Ford Lehman Damper Plate Replacement

Hi All,

Well six months later and both damper plates have been replaced. The ideas put forward on this thread made it possible. Thank you so much everyone!

For any one who is taking on this task I did the following (with the boat in the water).

1. Purchased rear engine mounts brackets from ADC and bolted them onto the engine. I put some 1/4" steel plates on the stringer below the engine mount and then used a 5/8" bolt/nut through the engine mount and tightened only enough to support the engine. Disconnect the shift cable and hoses from the transmission.

2. Replaced 6 of the bolts holding the bell housing to the engine block with 8" Grade 8 bolts. I did every second bolt starting at the top and going around the outboard side of the transmission so it wouldn't interfere when I pulled the damper plate out. (The 8" bolts supported the transmission and allowed it to slide back) I then removed all of the rest of the bolts holding the bell housing onto the engine block.

3. Removed the Transmission mount brackets and then removed the mount from the stringer. I then reinstalled the brackets so they were hanging off of the transmission.

4. Using some 5/8' ready rod, nuts and large washers, I made a press between the engine block and the transmission brackets. Alternating back and forth between sides, I pushed the transmission (shaft, and props as well I guess. I was a little concerned about the distance between the prop and rudder but had a picture from when the boat was out of the water so I knew I had at least four inches).

5. Once the transmission was pushed back 3" to 4", I was able to reach in and take out the 1/2" bolts that hold the damper plate to the flywheel, taking note of the orientation of the holes in the old plate to the holes in the flywheel. I laid the old plate over the new one and marked the holes I would be using and installed the new plate.

6. Using the ready rod/nut/washer setup, I pulled the transmission forward until the spline input shaft from the transmission was just touching the damper plate. A friend rocked the crankshaft back and forth from the front of the engine while I drew the transmission forward so the spline shaft would settle into the damper plate.

7. Once the transmission was close enough to the engine block I used the regular bolts to pull it the rest of the way (alternating tightening the bolts around the bell housing for an even pull). I then replaced the six 8" bolts with the originals.

When I did the second engine, the whole process took about 3 hours. I have pictures of what I did if you are interested. Let me know and I will send them to you. (I don't know how to post them)

Fourteen hours on the engines since doing this and no problems so far.

Thanks again everyone!

Good job. I just replaced my second damper plate on Tuesday. Since I had the engine and transmission out and stacked above the other engine I had great access. I used a floor jack to hold the transmission and roll it back to get to the damper plate. It took about an hour to do it. I am going to put the engine back in this weekend.

Thanks Comodave,

Now I am on to the electrical. I have to replace the house batteries.

Am debating :

1. Flooded golf cart (Three pairs which will give me about 650Ah.) cost $900 CDN
2. AGM golf cart cost $2200 CDN
3. Li batteries cost - don't have that much money

Considering upgrading the alternators to 120 Amp each but can't get a straight answer as to how much charging current the batteries will take.

Kevin.Bridgen said:

Thanks Comodave,

Now I am on to the electrical. I have to replace the house batteries.

Am debating :

1. Flooded golf cart (Three pairs which will give me about 650Ah.) cost $900 CDN
2. AGM golf cart cost $2200 CDN
3. Li batteries cost - don't have that much money

Considering upgrading the alternators to 120 Amp each but can't get a straight answer as to how much charging current the batteries will take.

Click to expand...

Good write up on the damper.
I read somewhere that charge batteries at no more than 25% of the total AH. So the 120 amp should be no problem. (remember going on memory)

Kevin.Bridgen said:

Thanks Comodave,

Now I am on to the electrical. I have to replace the house batteries.

Am debating :

1. Flooded golf cart (Three pairs which will give me about 650Ah.) cost $900 CDN
2. AGM golf cart cost $2200 CDN
3. Li batteries cost - don't have that much money

Considering upgrading the alternators to 120 Amp each but can't get a straight answer as to how much charging current the batteries will take.

Click to expand...

The best place to get that answer is from the battery manufacturer but typically standard flooded batteries are specd at no more than 15% of AH capacity. That said, standard alternators will only give about 50% output continuously. Very heavy duty alternators like Leece Neville or Balmar can do the full rated output continuously. Also, 120a alternators will require a belt change. Either 2 V belts or a serpentine belt.

Ken

Thanks Steve,

I read that as well, 25% of the total bank Ah rating however that was an AGM spec and I can't find one for a flooded battery bank.

Also, it would be two alternators so a potential charge current of 240Amps.

I would like to cut the charge time down as much as possible so I don't disturb everyone for four hours. Also, still looking at solar.

I put in 3 105 AH LiFePO4 batteries for the house. It will give almost 300 AHs for the house. They only weigh 23 pounds each and so the house bank is physically much smaller. They do have some restrictions but overall I like them. They will take a charge very quickly. I am putting a 120 amp alternator on one engine just to charge the house bank. The stock alternator will charge the 2 start batteries with an ACR. The 3 Lithium batteries cost me about $2300. They have a lifetime warranty and are rated for 3500+ cycles. But nothing wrong with flooded or AGMs.

Thanks Ken,

I was looking at a couple Balmar 120s. I already have double Vs just for redundancy sake on the circ pump.

Trying to get info out of manufacturers is like pulling hens teeth.

If it wasn't for the price I would be considering Li. A 600Ah bank here is around $7.5K CDN.

This question is generally answered by saying 'no more than 2 x 2.4 Ah (amp-hours) per cell...or 6 x 2 x 2.4....or no more than 28.40 Amp-Hours per battery, up to approximately 1/4 (0.25) of the battery's rated Amp-hours...so, a 100-Ah deep cycle battery could be charged up to 100 * 0.25 or 25-Amp-hours charge at 14.58 volts...so if you have a 100 Amp-hour battery, you can charge it at 25 amps at a given 14.5 volts for around 5-hours (testing for when it reaches approximately 14 volts at the battery posts), and be at or near 100% retained charge.

Click to expand...

Like pulling hens teeth

source

Kevin.Bridgen said:

Thanks Ken,

I was looking at a couple Balmar 120s. I already have double Vs just for redundancy sake on the circ pump.

Trying to get info out of manufacturers is like pulling hens teeth.

Click to expand...

Trojan says 10-13%, Crown says 10-20%, Rolls recommends 10% with 5% min and 20% max.

If it helps, I have a 920 ah bank (Deka FLA) charged by two Balmar 100-amp alternators. It takes 4.5 hours to charge them to 100% when discharged to 50%. Assuming a continuous output of 80 amps, that is a total of 160 amps of potential charging. However, the batteries will only accept a fixed number of amps so increasing alternator output charge the batteries any faster. Using 15% as the CAR yields 148 amps so I have no use for larger capacity alternators.

As for the higher acceptance rates of AGMs, they are of no advantage in this regard without alternators capable of delivering more amps. But, as others have noted, alternators in excess of 100 amps require dual drive or serpentine belts. Converting will cost $500 per engine not to mention another $1,000 or more for a higher output alternator. And then you may encounter bracketry challenges.

AGMs are an answer for some situations (difficult access to water batteries, for example) but I see no functional advantage over FLA for most use profiles. Also, AGMs fueled by low-amp internally regulated alternators will be murdered in short order. See Rod Collins' article on his MarineHowTo website for a detailed explanation of why.

Thanks catalinajack,

That is good info. I will check out the "marinehowto" website.

Drive Dampers

I see the discussion of replacing the drive damper plate.
How do you know when it is time to replace?
I have the Lehman 120s and have started hearing a ringing noise in one engine when in gear. Generally at 1000-1400rpm. Noise goes away out of gear even at the same rpm.
I have owned this boat for 12 years and put approx 1200 hours on it.

It is hard to diagnose because they fail gradually.

It had not been replaced when I bought boat.

Engine was noisy at idle, a lot of rocker clatter.

Once changed, very easy, engine room noise cut in half.

Here's my experience doing a solo examination of my damper plate using a block and tackle with some wood scraps. I now carry everything needed on board.

https://www.trawlerforum.com/forums/s32/my-onboard-lehman-damper-plate-repair-kit-65045.html

Take a look at alternator output curves before you decide on an alternator.

for example https://balmar.net/balmar-technology/alternator-output-curves/