I fitted a nice rebuilt engine today, all went well, fired up after a few turns and idled no probs, really quiet and smooth....
After a few mins of running top end starts knocking really loudly, like when you've just fitted a new set of lifters and they havent filled with oil yet.

Doesnt really do it on idle (but you can tell the sound is there), more when you accelerate and back off.
The car runs fine other than this, so I cant figure it??!!

Needles to say after 2 miles of it not quietening down it's back on the drive, didnt want to risk anymore running like this.

Engine has done about 600 miles since the full rebuild, only parts that were not changed where crank, rods & pistons everything else is new!

Any ideas?

 

did you rev it to 2k rpm for 20 mins or so to get the oil up to the head/cam/tappets

 

No, the lifters where not noisey when i first started it only after a few mins of running so I assumed the oil was up there ok.
Why would they still be noisey now,should be plenty of oil going through?

 

is it more of a ringing sound and is it a s1 engine in an s2 if so could be knock sensor backing of the timing slightly at the dizzy sould cure it

 

no it's a tapping sound, the knock sensor is disconnected cos the ECU is pre-knock sensor.

 

Sounds like you didn't run the cam in properly to me. 2.5k for 20 minutes is essential CVHs or else. You mustn't allow the revs to drop to idle when the engine is first started.

 

Like i said above the engine had already done 600 miles so the cam was run in before i fitted the engine!

It has been stood for a while so is it possible something has happened to the Oil? I didnt change it having only done 600miles.

 

so engine has done 600 mile,was it shit oil as it should be for the first 1k mile for a fresh build
anyway drop the oil and replace it.should have been first on ur list anyway,cvh engine is a shit engine,even worse if you dont take care of it

 

Changed the Oil twice, ran for 10mins in between, just to make sure everything was flushed out still knocking.

It has a Piper T2 cam and a vernier, and I fitted a new cam belt and set it to TDC as you would normally do the vernier is at 0, perhaps it's vales hitting the pistons because the valve timing is out? Is that possible??

 

What exactly do you mean by this....?
Hopefully not that you drained the oil and ran the car 10 mins. before you filled it with new oil......... (no offence just checking)

In theory yes. But when this happens it is very likely that the engine won't run properly anymore.

 

lol, i ran it for 10mins with the fresh oil in then drained, refilled and ran again for 10mins, then drained and refilled plus a new filter.

Yeah i'm thinking valves will not last long hitting the pistons...

I might try moving the cam belt one tooth in each direction and see if it makes a diference...

 

Be carefull with doing that. Place a spanner on the pully bolt on the crank and turn 2 revolutions over by hand to make sure you're valves are clear.

 

yeah good plan! Or I could adjust the vernier from one extreme to the other thats probabaly about as much movement as one tooth on the belt...

 

Forgot to say when i changed the oil it was grey in colour which i thought looked odd?
Had only done maybe 3 miles and it was clean as a whistle before i ran the enigne.

 

Are you sure it is a top end problem if so i would still say its a cam or follower problem have you visually checked these if not take each tappet out and check the bottom of the tappet for wear or if you find any of them are a little stiff to pull out check in more detail as this normally means there is sighs of wear, if not try and press the (little button) on top of the tappet down these should be quite stiff. but when you say

"Doesnt really do it on idle (but you can tell the sound is there), more when you accelerate and back off.
The car runs fine other than this, so I cant figure it??!!

I would say it is big end bearings the only way of checking this is to take the sump off and remove the bearing caps and have a look, remove each one and make sure they go back exactly how the come out it will be easy to identify. If you live by worcestershire bring it down to my unit as i have a ramp and you can take it off there 'no charge at all'. but dont drive it until you find the problem my bigend bearings totally give up in 40 mile of knoking and sent a piston through my block

 

Yeah after some more investigating today i'm thinking big end bearing, it is suposed to have had new shells though!

Thanks for the offer but i'm in suffolk, and thankfully I have access to a lift here! I'll take the sump off and look!

 

Right it's the big end shells on No. 1, they are fucked!!
Am I right in saying that there should be a hole for the oil in both of the shells not just one of them??

 

Only the upper shell has the hole in. It should align with the small hole in the conrod to lubricate the cylinder wall.

 

After looking closely it appears that there was a hole in both shells, but one has filled with swarf from the shell itself!!!!

Why would a shell wear like this after only 600 miles??

 

wrong size, oil pump died? laid up cvh's love to kill a pump, ive had loads of good lumps sit about then be fucked next time i use em cos the pumps gone wanked

 

The shells are all the same size, 0.25mm.
If it was the oil pump (which is also new) the lifters would be tapping and the oil light would be on.

I'm thinking blocked oil way in the crank....

 

im thinking that two mate....

 

Ok removed the rest of the shells today (only removed No. 1 yesterday cos that had play and the others didnt) and they are all heavily worn/scored woth No 1 being the worst!

Why would i have no oil to the crank, and does this mean i now have bore wear because there was no oil being pumped up the con rod??

 

Did you build the engine up yourself? Im thinking if you used a new oil pump did you prime the engine before you started as the oil pump is dry you need to turn the engine over with the coil unplugged till you get oil around the engine, also did you use any assembled grease i.e. grafegen (sp?) on the big end bearings (this is a must in my opinion) this allows for the oil to get around the engine before wear starts if you never done either of these this could well be the reason all caps are worn.

 

No i didnt build it, I bought it after being built and having done 600miles.
But yeah that could be the reason, the other thing that sprang to mind was that perhaps the engine had been started with no oil in after the build!! One of those thing someone might overlook when hurridly wanting to fire up a new lump and see how it runs?!

 

yeah could well have been when someone started it up with no oil but there is no way of telling unless you fitted new bearings and started again... but its deffinatly an oil problem, ive seen bearings worn like that before on a car that had oil as thick as grease as it wasnt changed in years.

 

Just got back form the engineers (took my shells to show them), they agree either it's been started with no oil in, or going by the deeper score marks in the shells there was dirt in between the shells and the crank!
They recommend a complete strip down, cleaing of all engine parts, flushing of all oil ways to remove any remaining swarf, and have also said that my cam may be damaged because of swarf embeded in the journals, the con rods will need resizeing because of heat distortion and that the crank is probably scrap because it's been reground to 0.25mm oversize already!