OK..I will try and make this short. I bought this GEN V, supposedly rebuilt 6K miles ago. I built an engine stand to test run it, things seemed ok. Ran good, 40-50 psi oil pressure, but it made a noise like some body put a screwdriver against the flexplate when I throttled it up to 4500 or so. Now, I put the thing in the car and fired it up today with my son, man it sounded good through the Dynomax muff's and 2.5" pipes.

Now I let it warm up some and hit the throttle a few time and WAM...sounded like all hell broke loose. Sound was like metal on metal, but not squeeling. I shut it down waited a few and bravely started it back up. No bad sounds while idleing except a light tappet ticking, but, when I throttled it, all hell broke loose again.

I know it is hard to trouble shoot a sound over the net, but, does any one have an idea, or do I just tear it out and tear it apart. :(

TIA

Mike

My 350 did that a year and a half ago when I spun the rod bearings...it knocked all the time though. :confused:

Are your sure the flexplate is tight?

If its still on the stand, why don't you at least take the pan & intake off to see what the heck is going on... I haven't heard it, but by the way you discribe it :eek: , it sounds like its something kinda bad.

FLexplate cracked? Transmisson loose? If you're worried its from inside the engine, pull the oil filter and tear it apart. See if its coming unglued. It's really hard without hearing the noise.

My 406 SB's stick bellhousing front mud-guard, hole cover that fit between the starter snout and the bellhousing rubbed the flywheel or the crank (??) ever so slightly when I first fired her off!! Made a h-ll of a racket!!..

I just crawled under her and cut the sucker off.

Left the hole open after that...

pdq67

Hello all; Longtime eavesdropper,first reply.I had the same noise last year.It was flexplate teeth hitting the drive on the mini-starter.If you're using any aftermarket high torque mini-starter,it should have about .060" (or 1/16") or more clearance at rest between the drive gear and flexplate teeth.The flexplate will balloon slightly when the engine is revved,and makes a horrible racket.If that's not it,check for a cracked flexplate by pulling back and forth,and you should here it clicking.Hope this helps,as I'd hate to see you tear down a perfectly good engine.

Well you guys are confirming my worst fears...but check this out. I pulled the distributor last night and found that the "spring" washer just above the drive gear was shot. Now this distributor only has about 50 miles on it. And I also have an extremely suspicious looking wear pattern on the drive teeth. It looks like the thing was moving around and chattering. If you have ever used a die grinder to ream out a hole and had it chatter, that is the sound I have.


I am heading out of town for a couple of weeks to earn some overtime to fix this thing, so keep the ideaws coming and I will update you guys on my return.

Thanks

Mike