Join Date: Nov 2005
Location: New Jersey, USA
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95 525i engine TDC w/VANOS
Hi! New to this board. Also quite new to BMW also. The only BMW I have in the past was a 86 325es given to me by a friend years ago. I sold it two months ago. Posted this to the 5 series board. Didn't get a peep. I thought I try my luck here.
Some background. I bought this 95 525i in spring. Wanted to take it apart like I did to all of my cars and put together again, at least the drivetrain. So I'll start with the drivetrain removed, gearbox separated and the engine on the stand and parts all over the floor in my two car garage.
I already have the 95 525i engine reassembled. No I did not separate the head from the block because I did not want to touch the pressure boundary when the engine came running. But I am a little concerned after reading the Pelican Parts VANOS timing article so I took the valve cover off again to re-examine the assembly.
Further more I am still waiting for some parts on the chain tensioner. Accrding to the Pelican article the bolts on the exhaust cam sprocket has to be tightened with certain (very small) chain tension so that part still needs to be done even if I got the TDC spot on.
Since I did not have the BMW tool to lock both cam shafts at No. 1 piston TDC, I am somewhat at risk. Actually I could not have done it either because I removed both cam shafts and the lifter housings.
At No. 1 piston TDC, the toothed disc at the front of the crank shaft has a mark to be lined up to same on the timing cover. I could not have missed that. In the valve train, the exhaust sprocket has an arrow pointing at 12 o'clock relative to the engine. The two lobes on each cam shaft for No. 1 piston point to each other at 10 o'clock (intake) and 2 o'clock (exhaust). (this is kinkd of obscure. Isn't it? But Bentley says so.) And the square end on each cam shaft lines up to vertical. (This is my guess. I guess the BMW special tool clamp on the cam shaft in this orientation.)
But I am not at all sure how the secondary chain sprockets should be lined up except what Bentley said the holes on the exhaust should be biased to the left. Even more obscure is how the VANOS unit should be oriented at No. 1 piston TDC. Is it because of the variable timing that there is no clear mark on the intake side?
On the SAAB 9k 2.3L engine that I am familiar with, there could not have been any mistake. At No. 1 piston TDC, the crank shaft has to be at certain orientation lining up to some mark. The flywheel has a mark. Both cam sprockets havs a mark. And both cam shafts have a mark. But again the SAAB engine does not have VANOS.
Colud someone straighten me out?
95 525i 5 speed 5/94,
94 540it built 3/93, converted to 6 speed w/a 93 e32 M60 engine
01 540it, 6/01
03 325i, 9/02
10 mini 6 speed