OMC 4.3 knock at idle

[whickety2007]

Re: OMC 4.3 knock at idle

MikDee....Yup went ahead with the new rings. Squared each one up in its appropriate cylinder with a piston to measure the end gap. It was typically around the 0.018 in. range give or take a thousandth. Installed the oil ring/s with the spacer's gap at 6 o'clock top oil ring at 8 o'clock bottom oil ring at 4 o'clock. The compression rings were installed with the top ring's gap at 2 o'clock and the second ring's gap at 11 o'clock both with the dot facing up. This is all in reference to the arrow on the top of the piston pointing toward the front of the motor. All were slathered in 30 weight, hose over the rod bolts, and punched carefully through the piston ring compressor. The oil pump was replaced, and the pickup tube welded to the pump after claying it to the bottom of the pan for about a 3/8" gap. You should have seen the old pump....scored and gored and full of crap.
Wire2...nice description of glyptal. I wont be using it in a motor again, but I will tell you guys that I coated my bilge with it 3 years ago, and it still looks great. Its got a nice reddish brown color. Plus, like you said, it's impervious to petrochemicals.

I dropped of the engine for installation today. When the engine came home, it was much easier to handle with no pan, and crank. I had to bolt a 7" piece of 4x4 to each motor mount and leave the top potion of my engine stand bolted to the bellhousing. The back just sat on some blocking. The whole thing was chained, and held down with a come-along.

Tonight the mechanic left me a voice-mail without much info..."This is Bob, please call me about putting your motor in". I'm a little worried he ran into trouble. Maybe its in, and running Like I said a few days ago...The planets are going to have to align to get me off on a lake vacation by Saturday.

 

[whickety2007]

Re: OMC 4.3 knock at idle

Ok, so I spoke with the mechanic this morning. The motor went back in the boat last night. He wanted to know if I had adjusted the valve lash, because I had left him my notes on assembly with some things I couldn't get done. Rear seal housing bolts needed tightening ( couldn't do this on the stand). Harmonic balancer installer...I couldn't get the crank bolt to 60 ft pounds on the stand.
Also listed out some other small stuff. I want new plugs/fuel filter/etc.
I let him know that I adjusted the lash (with each lifter down) to zero, and then gave the nut 3/4 more of a turn.
I realized this morning that for some dumb reason I had set the ignition timing 90 degrees out. the intake valve on number one was just about to open. He wasn't thrilled as now its more difficult to pull the distributor with it in the boat. All he has to do is clear the gear and turn the crank one revolution. This way #1 will be on the compression stroke.
I never heard from him this afternoon. He just has to hook everything up and fire it up. I hope he knows to run it at high idle.
Does anyone know how long should be run be run on initial startup?
Should he turn the idle down to get the timing set with a timing light or just run it at high idle (around 1500rpm) and tune the timing by ear at first. Later to be dialed in with the light?
Thanks

 

[RCSConstruction]

Re: OMC 4.3 knock at idle

Did you use new lifters? If so, then I would run it at 1800 rpm's for about 15-20 mins. (it's non-roller, right?)
If you used the old lifters then, no. If you used the old lifters I hope you got them back the way you took them out. Sounds like you know what your doing but had to add that.
I have always timed it by ear while breaking in the cam, then set it with a light after.
P.S.
If the lifters are roller's then you do not have to break-in the cam.

 

[whickety2007]

Re: OMC 4.3 knock at idle

I was able to use the original lifters (in their original locations). Same cam. (non roller)
This motor wasn't apart long enough to have what I laid out so carefully mauled over by my 10 year old and all mixed up.
I guess I was more concerned about the rings seating properly.
What is a proper amount of time to have the rings get acquainted with the bores?
I would like to run this motor quite a bit next week, and my kids are really looking forward to tubing. Am I going to put to much pressure on it, pulling
a tube after 1 or 2 days of light duty tooling around?
Thanks again for your responses.

 

[95yj]

Re: OMC 4.3 knock at idle

Actually, pulling the tube around will probably be good break in. Water skiing on the other hand would probably not be a great idea. You don't want to do full throttle starts and run at WOT, but pulling kids on a tube you won't be doing that. To get the rings to seat at their best, you don't want to run at the same R's for long periods of time. Pulling the tube will probably force you to change speeds a lot. You'll also get different loads on the motor which is good. The other thing you don't want to do is let it idle for very long.

Really glad the motor is working out for you. You can see some other threads in here where the mechanic they are working with is a nightmare. Nice to hear when there're guys who know what they are doing.

 

[RCSConstruction]

Re: OMC 4.3 knock at idle

Just to echo what 95yj said,,, You want to vary your rpm's. 5 mins at 1200, 5 mins at 2500, 2-3 mins at 3500 etc... Go from 3500 down to 1000rpm's quickly as that aides in seating the rings. Towing a tube so soon, ehhh, I didn't do it but if it is a single person and a fairly buoyant tube, then I do not see why not. Change your oil,filter,fuel filter at 10 hours and again at 20 hours (run 2-3 minutes at WOT at this point), then at 50 and she would be very well broke in. (even after 20 she should be good) I would switch to synthetic at 50 hours but that is my opinion. (some say 100 hours)
Have a great weekend

 

[whickety2007]

Re: OMC 4.3 knock at idle

All right! She is back at home in my driveway!
Thanks to all of you and your comments/suggestions, and expert opinions.
I had to hook up the muffs as soon as it was home, and man does it sound great. The mechanic ran it in for about 40 mins varying the throttle from 1600 to 2000 rpms. He put new plugs in it, and set the timing to 6 degrees btdc.
Oil pressure is great...50 psi at idle 65 at 2000 r's.
He replaced my ESA module also, of course I haven't had a chance to shift it in the water yet, but it was always a bit rough. Looking forward to easy shifting especially approaching the docks.
So I will live by a couple of rules for the next few weeks...no extended idling, varying the throttle...no wot for more than a minute or two...light duty tubing.
Thanks again, and I'll put an update out after this upcoming week on the lake.

 

[whickety2007]

Re: OMC 4.3 knock at idle

Ok...so what a week.
The owners of the place I rented had installed a new dock, and covered electric boat lift. Man was that a nice way to take it in and out of the water.
Absolutely beautiful western NY weather all week....probably the best of the summer!
I ended up putting 14 hours on the "new" engine. Everything went well, and it ran great all week. With the engine cold I get about 45-50 psi of oil pressure at idle, with it hot, it drops to about 18-20 psi. Running with any amount of rpm's above 2000 the pressure runs at about 62 psi hot or cold. This seems fairly low when hot at idle....is this normal?
Most of the time was spent running at varying engine speeds, with no more than about 15 mins. at the same rpms. Some light duty tube pulling, and some WOT for a minute or two at a time. It has never run out so fast! Able to get about 4600 rpms out of it when trimmed up just right. Unfortunately I broke my speedo pitot with the lift bunks on the first day...so I was unable to convert it to mph. (I ran a 19p X 14 1/2 dia prop) I did burn about 1/2 of a quart of oil last week, but over the last few days the level has stayed up just fine, a lot less gunk on the transom as well.
I am going to change the oil and filter tomorrow. Going to continue to stay with conventional straight 30w for now.
Anyone know how to zeroize a simple 12v hour meter? It has dials like a car odometer, but is sealed....I guess there may be a reason they can't be reset huh?
Thanks again for all of your help!!