bent valves again, something is not right w/ the timing of the cams, etc... You really need to have those timed correctly, otherwise you're going to keep having an issue and we'd hate to see you having to constantly go through $$$$$$....

Make sure you:

drain ALL of the oil that is currently in that engine - you don't want oil/coolant contamination

drain ALL of the coolant and replace w/ new

be sure there is NO coolant left in the cylinders

locate the online Bentley Manual (or other BMW manuals) and follow those engine rebuild instructions.

Like others have said, these engines are not just plug-n-play, you really need to read up on how to get the cams timed, how to get everything aligned nearly perfectly before starting the car - especially after doing a major head replacement. If those cams or sprockets are not timed correctly, you're going to mash valves again.

These engines are known as "interference engines" - meaning that if a timing chain breaks or the timing is not 100% correctly timed as stated in the manuals - the possibility of mashing valves into the pistons is extremely great...

nomad · « **Reply #19 on:** May 12, 2008, 06:01:54 PM »

wow, that sucks man!
FYI - there is no way the machine shop can "set the timing" for you when they give the head back to you. The timing is 100% set at the time of installing the timing chain and making sure everything is in the right position.

Check that the cams are in the right carriers! One cam has an E on it and that DOES NOT mean exhaust. The "A" is for Auspuf which is exhaust.

Cobra Jet · « **Reply #20 on:** May 12, 2008, 06:34:18 PM »

http://ee1394.com/bmw/docs/factory/repair/index1.htm

this may help

elementskater_xx · « **Reply #21 on:** May 13, 2008, 06:57:22 AM »

Ok so i looked at my pistons and my timming was def off. I have stamp markings in my pistons. They are off from the original ones. Like right next to it. I am probably picking up a new block within the next week. But i am not sure. Anything I can do to maybe resurface my pistons without taking my engine out of my car?

RED IS 91 · « **Reply #22 on:** May 13, 2008, 09:57:39 AM »

I can tell be reading this that you are in way over your head ( i mean the head on your shoulders not the one in the car) .
You need someone that knows these motors to either help you or do it for you before you ruin more stuff or go broke.

D'Agostino Brothers
Joe D'Agostino
Stamford, CT
203.324.3966

Sports Car Restoration
33 Norton St, Southington, CT
860-621-2002

I found these two by googling . Maybe you can search the yellow pages or call the people above and they can recommend someone.
You need special tools to set the timing on these cars .I am surprised that there are no members from conn. on this board that can recommend an independent shop or offer some assistance.
Which ever way you go "GOOD LUCK"

bmwpower · « **Reply #23 on:** May 13, 2008, 11:34:16 AM »

Whatever you do, before you turn the key again...

- You'll need a new headgasket, new crank bolt and new head bolts. These are not reusable.

- You'll need to torque the head bolts in the proper sequence using a torque wrench and torque angle meter (or make one yourself).

- You will need to have the cams locked in place (preferably using the proper tool for the job) in the proper orientation before putting the chain back on and aligning the cam sprockets. This is key. A second set of hands would be helpful here, but not necessary.

- Make sure you manually rotate the engine several times by using a socket/ratchet on the crank bolt. Rotate the engine clockwise (as you stand in front of the car). Make sure there are no weird noises. Make sure nothing binds.

Let us know where you are right now in the process and we can help you out.

peerless · « **Reply #24 on:** May 13, 2008, 11:36:00 AM »

Quote from: elementskater_xx;49207

Ok so i looked at my pistons and my timming was def off. I have stamp markings in my pistons. They are off from the original ones. Like right next to it. I am probably picking up a new block within the next week. But i am not sure. Anything I can do to maybe resurface my pistons without taking my engine out of my car?

What do you mean resurface your pistons?

How bad can they be. I am doing a engine build for a guy who bent all 8 exhaust valves. Pistons are fine. Don't get me wrong, they got some dings in them, but nothing major. I have done many a head job with busted belts and chains, never have had to replace a piston. If your pistons are bad enough to need to be resurfaced, (which you can't do) they need to be replaced.

Lets see some pictures of these pistons.

I can't imagine what your old drill sergeant say to you right about now. I can only imagine.

elementskater_xx · « **Reply #25 on:** May 13, 2008, 03:02:37 PM »

Ok I am taking some pics tonight. I also just bought a truck to get me around while i do this. Plus someone in mass is selling me a block. So it will come in handy. I am right now waiting for my head to come back from the shop. I had 3 bent exhaust valves. I am just going to take it slow on the rebuild. Not to slow cause i love my car and the way it drives.

Cobra Jet · « **Reply #26 on:** May 14, 2008, 07:54:52 AM »

take LOTS of pics of the current state of the engine as it sits in your vehicle NOW... These pics will help others on here to diagnose OR point out ANY OTHER possible problems or issues BEFORE you reinstall the next head...

Some more questions:

did you check the condition of the cam/timing sprockets?
did you check the condition of the chain?
did you check the condition of the timing chain tensioner?
did you check the condition of the timing chain guide rails and any other associated parts for the timing system?

Since you have everything apart and if you have not checked those above items, I really suggesst doing so, because if they are worn or in need of replacement, it's better to do it now, rather than getting everything all back together and having to tear it down again due to a timing related issue or noise.

bmwpower rebuilt the M42 that's in my 318ic, so he (and many others on here) know how intricate these engines are and what the proper procedures are for a correct rebuild & start....

ask many questions and as asked by others, take plenty of pics and get them posted up for others who can possibly assist (or can point out potential issues).

elementskater_xx · « **Reply #27 on:** June 11, 2008, 11:17:21 AM »

This is where i am at so far. Sorry it took so long had some stuff to finish up. I got my head back again. They said i bent all my exhaust valves. I tried looking for the tool needed to set my cams but can't find it anywhere. Anyone have any advice?

Wise Old Dog · « **Reply #28 on:** June 11, 2008, 03:45:04 PM »

http://cgi.ebay.com/ebaymotors/BMW-Camshaft-Alignment-Locking-Cam-Timing-Holding-Tool_W0QQcmdZViewItemQQcategoryZ35625QQihZ015QQitemZ250257935612QQrdZ1QQsspagenameZWDVW
You also need a tensioner tool to get the chain tight. The one on the engine is too weak for this procedure.

peerless · « **Reply #29 on:** June 11, 2008, 04:57:34 PM »

Quote from: Wise Old Dog;51071

You also need a tensioner tool to get the chain tight. The one on the engine is too weak for this procedure.

Can you elaborate on this tool?

I haven't seen it, nor read about it before in the service manual. Am I missing something?