| Author | Message | ||
     Timothy Riccardi (Boxerhips) New Member Username: Boxerhips Post Number: 26 Registered: 07-2002 |
I have replaced 3.9 with 4.0 and now have a vibration around 1700 rpm's. I swaped 3.9 harmonic balancer onto the 4.0(I had to make spacer) and was wondering if they were balanced the same? I have also been told that the balancer could "slip" because it is two pieces. Thanks Tim | ||
| Geoff 93 RRC (Geoff) Member Username: Geoff Post Number: 47 Registered: 11-2002 |
I have had the problem, but original engine. Always thought it was the fan hitting a resonating point or the exhaust system doing same. Also, I thought these engines are internally balanced. No harmonic balancer (just pulley with timing marks, but could be wrong. | ||
| Tbow (Tbow) Member Username: Tbow Post Number: 45 Registered: 12-2002 |
If you had to put a spacer then they are not the same. How did you make the spacer ? Did you have a slot for the keyway? Was it machined and balanced? the wrong harmonic balancer can cause the vibration you mentioned. I may have a spare harmonic balancer for a 4.0 if your interested. Let me know, I'll have to look for it. | ||
| Timothy Riccardi (Boxerhips) New Member Username: Boxerhips Post Number: 27 Registered: 07-2002 |
Tbow Yes, I would be interested in your 4.0 balancer. The spacer was made from the old oil pump gear that was replaced when the motor was. It was "ground down" to fit, it was not balanced. It has a keyway in it, and is only about 1/2 inch thick. I didn't think a piece so small would matter when it comes to balancing. I will remove the fan later today to rule the fan out. | ||
| Tbow (Tbow) Member Username: Tbow Post Number: 48 Registered: 12-2002 |
OK.. I'll look for it.. You got mail. | ||
| Timothy Riccardi (Boxerhips) New Member Username: Boxerhips Post Number: 28 Registered: 07-2002 |
Thanks Tbow I'll email you Friday. The picture you sent looked like it was just a pulley. Does anybody know if these engines (4.0) are internally balanced? How about the 3.9? If the 3.9 isn't and the 4.0 is that would explain my problem. Thanks | ||
| Tbow (Tbow) Member Username: Tbow Post Number: 50 Registered: 12-2002 |
It's more than a pulley.. It's weighted, my guess 8-10 lbs and has a balancing weight. It's listed as a Harmonic Damper and there is a difference between the 3.9 and 4.0. 3.9 part # is ERR3442 AND THE 4.0 IS ERR7373. Check it out. The purpose is to dampen the vibrations from the pistons vertical motion with the rotational movements of the crankshaft. There is no internal counterbalance on the rover V8's or most v8 for that matter. You typically see internal counterbalance shafts on inline engines not V-motors. What you want to check is the depth of the shaft / oil sealing portion which is 1 1/2 inches and the pulley type is for a serpentine belt. | ||
| Geoff 93 RRC (Geoff) Member Username: Geoff Post Number: 48 Registered: 11-2002 |
I found this on http://www.aluminumv8.com/connectingrods.htm: "The Buick/Olds/Rover 215/3.5L engines are internally balanced as opposed to the Buick 300 that is externally balanced. Internal balancing means that there is sufficient mass in the crankshaft counterweights to balance out the reciprocating forces of the pistons, wrist pins, etc. Balance is achieved by adding or subtracting weight from the counterweights. To remove weight, material is ground or machined from the counterweight. To add any needed weight. The counterweights are drilled and a plug of Mallory metal is installed in the drilled hole. The crankshaft pulley can be changed without altering the engine balance, assuming it is in correct balance itself." From what I can tell nothing changed for the 4.0/4.6. The crankshaft damper is neutrally balanced (no counter weights). |
