Having knocking issues and can't figure it out,need help!

[Trevontls 0]

I recently pulled my motor on my 2002 vw golf vr6 because there was a knocking noise and I thought it was a bent rod or something, I pulled it completely out and pure stupidity on my end I didn't unbolt the oil pan and check if it was a spun bearing so when I pulled everything out I pulled the oil pan (I know pure stupidity) but it happens, checked the beating and on the first cylinder the bearing was shredded I had purchased eagle rods with 5/16th arp bolts thinking I had to replace the rods but I changed the bearings put it all back together torqued everything down and out the motor back in, started it and there is a slight knock what sounds like from the timing area and I don't know what it could be I changed the oil to a thicker oil and it made the noise subside a bit 

when it's idling it doesn't do it but when you give it a bit of gas and hold it around 2500-3000 Rpms you can hear it, I have no idea what it could be and any advise or knowledge would be greatly appreciated. 

This is the first motor I've ever pulled and done work to and the person I bought it from rigged a whole bunch of things so I really don't know I'm getting to the point where I'm just goin. To take it in and half a full rebuild and the eagle rods I bought put in if it's something serious. 

Mod list: 

borg Warner s256 

full 3 inch exhaust 

tial wastegate 

450cc injectors 

big fuel pump 

Je pistons

bigger cams

short ram intake manifold 

bigger fuel rail and braided fuel lines with pressure gauge 

some sort of i beam rods 

Arp rod cap bolt 

arp crank bolts 

ngp head bolts 

bored 80 over 

stage 2 clutch 

titanium valve springs 

timing has been replaced 

short throw shifter 

forgetting some things I'm sure 

 

if anyone could help me that would be great 

thank you 

[Toddy 8]

Have you checked your Timing?

[Trevontls 0]

Not yet I read somewhere it could be the timing chain guide? 

[Toddy 8]

Chain guides don't knock. Just rattle really.

Perhaps post up a video and it'll be easier to help

[VR6Pete 1,455]

Did you do big ends?

[Trevontls 0]

Big ends?

[Craig Butler 1]

Hi to you all. I have seen this befor on a mates vr. It had knackerd one of the conrod bearings he put a whole new set in, and it just happend again. First of all if you replace bearings they have to be matched and have the crankshaft reground, this obviously means a full engine overhaul. In the end he just got another short block instead. Hope this helps someway even though this sounds like bad news.

[VR6Pete 1,455]

Sorry, the main bearings on the crank is what I refer to as the big ends.

 

What Craig Butler says is very valid and taking a second look at that knackered bearing I would say there is some wear on the crank - sometimes you can get away with it but I suspect this time you may have more damage.

[c00k 435]

Use the old block of wood or screw driver trick to help pin point the sound more, 

Put a thin bit of wood or long screw driver on the touching underneath of sump put you ear touching the wood or screw driver, and listen for the knock. 

Now repeat on cylinder head, time chain covers, the louder the knock the near you are to the problem, 

by testing in different places you should be able to determine the rough area of the problem.

 

If the con rod bearings have spun badly and misshaped or scored the crank, just replacing the bearings will not fix it. 

As mentined above the crank would need to be re-ground and oversized matched bearings fitted. 

Or get a new replacement crank 

I replaced the engine in my mulberry highline because of crank shaft damage, 

it was easier for me to build up new engine and drop that in than do a full bottom end rebuild and crank re-grind. 

 

Worth going for the ARP bolts if you going for higher figures with forced induction. 

Also uprated con-rod bearings, and main bearings (big end bearings) 

while in there and sump (oil pan) is off, check and clean oil pick up, 

 

Edited October 20, 2016 by c00k