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I'm currently working up my 3500 for install into my Fiero. I mentioned in an earlier thread about a month ago that the 3500 is an interference engine. Well, while rotating the crank after installing the pushrods, I felt a little binding point and thought there maybe piston to valve contact causing it. That was a panic conclusion since my cam was reground, I didn't stop long enough to think that maybe it was the combination of valves being opened causing a little more load at that point which is what it was.
Before I arrived at that point however, I had feverishly removed the timing cover and unbolted the cam sprocket and turned the crank by hand forgetting about the interference and bumped a valve, I didn't think it was very hard but it was enough to spook me, so I put it back together successfully, forgetting to retorque the cam sprocket bolt which I did go back and do. I also realized that I should have done what I first thought to do, loosen the rockers to check for it. Problem was I had just sealed the covers and didn't want to which actually would have been easier because I ruined the new timing cover gasket where the v-cover seals were reusable.
Anyway I just completed the compression test on an 05 3500 with 7K on it:
1. 90 then 100
2. 244
3. 220
4. 140 then 210 this cylinder has the same timing as #1 remember
5. 188
6. 225
What I did wrong was spray WD40 in the cylinders before the test, I did so as a precautionary measure because I didn't know how long the engine had been sitting before I purchased it and didn't want to spin it with the starter in that state. There is a little fiz at the exh valve at #1 and 4, here is the kicker though, on both those cylinders a situation occured where the engine seemed to freewheel where at one point #1 didn't build pressure past 45 during the beginning of the test.
Here's what I'm going to do, nothing at first, whatever the issue given the improvement seen in #4 I believe the engine actually running and the valves slamming down at 6000 or more rpm at 10 psi will pretty much correct it and if it doesn't, I'll slip a little lapping compound through the exhaust port and remove the spring and rocker and gently lap it using my drill. That method worked wonders for me on past applications not associated with this issue though. We'll see I'm also going to install stronger springs but hopefully I'll get the 3900 in time enough to not have to worry about it. But if not, well then you know what I'll end up doing.
Before I arrived at that point however, I had feverishly removed the timing cover and unbolted the cam sprocket and turned the crank by hand forgetting about the interference and bumped a valve, I didn't think it was very hard but it was enough to spook me, so I put it back together successfully, forgetting to retorque the cam sprocket bolt which I did go back and do. I also realized that I should have done what I first thought to do, loosen the rockers to check for it. Problem was I had just sealed the covers and didn't want to which actually would have been easier because I ruined the new timing cover gasket where the v-cover seals were reusable.
Anyway I just completed the compression test on an 05 3500 with 7K on it:
1. 90 then 100
2. 244
3. 220
4. 140 then 210 this cylinder has the same timing as #1 remember
5. 188
6. 225
What I did wrong was spray WD40 in the cylinders before the test, I did so as a precautionary measure because I didn't know how long the engine had been sitting before I purchased it and didn't want to spin it with the starter in that state. There is a little fiz at the exh valve at #1 and 4, here is the kicker though, on both those cylinders a situation occured where the engine seemed to freewheel where at one point #1 didn't build pressure past 45 during the beginning of the test.
Here's what I'm going to do, nothing at first, whatever the issue given the improvement seen in #4 I believe the engine actually running and the valves slamming down at 6000 or more rpm at 10 psi will pretty much correct it and if it doesn't, I'll slip a little lapping compound through the exhaust port and remove the spring and rocker and gently lap it using my drill. That method worked wonders for me on past applications not associated with this issue though. We'll see I'm also going to install stronger springs but hopefully I'll get the 3900 in time enough to not have to worry about it. But if not, well then you know what I'll end up doing.
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