351 w harmonic damper wobble
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=43092
Printed Date: April-28-2024 at 5:20am
Topic: 351 w harmonic damper wobble
Posted By: tmcboat
Subject: 351 w harmonic damper wobble
Date Posted: July-06-2018 at 5:39pm
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HI All, I had a 351 w 1984 rebuilt- I installed a new Jeggs 28 0z. 3 bolt harmonic damper and notice a slight wobble but thought it was ok.- now I have about 110 hours on the engine and I now noticed after measuring with a level that the harmonic balancer is 1/4 inch recessed in and the lower damper pulley needs to be spaced out 1/4 inch to align with the alternator pulley and raw water pump pulley. I have found a spacer from summit racing that will work.My concern is what is causing the wobble. I plan on removing the lower pulley and using a dial indicator on the outside front edge of the harmonic damper to see if its within .002 tolerance? On marine ford engines are they internally balanced or externally balance. I was told if they are internally balanced that means they are to be neutral balanced and that I have to remove the counter weight in the harmonic damper? I plan on removing the harmonic damper as well and checking the run out on the snout where the damper is bolted on the crank shaft end. I found info saying that the axial tolerance is .3mm or .0118" and the radial tolerance is .5mm or .196 inch. Does anyone know about this kind of stuff?I have a 28 0z. flywheel and torque plate bolted on the rear of the engine and a short drive shaft attached to my volvo penta stern drive. Also the engine runs good base timing set at 10 degrees and total advance timing of 34 degrees.Your thoughts and suggestion please. thanks, tmc |
Replies:
Posted By: KENO
Date Posted: July-06-2018 at 6:32pm
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Externally balanced 28 oz. I don't know where you got the numbers, but I do know the math "don't quite add up". Your conversion of 0.5 mm is off by a factor of 10, it should be .0196 inches. Is this the same harmonic balancer you had on it in April or another one? |
Posted By: tmcboat
Date Posted: July-06-2018 at 8:57pm
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Hi Keno, Thanks for your quick response. Yes I still have the original Jeggs 28 oz.Harmonic balancer from April. and yes the .0196 is right. I did some research on google? and they said that most rebuilders do external balancing like ford and it works fine,.. The racing and high performance rpm guys do the internal balancing but i will call my rebuilder Monday to see what he did. When I called in April about the wobble and that I wanted to install a new Harmonic balancer he said save the $100 and put the $ in the gas tank!? So I did but I think the wobble is a little more now. If its a bent snout? or crank shaft? the engine is out of warranty- I would have to pull the lower stern drive and pull the engine and install a new rebuilt engine - ouch! a lot of trouble-,time and $$$. I used my boat's 1973--302 -oem waukasha/.pleasurecraft flywheel and torque converter on the 351w. I understand that ford used the 28 oz Harmonic balancers through the mid -late 1980's on the 351w. Your thoughts and suggestions on trouble shooting the wobble. thanks, tmcboat |
Posted By: KENO
Date Posted: July-06-2018 at 10:48pm
Ford used the 28 oz balancers through the whole life of the 351w. 302's changed from 28 to 50 oz. in the early 80's. I think what you're doing sounds like a good plan |
tmcboat wrote:Posted By: Duane in Indy
Date Posted: July-06-2018 at 11:31pm
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They are two piece and mounted in rubber Never seen one yet that ran perfect. I say run it and not worry Just keep an eye on it to see if it changes FluidDamper makes some nice units but they are not OEM ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: SNobsessed
Date Posted: July-07-2018 at 10:07am
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If there is a functional problem, I think you would feel high vibration. Go ahead & shim for pulley alignment, that is an obvious one. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: tmcboat
Date Posted: August-16-2018 at 12:14pm
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Hi all, All you guys were right . I installed another new harmonic balancer and there still is a slight wobble- dial indicator .oo5 verses .002 max run out on snout and balancer. Either the snout is bent or the engine rebuilder did not true the crank shaft? I am just going to run it till its a problem- then the heart burn of pulling the engine, lower unit and reinstalling a new rebuilt engine. I set the timing at 10 degrees base and total advance timing is 34 degrees. My 27 ft express pops up on plane at 3300rpm with 3 people on runs good. The max rpm on the 351 winsor is 4,400 rpm but Pleasurecraft says engine cruise at 3,600 rpm. My boat is 6,000 lbs and at 3400 rpm runs at 25mph-- in the ocean with waves 2-3ft thats about as fast as we want the boat to hit it. Is it ok to cruise the boat in the 3200 to 3400 rpm range for 2 1/2 hours running straight out in the ocean- about 50 miles? THANKS AGAIN FOR ALL YOUR THOUGHTS TMCBOAT |
Posted By: SNobsessed
Date Posted: August-16-2018 at 4:55pm
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Sorry for being a downer, but I wouldn't go out 50 miles into the ocean with anything wrong with my boat, esp if it only had 1 engine. JMO ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: tmcboat
Date Posted: August-16-2018 at 5:37pm
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HI All, please let me clear this up-- we will be running about 4 miles off shore- clear sight of land the whole time running south along the florida coast line for about 50 miles- and will have inlets with marinas every 15 miles and coast guard coverage the whole way and i have extra belts, alternator, raw water pump kit, prop/nut/washer,fuel filter, back up hand held marine vhf, a spot locator, and hand held gps + boat us towing unlimited--but of course anything can go wrong but i hope not*** |