Timing problem after head rebuild

[MrGriff750]

I've done some research and haven't found much pertaining to my situation.

I put a rebuilt cylinder head on my 6 bolt and am having a timing problem now. The timing is far too advanced. When i retard my timing as far as the CAS will allow, it only gets down to +5, and the strange thing is it runs WORSE than it was at about +20 (estimating because its off the marks). Initially it was idling at about 1k so i adjusted the BISS so it is about 750 now, but it still runs rough no matter what the CAS has the timing adjusted to. I did all this with the ecu ground plug grounded. I double checked the Timing belt at TDC and everything still lines up.

Anyone have any ideas what could be causing this?

 

[Colt4G63 also]

Bad harmonic balancer.

 

[NOSLO2PT0]

If you are referring to the timing marks on the crank pulley, verify the crank pulley hasn't started to slip or the rubber portion separated from the pulley. That's VERY common. Put #1 cylinder to TDC. Then check to see if the timing mark on the crank pulley is at TDC mark on the lower timing cover. If it's NOT, see if the crank pulley was installed 90* out of phase. If it was installed correctly, then the pulley has separated and it's time to replace it.

 

[MrGriff750]

Alrite, so i put cylinder 1 at TDC and checked the timing mark's placement. It's sitting at about 0. Whats confusing me is how the pulley can go bad? Is the harmonic balancer the same as the crank pulley?

Also, i have a check engine light now too.

 

[92AWDHX40]

Same pulley, crank harmonic balancer same thing.

 

[Colt4G63 also]

Did you physically check that the piston was at TDC?

 

[MrGriff750]

Yeah, i put a screwdriver through the spark plug hole and made sure it was at TDC.

 

[Colt4G63 also]

The timing belt is probably off a tooth on the intake cam.

Ps. To answer your previous question: The outer ring of the harmonic balancer is isolated from the center hub by a strip of rubber. They commonly slip, rendering the timing mark inaccurate.

Ha ha fixed my spelling. I had like four typos. Funny ones to boot.

This one came off my car last month:

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It was only twisted enough to throw the timing marks off by a few degrees. If I hadn't noticed the rubber shreds forming during my pre-shootout checkup, it would probably still be on my car.

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[MrGriff750]

Here is a pic of the cam gears. This is the best pic i could get with my crappy camera phone. It's sideways, i know. I wanted to get the best shot with the dowel pins and notches.

Today i re-did the timing belt and nothing changed.

 

[Colt4G63 also]

It's really hard to see anything in that photo. I like to use all four timing marks, and draw an imaginary line across the top of the head where it meets the valve cover.

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Laying a straight rod across there may help you make sure it's accurate.

 

[MrGriff750]

I set a rod across the 4 notches and noticed that the outer ones are higher up than the center ones. Not sure if that is normal or not.

 

[kchaazz]

Yeah, the outers are always slightly higher. If the harmonic balancer is good, and the timing marks all line up, put it at TDC and then remove your cas and look at the part that goes into the slot in the cam. There will be two marks on the cas and Im willing to bet yours is 180 degrees out.

 

[twicks69]

Was the cylinder head decked and resurfaced? How much was taken off? What head gasket are you running? Is it the same thickness as the previous one used? List what has changed from before the head rebuild to after the head rebuild so we can further deduce the problem.

Tim Zimmer via Evo Phone

 

[MrGriff750]

Yeah, the outers are always slightly higher. If the harmonic balancer is good, and the timing marks all line up, put it at TDC and then remove your cas and look at the part that goes into the slot in the cam. There will be two marks on the cas and Im willing to bet yours is 180 degrees out.

I checked that yesterday and ran it both ways, and no change. I have it set back to normal now.

Was the cylinder head decked and resurfaced? How much was taken off? What head gasket are you running? Is it the same thickness as the previous one used? List what has changed from before the head rebuild to after the head rebuild so we can further deduce the problem.

Tim Zimmer via Evo Phone

Yes it was decked and resurfaced. I don't know how much was taken off. I purchased the rebuilt head off a guy who had all the work done. I'm waiting for all the paperwork for it in the mail. I bought a Topline head gasket, and im not sure what was in there before, probably stock. I redid my vaccum lines by removing unnecessary ones and replacing the remaining ones. I put ARP head studs in. Tightened them in four steps, and in the right order.

 

[twicks69]

I would measure the head deck height to find out how much was cut off. If you have too much cut off, it will affect your timing. You will either need a thicker gasket to compensate, or adjustable cam gears to get it dialed back in properly, or start over with a new head that isn't decked as much if the head is specifically the problem at hand currently.

 

[BogusSVO]

My first post in this fourm, the title of this thread caught my attention.

I will agree with twicks69.... the head may be too thin, a thiker HG may help restore the time marks or adjustable cam gears and degree the cams back in.

But if you want to measure the head....

http://www.dsmtuners.com/forums/cyl...how-measure-4g63-cylinder-head-thickness.html

 

[MrGriff750]

I got a buzzer to check the CEL and it gave me a code for the knock sensor. I'm looking for a replacement as we speak, and I will update again after I install it.

 

[kchaazz]

Hmmm... I do believe that the ECU will automatically take out 7 degrees of timing if its seeing a problem with the KS, though this SHOULDNT have any effect on timing readings when adjusting base timing, because the ECU relinquishes timing control when you ground the plug...