Inlet/exhaust valves
- Thread starter oxrod
- Start date
-
nm9stheham
Well-Known Member
Your post is not clear....
1. Do you mean that the intake and exhaust valves on cylinder 4 are opening and closing at the same time, and the same is happening on #6 (but at a different overall time than 4)?
2. Or do you mean that the intake valves on 4 and 6 are opening and closing at the same time, and the same for the exhausts on 4 and 6?
Is this observed while running or when turning the engine over by hand?
And you do realize that it's normal on all cylinders that the intake will start to open before the exhaust has finished closing?
1. Do you mean that the intake and exhaust valves on cylinder 4 are opening and closing at the same time, and the same is happening on #6 (but at a different overall time than 4)?
2. Or do you mean that the intake valves on 4 and 6 are opening and closing at the same time, and the same for the exhausts on 4 and 6?
Is this observed while running or when turning the engine over by hand?
And you do realize that it's normal on all cylinders that the intake will start to open before the exhaust has finished closing?
Thanks for your reply, Option 1, both valves on cylinder 4 are opening at the same time. Cylinder 6 seems to be as normal, car was being driven at the time and developed a knock sort of like lifter noise only louder.
I do realize your last point but these are both moving in identical sequence
I do realize your last point but these are both moving in identical sequence
pishta
I know I'm right....
remember the way a six is set up, goes EIEIEIIEIEIE so if your looking at the rockers moving, dont let that fool you. still should be 90 apart. #4 is between oil gear and bearing.
2 Darts
A-body Addicted
On a 4-stroke, inline 6 cylinder engine, a "firing event" should occur every 120 degrees. The firing order for the G/RG engine is 1-5-3-6-2-4.
Oh hell. Sometimerz Disease has struck. Past my nap time, anyway. Will edit if the train returns to the station.
Oh hell. Sometimerz Disease has struck. Past my nap time, anyway. Will edit if the train returns to the station.
nm9stheham
Well-Known Member
Almost seems like a valve spring is broken on one of the #4 cylinder's valves, and the separator rings between the Intake and Exhaust valves is bonded to them both, locking them together; but all of that seems pretty far-fetched.
Other possibility is that the camshaft broke between the I and E lobes on #4 and the back portion slipped about 90-130 degrees before hanging up on the front half. Broken cranks can do odd things and still get locked back together so why not a cam? The timing of the intake and exhaust valves on 5 and 6 would be out of proper sequence relative to 1, 2, and 3 if this was the case; i.e., you would not see a valve open every 120 degrees of crank rotation.
Turn the crank backwards by hand and see if the 4E and the 5 and 6 don't move for a while as the front valves are working.
Other possibility is that the camshaft broke between the I and E lobes on #4 and the back portion slipped about 90-130 degrees before hanging up on the front half. Broken cranks can do odd things and still get locked back together so why not a cam? The timing of the intake and exhaust valves on 5 and 6 would be out of proper sequence relative to 1, 2, and 3 if this was the case; i.e., you would not see a valve open every 120 degrees of crank rotation.
Turn the crank backwards by hand and see if the 4E and the 5 and 6 don't move for a while as the front valves are working.
Hey thanks for your comments guys, I was acting on behalf of my old timer father in-law, I went and had a look for myself today, turns out the engine had been sitting for several years, after investigating it turns out the lifters (And everything else) were all filled with sludge and all the rocker gear is in order. Sorry if I have wasted any ones time.
nm9stheham
Well-Known Member
No problem; wild speculation on causes for problems can be fun...LOL
-
