richardm6994 Posted September 18, 2015 Share Posted September 18, 2015 Hi, I would be most grateful if you could watch my video and offer suggestions as to where the rattle / knocking noise is coming from. A bit of background - it's a 3.9 V8 that was complete rebuilt less than 5000 miles ago. The knocking / rattle is there straight from a cold start (doesn't need engine to warm up). I've done a Oil change (using 20/50) The noise sounds as if it's coming from the passenger-side cylinder head. I've since taken the rocker cover off and nothing obviously wrong. I've also taken the inlet manifold and valley gasket off and all of the lifting seem alright (pumped up hard) I'm at the point where I'm thinking of taking the heads off to investigate further (big-end bearings)......but before I do I was wondering if anyone else had any ideas? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 18, 2015 Share Posted September 18, 2015 That sounds more than I would be happy with too, and doesn't sound like an exhaust manifold leak, which as I am sure you know is pretty common. What lifters did you use? Genuine or Rhoads are the only ones any good IMHO. Otherwise it does sound like head/sump off time .... or if you have it, a borescope to see what's going on in the cylinder? I twice had a very small screw fall out of a carburettor causing similar noises, embedded itself in the piston, I'd assumed something serious had let go. Quote Link to comment Share on other sites More sharing options...
richardm6994 Posted September 18, 2015 Author Share Posted September 18, 2015 Yes not a very nice noise at all......especially when the engine is normally as smooth as silk! The valve train is duplex timing chain, Piper 285 cam and rhoads anti-pump lifters. You're right in so much as its not an exhaust leak.......I'm also assuming it's not a slipped liner as it makes the noise straight from cold. Quote Link to comment Share on other sites More sharing options...
richardm6994 Posted September 18, 2015 Author Share Posted September 18, 2015 ps.......how would I know by looking / inspecting the lifters if one was dodgy? Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 18, 2015 Share Posted September 18, 2015 Rhoads lifters are renowned for being "ticky" but not THAT ticky.. As suggested, maybe head off time. I don't think the noise sounds "heavy" enough to be bottom end but I've been wrong before.... Quote Link to comment Share on other sites More sharing options...
richardm6994 Posted September 18, 2015 Author Share Posted September 18, 2015 To me, it doesn't sound like big ends are knocking.........but this is the first RV8 engine I've played with so I could be wrong. Are the little ends known for going on these engines? What puzzles me it that it sounds like the noise is from up top.....but everything looks alright. Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 18, 2015 Share Posted September 18, 2015 Little ends aren't known for going normally. How old is the rocker gear? Have you checked for rocker arm-to-shaft clearance? Haven't heard any rockers that bad but you never know.. Quote Link to comment Share on other sites More sharing options...
richardm6994 Posted September 18, 2015 Author Share Posted September 18, 2015 The rocker arms and shafts are the original's.......I didn't notice anything out of the ordinary with them but will given them a closer look. What should I look out for on the lifters should one of them be failing? Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 18, 2015 Share Posted September 18, 2015 The thing about the rocker gear is, unless you have the assemblies stripped down it can be difficult to determine the condition due to the tension of the springs. I know I had to renew all of mine as there was a lot of play between rockers and shafts. What it would have sounded like I've no idea as I never ran the engine like that. Also I've never heard of rhoads lifters failing to the point it makes same noise as yours. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 18, 2015 Share Posted September 18, 2015 As above, don't think it big end, if nothing shows up in valve train, would probably start with head off and pray there is something obvious, not too big a job after all. I'd be surprised of Rhoads have failed, yes they ticky, but that is in their design If one had failed the rocker to pushrod clearance would open up, quite a lot, or when pushed on the pushrod it would open up a gap far too easily. Quote Link to comment Share on other sites More sharing options...
richardm6994 Posted September 18, 2015 Author Share Posted September 18, 2015 Thanks for the advice.........this forum has always been a great help when it comes to my V8. I'll strip the valve train down completely and see what I find........I understand what you're saying about things not being obvious when it's all assembled because of the tension it's under. There is a small sigh of relief that you agree it doesn't sound like big-ends.......but still the obvious question mark hanging. My hope is that I can resolve this issue without taking the engine out of the car.........being a small kit-car, this engine had to be shoe-horned into place and it's a horrible job getting it in and out. Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 18, 2015 Share Posted September 18, 2015 No worries. Take the rocker assembly off the side you think is making the noise. Strip it down and make sure that there are no wear ridges on the rocker shafts where the rocker arms are. If that side is knackered, the other side is too. It's a quick job removing the rocker assembly. If all looks ok when you have stripped it, then it's head off time methinks Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 18, 2015 Share Posted September 18, 2015 Even a fair amount of wear on rocker gear won't make that kind of noise, if it is the rocker shaft, then I'd be looking for something broken... Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 18, 2015 Share Posted September 18, 2015 Broken valve spring? Has the noise suddenly developed? Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted September 18, 2015 Share Posted September 18, 2015 Sounds like a lifter to me .............. probably one of them is not rotating and filling ........... looking at the top of each lifter might give you a clue. Have a good listen with a stethoscope to pin point the approximate location before you start tearing down. The rocker shafts wear very badly on the underside (the thrust side) ........... the rockers themselves also wear. However, the wear is taken up by the lifters so you rarely get noise from the top end valve gear .......... you just get less valve lift. If you fit new shafts, then also fit new rockers ............. a little heat is needed to get the posts off. Do both sides ! .................. then re- check the preload on the lifters as you have a non standard cam. Quote Link to comment Share on other sites More sharing options...
richardm6994 Posted September 18, 2015 Author Share Posted September 18, 2015 apologies if this is a bit of a long-winded explanation, but here is the background of when the noise started; Last winter, I took the car for a track-day......it was the first track-day for the V8 and the morning was very wet so as you can imagine in a 600kg V8 kitcar, the back end was very lively and as such I wasn't really able to open-up the throttle........until the afternoon when the track started drying out. On the dry track, I was still careful with the engine, making gear changes around 5k rpm. Then, all of a sudden, smoke started pouring out of the bonnet......luckily I was right next to the pit entrance and so headed immediately in. What had happened was the dip-stick had been blown up out of it's tube and oil followed up the tube covering the engine bay and exhaust headers.....luckily no fire!! When looking over the engine in the pits.....we noticed that the main breather pipe from the rocket cover had kinked (my fault) and as such, we assumed the blocked breather was the cause of the block pressurizing and popping the dip-stick out of its tube. The other problem was....the engine had also developed a loud rattle on RPM dropping and so I decided as there was only an hour of track time left to call it a day. Fast forward a few days, I started the car up to listen to the loud rattle again but it had completely gone......warmed engine up, still nothing. Went for a 20 mile drive, engine sounded it's normal self......so I just assumed the loud rattle I heard at the trackday was a result of very hot oil causing noisy lifters - especially as it was only on RPM dropping (i.e. lower oil pressure). Fast forward a few months and having not used the car since the 20-mile test-drive, I drive the car to the MOT station. On the way there it is fine.......reversing out of the garage and the rattle (as per the video) starts up. It has now rattles constantly from cold to hot.......but is particularly loud on RPM come-down The track-day thing could be a red-herring or the start of the problem.......but I can't understand why the problem went away after the track-day and then reappeared after my MOT......... PS...the MOT was done by a mate with me there so I know it wasn't caused by the garage. Quote Link to comment Share on other sites More sharing options...
richardm6994 Posted September 19, 2015 Author Share Posted September 19, 2015 Hi everyone, I've stripped down the valve train and still not found anything wrong. The only thing Ive seen which is questionable is the amount of end float on the camshaft......I don't remember it being this bad before but my memory isn't great..... I would greatly appreciate an experienced pair of eye to watch this video and let me know if this is normal or not? Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 19, 2015 Share Posted September 19, 2015 Dont think that's your problem. Some of the older engines didn't even have a cam retainer plate at all.. You've still not found it I'm afraid Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 19, 2015 Share Posted September 19, 2015 Normal. Head off.. Quote Link to comment Share on other sites More sharing options...
richardm6994 Posted September 19, 2015 Author Share Posted September 19, 2015 Oh well..... The strip-down continues.... I did also find 10thou deep scuff marks on the oil-pump cover where the time chain had rubbed.....I'm guessing with the end float and double timing chain it's just caught the oil pump cover......however.I don't think that's my problem either. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 19, 2015 Share Posted September 19, 2015 Hmm, could actually be clacking timing chain.... how loose and close is it? Is the dizzy stub worn? Quote Link to comment Share on other sites More sharing options...
richardm6994 Posted September 19, 2015 Author Share Posted September 19, 2015 Really appreciate the help folks The engine runs a megajolt and so there is no dizzy gear engaged onto the cam gear. Here is another video of the mark of the oil pump cover and timing chain.... Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 19, 2015 Share Posted September 19, 2015 I did also find 10thou deep scuff marks on the oil-pump cover where the time chain had rubbed.....I'm guessing with the end float and double timing chain it's just caught the oil pump cover...... Your onto something now I think.. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 19, 2015 Share Posted September 19, 2015 Take it you are on a serpentine front end? I was under the *impression* that you still needed the stub of the dizzy in the hole, to engage with the drive gear on the cam, and that this is what stopped the cam from coming out too far.... and scrapping the front cover. I may be wrong on that though! Either way, I think you have probably found your noise, what make was the timing set? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 19, 2015 Share Posted September 19, 2015 Also, how tight is the keyway in crank/bottom sprocket, looked like it moved when you switched sides on wobbling the chain.... What about in-out movement in the chain? Quote Link to comment Share on other sites More sharing options...
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