Valvetrain Troubles

[JonnoHR31]

Ok, so here the story. Last year i built a slapper 25/30det which consisted of a bog stock 150k 30e bottom end and ~120k s1 25 head. All went together well and got it running without any major problems. A couple of months later (only 300-400kms, doesnt get driven much) i gave it some stick in 3rd one day and it pinged 3-4 times around peak torque. Later that day driving home (a good 60kms after the pinging) it started running like shit and just before i got home it got to the point where it needed full throttle just to maintain 30km/h. So i parked it up and there it sat for a few months (had bigger issues to deal with). I later discovered the BOV return hose had popped off the intake pipe and therefore it was sucking in a bit of unmetered air and running slightly lean. This, combined with on the edge timing, caused it to ping. So it sat for a while. I finally got around to looking at it, started it up and it ran perfectly fine, took it for a drive and the instant it hit 0 boost (ie no vacuum) it started running shit again and needed full throttle just to idle, kept it going for a while and it slowly came good again to the point it was idling perfectly until it saw 0 boost, then the same thing again. Next time i started it up a few weeks later it did the same thing then after a while of idling started making bad knocking noises.

So out the motor came and off to a workshop it went, where it sat for another 3 months while they screwed me around. Ended up cracking the shits and picking it up after not hearing from them. They had disassembled it but not done anything else i asked. Anyway it had 3 or 4 marked big ends and the crank had slight marks on it, none were completely spun though. No 2 big end had a groove through the centre of it the whole way around which looked like debris damage but the rest just looked like they'd rubbed the crank. 1 main bearing was slightly marked aswell. I also discovered some pitting in the top of the pistons and on the face of the head, which i assumed was detonation damage.

I then picked up a complete 30e and stripped it down for the bottom end. Put new standard size rings (hastings) and big end bearings (acl race) in it with a mate whos built stocker motors before. Shouldnt have bothered in the end as the rings and bearings that came out were still like new. The whole bottom end was immaculate despite the head being completely full of oil grime. Assembled it all and dropped the motor in, started it up and after running for 30 seconds or so it made the same knocking noise as before. Common sense said it had to be head related as the bottom end had been completely swapped and a big end wouldnt make the car run that shit. So i bought another head complete with valves, lifters and cams etc, swapped the cams and lifters over into the head on the motor and tried again, same result. Pulled the head off and the pistons and head had the same pitting as the last motor, which im pretty sure is debris damage from a cooler pipe with some slag falling off a weld. Cleaned up the pistons, had the head faced again and all the valves and springs checked, all were as good as new apparently. Put the head back on and decided to clean all the lifters before putting them in, so i disassembled them and washed them in some petrol, thoroughly cleaned and dried them then half filled each section with fresh oil before putting them back together and back in the head. They were pumped up a little from the oil in them but i figured they'd bleed down once the cams were bolted in and they had spring pressure on them.

It came time to start it and it wont start, coughed a couple of times once i sorted out the ignition timing and injector opening time (changed injectors at same time as build) but refused to start. Did a compression test today and cylinder 2 has absolutely 0 compression. So basically would this be from a pumped up lifter? Surely even if a ring was completely f**ked it would make a tiny bit of compression? If it is a lifter will extended turning over at decent rpm clear it up? Wanna try a few things and figure out whats actually wrong before i pull the motor out again. Any ideas?

[R31 POWER]

Burn it.

[JonnoHR31]

very tempting....

[Dasmbo]

Ok, so here the story. Last year i built a slapper 25/30det which consisted of a bog stock 150k 30e bottom end and ~120k s1 25 head. All went together well and got it running without any major problems. A couple of months later (only 300-400kms, doesnt get driven much) i gave it some stick in 3rd one day and it pinged 3-4 times around peak torque. Later that day driving home (a good 60kms after the pinging) it started running like shit and just before i got home it got to the point where it needed full throttle just to maintain 30km/h. So i parked it up and there it sat for a few months (had bigger issues to deal with). I later discovered the BOV return hose had popped off the intake pipe and therefore it was sucking in a bit of unmetered air and running slightly lean. This, combined with on the edge timing, caused it to ping. So it sat for a while. I finally got around to looking at it, started it up and it ran perfectly fine, took it for a drive and the instant it hit 0 boost (ie no vacuum) it started running shit again and needed full throttle just to idle, kept it going for a while and it slowly came good again to the point it was idling perfectly until it saw 0 boost, then the same thing again. Next time i started it up a few weeks later it did the same thing then after a while of idling started making bad knocking noises.

So out the motor came and off to a workshop it went, where it sat for another 3 months while they screwed me around. Ended up cracking the shits and picking it up after not hearing from them. They had disassembled it but not done anything else i asked. Anyway it had 3 or 4 marked big ends and the crank had slight marks on it, none were completely spun though. No 2 big end had a groove through the centre of it the whole way around which looked like debris damage but the rest just looked like they'd rubbed the crank. 1 main bearing was slightly marked aswell. I also discovered some pitting in the top of the pistons and on the face of the head, which i assumed was detonation damage.

I then picked up a complete 30e and stripped it down for the bottom end. Put new standard size rings (hastings) and big end bearings (acl race) in it with a mate whos built stocker motors before. Shouldnt have bothered in the end as the rings and bearings that came out were still like new. The whole bottom end was immaculate despite the head being completely full of oil grime. Assembled it all and dropped the motor in, started it up and after running for 30 seconds or so it made the same knocking noise as before. Common sense said it had to be head related as the bottom end had been completely swapped and a big end wouldnt make the car run that shit. So i bought another head complete with valves, lifters and cams etc, swapped the cams and lifters over into the head on the motor and tried again, same result. Pulled the head off and the pistons and head had the same pitting as the last motor, which im pretty sure is debris damage from a cooler pipe with some slag falling off a weld. Cleaned up the pistons, had the head faced again and all the valves and springs checked, all were as good as new apparently. Put the head back on and decided to clean all the lifters before putting them in, so i disassembled them and washed them in some petrol, thoroughly cleaned and dried them then half filled each section with fresh oil before putting them back together and back in the head. They were pumped up a little from the oil in them but i figured they'd bleed down once the cams were bolted in and they had spring pressure on them.

It came time to start it and it wont start, coughed a couple of times once i sorted out the ignition timing and injector opening time (changed injectors at same time as build) but refused to start. Did a compression test today and cylinder 2 has absolutely 0 compression. So basically would this be from a pumped up lifter? Surely even if a ring was completely f**ked it would make a tiny bit of compression? If it is a lifter will extended turning over at decent rpm clear it up? Wanna try a few things and figure out whats actually wrong before i pull the motor out again. Any ideas?

Hi i would take plugs out and rocker covers off and do a visual and turn motor over by hand taking the motor out is a pain in the #ss

[JonnoHR31]

to see what?

[DVS JEZ]

Maybe they didnt check if the valves were seating correctly.

Try and check if cylinder 2 has any freeplay between the cam base lobe and the bucket with feeler gauges.

It should still start even with 1 full dead cylinder.

[JonnoHR31]

valves were all seating perfectly when the head was off.

will pull the cam covers off again and check for any free play but there was none before.

yer the no starting has me f**ked, cam and ignition timing arent perfect at the moment but more than close enough to start

[Rolls]

Incredibly unlikely but I snapped my exhaust cam shaft which had these symptoms. Good compression, turns over fine, no funny noises but won't start! Probably had bad compression at times when the cam didn't happen to be in the right place.

Take you 30 seconds to take the rocker covers off. Wouldn't really make sense for this to happen, but f**k it worth checking.

Edited July 31, 2011 by Rolls

[JonnoHR31]

Try and check if cylinder 2 has any freeplay between the cam base lobe and the bucket with feeler gauges.

Just pulled the cam covers off and checked this. Could fit a .3mm feeler gauge between most of the lobes and the lifter with a small amount of force. However a few here and there and all 4 on cylinder 2 were hard up to the lobe and didnt have any movement in them at all which makes me think they may still be pumped up with too much oil and holding the valve(s) open slightly. So is there anyway to clear this up with lots of oil flow or do they need to be removed and pulled apart? I know the lifters have a 1 way valve on the oil feed to help keep some pressure in them for startup but i thought the exit oil path was clear (apart from the cam lobe obviously) and they'd slowly bleed down with the valve spring pressure on them?

Checked the cams too, they're all good and getting plenty of oil.

[JonnoHR31]

Anyone? If i keep the motor turning over with some decent revs can i expect the lifters to sort themselves out with some movement?