Author Topic: how acurate should cam timing be? (Read 3887 times)

willmoodom · « **on:** April 23, 2009, 09:34:22 PM »

I recently replaced the head due to a few cracks. car is a 93 318 cpe auto.
after numerous times of locking the crank and cams in position, rotating the engine by hand a couple times back to TDC, the cams according to the blocks at the back seem a little off. everything else is kosher. arrows up and lobes pointing toward each other and crank locked. Is it normal for the cams to be a little off after rotating or are they suppose to fall inline each time wherever you set them? all guides are installed and tight. TCT is installed with tension on the chain. everything turns fine. a little tight at the peak of the cam lobe but that's expected. I haven't started the car up yet because I'm scared to death of bending some thing. Head is pretty much brand new. it was fully rebuilt. cracked one sitting in the garage as a door stopper. If there was any interference, I assume the engine would not rotate with out putting your body weight into it. Can some one ease my concerns?

nicknikolovski · « **Reply #1 on:** April 24, 2009, 04:24:28 AM »

Can you post a picture of how far off they are?

doitover · « **Reply #2 on:** April 24, 2009, 08:18:38 AM »

Mine is also not perfectly flat but I don't have any resistance at the top of the cam lobs. I should say was, I retarded the intake timing a little having read you can do that with a supercharger and improve mileage and emissions a bit.

I believe I could have gotten them flat with a real alignment tool. With the cross coupled crescent wrench approach there was always a little slipping when tightening the cam gears.

JP 91iS · « **Reply #3 on:** April 24, 2009, 01:11:28 PM »

My cams were not flush square with the head or each other either, but I rotated them individually until they were. I just used a crescent wrench on the square to rotate the cam while it was unbolted from the gear- I did this for both cams. I'm not sure if that is a good way to go about correcting the alignment but it worked great for me. I used a ruler to check for square.

My cams were only a little bit off to begin with though. It sounds to me if you don't have interference from cranking it over by hand that you won't have it with the engine running. But one or both of your cams may be advanced/retarded?

willmoodom · « **Reply #4 on:** April 28, 2009, 06:54:15 AM »

Quote from: JP 91iS;70680

My cams were not flush square with the head or each other either, but I rotated them individually until they were. I just used a crescent wrench on the square to rotate the cam while it was unbolted from the gear- I did this for both cams. I'm not sure if that is a good way to go about correcting the alignment but it worked great for me. I used a ruler to check for square.

My cams were only a little bit off to begin with though. It sounds to me if you don't have interference from cranking it over by hand that you won't have it with the engine running. But one or both of your cams may be advanced/retarded?

Thanks for the reply all. I've changed the oil, filter and refilled the coolant. I need to route the and installed spark plugs and torque down the VC. will probably be cranking it over today. fingers crossed. BTW JP, my cam angles looked just like yours in the photo.

Isamemon · « **Reply #5 on:** April 28, 2009, 03:08:53 PM »

I am relitively new to the m42 motor, and did the same thing with a cracked head, I had the alinging tools, yet " felt" and feared if it was right, and with help at the forums, double checked everything
I had no interference

but my big scare came when I went to first turn it over and build pressure in the oil systme ( wihtout plugs in ect) and got this strange knocking noise
, worried me, looked into it,again, since I was new to the m42 and I had already spent a ton on repairing the cracked head, I did not want to proceeed without checking wiht others checked on the forum and found it was the tensioner and gudes slapaing until they had oil pressure

after cranking several times and having good oil pressure, and no slapping, I put the plugs in and started it

willmoodom · « **Reply #6 on:** April 29, 2009, 12:02:36 PM »

congrats on that. today I just cranked mine over. no noises what so ever. though I am wondering about the oil pressure. I thought after cranking and once oil pressure was up, there might be a squirt of oil seen from the driver seat. I did'nt see any, though I noticed oil seeping out the oil filter housing bolt. I did'nt torque that down purposely to assist me with recognizing some form of pressure.
So I have 2 questions. first, is there a tell tell once oil pressure is up? and how in the hell is everyone getting the seals on to the VC bolts? after that, i can install the the plugs/cables and start her up.

JP 91iS · « **Reply #7 on:** April 29, 2009, 12:11:29 PM »

You can use a deep socket the same size as the valve cover bolts seals and press them on with a vise.

willmoodom · « **Reply #8 on:** April 29, 2009, 12:34:59 PM »

Quote from: JP 91iS;71078

You can use a deep socket the same size as the valve cover bolts seals and press them on with a vise.

Thanks. I'll try that. any lube on it?

willmoodom · « **Reply #9 on:** April 30, 2009, 11:36:36 AM »

I finally had the car running for short bursts at a time. 2 issues stand out after head rebuild and install.
front portion of valve train is noisy as hell. like no oil reaching lifters. but I know oil is circulating up top. I cant remember the top end being that loud. almost scared to rev it fear of breaking or bending something. I haven't rev it to the 3000rpm mark because of the noise. My other issue is cooling. new water pump and tstat. coolant doesn't seem to be circulating. and a slight leak or drip somewhere at the back corner of vC. after about 5 min some smoke will appear from the exhaust manny.

Good thing out of all this, is the engine no longer blows white or blue smoke. which it was previously doing due to cracked head in 3 places.
any thoughts?

JP 91iS · « **Reply #10 on:** April 30, 2009, 12:46:50 PM »

There will be some noise with the new components. Mine mostly whines when I rev it up. Here's a low quality video of my chain noise:
http://www.youtube.com/watch?v=75MrTAdDTg4

You may need to re-bleed your coolant. It took me a couple times before I got it bled properly. Check the coolant hoses to and from your heater core for a leak.

willmoodom · « **Reply #11 on:** April 30, 2009, 03:01:36 PM »

maybe I can do a sound clip. It definitely sounds like lifter noise.
as for coolant, I am not seeing a change so I will most likely need to try a rebleed. No heat coming from the vents at all. I tried opening the valve below rad on right side. All I saw was coolant draining. again no change with the level in the reservoir. I wish I could depend on the temp gauge but now I'm not sure it's working correctly. ran the car for about 10 min and moved forward and backward in the parking lot. gauge stayed at half or a little above half. fan clutch is shot and that's why I'm wondering about the gauge. The gauge did show hot before the head swap. Now I understand that this car is only rated at a hundred hp, but is there any sluggishness when stomping the gas halfway? It seems to pull kind of slow.

nicknikolovski · « **Reply #12 on:** May 01, 2009, 03:14:08 AM »

Yep, slightly slow cause its got a big twin mass flywheel which weighs in at 27lb.