mc100

I have a sti version 5 type r with knocky big ends, they have been like this for about a year now and I'm concerned that they will go caput at any time and cause more damage.

I have been quoted between £1500 and £2000 to have them replaced.

Does anybody know how hard these are to change yourself?
Is it an engine out job?

Or Is it a job to leave to the proffesionals?

Any advice is much appreciated. Thanks in advance

jaytc2003

iTrader: (1)

it is an engine out job, and to be honest if you need to ask then its probably best left to the proffesionals. Are you sure it is the big ends? If its lasted a year then it has done very well. £1500 sounds possibly on the steep side, depends on what they are doing for the work.

fwdnutz

hi mc100 as jay says are you sure its bigend because it would not have run for a year if it was and noise would have become unbearable and eventually it would have locked up/seized due to lack of oil pressure!

trust me i know firsthand! sometimes tappets on early cars can be quite noisy and steering pump/alternator can make noises as their bearrings get tired.

if you are not sure drop the oil after warming up of course and then inspect the oil with a magnifing glass if you see little bit of gold swarf settled at bottom of container then these are signs of bigend bearings failed.

if you are still unsure give Apidave a email/call you will find him as a sponser on scoobynet and for my money he is one of the best when it comes to scooby engines!

also if i remeber rightly there is a post on scoobynet somewhere (do a search for bigend knock) that actually is recorded sound of a failed/knocking bigend to compare yours to. l8r c.

mc100

Hi guys, thanks for the replies,

I am saying it's the big ends as that was what I was told at scooby clinic when I had it there last feb for MOT etc.

The noise definately hasn't got any worse really since well about 3 months before then.

If it was the big ends would the knock be there all of the time?

My knock is at certain rev range & when I start it in the mornings for about half a second.

Shark Man

It's not unknown to have a slack big end(S) through wear and tear that'll knock away and continue on for quite some time if nursed and driven sympathetically, plus using thicker oils to compensate for the clearances.

Most people do go unawares with this problem and one day (usually after a service), it fails properly.

Two schools of thought: First in is this state the worn bearing(s), through leakage will cause wear and damage on other bearing through starvation and higher oil temps. Resulting in more work than jsut replacing the bearings shells.

Secondly is that due to the impreza being a relatively noisy engine, a marginally worn bearing is often undetected or misdiagnosed.

Either way, engine removal and entire stripdown for inspection and measurement is the only course of action. It's not hard if your experineced with engine building, although a little different to the norm, owing to the flat 4 design (unless you've done beetle or motobike engines before).

jaytc2003

iTrader: (1)

the knock would be there all of the time, if it is there when the car is started in the mornings but disappears when you get some temperature into the engine, then it could very well be piston slap which did affect certain years of cars

Shark Man

Piston slap lasts for 5-10mins, not half a second. It doesn't occur immediately on start up, but appears after about 10-20seconds of running from cold.

A half second knocking noise on start up suggest draining down of oil and lack of oil pressure/flow. Or a dicky cambelt tensioner.