Compression or exhaust stroke

Use at the timing marks as you call “aft” (I assume you are referring to the scribed factory assembly marks) and when you are close to those you must be in compression at TDC.

No way your cams are ~180 degrees off, your engine would be toast if they moved that much.

My 2 cents: You should degree the cams properly not just rely on those marks.

 

Yes.

And I meant intake.

 

"Degree" = do it with a degree wheel.

 

What exactly are you trying to do and how did you get to this point? I'm a big DIY guy but some things are better left to professionals to avoid damage. If you are asking this question on a forum maybe you should take it somewhere or study up more before going any further. The "thumb" method will only get you within a few degrees or so of true TDC, you need proper gauges or even a dead stop to determine TDC if you intend on timing the motor.

 

If that's all, assuming you have not rotated the crankshaft since you originally got the marks lined up (please tell me you got the marks lined up prior to taking off the belt) then you should be fine moving the cam back to where the factory timing marks on the pulleys match up and the belts are on the teeth. For future reference, I always make several marks on the pulleys (all 3) and the belt to line them up, that way if a cam shifts I can use the old belt and get everything lined up exactly as it was.

But since you are asking this question, I have to enquire if you had the timing marks lined up properly prior to taking the belts off.

 

My question remains have you turned the crankshaft since you removed the belt?

 

Drop the tools before you damage something if you haven't already. Rotating the motor with the cams present and locked and out of time is one of the worst things you can do. The cams should be removed from the engine so all valves are closed, rotated back to TDC and cams reinstalled and timed properly.

 

No disrespect but I disagree with redneck. FWIW neither of us are pros.

If you have already spun the engine around, then if there is damage then it’s already done (I doubt damage even a cam is a little off). So in my opinion you don’t need to remove the cams.

Get the engine into tdc with the cam assembly marks close so you know it’s in intake stroke at tdc.

Get the cams lines up to the factory scribe marks, then Take it from here and degree the cams as per the workshop manual.

And if you want to make yourself feel better do a compression or leak down test.

I agree that perhaps you maybe should bring it in to a pro if you are not sure you can accomplish the degreeing.

See what other feedback you get.

-Ray

 

True I'm not a pro but I have taken the cams out of my engine...but it sounds to me like the belts are not on the car and the cams are still in situ and he wants to rotate the motor (see post #9) or already has without the belts on...maybe I misunderstood that...but if I'm right and that is the case, there is a large risk of damage by rotating the crank independent of the cams. Maybe he does not realize this is an interference engine?

If the belt service has already been completed and the timing marks are just slightly off, I doubt he would be asking whether he was TDC at compression vs exhaust, he would just move the cam back to where the pulley marks line up and he will be right back where he was, since he confirmed that he had the motor at TDC before removing the belts. I'm definitely erring on the side of caution based on the question that was asked

@Rariday maybe you could clarify and perhaps provide some pictures to better understand what you are dealing with. With the information that was given so far, I stand by my advice.

 

Questions asked tell a lot about a persons understanding of the relationship of vales, pistons and crankshaft location.

And the fact it is even mentioned to use a thumb as a method to find TDC tells me all I need to know about how well equipped we are to do this job.

In my opinion this job should stop now and be sent to a shop.