4L SOHC Cam Alignment

[rogi]

Having finally received the special alignment toolkit, I set my left cam. I got everything locked down with the aligment tools and applied the spec 62 ft lbs to the sprocket bolt, and the bolt torqued to 62 lbs, but kept moving (at that torque). Q: do I have a striped bolt, or is this normal?
Rogi

 

[cjmedina]

First you made sure BOTH cam slots are facing the same way, up or down. My book says facing down. The right cam is a reverse thread so to tighten is counter clockwise. The bolts are non torque to yield so they do not stretch so unless your turning in the wrong direction the bolt should lock down.

Cliff

 

[rogi]

Slots were set sideways on mine, and being the left head, thread direction is normal. It has 62 lbs applied, but it keeps turning at that torque. The engine seems to turn over by hand okay, so I guess I'll zip it up. Strange.

 

[cjmedina]

Note slot is closer to bottom. Both cams have to be timed the same or you will bend the valves. with one came going down and the other going up you'll be 180 out.... BENT VALVES!. you shouldn't even crank the engine by hand if that's the case.

Cams are not keyed so that torque is critical. You better find out why its not.

Cliff

 

[rogi]

I've only removed the left head. The right cam and jack shaft were never touched. The tool only allows the slots to be in only one postion and also forces TDC, so I believe the cam's position is okay. Its just that the bolt will not torque past the spec ft lbs (will not get any tighter).

 

[cjmedina]

That was one of my stock photos. Disregard that it says right head. It's the cam slot I'm showing you. Both cams HAVE to be the same.

Since you didn't put the engine at TDC left cam nub up then you don't know if your REALLY at TDC or 180 degrees out! Without confirming the cam slot on the right head it can be 180 degrees out now since you didn't start at TDC!

you have to remove both valve covers and make sure you are at TDC. If you put the left head on make sure all valves are up and have the gear loose before you turn the engine to TDC. Also left cam will have sensor nub up with slot down.

You have to make sure both cams are the same slot down! I hope you didn't bend any valve when you turned the engine. Many have learned the hard way even with the cam tools!

Here's your instructions. See page 21

http://home.comcast.net/~cjmedina/Forums/SOHC_Engine.pdf

 

[cjmedina]

That was one of my stock photos. Disregard that it says right head. It's the cam slot I'm showing you. Both cams HAVE to be the same.

Since you didn't put the engine at TDC left cam nub up then you don't know if your REALLY at TDC or 180 degrees out! Without confirming the cam slot on the right head it can be 180 degrees out now since you didn't start at TDC!

you have to remove both valve covers and make sure you are at TDC. If you put the left head on make sure all valves are up and have the gear loose before you turn the engine to TDC. Also left cam will have sensor nub up with slot down.

You have to make sure both cams are the same slot down! I hope you didn't bend any valve when you turned the engine. Many have learned the hard way even with the cam tools!

Here's your instructions. See page 21

http://home.comcast.net/~cjmedina/Fo...OHC_Engine.pdf

I assume all valves were up on the left head when you first installed the head and you had the crank turned to 0 but since you didn't make sure you where at true TDC when removed. you still have to follow the procedure correctly. the crank has to be turned again when you put the cam gear on with the bolt loose so as to take up any slack on the traction side of the chain then locking the crank.

 

[2000StreetRod]

does the sprocket rotate with the bolt?

When you attempt to tighten the sprocket retaining bolt does the sprocket or camshaft rotate? If so, then the timing tools are not correctly installed. The camshaft locking tool only fits when the timing slot is below the camshaft axis and parallel to the head surface that mates with the valve cover. The pins in the sprocket holder should fit in the holes in the sprocket. The hydraulic tensioner tool keeps the chain taught. The crankshaft holder should keep the crankshaft at TDC. Even though you have not loosened the jackshaft sprocket retaining bolts or the right camshaft sprocket retaining bolt as cjmedina states you should confirm that the right camshaft is aligned properly before timing the left camshaft. The engine will start and run with the camshafts 180 degrees off but not for long. The camshaft sprocket retaining bolt being tight is the only thing that keeps the timing correct. If it is not tightened to specification the sprocket might slip and the valves could be damaged. If the tools are correctly installed and the bolt slips at 62 ft-lbs I would remove it and inspect the threads.

 

[rogi]

Nothing else was moving when I tightened the bolt. Before I put the left head back on, I made sure the engine was at TDC by feeling for compression at #1. So I'm certain it's not 180 out. The bolt is actually at 62ft lbs now, but I can pull it apart and check the threads if you think it advisable.

 

[2000StreetRod]

stopped moving?

. . . The bolt is actually at 62ft lbs now, but I can pull it apart and check the threads if you think it advisable.

If you held the torque at 62 ft-lbs and the bolt eventually stopped turning then it should be OK. If it didn't stop turning then I would be concerned that the bolt is failing and would consider replacement. The sprocket retaining bolts are reuseable but it could have been overtorqued in the past. How difficult was it to remove? The danger of trying to remove it now if the bolt is failing is that it may break off. That might result in having to replace the camshaft. It may be best to just leave it as is and hope for the best.

 

[rogi]

The bolt was not difficult to remove initially, and since it required (say just over 65lbs) the specified torque to move, and moved very slowly at that level, I'm inclined to go with your last suggestion and leave it alone. As I said, the engine is turning over okay by hand, and to remove the bolt would also mean putting the tools back on (the crankshaft holding tool was a pain to set!).

 

[cjmedina]

What are you using for torque wrench? Beam or Click? If your turning past 62 you could of over torqued. I have seen where that bolt broke in a cam.

If that cam gear slips your talking about bending valves for sure!

Also if your sure there is compression on piston #1 when left nub is up it should be timed correct but to be sure right valve cover should come off and double check that slot is down.

 

[rogi]

My ft lb wrench is a beam (wish I had a click), and yes, the left nub was up.

 

[cjmedina]

OK Now.....That's why....You have to stop when it hits the 63 mark!

If your sure, then it looks like your good to go.....

You can also do a final check of compression on the left head.

Cliff

 

[cjmedina]

So How did it go?

 

[cjmedina]

Hi Dale,

Did you ever get a PM from ROGI saying how it went?

Cliff

 

[Jasonx521]

Old thread I know, but I wanted to add. I had my passenger side (right side) cam sprocket bolt while trying to torque down (counter-clockwise) it never wanted to reach the torque spec. I then looked up the torque spec at a few different sources to make sure I had it correct and I did. While I was looking this info up, my buddy decided to try and torque it again, and I heard a snap!!! and sure enough he busted the bolt inside the camshaft. I was very lucky that we were able to get both halves of the bolt out of the camshaft with ease. I had a spare right cam sprocket bolt and it torqued down just fine.

So, the moral of this, is if the bolt doesn't torque to spec and levels off and keeps turning without tightening anymore, the bolt is no good!!! Do not use it. I would remove it (which it should come out with out problems) and replace with new.... I would not question this, especially on something like the timing on a interference engine like the SOHC...

 

[2000StreetRod]

click torque wrench

Many of the click type torque wrenches do not work when tightening in a counter-clockwise direction.

 

[Jasonx521]

Good point, I know my torque wrench has a different accuracy specification in the counter-clock wise direction.