Sorry, I'm new to blogging. The issue is after rebuilding the motor I have a vibration at higher RPM and load throaty sound at idle (only in the cabin) and at higher RPMs which I think are cause by the vibration. The throaty sound is similar to an exhaust manifold issue but I ruled that out. I believe the vibration is from un-timed balancer shafts, or something else I screwed up in the rebuild. I need to understand the effects of un-timed balancing shafts.
For background, I acquired a 2004 CRV, AWD, AT 2.4L from a friend that lost timing and blew the engine. The damage was sever: the 2 intake valves were smashed, the valve seats in the head were ruined beyond repair,the piston was canted in the cylinder with a hole in it and the side skirts were smashed, and the connecting rod was bent slightly preventing the crank from turning a whole revolution. I found bits of metal in the intake manifold, oil pan, oil pump, and the oil screens.
I rebuilt the motor in my garage using a combination of aftermarket parts, junk yard head, and a few honda parts. I replaced all bearings (main/connecting), pistons/rings, valves, one connecting rod, cylinder head, timing kit, and a variety of sensors; honed the cylinders, and changed the trans fluid. I lapped the valves on the junk yard head, set the rocker arm gaps to spec, and measured all the specs I could and they were good. I did not take anything to a professional for refurbishing or balancing.
Slapped it all back together and it runs. The only issue is the previously described sound/vibration. I took it to a muffler shop and he said the exhaust was fine but the noise sounds like its coming from the transmission. He said it was down a quart and when you change the trany fluid or are low on fluid, can some times cause vibration. I added a quart and no change.
After more research I realized what the balancing shafts are! I didn't set any timing when installing; I just installed it at whatever random position. So I attempted to set the balancing shaft timing and the vibration is much better, but still present. Upon further research I don't think I set the timing correctly.
Does anyone have experience with setting the balancer shafts and the effects of improper timing or just removing all together. I plan to try once to set the balancer timing. Thanks for ANY thoughts.
You can't just remove the balance shafts, that assembly is also the oil pump. You would have to research installing an oil pump from a 2.0L version engine but that will not help vibrations.
If you used overly cheap parts in the build that isn't going to be helpful at all.
Timing itself would trigger a check engine light if it's off at all. Balance shafts/oil pump timing won't however.
The transmission can cause issues and judging by what was wrong with the engine it's likely the transmission took damage as well. To do what he did he was racing the engine pretty hard when it came apart. Just slapping random parts together doesn't always play out well.
Parts are not cross compatible between different versions of the 2.4L which may also be part of your issues.
Flywheel, main pulley on the crankshaft are another couple of options for vibrations.
But a throaty sound when trying to rev engine along with a bad vibration sounds more like there is a misfire on one of the cylinders
Without hearing/seeing the issues it's hard to say. I would make sure you have proper compression on all cylinders, coils and plugs are good, fuel injectors are working etc.
So you don't think even if I get the balancer timing correct, it wont eliminate my problem? Even though my second attempt at timing balancers showed improvement? For more background the timing slipped due to low oil and poor maintenance. The driver was going about 25mph in his subdivision at the time of failure. I believe all the parts were for the 2.4L K24A according the websites but I can't confirm for sure. I have no error codes. After more research I understand how to set the balancer, so I'll set that at least rule it. Thank you for your insight.
Yes, the balancer shaft assembly (AKA Oil pump) was 95% the cause of the vibration. The used one was installed properly this time and the engine runs smooth when touched with my hand. No resonating vibration in the cabin. The only disappointment is there is still a slight vibration at middle RPMs. But given its a 4 Cylinder and a rebuild by an armature I'm considering this success if it keeps running. Thanks for all the help!
Just updating. I have about 850 miles on the rebuilt motor and it still works. The small vibration is still there and a little noisy in the cabin. I changed the oil at ~ 700 miles and there was metal bits in the oil and filter. I've read conflicting assessments of this. Some say its a failed something, others say its normal for a engine brake in. I'll just keep going and check the oil in another 500 miles.
July 2019 Update - I ran it for another ~750 miles (~1500 total) and changed the oil again. No metal in the drained oil or in the filter. I sent the oil for analysis to Blackstone and the results was pretty good. There were high chromium and iron levels but that may still be the engine breaking in. I'm going to run it for 3,000 miles and check again.
I also took it to a dealer to diagnose the slight vibration and they were not concerned. They wrote it off to just being an old vehicle and not noticeable enough to be concerned. So far so good.