R16 noise, help me out

[cbez]

Ok this is a 'fresh' motor that was rebuilt years ago, when I took possession it was running real quiet and it's gotten quite a bit louder in only like 100 miles. All I've done engine-wise is an oil change (VR1 20-50), checked the valves (hot, loosened the nuts with pressure on the adjustment screw while checking/adjusting .017). Also installed Pertronix.

The plugs look good. It starts quick every time and runs pretty well. Seems to actually be noticeably quieter with load on it. First feels strong, second a little weak, third strong again, kind of seems to run out of breath in 3rd and 4th and not want to rev out much, but will get up to 70+ no prob. I'm still getting used to the engine and trans combo so not sure what to expect from it.

Video A: When I picked it up. Was even quieter than this sounds, my phone seemed to pick up a lot of extra noise.

https://vimeo.com/593089672

Videos B and C: how it sounds now. If anything they may be understating it. I know videos aren't the best but maybe you guys might have some ideas.

https://vimeo.com/593090803

https://vimeo.com/593091806

[theunz]

Hard to tell from the videos, but could be an exhaust leak. More than likely valves may have come out of adjustment. I would check valve adjustment again to rule that out.
Harbor Freight sells a cheap stethoscope that really helps isolate noises.

[cbez]

Hard to tell from the videos, but could be an exhaust leak. More than likely valves may have come out of adjustment. I would check valve adjustment again to rule that out.
Harbor Freight sells a cheap stethoscope that really helps isolate noises.

I have a stethoscope coming tomorrow . First time using one should be interesting.

Video C is right after a double checked valve adjustment tonight. I am thinking of taking them down to like .014 or .015 just to try and rule out valve noise.

[C.Costine]

I would drop the oil pan and check the rod caps. Easy to do and enables you to eliminate the very expensive worst case scenario.

[23yrRebuild]

To me, it sounds like the kind of noise that has always made me want to check my oil levels, in all of the various cars I've owned, and usuall they were low. I would bet you've already done that, though. One other thing I'll share....I had a 3 main R16 that I had rebuilt, and filled with new oil, ran great, and quiet. Then it was parked for probably 3 or 4 years without being run. I had other domestic priorities at the time. Well, when I finally started back to the Roadster project, I started it up, and it sounded like yours, only much louder. So...I checked the oil level...it was up to full, but it looked kind of weird. Kind of like jelly. I thought "something ain't right"...so I went to drain it and it sort of just "glopped" out of the oil pan. Some further research informed me of the various motor oil compositions. One of them being paraffin based oils that will "gel" over time, ....and the Pennzoil I had put in, happened to be paraffin based, ....Not intending to bash on any kind of oils or brands, but I don't used that one anymore....YMMV...
Mike

[Bwk2000]

Everything discussed above could be correct; these rattles are always tough to track down. Adding my $0.02, I would try the following in addition to what’s already been mentioned:

1. Loosen off the belt completely, start it and see if the noise has been reduced or eliminated. If no change,
2. Get out the stethoscope, and before you do any further adjustments to the valve clearances, put the stethoscope next to the valve cover by each of the four valve sets. Listen for noisy lifters. If the lifters sound noisy all the way down, it is highly unlikely that you equally misadjusted all of them. Likely cause is a worn timing chain that has too much slack in it, or the tensioner.
This could also explain the lethargic performance. You can try to listen for a worn chain at the front of the chain cover, but unless it is really bad and ‘slapping’ the inside of the cover, it’s usually too noisy up in front to really get a definitive result.

[itsa68]

That racing oil weight might be a little aggressive. I'd change it out to conventional oil to see if it pumps better and tones down the engine noise.
I was also under the impression that the VR1 oil can sludge up and should be changed about every 500 miles.

Cheers
Ray B.

[Gregs672000]

My first thought was exhaust leak as well, and I would certainly look things over for a leak. I always check over my bolts after a rebuild, and almost always find nearly every one has loosened a bit with some heat cycles. My understanding with rod bearings has been that they knock as you rev the engine, quiet up some when you hold revs (say 3000-4000rpm), then knock again as you release and rpms drop. That's when testing an unknown engine and may only apply to older/worn out engines, but I would think the "cause" (loose rod beaings allowing slop) would be the same and have a similar noise when tested. However, that's not something one would expect to happen in a short period of time, and if they had been wrong to begin with then I think you would have noticed (and it's not present in the first video... so good to have a baseline!). Still, an area of concern.

I'd start with what you changed, which was adjusting the valves. I know there are specs, but I also know some R16 owners will tighten them up until they are quiet and make sure that they have some lash left for the valve to seat. If the valve doesn't seat fully it doesn't transfer heat to the head and that can lead to a bunt valve. The lash spec is set to cover all scenarios in temps/expansion/retraction etc, so they may be a bit looser than optimum. I would get some more opinions on a hot engine lash spec from R16 folks here, then run her up to temp and tighten the valves up. I run my U20 at a tight feeling 6in/8ex COLD and they'll loosen to 8in/10ex hot. An OHC head is different than a pushrod engine, so I don't know what is considered a safe lash, but I'd want at least 6in/8ex hot so I know the valve is safe. I'm sure there are racers on this site who run as close a lash as possible to get the most out of their cam, so they and others should be able to provide more guidance. I'd also inspect the whole valve train for anything loose (R16 owners talk about set screws backing out etc).

Another much more terrible thought is that you have a loose valve seat. If there's any indication of that DO NOT RUN THE ENGINE any more than absolutely necessary. It will INSTANTLY destroy the engine if it drops, even at idle (ask my friend Unklpat). Kinda scary huh, cause you kinda have to run the engine to diagnose it! I would think it would be a distinct tap tap tap and probably only one, so the stethoscope may help pin point that (BTW, be careful with your ear using that thing... smack the probe against something hard and you'll know it!). If you have eliminated a loose lash as the source of the sound and it's still up top, then maybe? Not common, but it does happen. (Consider info in above posts too by R16 knowledgeable folks!)

Do check around for loose accessory items. While it doesn't sound like it is non-engine related on your videos, a friend once confused a loose air cleaner nut with the famous U20 death rattle until he happened to place his hand on the right spot...

You mentioned it goes flat in 2nd... sounds more like tuning (ignition, air/fuel) related, but let's see what's what first with the noise.

Hope this helps, keep digging!

P.S. Good posts above! Regarding VR1, I've had no problems, but agree that 20/50 may be a higher weight than needed... it comes in 10/30 too. I had rocker arm/cam wear (high lift cam) so I went to VR1 20/50 and added Hyper Lube Zinc Replacement (which contains NO added zinc) and the cam has been beautiful ever since.

[greydog]

I had the same noise on an R16 that I'd done a top end rebuild on. Turned out the cam sprocket bolt was loose.
Dan

[Curtis]

For the pertronix, did you remove the drive gear that sits down in the distributor tower? If not then that is likely not the problem unless it was installed incorrectly before you got the engine. I had mine off a tooth and it would run okay, flatten out and start to run again at higher RPM and then crap out again.

[cbez]

https://vimeo.com/593402988

Was expecting a little more top end oil action with it running valve cover off but what do I know?

Similar noise with belt off. Head torque and the rocker tower bolts were all good. Oil level is good. I didn't mess with the distributor gear. Tried pulling one plug at a time but didn't change.

[Curtis]

Mine are oily as can be when I pull the cover. Makes a mess.

[rwmann]

No experience with the R16, but a U20 top end in operation distributes much more oil than that.

[cbez]

https://vimeo.com/593431655

Good thing I dug in, brought this to my attention.

Oil pressure is high, like 50 psi. I was kind of expecting it to be shooting all over with the valve cover off..

[rwmann]

Fuel leak?