D15z1 vibrations, frustration running high

[honerscivic]

Just checked the plugs and 3 out of four are perfectly clean on the insulator. The fourth one is a nice dark tan color. I used 3 injectors from the junkyard motor (the fourth one was stuck closed) and a fourth from the engine that just came out. Im guessing that the injector that gave the good pattern is the one from my old engine. This is exciting because an imbalance in fuel ratio could be the vibration (and spark knock sound) Im chasing.
I will install the 3 other injectors from my old setup and report back. Any votes of confidence that this is the cause?

[hondaguy72]

Vote +1

Not only could the pattern be bad, but the injector size could be incorrect. Are you sure you are running four 190cc injectors? Many other models use 240cc injectors and that would 100% cause a problem.

[honerscivic]

I ended up puting all 4 injectors from my old motor back in and no difference in running except peace of mind. I took it to the machine shop and they said the engine seems to be fine but the noise (knocking) Im hearing is from the distributor area. This is a unit I never ran before so willing to try it but doubt full that it could produce a sound. He said the vibration in the clutch is most likely the throw out bearing but that is new as well. I will let you know when I change the distributor.

I plan on posting a different thread on how to tell the difference between injector types because I was aware of the different flow rates. The only identifying marks are in four holes on the left side of the injector body. Mine read 2HA7 and 2HA8. There is usualy a little smear of white paint here and there is sky blue paint around the injector body as well. I have another random set that read 5JCW with a smear of yellow paint

Anyone care to report the alphanumeric on the side of the D15z1 and the rest (lx-EX)? I looked in google for these numbers and would like a way to tell with all of these loose injectors.

[benfrogg]

A couple of ideas-
Possibility of the timing belt being off a tooth? Worth checking out, it would cause vibration/ lack of power, etc.
Ignition timing way too advanced.... which could be related to a timing belt on the wrong tooth....

I doubt highly noise could be coming from the dizzy. I suppose vibration at the pedal could be the throw out bearing, but you had it replaced.... so....

After those ideas, I'd start to think about faulty bearings/machine work. It's possible the new bearings had problems before going in. They could have been defective from the factory. It still seems terribly unlikely since the shop should have noticed that after assembly.

How's the idle? (rpm, smooth, etc) How does the engine feel in terms of general power? Did you replaced all plug wires/dizzy cap/rotor etc when doing the rebuild? Bad plug wires could cause some vibration, me thinks.

B

[honerscivic]

Timing is set to middle notch. Checked that twice. Talked to the machinist about mabe cam timing and he said it would not run as smooth as it is had it not been right. I checked it three times when setting up the motor but did it with the damper pulley on the cam cover because I did not notice the index on the crank gear. I thought I could have put that on backward but figured if the damper matched the 0? mark on the cover, should be good right. That is the only anomaly I can think of.

I reused the wires from my old setup because they are new. Cap and rotor from new dizzy had brass inserts so I decided to keep using them. Put the old dizzy in and same noise. I will have to make a vid of the sound but next thing I could do is replace the entire cam/rocker assembly with the known good setup. The machine shop said they could check the cam for straightness. What a pain.

[GasSavers_Erik]

I really don't think that a bent cam would cause as much engine vibration as you described.

How did they determine that the head/dizzy was the source of the noise/vibration? The only way that I know that works is a long screwdriver pressed to the ear.

[honerscivic]

We used a mechanics stethoscope and I kept bouncing the rpms in the noticeable range 1500-2000. I listened and it was loudest on the distributor housing but I suggested that maybe the hollow chamber in the dizzy actually resonated the sound making it louder there. I guess I was on the right track because it was no help. The noise is so dense sounding that its hard to point out. After listening to rod knock vids on youtube, it almost sounds that way but it only happens with quick revs in neutral or when shifting and I happen to change gears at that RPM. Machine shop says I should get knocking on cold start and I dont. I really think that whatever is causing that noise is also sending the vibes through the input shaft and release fork. Need to get a vid posted.

[GasSavers_Erik]

Have you been able to view the flywheel while it is running? If the flywheel is wobbling it would definitely transmit this motion through the release fork. If you manually push on the release fork with the engine idling, does it shake?

I have heard that a rod knock will get louder when the spark plug wire for that cylinder is removed- you could try that.

Piston slap makes a rattling noise that is worse when the engine is cold and gets less noticeable as the engine warms up (maybe they got the piston to bore fit a little loose).

[GasSavers_Erik]

Any chance your tranny input bearing is bad and is causing the noise? Is it still noisy when the engine is reved when the clutch pedal is pressed?

[theholycow]

+1 on the flywheel. Also check the cooling fan. Both could be close but clearing ok under most conditions, but a little bit of flex in the engine mounts could make the difference under certain conditions.

My truck has piston slap when cold and it doesn't sound like rattling to me, it sounds like a general diesel engine idling sound (not the clattering portion of that sound but the smoother portion).

AFAIK rod knock always gets louder under heavier load.