New 347 stroker knocks, please help

KrashedMy5.0 · 07-26-2001, 02:20 AM

I just finished installing and starting my new 347 in a 89 GT. It has a terrible knock, I don't know where it's coming from. The short block was assembled by a reputable machine shop, and I'm sure the block was notched to clear the longer throw of the crank. My first guess was the rockers hitting the valve covers, but it's ok. Now I'm thinking it's coming from the bottom end. Does anyone know if the crank or rods could be hitting the stock oil pan or oil pump pickup tube. I never thought to check this. The engine has good oil pressure, and runs great. I am hoping someone has expierenced this before and could ease my mind by letting me know that it's not something serious.

WADS56 · 07-26-2001, 03:39 AM

It's hard to say with out hearing it. Are you sure your valvetrain is adjusted right? Did you check piston to valve clearance? If you checked all the normal stuff and you still think it is the rotating assembly you can pull all the plugs and rockers then turn it over by hand. If you feel any little thumps or it gets stuck somthing is not right.

When I assembled my 347 the rod bolts would hit the girdle when I did the final check before putting on the oil pan. The girdle was for a 347 and allready had notches ground in it but it still was not enough.

------------------
NA 347 W/ stage 2 Canfield heads, out of the box Victor 5.0 intake, solid roller cam, Aeromotive fuel system.
MY CAR http://www.mustangworks.com/cgi-bin/...splay.cgi?1288

07-26-2001, 02:20 AM	#1
KrashedMy5.0 Registered Member Join Date: Jul 2001 Posts: 2	New 347 stroker knocks, please help I just finished installing and starting my new 347 in a 89 GT. It has a terrible knock, I don't know where it's coming from. The short block was assembled by a reputable machine shop, and I'm sure the block was notched to clear the longer throw of the crank. My first guess was the rockers hitting the valve covers, but it's ok. Now I'm thinking it's coming from the bottom end. Does anyone know if the crank or rods could be hitting the stock oil pan or oil pump pickup tube. I never thought to check this. The engine has good oil pressure, and runs great. I am hoping someone has expierenced this before and could ease my mind by letting me know that it's not something serious.

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07-26-2001, 03:39 AM	#2
WADS56 gear banger Join Date: Aug 2000 Location: CHICAGO Posts: 1,144	It's hard to say with out hearing it. Are you sure your valvetrain is adjusted right? Did you check piston to valve clearance? If you checked all the normal stuff and you still think it is the rotating assembly you can pull all the plugs and rockers then turn it over by hand. If you feel any little thumps or it gets stuck somthing is not right. When I assembled my 347 the rod bolts would hit the girdle when I did the final check before putting on the oil pan. The girdle was for a 347 and allready had notches ground in it but it still was not enough. ------------------ NA 347 W/ stage 2 Canfield heads, out of the box Victor 5.0 intake, solid roller cam, Aeromotive fuel system. MY CAR http://www.mustangworks.com/cgi-bin/...splay.cgi?1288