Was out in the car earlier today and noticed as you reach 3000rpm could hear a knocking sound but not loss in power, it has not got any worse but is quite audible once over 3000rpm and it seems to coming from the middle of the engine. Any ideas?

banny

 

big ends, drive it as little as possible until confirmed, don't take it above 2000rpm if possible. Preventing further damage could save you serious money.

 

Cheers Paul, worse case secenario how much damage could there be?

 

at the moment, just the shell and possibly the crank and relavent rod.

Carry on driving.........whole engine and turbo etc.....

dump your oil out to confirm, you will see little twinkly bits if a shell has gone. you may also notice low oil pressure if you have a gauge

 

Would it be best to replace the entire block or just the damaged components?

 

the shell bearings are usually a gold colour. Drop the oil and see whats in it. You dont wanna know the worst case scenario trust me! The worst case is a damaged bore due to a floppy piston and a con rod that has a floppy big end (the bearing on the crank). Its then a case of if its cheaper to remove the block from the car and re-line the bore or just to replace the block. When you or the garage remove the sump and con rods you should take a look at the bore. If its a completly different colour or has huge scores or score in it then you better get out your savings account. You should check the pistons too. Its usually the little end that makes them tilt over but if one has it will show how its rubbed in the bore!

 

The dreaded question, what should i expect cost wise?

 

2K-5K depending on who you take it to and the extent of the damage.

 

I have been quoted £1200 for a replacement block from a P1 and labour, it is from a local specialist does this sound reasonable?

 

Sounds a tad cheap, Id go with Api, David ensures his rebuilds are done right and has a cast iron guarantee.

 

Cant you get a new 2.5 shortblock from the graham goode ebay shop for around about £1200? maybe an option, and just transplant all your stuff over to it.

 

Exactly the same thing has happened to my 95 import. I ran mine for months with the same knock and eventually it fooked. Its currently at api getting the engine rebuild + a few little extras I've been reasured there top notch craftsmen + david was really helpful. getting mine back in a couple of weeks can't wait

 

Same thing happened on my 03 MY Blobeye.Sounds like one end failing.........probably the dreaded number 3 end!
I'm having the rebuild done at api also which i get back at the end of April.

 

Is that price for a short engine or just a block with nothing in it. Dont forget that if a big end is fooked you could have damage to the crank and con rod. A real estimate cant really be given till you strip the car. The block and the bore could be fine as could everything else it might just be a case of replacing the shell bearings on the big end!

 

That is the price for a short engine and labour.

 

OK a short engine is good. Im not sure you will need it though. Saying that i would have to see it with the sump off. Best of luck!

 

Thanks mate, what would be the main cause of big end failure?

 

Oil starvation, det, over revving,failed oil pump,high mileage wear??

 

Can be many
1 general wear and tear! SH*t happens...nothing lasts for ever
2 oil starvation the oil to the big end bearings goes through very small holes in the crank if they carbon up the furthest cylinder from the oil pump gets "oil starved" on the scoob flat 4. Also see weak oil pump! or blocked oil pump strainer!!!!!!!!!!!!! (basicly the oil pump has a kind of sieve on the end if the oil got real dirty then it blocks this "filter" and reduces oil pressure!)
3 bad luck again "s**t happens. Maybe the big end shells were of poor quality or slightly damaged when they were fitted
4 oil contamination. maybe you got something in your oil that went onto the big end shells and stayed there wearing them out.
5 the little end. If its not up to scratch and wobbles a bit the big end takes the brunt of it because of the lever effect. Ie the little end the place where the con rod connects to the piston is a bit loose or out of line. Each stroke of that piston is on a slight wobble. That wobble of the con rod transfers down the 6 inch or so of the con rod. what was a 5 micron wobble at the little end becomes a 35 micron wobble at the big end (rough maths dont quote me please) this then stresses the big end bearing and it wears out faster.
6 a main bearing fault. The main bearings control the crank. if the far main bearing wears out or is out of line then the crank will start to stress the other main bearings. Eventually the crank will "float" from side to side and the far cylinders will experience stress.
7 badly ballanced flywheel. The flywheel is a large centerfugal weight on the back end of the engine. if it is so out of ballance it will transfer its "wobble" into the crank shaft since its bolted to the end of it.

Hope this helps some.
Wow i feel like im back doing my apprenticeship again. Im not a mechanic just a hobby one but im a maintenance engineer.
I just answered the question "from what you learned so far what could cause X failure"...LOL

 

Banny,

£1200.00 for a good STi short engine, installed is very good, assuming there aren't going to be any "surprises". Does that include all the gaskets, seals, O rings ?


To rebuild your engine, on top of what you'd need if you get a replacement short engine, at the very least, you'll most likely need,

New crank, at least one rod, new mains, and big end bearings, oil pump, possible bore hone, and maybe new piston rings, depending on mileage.

Circa £650-£850.00 + vat for these parts/hone.

On top of that, you still have the gaskets, seals, cam belt (?) oil filter, etc', and labour.


This all assumes it does turn out to be a big end issue.


Mark.

 

I would take it to a specialist, or at least get your other people primed with all the info they need to prevent further damage. If the knocking is as obvious as it sounds, then metal fragments will have worked their way into the oil cooler and may dislodge and get into your new engine. Things like this are often overlooked, and you will often hear stories of how someone has had 2-3 engines in 6 months. Even with a replacement short engine, you should look to do the following.

Replace modine oil cooler.
Strip, check and refresh heads
Check oil pump for loose screws, strip and check plunger and rotor for wear, replace pump if required.
Get mapping checked, as it may be a contributing factor to initial failure

Paul

 

The engine was rebuilt when the car was imported from japan in 2004, two pistons and the crank where replaced, at the sva test the tester over revved the engine and broke the cam pulleys bending all the valves. Some new sti heads were sourced and used. The car has been remapped using an apexi power fc by JGM for optimax and has covered a total of 17000 miles since the heads were changed.

 

When the pistons hit the valves it may have put some stress on the bearings and its been down hill ever since then...

Unless you drive with "spirt" offten? ??

Also a lot of people never check their oil levels..

 

That and you drove it around on the standard Apexi map at high boost for a while before it was mapped, it was running very rich and way too much ignition.. but then it was mapped a long while ago now.. sounds like one of those unfortunate failures or just wear and tear..

 

ej25 would be nice, but you'd need a remap of some sort to even run it, let alone take advantage of it. Something to build on though...

 

eh?

 

This happened to me a few weeks ago - due to a past owner having re-ground the crank which went pop a few thousand miles after i aquired it.

best off with a short block mate - if you are gonna be spending 3k you might as well get a 2.5 block.

i had a decent nick 2.0 sti short block fitted for substationally less than thius from someone who really knows his stuff.

he is based in Diggle which is not far from west yorkshire.

if you are interested then PM me and i can forward you his details


edited to add!!! as paul said drive it as little and gently as possible - for what its worth get a low loader to tow it to a garage, trust me mate its worth spending 50-100 quid rather than risking further damage

 

The car has been parked up since the day i noticed the noise and has not been driven at all, do not want to take any chances.
I would like to stick with the 2 litre engine, the 2.5 does not appeal as much as a high revving 2 litre.
Is there any benefit in using the short engine or components from a new age STI?

 

Yes the STI has forged pistons and crank (so i've been told) and is generally a little stronger

 

yhpm chief