[glhs#116]

So, today was a bit of a roller coaster.

Started the car and warmed it up in the garage. Let it run a good fifteen minutes or more. Totally warmed up. Tried to reproduce my hammering noise by driving it against the torque converter. Couldn't make it happen. Never mind. Good time to do a compression test.

Did compression test. Values are not too far away from the last one I did about a year ago. Put all the plugs and wires back in. Fire it up again. Now I can hear some real clatter from passenger side valve cover. Hmm, maybe something valve related. Ran it with the valve cover off. Number 6 intake is really loud. I can feel it feels not smooth like the others. I don't know, a little, like, mildly crunchy. Check the poly lock nut depth. It's in line with the others. Recheck the lash. It's about right but it is one of those lifters that compress really easily (unlike, for instance, the one next to it). I tried just dialing it down to almost no lash (just slightly up from the bottom instead of "plus 1/2 turn"). Seems quieter. Take off other valve cover. All the others feel smooth. Swapped number 6 intake and exhaust rockers to see if it is the rocker. Nope. the lack of smoothness stays with number 6 intake. Swap back. Relash again. Now, all is quiet again. All seem good. Hmm.. Maybe I just flushed something or whatever.

Anyway, now valvetrain is quiet. Won't knock against the torque converter. OK. I'm going to try a short drive. Pull out of my gate onto the road and bam! Instantly the moment I'm actually accelerating from low speed I'm hearing the knock. Now I have to go a ways before I can safely turn around so I play with it a little. No hammering at constant load even at higher revs. Less of a hammering if I apply the acceleration at higher revs. Anyway, I get turned around and drive back. Seems it is the same but the engine just needs to be totally totally warmed up through. I guess that means the clearance in <whatever> is only just slightly excessive. Anyway, park it in the garage and I'm dejected of course because I know I can't drive it like that. But then I realise the only chance I have to try pulling spark plug leads is now. So, given as it always sounded passenger side to me and like it was rearward, I try pulling number 8 lead. No knocking against torque converter. Pull number 6 and reinstall number 8 and I can make it hammer against torque converter. So it does seem to be number 8.

So from all of that I take it that I have some genuine trouble under load to do with number 8. Rod bearing? Hard for me to credit. I didn't see any obvious difference in its bearing from the others. And it was replaced with the others. And it was making this noise before and after the rod bearing replacements. Same with stretched rod bolts. They are ARP bolts and I tightened them to spec with the ARP lube. Yes, I know a stretch gauge would be better. But also none of them were slow to gain torque or felt off. But, I dunno. Maybe I collapsed a skirt. Maybe the big end is deformed from detonation or something and I just didn't notice. Whatever it is the obvious to me thing is that this car isn't going anywhere, least of all to Street Weekend in two weeks without a replacement piston/rod assembly with rings that I can just swap out.

I mean, pretty clear that I'm about at needing to rebuild the short block. but that's not something I can fund this year and it's not something that will get me running in two weeks.

Well, thanks for all the help, all. I'm thinking it can't be any of those other things if I can pull a spark plug lead and it goes away. So it seems exactly like rod bearings on number 8. Except that those bearings are new. Or stretched bolts. Except that they seemed fine. Or deformed rod. But how? That crank journal looked fine. Oh well. I guess I don't have all the answers. But number 8 does seem to be the problem.

Sam