Author Topic: How to set TDC with an aftermarket flywheel... (Read 7005 times)

JiXer · « **on:** June 23, 2007, 01:24:16 AM »

So, I had to overhaul my timing system and I have most of it complete, but I am nor paranoid that I am not at TDC. I have an aluminum flywheel which does not have the convenient little 8mm whole for setting TDC.
So I had to guess.

Is there another way to make sure that I am right on TDC?

I also want to set my intake cam to 5^ advanced, but I am not sure how to be sure that I am right on 5^.

Help is greatly appreciated as I need this car for Monday morning.

Thanks in advance.

J.

AL GReeNeRy · « **Reply #1 on:** June 23, 2007, 03:40:54 AM »

the crank pulley should have a mark for tdc. search for a thread regarding the timing chain procedure. that should help

JiXer · « **Reply #2 on:** June 23, 2007, 10:36:55 AM »

Quote from: AL GReeNeRy;28322

the crank pulley should have a mark for tdc. search for a thread regarding the timing chain procedure. that should help

Unfortunately, I don't think it does.
And I have searched and searched, but everyone just uses the flywheel.

J.

16v of Fury · « **Reply #3 on:** June 23, 2007, 01:27:41 PM »

Quote from: JiXer;28339

Unfortunately, I don't think it does.
And I have searched and searched, but everyone just uses the flywheel.

J.

Are you sure? I'm willing to bet there's one at the front of the engine somewhere.

JiXer · « **Reply #4 on:** June 24, 2007, 12:39:09 AM »

Quote from: 16v of Fury;28347

Are you sure? I'm willing to bet there's one at the front of the engine somewhere.

What exactly are you willing to bet?

J.

nobrakese36 · « **Reply #5 on:** June 24, 2007, 01:31:56 AM »

When the woodruff key is straight up. Like in photo, also observe cam position.

AL GReeNeRy · « **Reply #6 on:** June 24, 2007, 02:21:17 AM »

Quote from: nobrakese36;28386

When the woodruff key is straight up. Like in photo, also observe cam position.

i rest my case. thanks nobrakes, ive been trying to figure out the name of that damn key for about 2 weeks now. i recently did a head swap on my friends integra gsr and those keys are important pieces on the cam gears. for the longest time i couldnt remember that one word before key, but i KNEW it started with a "w"

damn WOODRUFF key lol

16v of Fury · « **Reply #7 on:** June 24, 2007, 10:48:51 AM »

Woodruff key? What's that?

gearheadE30 · « **Reply #8 on:** June 24, 2007, 12:02:03 PM »

Yes, an explanation would be nice, as I am gearing up for the same overhaul.

romkasponka · « **Reply #9 on:** June 24, 2007, 02:12:26 PM »

the best way is to measure real TDC through spark plug hole.

JiXer · « **Reply #10 on:** June 24, 2007, 11:49:11 PM »

Quote from: romkasponka;28428

the best way is to measure real TDC through spark plug hole.

This does you know good.
There is at leat 10^ of rotation in the crank while the piston is in the top position. Top DEAD center is when the piston is at the top and the crank is at the very center of the rotation. There are 36 points on the cam sprocket which means each tooth is ten degrees. So this is not a sufficient method of finding TDC.

The stock flywheel is the ONLY way to be totally sure. You can all but garauntee you will be with in a tooth, but that will still prevent the motor from turning over.

The best way to do this job is to actually take the outer timing covers off and scribe points on the end of the crank and and the oil pump cover and then do the same to the cam sprockets and the head. Don't use a grease pencil. It will wash off. Actually scribe it with a file or something.

I finished mine today and had everything set up with the intake cam about 6^ advanced and the exhaust cam at zero. It made a very horrible clacking noise. I had to back the intake cam off to maybe 2^ or 3^ advance for it to run properly. It pulls strong, but when it comes off throttle, I still have a little rattle that I can't figure out. It might be somewhere else in the motor or might just be the way that motor sounds?

It also GROWLS when its approaching 7,000 RPMs. I don't remember it sounding like that before. Not sure of thats a bad thing or not?

J.

romkasponka · « **Reply #11 on:** June 25, 2007, 03:53:26 AM »

Thi

Quote

s does you know good.
There is at leat 10^ of rotation in the crank while the piston is in the top position. Top DEAD center is when the piston is at the top and the crank is at the very center of the rotation. There are 36 points on the cam sprocket which means each tooth is ten degrees. So this is not a sufficient method of finding TDC.

It depends what accuracy you have. You can mark the middle of these 10deg, right?

Quote

The stock flywheel is the ONLY way to be totally sure. You can all but garauntee you will be with in a tooth, but that will still prevent the motor from turning over.

The best way to do this job is to actually take the outer timing covers off and scribe points on the end of the crank and and the oil pump cover and then do the same to the cam sprockets and the head. Don't use a grease pencil. It will wash off. Actually scribe it with a file or something.

Totaly agree.

Quote

I finished mine today and had everything set up with the intake cam about 6^ advanced and the exhaust cam at zero. It made a very horrible clacking noise. I had to back the intake cam off to maybe 2^ or 3^ advance for it to run properly. It pulls strong, but when it comes off throttle, I still have a little rattle that I can't figure out. It might be somewhere else in the motor or might just be the way that motor sounds?

It also GROWLS when its approaching 7,000 RPMs. I don't remember it sounding like that before. Not sure of thats a bad thing or not?

I had the same problem. If you want better top end you should advance cam, but I had terible noice when intake cam was retarded. Are you shure that you advanced it?

JiXer · « **Reply #12 on:** June 25, 2007, 12:28:37 PM »

Quote from: romkasponka;28466

I had the same problem. If you want better top end you should advance cam, but I had terible noice when intake cam was retarded. Are you shure that you advanced it?

Well, if I am correct in saying that the M42 turns clock wise (when standing in front of the car, looking down at the motor), then I definitely had the intake cam advanced and less than the max, but something was not happy.
I am still slightly advanced, but not nearly as far as I could go.
Which begs the question, why would BMW build in adjustability to the point of near catastrpohic failure in an interference motor?
J.

bmwman91 · « **Reply #13 on:** June 25, 2007, 02:33:40 PM »

I had the same issue when I rebuilt my timing case on a lighter flywheel. Using some welding rod we got it about as good as it can get. It does not take anywhere hear 10 degrees of error to get valves hitting postons (ask me how I know). It runs strong up to redline. Maybe your growling noise is something that timing case noise was masking before? If the timing was way off, you would definitely know, and it would not be terribly willing to redline or idle nicely. Good luck.

romkasponka · « **Reply #14 on:** June 26, 2007, 02:21:21 AM »

Quote from: JiXer;28482

Well, if I am correct in saying that the M42 turns clock wise (when standing in front of the car, looking down at the motor), then I definitely had the intake cam advanced and less than the max, but something was not happy.
I am still slightly advanced, but not nearly as far as I could go.
Which begs the question, why would BMW build in adjustability to the point of near catastrpohic failure in an interference motor?
J.

Sorry for my mistake, you should retard intake camshaft for better top end. The valve shoud be opened later and closed later. My first atempt was to advance intake, after that I got terible noise and weak top end. After I retarded intake camshaft at max posible position. And after this I lost low end torq, but top end was much better. Limiter is 7200rpm.

You can try to simulate it on the DynoSim 2003.