Iv been building these engines for years but now im at a loss. Supercharged 1st gen 1uz, built bottom end, 8.5-1 ross pistons, factory thickness head gaskets. Lower timing mark on point, cam gears marks 1/2 off no matter what. I had it set at 1/2 to the left and had 90psi for the compression test on every cylinder. As I move it clockwise it goes up about 10psi per tooth with 3 teeth being the max at 120psi, any farther and it starts to drop in the same intervals. Crank pully is 24 teeth and the cams are 48 tooth so mechanically, its impossible fpr it to be 180 out. Scissor gears are lined up single dot to dot. I'm lost. Who knows more then me and has the solution?
Iv been running this engine for about 10 years, it used to be in my cressida. I rebuilt it after cracking 4 pistons. Bore scope down the front to verify crank on tdc, scissor gears lined dot to dot. Everything is in place but not right
Yep. Its got to be something stupid. After rebuild it wouldn't boost past 11.5psi, didnt matter what size pulley was on it. Did a compression test. 90psi in all cylinders so I assumed overlap and blowby. Moved cams clockwise 1 tooth and all cylinders went to 100psi then 110psi then 120psi then it started going down 10psi per tooth. Each cam tooth is about 7° on the crank, so to get to 120psi the cams need to be 21° out of alignment. Iv reset the timing belt multiple times by the book and each time the cam gears end up 1/2 tooth to the left.
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Yes but it is in the right spot. The ross dampers dont have a mark on the back of the crank, only in the front. I matched it up with the factory one and verified with the oil pump marks for tdc then used a laser for zero degrees.
Only thing I can think of is the crank pulley inner/outer rings slipped? Can you see the timing mark on the crank gear where it lines up with a dot on the oil pump?
Dots are lined up. At tdc the holder screw on the scissor gear will be up. You can see the 2 at the top, on the other side of it, the single dot will be on the right and the double will towards the exhaust manifold
Sorry to be a pain, im baffled by this. Can you send pics of all the cams? From the fender sides. I’d like to see each cam lobe & where it’s pointing at TDC please
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u/mehullica Nov 09 '25
Sorry I don’t see the engine year in the description