knocking after 3000rpms?

bigd112 · 02-09-2010, 09:36 PM

i am new to this forum and i just bought a 1989 supra. the car had an engine swap (7mgte) and a tranny swap (r154) about 1.5 years ago. he use to drive it as a weekend car and the rest of the time it sat around. all that is done to it is a 3" down pipe and 3" catless exhaust, 2.0mm head gasket with arp headstuds 90foot bound. one day he stated it up and it knocked after 3500rpms or so. it doesnt sounds loud at all, i dont know what it could be, rod knocking is too deep and is real loud at all rpms and valve tap is constant and doesnt start at higher rpms. it sounds like it is coming from the back left of the motor(if you are sitting in the driver seat).

PLEASE HELP!! thanks!

mirage83 · 02-10-2010, 12:36 AM

You seem to be operating under a misconception in regards to rod knock. It can and often does (especially when it's just starting the problem) only show up in specific rpm bands. It's not at all unusual for a GTE to knock in the rpm range you're talking about. Test drove a n/a once which did the exact same thing... idled beautifully, couldn't even feel it running. It even accelerated fine and was still quiet until a little over 3k rpm. Then I knew why the price on it was so great.

In a way you're lucky it's only in that rpm range, as it's probably not too bad at this point. Just don't drive it any more than you have to until you have it checked out. It's possible that pulling the oil pan and replacing the bearings on the #5 (or #6, can't recall) connecting rod will more-or-less fix it for you if you don't let it get any worse.

bigd112 · 02-10-2010, 01:08 AM

Ok thanks. I wasn't too sure. The guy who I bought it from said that's what he thinks is wrong. Ok I will go ahead And take a look at them. Thanks!

02-09-2010, 09:36 PM	#1
bigd112 Stock Join Date: Feb 2010 Location: lancaster pa Posts: 9	knocking after 3000rpms? i am new to this forum and i just bought a 1989 supra. the car had an engine swap (7mgte) and a tranny swap (r154) about 1.5 years ago. he use to drive it as a weekend car and the rest of the time it sat around. all that is done to it is a 3" down pipe and 3" catless exhaust, 2.0mm head gasket with arp headstuds 90foot bound. one day he stated it up and it knocked after 3500rpms or so. it doesnt sounds loud at all, i dont know what it could be, rod knocking is too deep and is real loud at all rpms and valve tap is constant and doesnt start at higher rpms. it sounds like it is coming from the back left of the motor(if you are sitting in the driver seat). PLEASE HELP!! thanks!

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02-10-2010, 12:36 AM	#2
mirage83 12psi boost Join Date: Feb 2007 Location: Georgia Posts: 359	You seem to be operating under a misconception in regards to rod knock. It can and often does (especially when it's just starting the problem) only show up in specific rpm bands. It's not at all unusual for a GTE to knock in the rpm range you're talking about. Test drove a n/a once which did the exact same thing... idled beautifully, couldn't even feel it running. It even accelerated fine and was still quiet until a little over 3k rpm. Then I knew why the price on it was so great. In a way you're lucky it's only in that rpm range, as it's probably not too bad at this point. Just don't drive it any more than you have to until you have it checked out. It's possible that pulling the oil pan and replacing the bearings on the #5 (or #6, can't recall) connecting rod will more-or-less fix it for you if you don't let it get any worse.

02-10-2010, 01:08 AM	#3
bigd112 Stock Join Date: Feb 2010 Location: lancaster pa Posts: 9	Ok thanks. I wasn't too sure. The guy who I bought it from said that's what he thinks is wrong. Ok I will go ahead And take a look at them. Thanks!