brand new motor knocking... got any ideas?

[wesleya1018]

So, heres the deal I just got done building my motor its a ls/vtec ( b18b1 block b16 head) I put a new crank, eagle rods,wiseco pistons, the head is stock however i do have itr cams in it...i have all new bearings from honda they all match the block...the problem im having it it sounds like something in the bottom end is knocking. It only does it when i accelerate.when its sitting still it sounds perfect... I adjusted the valves and i still need to do some more adjusting. So does anybody know what the hell the problem could be? tnks

[wesleya1018]

oh i forgot to add its boosted haha and its a closed deck

[Tech5]

sounds to me you didnt match the bearings with the new crank, you cant use OEM bearings with a new Aftermarket crank or a Reman crank, So you didnt Plasti-Gauge it?

[wesleya1018]

oem crank just been reworked at the machine shop good as new

[Barefoot]

just been reworkeddefine

[wesleya1018]

scholars believe the translation was lost thousands of years ago...

[Tech5]

Well if the crank was refinished you needed bearings for that not OEM!

[mitch lab]

correct, if the crank has been reworked, the machine shop usually gauge it for you. But if they don't then it's always a good idea to plastic gauge it.

[EmminoDaGreat]

So no plastigauge or nothing? Probably, main knock or both.

[wesleya1018]

alright im going to take it apart tomorrow and go from there

[SPOOLIN]

if it was just polished which is what im thinking than the crank is fine. You can use oem bearings with an aftermarket crank. thats what sizing is for.

usually a knock under engine accel is a rod bearing. make sure you torqued the rods properly. how long have you let the engine run for? what is your piston wall clearance? if it has never heated up then maybe you should let the engine get to OT and see if it still persist, if you have a slightly larger than normal clearance on your walls then it can cause a slight "knock" until its heated up.

[Z0_o6]

i was thinking piston slap myself, esp. if it has forged slugs. however if you didn't plastigauge then yeah...not good.

[wesleya1018]

im thinkin its a main bearing im going to look over the motor tomorrow so i should know whats going on with it ill keep you guys posted

[Tech5]

:goodjob: :goodjob: :goodjob: :goodjob:
im thinkin its a main bearing im going to look over the motor tomorrow so i should know whats going on with it ill keep you guys posted

[wesleya1018]

main bearings look good...: /

[RhdDc2]

Was the engine properly primed before starting? Doesn't take long for the soft babbet metal to wear on the bearings. Could be the cause. Do you have an oil pressure gauge?

[jfman]

My cousin had an itr block that knocked 10 minutes after rebuilt. The machine shop had turned the crank and the clearances were wrong the crank was fubar he had to buy a new one.


Take it appart and look at the bearings, if they look worn out the your crank is most lilkely damaged as well.

[wesleya1018]

yeah i have an oil pressure gauge but i got to listening to it and it sounds like its in the head...so im takin it back to the machine shop tomorrow and going to let them run a pressure test and have it milled again but it pisses me off bc i have to buy a new head gasket from cometic again and those arnt cheap lol

[SPOOLIN]

Was the engine properly primed before starting? Doesn't take long for the soft babbet metal to wear on the bearings. Could be the cause. Do you have an oil pressure gauge?

no need to prime, dry starts are perfectly fine.

Only knocking noise generally from the head is the lost motion assemblies. How old is the head?

as far as head gasket, USE OEM, YOU CANT BEAT IT.

[Init2winit]

What kind of bearing clearance do you have? Are you positive that the pistons are the correct diameter for your bore?

[RhdDc2]

no need to prime, dry starts are perfectly fine.


Not in my opinion.

[wesleya1018]

ok i took the head to the machine shop the exhaust guides were pretty loose maybe that was my problem