zeus87gn

I'm still working through this timing issue

For anyone that has done the timing belt on the early model SC400, the clearance motor:
When you put on the crank pulley (balancer, serpentine drive pulley), did you have to turn the crank to align the crank to 0deg TDC before you put the belt on the cam pulleys?

Although I don't see any evidence of it, I'm wondering if my pulley has lost its alignment
I can't seem to get compression on the right bank

salimshah

At the end it doe not matter where you set the main at ... once the belt is on the main and the two cams must all be at 0 mark at the same time.
So .. start by setting all of them at 0 and the install will be in sync and you confirm it by cranking the main by at least 2 turns (letting the tensioner settle etc). You visually confirm before starting the engine.

Note: SC has 4 stroke engine, 0 of main can be tdc of the piston 1 compression stroke or the exhaust stroke. Only the compression stroke is the correct position. One should not turn the main once you take the belt off. If it is off then you have to turn the main another 360 turn. Cam gears make 1 turn for 2 turns on the main gear so, even if they spin the mark will aways be correct for the cams.
Note on Note: SC400 unlike other engines has the spark timing right on the cam so the above note may not be of significance. For other engines where the rotor is driven by the engine, the main pulley out of sync by 1 turn can be a pain.

Experts?

Salim

zeus87gn

If I line them all up at 0, i get no compression on the right bank of cylinders - I've been experimenting today and with the crank at +5 or 6 teeth to the came, I'm getting compression on the right bank now - but the numbers are all over the place on the whole engine

zeus87gn

I started getting compression back at about +2 teeth on the crank

zeus87gn

I'm going to go back to +5 on the crank and run compression on all cylinders again to see if the numbers stabilize

zeus87gn

So I ended up with the crank advanced 4 teeth from the 0 mark to get the best compression numbers
I haven't tried to start it yet, I'm repairing the wiring harness again

I did get a new Lexus crank pulley/vibration dampener
It is aligned the same as the old one that I thought might have slipped due to a hairline crack I found

So with the engine timed per the correct marks, I get good compression on the left bank and no compression on the right bank
I did double check the belt gear on the crank - it appears to be fine - I didn't take it completely off, but it did slide back and forth on the keyway about an inch

Does anyone have any idea what is going on here??
Have I got a twisted crank?
is it possible for the cam gears to jump time w/r/t the cams?

I'm open to any ideas at all

zeus87gn

So after getting a running replacement long block, I found out how it was aligned - it uses these marks on the FRONT of the timing gears - I had been aligning them using the tabs on the BACK of the timing gears - I now have more even compression across the cylinders (albeit low from not having run in 2yrs) - I'm going to put it back together and see what happens

zeus87gn

It worked - I was lining it up wrong - she's back to running like a champ again except for a high idle problem
something else I noticed while lining it back up - when the motor is lined up with the marks on the FRONT of the cam gears, the rotors point towards marks on the distributor cap housings that I never noticed before - DUH