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300m timing belt. Did I do it right?

Posted By: 392charger

300m timing belt. Did I do it right? - 07/19/13 07:39 PM

I overheated my 2000 300m, blew the head gaskets/warped the heads. Had the machine shop check them out. They checked okay but had to milled them about 10 thou due to warpage.I put it all back together and now it has a rough idle, seems sluggish at takeoff, almost like you're taking off in 2nd gear, other than that, midrange and top end power are great. The check engine light came on, code said "system rich right bank". I checked all of the vacuum lines, fittings connectors, ect... can't find anything wrong. Now the check engine light went off by itself and still idles rough. Is it possible the timing belt is off one tooth on the passenger side, or would it not even run? I ask because I had to put the belt on 4 times before I got all the dots lined up correctly, the passenger cam kept moving one tooth when I put the tensioner on, but eventually I got it figured out. Even rotated the motor over a couple times via the crank bolt, and all the dots lined up. Any suggestions or help would be appreciated!
Posted By: Pacnorthcuda

Re: 300m timing belt. Did I do it right? - 07/19/13 07:50 PM

Might want to give it compression check.
Posted By: HemiRick

Re: 300m timing belt. Did I do it right? - 07/19/13 08:30 PM

if youre absolutely positive of this part, "Even rotated the motor over a couple times via the crank bolt, and all the dots lined up." Then no need to check it again. But if any doubt, its not too hard to pull the covers and check it again.
Posted By: 392charger

Re: 300m timing belt. Did I do it right? - 07/19/13 08:58 PM

Thanks for the replies. I am curious to know if it would run well with one cam off a tooth... or would there have been valve to piston carnage immediately?
Posted By: 392charger

Re: 300m timing belt. Did I do it right? - 07/19/13 10:45 PM

I think pacnorthcuda has it right. I'll do a compression check and see what happens. I would imagine the compression would be all out of whack on that bank if the belt is off one tooth!
Posted By: buildanother

Re: 300m timing belt. Did I do it right? - 07/19/13 11:21 PM

It should be fine if you had it all lined up timing wise. Even though that setup is odd with the slop that is in the cam gear to cam fitment.
Posted By: HotRodDave

Re: 300m timing belt. Did I do it right? - 07/20/13 12:24 AM

The slop in the cam/cam gear fitment can cause rough idle conditions sags hesitations... all kinds of drivabilyt issues. I had to break down and buy the tools since I have been transforming all the 2.7 cars in the area into 3.2 and 3.5 cars. You can eye ball the dots in the back end of the cams and get them all level horizontally and it will run OK (not perfect). The dots on the cam gears basically mean nothing, just get the crank gear dots lined up and the dots on the back end of the cam level and you are in factory specs, sometimes the dots on the cam gear don't line up exactly but it is OK as long as the cam and crank relationship is correct.
Posted By: 392charger

Re: 300m timing belt. Did I do it right? - 07/20/13 01:31 AM

Hotroddave I am not sure I understand the cam level comment. I simply had the dots on the cam pulleys lined up between the two dots on the timing cover. Is that not the correct way to do it?
Posted By: gtx6970

Re: 300m timing belt. Did I do it right? - 07/20/13 02:24 AM

Quote:

Thanks for the replies. I am curious to know if it would run well with one cam off a tooth... or would there have been valve to piston carnage immediately?




1 tooth off - will it run? yes, but not right
Posted By: buildanother

Re: 300m timing belt. Did I do it right? - 07/20/13 02:35 AM

The cams and cam sprockets have an indexed flat built in so they only go on one way, but there is a slop fit to them so apparently you need to use a special tool or procedure to align them correctly before they get final torque down. I lucked out and made some shims so the cam gear fit snug on cam, and that 3.2 car I've been driving for 5 years and gets 28 mpg avg so it must be close to perfect to me.
Posted By: hemi71x

Re: 300m timing belt. Did I do it right? - 07/20/13 02:46 AM

There are tools used to keep the cams in place, on DOHC engines, when installing a new timing belt, and locking down the tensioner.

Attached picture 7782974-DOHCTool.jpg
Posted By: ditchdrift

Re: 300m timing belt. Did I do it right? - 07/20/13 07:07 PM

you need a new machine shop... you don't machine the head surface to fix warpage... you have to straighten it. Ridiculous...
Posted By: rowin4

Re: 300m timing belt. Did I do it right? - 07/21/13 02:35 AM

Quote:

you need a new machine shop... you don't machine the head surface to fix warpage... you have to straighten it. Ridiculous...





Ah, this is the first time I have heard of this process, can you tell us how it is done?
Posted By: ditchdrift

Re: 300m timing belt. Did I do it right? - 07/21/13 07:24 AM

Quote:

Quote:

you need a new machine shop... you don't machine the head surface to fix warpage... you have to straighten it. Ridiculous...





Ah, this is the first time I have heard of this process, can you tell us how it is done?




First time? really? the head is bolted to a torque plate, usually a really thick piece of machined steel and then the head is heated to 400-500 degrees for 2 hours or less and let to cool slowly while still securely fastened to the plate. If your cylinder head was warped and it was just surfaced, that means the sealing surface may be flat, but all other parts of the cylinder head are not. including the cam journals, which can cause galling of the bearing surfaces and also cam failure.
Posted By: HotRodDave

Re: 300m timing belt. Did I do it right? - 07/21/13 09:06 PM

The cam and cam gear get out of proper relationship with eachother any time the big bolt is loose so you need to pull the small plate on the small plate on the back of the head there are two holes on the back end of the cam and when they are level and the crank dots are lined up THEN tighten the bolts in the front of the cam. It may .be off a couple degrees but it will be close. The holder tool is the only way to get it prefect. Once the front cam bolt is loosened this is the only way to get it lined up. Tightening the bolt and lining up the dots without holding the cam still will allow the timing marks to line up but in reality it can be a couple teeth off.

I have warped heads milled all the time and have never had a problem.
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