Fluidplay

Some of you may have been following my frustration with some excessive lifter & knocking noises...well I finally decided to remove the cam housing to inspec the lifters and found that 4 of them were shot, one was so spongy I was amazed it didn't fall apart. I'm hoping this solves my noisy lifter racket.

Anyway, in removing the assembly I marked what was then TDC alignments on the belt before removing. Nothing was moved in the engine compartment while working on the cam housing and while reinstalling and double checking nothing moved I tightened down the cam housing noting the cam gear turned slightly as I torqued it down...this is normal. What suprised me was that when I realigned the cam gear to the notch on the back cam cover and pulled the belt up tight on the gear my original mark is 4 positions off. If each tooth represents 9 degrees, this is a problem. Could this have been my knocking noise all along or is this timing so far off that it wouldn't even run? I know the belt didn't move. What's up here?

Please help!!

Tom M'Guinn

You can't reliably set the timing by marking the belt. Check to see if the flywheel tdc mark and cam gear tdc mark are both lined up at the same time. If not, it is out of time. If so, safest thing to do is remove the tower, set flywheel and cam gear to TDC, and reinstall.

Fluidplay

Tom - had both FW & cam gear aligned at TDC when disassembled. Nothing was moved in the engine compartment while I worked on the cam. I checked & double checked the TDC marks on both FW & cam gear after reinstalling. It was when I pulled the belt up to the cam gear tight and placed on the gear that I noticed my mark on the belt was off. I then checked again the timing marks on the FW & gear and both were right on. I'm wondering if the timing was off all along creating my knocking (timing being off) and low compression numbers (valves not closed all the way). I'm not a mechanic, but it seems reasonable. Could the engine run being that far off? 36 degrees is huge!

So, I guess if my FW & cam gear marks are lined up properly, I should asssume it was off at the start and go with it??? Am I gambling here?

Tom M'Guinn

More likely, the bottom of the belt went slack at the bottom when you pulled the tower off and, upon reassembly, went back onto the crank a few cogs off. If the flywheel and cam gear marks are both at TDC, then you should be good to go...

Fluidplay

Keeping my fingers crossed...thanks

m42racer

Building engines has nothing to do with crossed fingers. If you are unsure about anything, stop right now. It could cost a lot to fix. Valves,Pistons, Head, and more. My advice is to ask someone who knows what to do, and have them do it for you. Even if you have to pay. The cost to do this is insignificant compared to the cost of repair if you screw it up.

Ski

In the notch, in the bell housing, you should be able to see a slightly notched/indented area(about 1/4" or 6mm wide) on the flywheel - this is TDC when that flywheel notch is in the middle of the notched opening in the bell housing; this is where a flywheel lock comes in handy when doing belts.

Take a careful look at the bell housing - do not turn the engine, take the belt off. Loosen the cam tower until it just pops up about 1/4" off the head. It helps to have someone on the crank bolt to turn it slowly back until you can see the flywheel area in the opening, then stop. Set the cam gear notch to the notch on the back of the housing, bolt down the cam tower, then torque it down.

Pull the belt tight, feeding it from the bottom to the top, toward the notch and install it. Now set the tensioner or pulley, just to make sure it doesn't move. VERIFY flywheel notch is in the middle of the bell housing opening and VERIFY cam gear mark and cam back housing mark are good. Now, set your tension on your belt. With the plugs out - so you won't think your hitting something - rotate the engine a couple of times and verify your marks. check your belt tension, install the plugs, get the rotor, cap, wires on and fire it up.

Fluidplay

Bret - I've checked and rechecked for TDC on both the FW & cam gear notches. Once I had the cam housing in place and tightened, I checked the FW again (notch in sight) and turned the cam gear (belt not installed) to match up with the notch at the back of the cam gear cover. I then stretched the belt over the gear and noticed the mark I had placed on the belt was off by 4 cogs. As Tom M'guinn mentioned it could have slipped while it was off.
Your plan is exactly what I was planning to do...once the belt is tensioned I was going to rotate the engine several times to confirn placement and alignment of the notches. it won't be fired up until this step happens. Is there any chance of damaging anything by rotating the motor by hand?

Tom M'Guinn

This is not the right way to do it. When you turn the cam gear, the valves will open and close. If the motor is sitting still at TDC, then the valves will contact the pistons if you independently turn the cam gear any meaningful amount.

m42racer

Not to bring any more to your already overwhelmed plate, but it is clear from what you are asking and saying, you have no clue on what you are doing. If you get it wrong you put at risk the Top end of your engine. Is it worth it?

Tom M'Guinn

Sometimes the hardest lessons are the most valuable. I know a guy who made an exhaust bracket out of wood many years ago in highschool. It was a piece of art until it caught fire. Too bad there was no internet back then to get help and advice from others with more experience.

Chances are good that you have not hurt anything, unless you felt hard binding and forced the cam to turn anyway. Do triple check, however, that all the marks line up before rotating anything.

Fluidplay

Tom- I moved the cam gear only enough to bring it back to the notch in the back cover (4 cogs) The only time I turned the crank completely was when cam gear & FW were aligned and the belt was on...so things should be rotating just fine. I feel some tension and release as I'm turning the engine over to confirm the marks line up after a complete rotation of the motor back to TDC.

m42racer - I appreciate your warnings...but let's think positively here.

333pg333

Were there any marks in the top of your pistons when you opened it up?

eclou

if the cam tower is installed and the cam gear is set to TDC, should you not be able to rotate the crank without interference with the piston tops? I just replaced a valve and set TDC on the motor after setting TDC on the cam gear without any issues

Fluidplay

YES, It's done!!! Put everything back together this afternoon and with my "fingers crossed" (just for you m42racer) fired my baby up! ahhhhh... the sweat sound of success or should I say...lack there of. After a good warm up the lifters were much much quieter. So out we went...easy at first...checking all vitals...all sounds/feels good, OK, let's have some fun! Kicked in some turbo pulls on a couple of "simulation" speed runs. Ahhh the rush of the turbo kicking in...poetry! Yeah, liitle over the top, but I'm really glad this has a happy ending.

Plus, I now have a good idea where my knock is coming from. While turning the crank and watching the FW over and over and over, I noticed some areas where something was/is hitting the edge of the FW....I believe I'll take it in to have this checked. A mans got to know his limitations!

Anyway, I want to thank Bret (Ski) & Tom M'guinn for their assistance with this. Great support, great insights.

Thanks