Hi All,
Engine vibration at about 1250-1350 RPM. Seems smooth below that RPM and not as noticeable above. The vibration is just enough to feel and almost see in the steering and shake the mirrors on the car. Vibration occurs with manual transmission in or out of gear and clutch pedal up or down and happens when egine is "free wheeling" while sitting still and when driving in gear, same RPM. Here are the engine particulars:
>Brand new (less than 1000 miles since initial fire up) 98-99 Explorer 5.0 purchased from and assembled by a now out of business Ford Motorsports dealer in 2000. I did not pay to have it balanced.
>GT40P heads
>Hyperetic pistons
>B303 cam
>Correct balance 3-bolt pulley conversion damper and flywheel
>Ford (Cobra I think) diaphragm clutch.
I'm not sure if the vibration has been there since fire up, as it was so loud and rumbly with the first 75 or so miles with open headers and then 500-600 miles with cherry bombs on short pipes dumping out the sides in front of the rear wheels. It now has a new Magnaflow exhaust and I guess there is a slight chance of the exhaust causing a resonance issue, but I lean away from that because it is so RPM specific. I will probably try unbolting the exhaust from the headers before pulling the engine, just to see. I've already checked all the easy stuff like removing the fan belt and even removed the front pulley from the damper-no luck. The clutch and flywheel have been R&R-ed twice, to first deal with an oil leak caused by a dumb a$$ (me) not putting thread sealer on the flywheel bolts and then to replace an improperly installed (by assembler) rear main seal. This leads to a couple of issues/questions:
1-Is there a way to "index" the clutch cover/pressure plate? I notice a yellow paint mark on the pressure plate and a dot on the flywheel stamped in between 2 of the flywheel bolt holes.
2-What's the deal with the only M8-metric clutch cover bolts that I can find not having a shoulder to securely/precisely locate/center the pressure plate. They seem to allow a bit of slop/movement before tightened. It seems that a pressure plate even a couple thousandths off center could cause an imbalance issue?
3-If my only real solution is to pull and disassemble my new engine to have it balanced and reassemble it correctly, will I need to re-ring it and put in new main and rod bearings, or can I safely re-use all the stuf seeing as it's all nearly new? I'm assuming at least all new rod, main and head bolts, as they have already been torqued/stretched?
I really don't want/can't really afford yanking it and the whole process, as the engine runs so strong and well otherwise, but I certainly don't want it to shake itself to pieces! Are there any other simple things to check that I'm not thinking of, or should I just resign myself to the whole R&R/balance process?
Sorry for the long post.
TIA For Any & All Thoughts/Comments/Advice,
Gene
Engine vibration at about 1250-1350 RPM. Seems smooth below that RPM and not as noticeable above. The vibration is just enough to feel and almost see in the steering and shake the mirrors on the car. Vibration occurs with manual transmission in or out of gear and clutch pedal up or down and happens when egine is "free wheeling" while sitting still and when driving in gear, same RPM. Here are the engine particulars:
>Brand new (less than 1000 miles since initial fire up) 98-99 Explorer 5.0 purchased from and assembled by a now out of business Ford Motorsports dealer in 2000. I did not pay to have it balanced.
>GT40P heads
>Hyperetic pistons
>B303 cam
>Correct balance 3-bolt pulley conversion damper and flywheel
>Ford (Cobra I think) diaphragm clutch.
I'm not sure if the vibration has been there since fire up, as it was so loud and rumbly with the first 75 or so miles with open headers and then 500-600 miles with cherry bombs on short pipes dumping out the sides in front of the rear wheels. It now has a new Magnaflow exhaust and I guess there is a slight chance of the exhaust causing a resonance issue, but I lean away from that because it is so RPM specific. I will probably try unbolting the exhaust from the headers before pulling the engine, just to see. I've already checked all the easy stuff like removing the fan belt and even removed the front pulley from the damper-no luck. The clutch and flywheel have been R&R-ed twice, to first deal with an oil leak caused by a dumb a$$ (me) not putting thread sealer on the flywheel bolts and then to replace an improperly installed (by assembler) rear main seal. This leads to a couple of issues/questions:
1-Is there a way to "index" the clutch cover/pressure plate? I notice a yellow paint mark on the pressure plate and a dot on the flywheel stamped in between 2 of the flywheel bolt holes.
2-What's the deal with the only M8-metric clutch cover bolts that I can find not having a shoulder to securely/precisely locate/center the pressure plate. They seem to allow a bit of slop/movement before tightened. It seems that a pressure plate even a couple thousandths off center could cause an imbalance issue?
3-If my only real solution is to pull and disassemble my new engine to have it balanced and reassemble it correctly, will I need to re-ring it and put in new main and rod bearings, or can I safely re-use all the stuf seeing as it's all nearly new? I'm assuming at least all new rod, main and head bolts, as they have already been torqued/stretched?
I really don't want/can't really afford yanking it and the whole process, as the engine runs so strong and well otherwise, but I certainly don't want it to shake itself to pieces! Are there any other simple things to check that I'm not thinking of, or should I just resign myself to the whole R&R/balance process?
Sorry for the long post.
TIA For Any & All Thoughts/Comments/Advice,
Gene
I'm afraid the solution isn't gonna be cheap Or easy.
