Hey everyone, I was trying to stay off the forum until my car was rebuilt so I could show you all the progress pics at once. Alas, I need your help so I can stop stressing about my brand new engine!
Here’s the deal, reference this Youtube video: http://youtu.be/2cMJ_ympqIk
What you are hearing is a 92 LS 5-speed with a completely overhauled B18A1 (oem rebuild) that just fired up for the first time about three days ago. Immediately we get the squealing noise in the video. I have checked the vacuum lines and the belts. We only have the alternator hooked up for now. I can’t narrow it down. It seems to be coming from around the throttle body. In the video you can hear that it stops when throttle is applied but immediately starts up again without it. The engine is running at ~1,600 RPM at idle in the video because I haven’t left it on long enough for it to catch it’s true idle.
Any ideas would be fantastic and I know I’m probably leaving out some information here so feel free to ask.
Does not sound like a belt to me, but you could take of the alternator belt and start the engine on the battery alone (just b/c it is easy to do)
I would check the vacuum lines again, because some are easy to miss (and I see an open nipple on the dashpot diaphram, so you don’t have them all hooked up, which makes it even easier to miss an open one). Page 11-6 of the manual.
There could be a dry seal at one of the cams under the valve cover, or conceivably at the distributor coupling. Those only get lubrication indirectly, because you are not trying to drown them in pressurized oil, their purpose is to keep the oil in the engine.
that’s definitely a vacuum leak. sounds just like a whistle. especially considering it only appears under high engine vacuum. try capping that nipple. if not that, spray starter fluid to find it. or, ideally, use a smoke tester
Thanks, PMI and welfare! I have tried it without the alternator belt and it most definitely does not sound like it’s coming from the driver’s side of the bay. Also, I have an aftermarket intake that does not have the dashpot diaphragm connection available. When I bought the car the dashpot was not hooked up and it didn’t make this noise. Also, I put my finger over the hole and the noise persists.
I will bust out the carb cleaner tonight and see if I can find the leak again. Tried once before but maybe I am not listening for the right change.
Another question for you guys: I am trying to run the engine as little as possible until I find the source of the noise. Without any implied liability on your part, do you think that running the engine in it’s current state (timing off, vacuum whistle, and valve lash not addressed) will damage anything? I want to find the vacuum leak before I set timing and I want to set timing before I set the valve lash, but I will need to start her to get most of that done.
Thank you again for your responses. I have found so many of these threads that go unanswered at the end. I will report back if I find the source so hopefully this will help someone else in the future.
Sounds can fool you (been there done that). That nipple on the Dashpot is just a connection to the diaphram inside the little flat disc-shaped part, the vacuum leak would be on the other end of the vacuum line, and since you don’t have a connection point for that, not an issue.
Not sure I understand why the valve lash and timing would be off if the engine was just rebuilt? Or, put another way, if it was rebuilt, why would it not be set b/f assembling the valve cover. If I knew the timing was off, I would not run the engine, I would correct any known problems before tackling the unknown ones.
I would set the timing and adjust the valves before doing anything else, just on principle, especially if there are odd and unknown noises coming from the engine. Then I would rotate the crank a few times using the crank pulley bolt and a breaker bar, and recheck, to make sure nothing is loose or moving around.
And if in doubt, check whatever else you can, such as any bolts, camshaft holders and whatever you have access to.
set the valve lash first. as long as valve timing is correct. then, set the ignition timing. if the piston rings were replaced, under no cicumstances do you want to just let it sit and idle. you’ll glaze the cylinders. usually on initial start up, you want to hold the rpm around 2500 for a few minutes. the best thing you can do is load up the engine. driving up steep grades is ideal. you want that cylinder pressure up. this will seat the rings quicker
Thank you both, again. I will take your advice on the timing and lash. But first I found the source of the noise!!! It was (embarrassingly) the throttle body, specifically I had forgotten to tighten down the nuts that hold it on. No more whistling! Now I’m just going to set the valve lash and time her! You guys were great and definitely got me moving towards the source of the issue. Thank you again again!!
With respect to your break-in comments, I have never heard of “loading the engine” to get the ring to sit. So, I found this article that sort of backs up what you’re saying: Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power Essentially he is saying the pressure from the combustion gets behind the rings to help them seal under high load (while being sure to warm up the engine first). Is this what you would recommend as well? Sorry for the questions but I have only heard the usual “be easy the first 500 miles” argument and he doesn’t really do a great job of describing why that is not good but I see the logic in his methods if what he says is true. Your opinion?
[QUOTE=snuke;2321156]…I had forgotten to tighten down the nuts that hold it on…[/QUOTE]Well Welfare was correct, it was a vacuum leak, just in an unusual place (chuckle)…
Ha! And an unusually large idiot that put it back together! This whole ordeal has been a learning process. Luckily the lessons I learned haven’t cost me too much… yet.
I started adjusting valve lash and now I have an adjustment screw that is deformed on top because it would not loosen. Sigh. Really don’t want to take the cam shaft off again but I guess I’m going to have to if the jam nut and adjustment screw won’t work. Blah, so looking forward to this thing running. Trying not to get any further ahead of myself than I already have though.
Yeah, I know what you mean, I would probably make better progress myself if I just parked it and worked on it consistently, but I really want to drive it for a while before the snow starts to fall…
i didn’t realize it was a controversial topic. or some sort of secret lol. yes. he is absolutely correct. you want to load the engine up. the harder the better. a steep grade (aside from using a dyno) is the best way. you want that high cylinder pressure. this forces the rings out, against the cylinder walls. if you look closely at a primary compression ring, you’ll see the outer, upward facing edge usually has a bevel cut along it. this guides combustion gases toward the cylinder wall, while at the same time some gas will leak in between the ring and the land, further forcing that ring against the wall. this is where the need for a secondary compression ring is derived. for the gas that pushes/leaks between the primaries land and ring. this is also why when you look at a worn primary compression ring, you’ll notice that bevel edge starts to get very thin. to the point of becoming a knife edge. those combustion gases have worn that edge to a sharp point.
if you’re too easy on the engine, you won’t get that high cylinder pressure to force the rings to seat, and the walls will glaze before they seat adequately. this is especially true in diesel engines where compression/pressure is used to ignite your a/f mixture. leaving the ring seal as an absolutely critical component in engine performance.
immediately after start up, you want to quickly check for leaks, then hold that idle around 2500-3000rpm just to warm the engine. but without any resistance (load), you won’t get high culinder pressures to seat the rings correctly. an accurate comparison would be; imagine yourself riding a single speed bicycle. on a flat surface, it doesn’t take much effort to pedal and, in turn, rotate the wheels. take that bike up a steep incline. the force required from your legs is much greater. your engine works exactly the same. it takes a greater downward force on the top of that piston to rotate the wheels. that greater force, or load, is what you want to seat the rings
Haha! Didn’t see any rambling there, I need things laid out pretty clearly sometimes. Thank you for all the info! I will do everything I can to get her broken in properly then. Unfortunately I live in one of the flattest states in the country (kansas) and finding a hill will be difficult. Ha! But I can think of some places nearby that might help.
Having a REAL issue with a jam nut and adjustment screw that WILL NOT MOVE now though. I rounded an edge on the adjustment screw on top and now I can’t get any screwdrivers to get the thing to turn. Argh!!! I REALLY did not want to take the cams off again. So dumb. Thinking about using a dremmel to cut a deeper notch on top of the adjustment screw so I can hopefully get it to turn. Any advice on that topic would be much appreciated as well. I should probably start a new thread and title it “Idiot barely got engine together and needs your help now”. lol!
don’t sweat it, bud. everybody starts from the beginning. there’s absolutely no exception to that rule.
silly question, but you do have the jam nut backed off, yes?
if so, the adjuster is stuck, you do not want to use a screw driver. use a socketed flat blade bit, and a ratchet, and short extension. you’ll never get the leverage needed with a screw driver. make sure to push down hard while trying to crack it. keep it controlled. if you feel it start to slip, stop
what i like to do is push down on the ratchet head with the right palm, while pulling the ratchet with the left. always wanna pull when loosening/tightening a fastener. much more available torque and control. and always at a 90* angle.
but really, it’s whatever way that gives you comfort and control
[QUOTE=welfare;2321170]what i like to do is push down on the ratchet head with the right palm, while pulling the ratchet with the left. always wanna pull when loosening/tightening a fastener. much more available torque and control. and always at a 90* angle.
but really, it’s whatever way that gives you comfort and control[/QUOTE]
Yeah, I had the Jam nut loose, just will not turn. I’ll try what you said and see if I can get it. Going to have to borrow some of my buddy’s tools to do it though. Out of curiosity, where can I order replacements for these things and what does the dealership call them? I was looking around online and I can’t find replacements anywhere but I don’t think I know the proper name for them.
Factory manual just refers to them as “locknut” but I can only find the rocker arms themselves online. Might have to junkyard these things if I can’t get them to move. Bleh.
they’re not actually rocker arms. rocker arms are used in ohv engines. these engines use a cam follower. i would just call it a cam follower adjuster screw. they should know what you mean…one would hope
I ended up having to use a dremel and make the notch on top deeper to accommodate more grip to get them to turn. Finally got them all adjusted properly.
