engine noise

jrcurtis00 · January 19th, 2012, 11:39 PM

I have a 97 Mustang Gt 4.6l. I had the engine replaced and ttransmission rebuilt soon after I purchased the car because of high milage, a few leaks here and there, and I wanted to upgrade to PI heads. After installation of the freshly built engine I have a noise that seems to be coming from the engine compartment. Similar to a valve rattling noise. Only when engine is cold. and in high rpm situations . Usually starts around 2800 rpm. But car has to be moving. You can pull up to a stop sign, knock it out of gear and rev it as high as you want and it never knocks or rattles.Anybody seen this before? Any ideas on how to eliminate possible culprits like a lifter noise or timing chain tensioner noise? Also, I may try to do a compression test tomorrow. What should the compression be with PI heads on a non Pi block? Thanks for any help.

Durr4456 · January 19th, 2012, 11:49 PM

I'm no genius so just a guess that there isn't a lubrication because the engine is cold. Shouldn't be revving high up anyway with a cold motor. Someone else will come along with a more knowledgable answer though.

1996 GT · January 20th, 2012, 12:05 PM

^This is true.

Did you have your driveshaft lined up properly onto your diff? Is it backwards?

The compression should be around 10.5:1

yamanx · January 20th, 2012, 12:31 PM

Put some octane booster in your fuel and see if it goes away.

1996 GT · January 20th, 2012, 02:53 PM

I'd advise against octane booster. Cars tuned for 87, therefor should be staying on 87.

jrcurtis00 · January 21st, 2012, 05:05 PM

Driveshaft is on right. And the noise seems to be from the front of the car. I understand noises will travel thru the drivetrain. It would be much easier to diagnose if you duplicate the noise while sitting still with the hood up. Thanks for compression rario.

jrcurtis00 · January 21st, 2012, 05:09 PM

I havn't tried the octane boost yet but I di put the high grade fuel in with no improvement. It seems to be pronounced than a detonation problem. I'm not a engine builder- by far- but I lean toward thinking it's a bad lifter. Thanks for your input.

yamanx · January 22nd, 2012, 08:05 PM

You won't hurt anything running the Octane booster, just worth a shot.

And there are no lifters in the 4.6..so that is not your issue.

jrcurtis00 · January 22nd, 2012, 09:48 PM

I sometimes refer to the lash adjusters as lifters. sorry for the confusion.

Tang Stang · January 23rd, 2012, 12:00 PM

Originally Posted by 1996 GT

Cars tuned for 87, therefor should be staying on 87.

Is the car tuned? The OP didn't mention that it had been.

yamanx · January 23rd, 2012, 06:42 PM

Originally Posted by jrcurtis00

I sometimes refer to the lash adjusters as lifters. sorry for the confusion.

Haha well I guess at least you prefaced it with admitting you're not an engine builder

But Lash Adjusters and Lifters are two completely different things so you should probably only refer to LA when talking about your motor.

But with the PI swap it is very possible that your engine just needs a little octane boost to help with detonation, I have seen it happen before, comes with the higher compression ratio.

January 19th, 2012, 11:39 PM	#1
jrcurtis00 Newbie Join Date: Mar 2010 Posts: 9 iTrader: 0 reviews	engine noise I have a 97 Mustang Gt 4.6l. I had the engine replaced and ttransmission rebuilt soon after I purchased the car because of high milage, a few leaks here and there, and I wanted to upgrade to PI heads. After installation of the freshly built engine I have a noise that seems to be coming from the engine compartment. Similar to a valve rattling noise. Only when engine is cold. and in high rpm situations . Usually starts around 2800 rpm. But car has to be moving. You can pull up to a stop sign, knock it out of gear and rev it as high as you want and it never knocks or rattles.Anybody seen this before? Any ideas on how to eliminate possible culprits like a lifter noise or timing chain tensioner noise? Also, I may try to do a compression test tomorrow. What should the compression be with PI heads on a non Pi block? Thanks for any help.

January 19th, 2012, 11:49 PM	#2
Durr4456 Zip wants me 2005 Mustang GT, 1967 GT Join Date: Mar 2011 Location: New Orleans Posts: 5,250 iTrader: 0 reviews	I'm no genius so just a guess that there isn't a lubrication because the engine is cold. Shouldn't be revving high up anyway with a cold motor. Someone else will come along with a more knowledgable answer though. __________________ The day I finish paying for my mustang will be a great day. Although I'm more likely to die before it happens. Don't be stupid like me! Zip loves my penis.

January 20th, 2012, 12:31 PM	#4
yamanx Regular 1998 Mustang GT Join Date: Jul 2010 Location: Broken Arrow, OK Posts: 105 iTrader: 0 reviews	Put some octane booster in your fuel and see if it goes away. __________________ Mods: Full Griggs suspension, Koni coilovers, Cobra brakes with SS lines, sub frame connectors, 3.73s, 5-speed swap, TR6's

January 22nd, 2012, 08:05 PM	#8
yamanx Regular 1998 Mustang GT Join Date: Jul 2010 Location: Broken Arrow, OK Posts: 105 iTrader: 0 reviews	You won't hurt anything running the Octane booster, just worth a shot. And there are no lifters in the 4.6..so that is not your issue. __________________ Mods: Full Griggs suspension, Koni coilovers, Cobra brakes with SS lines, sub frame connectors, 3.73s, 5-speed swap, TR6's

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January 20th, 2012, 12:05 PM	#3
1996 GT Traction...? 1996 GT/ 2008 GT Vert Join Date: Nov 2010 Location: Canada Posts: 2,207 iTrader: 0 reviews	^This is true. Did you have your driveshaft lined up properly onto your diff? Is it backwards? The compression should be around 10.5:1

January 20th, 2012, 02:53 PM	#5
1996 GT Traction...? 1996 GT/ 2008 GT Vert Join Date: Nov 2010 Location: Canada Posts: 2,207 iTrader: 0 reviews	I'd advise against octane booster. Cars tuned for 87, therefor should be staying on 87.

January 21st, 2012, 05:05 PM	#6
jrcurtis00 Newbie Join Date: Mar 2010 Posts: 9 iTrader: 0 reviews	Driveshaft is on right. And the noise seems to be from the front of the car. I understand noises will travel thru the drivetrain. It would be much easier to diagnose if you duplicate the noise while sitting still with the hood up. Thanks for compression rario.

January 21st, 2012, 05:09 PM	#7
jrcurtis00 Newbie Join Date: Mar 2010 Posts: 9 iTrader: 0 reviews	I havn't tried the octane boost yet but I di put the high grade fuel in with no improvement. It seems to be pronounced than a detonation problem. I'm not a engine builder- by far- but I lean toward thinking it's a bad lifter. Thanks for your input.

January 22nd, 2012, 09:48 PM	#9
jrcurtis00 Newbie Join Date: Mar 2010 Posts: 9 iTrader: 0 reviews	I sometimes refer to the lash adjusters as lifters. sorry for the confusion.

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