knock noise help please

[shiner6n]

i have a 1995 gst with a 18g turbo i just recently had the head rebuilt with everything new put in it a few days ago i started playing arount with it and i capped off all of the vacuum well all the vacuum that was on the throttle body and when i started the car up it runs fine just a slight decrease in vacuum i went from 20psi to 18psi i started to drive well about a mile or so in it sounds as though i threw a rod and i go and park it check it out at idle its still fine but when i accelerate and hit 3k rpm to 5krpm it knocks i'd appreciate anyones and i put the hose back on from the selenoid to the valve on the egr i read that can affect but it still knocks thanks in advance guys

 

[andymoraitis]

First things first. Please use complete sentences and not one huge run-on since that's a pain to read.

I'd recommend that you pull the driver's side wheel and inner splash guard to inspect the crank pulley (harmonic balancer). If this has separated it will beat against the lower timing cover and make sounds that mimic rod knock.

If the crank pulley is intact and straight when you run the motor, it's time to pull the oil pan and check for shavings. Silver and brass shavings will be indicative of spun rod bearings and you should prepare for a teardown and rebuild.

Start with the simple stuff first but the most important thing is to isolate whether the noise is coming from the head or from the bottom end. Remember that collapsed lifters or a loose rocker can also make nasty noises but those would generally start at idle. You can also pull the valve cover and look for a loose baffle underneath that will create a metallic contact noise (once again mostly at idle).

Let us know what you find,

Andy

 

[shiner6n]

thanks alot for the input. Sorry for the run on kind of in a rush. I already have checked the crank pulley actually at first i thought it was the tensioner so i replace that but still was knocking. I also am very positive it is coming from the head. I have taken the cover off and everything looked fine i just find it very odd also it is coming from the last cylinder on the passenger side intake side.

 

[shiner6n]

ok so i just dropped the oil pan no shavings whatsoever replaced the oil with 10 30 full synthetic new oil filter and i just put some lucas in. I also just did a compression test and the results as follow #1 155 #2 160 #3 155 #4 155. Does anyone have any idea as to what this knock might be or should i just take it to the dealer.

 

[sawnuoff]

just was wondering what you had done did the cylinder head, and which motor do you have a 4g63?

 

[shiner6n]

i have the 4g63 motor and when i had the head done i had it jet washed inspected pressure tested pretty much a good check to make sure everything is good. I haven't driven the car in two weeks and today when i drove it the knock got worse and now starts at 2k rpm also when i unplug the second cylinder from the passenger side i guess its the number three it stops knocking what is that a sign of?

 

[andymoraitis]

If you pull a plug and the knock stops, that generally points to a rod knock issue since you're taking the load off of the piston. What I find strange is that you have no shavings in the pan. You might also have a spun balance shaft bearing knocking around if you still have the b-shafts installed. I'd start saving for a rebuild if I were you.

Sorry,

Andy

 

[Froyd79]

Check for an intake manifold leak. Pressurize your system.

 

[shiner6n]

thank you all for you input and help. After i changed the oil i was hoping the knock would stop put some lucas in and everything. i started the motor and the knock got even worse after about 10secs of running. So i decided to do it again i took the pan off and dammit i found shavings not very happy. Since i wasn't sure of myself and since i wanted a pro opinion i took it to mitsu the thought it was my head. Let them take a look at it and the head was fine then the dropped the pan like i did and well they said the rod bearing was spun so i wasn't happy. now I found myself a nice lil jdm motor out of a 92 lancer that i'm about to swap in. and once more thank you all for your help