Perkins 4108 Vibrations At Tick-Over

[GordMay]

Originally Posted by Masterjuicer

... Digital verniers indicate 38-39 mm across the flats. Does this equate to 1 1/2" imperial? ...

38.0mm = 1.4961"
38.1mm = 1.5"
39.0mm = 1.5354"

[Masterjuicer]

Gord - thanks.
Indeed. I drew the same conclusion & should have asked a better question Do I buy a 38 mm, 39 mm or 1 1/2 " socket? (Don't have one this big in mm or imp.) My instincts tell me this is an imperial bolt but could I use safely use a metric socket especially with 150 lbf/ft torque required...

[donradcliffe]

I borrowed an 1 1/2 inch socket and it worked fine. I wrapped some old line around the front pulley to keep it from turning.

[cburger]

[QUOTEOK, I've checked various areas & discovered that 3 of the 4 engine mounting bolts were loose enough for the washers beneath them to be moved by hand. These are now tightened but my boats just out for the winter here in UK so I'll check the vibrations when I change the oil & filters next weekend. Engine mounts are 24 months old & in good shape.

Some Loctite on the threads of those motor mounts will work wonders.

[MikeTurner]

Originally Posted by Masterjuicer

I'm planning to replace the crankshaft front oil seal and timing case gasket to stop the only oil leak on the engine. Does anyone know the correct size spanner/socket for the large bolt holding the pulley? Digital verniers indicate 38-39 mm across the flats. Does this equate to 1 1/2" imperial? Also, does removing the timing case require re-aligning of the water pump">raw water pump drive? Finally, what's the best way to stop engine rotation when slackening/tightening this nut?
MJ

There's another thread running that relates to Perkins oil leaks. I'm also looking at removing my timing case to rix a pinhole leak due to corrosion. The shop manual says you can remove the raw water pump but not to remove the plate that goes over where the pump shaft runs - if you do remove this plate you need a special tool to re-align the plate to the shaft. I'm hoping to avoid this.

Originally Posted by donradcliffe

I borrowed an 1 1/2 inch socket and it worked fine. I wrapped some old line around the front pulley to keep it from turning.

Don, sorry to be dense, but what did you secure the line to to keep the pulley from turning? I've read somewhere that another option is to remove the starter and use a pry bar to keep the flywheel from turning, but I'd really like to avoid having to take the starter off if I can, the raw water pump, front pulley and the timing case itself are going to be a big enough challenge for me.

[SkiprJohn]

I can't remember how many times I loaned out my 1 1/2 socket to folks with Perkins engines. Yes, it works good.
kind regards,

[donradcliffe]

Originally Posted by MikeTurner

Don, sorry to be dense, but what did you secure the line to to keep the pulley from turning? I've read somewhere that another option is to remove the starter and use a pry bar to keep the flywheel from turning, but I'd really like to avoid having to take the starter off if I can, the raw water pump, front pulley and the timing case itself are going to be a big enough challenge for me.

I remember taking a couple of turns of 3/8" dacron line around the pulley, kind of like a rolling hitch, and then tied the other end to somewhere convenient, like a motor mount. I turned the engine over with the wrench until the line got tight and really jammed the turns on the pulley--the friction was enough to get the nut loose. Now I've reminded myself to use the same trick to get the front pulley off my Ford Pickup so I can replace the timing belt...

[Masterjuicer]

Folks - thanks for all comments. I've purchased a 1 1/2 in AF socket & plan to tackle the job over next few days using an old V belt to lock the crank pulley. Just waiting for new crank oil seal & timing cover gasket to be delivered. Any recommendations on sealant for this gasket? I'll capture the occasion with digital images & post my progress on the forum.
MJ

[MikeTurner]

MJ -

Looks like I'll be tackling the timing cover as well. Where did you get the crank oil seal and timing cover gasket? So far I've only found the gasket as a part of a larger gasket set, not individually.

Also, have you seen the Perkins shop manual re: aligning the shaft on the raw water pump at reassembly? Apparently alignment is critical. There's a special tool described in the shop manual, along with an alignment technique if you don't have the tool. From what I've read on-line if the shaft isn't aligned properly the water pump will be torn up pretty quickly.

[Masterjuicer]

Mike
Correct - I was obliged (why?) to purchase a large gasket set for just two items though I did locate the crank oil seal with UK company ASAP Supplies Ltd:
OIL SEAL PERKINS 4.108 FRNTCSHFT TC
Shouldn't need to re-align the raw water pump according to local engineering wisdom if I don't disturb the plate bolted directly to the timing cover that the pump's bolted on to. I'll let you know how I fair Also, I read somewhere that there's a down & dirty method of alignment without using the tool by slackening all bolts i.e. pump to plate & plate to timing cover, running the engine & "feeing" the alignment zone by hand. Apparently this method has got boats home when broken down at sea.
MJ

[Masterjuicer]

Hi Guys
I finally got around to replacing the timing cover gasket on my venerable Perkins 4108. It was reasonably straightforward apart from the fact that the gasket is quite delicate & over-tightening squeezed it out from between the timing cover flange & mating surface. Perkins et.al. recommended not to use sealant & after running at normal temperature for 30 minutes, the gasket & new crank oils seal are leak free. Enclosed are a few pictures of the job. I had no problems with raw water pump alignment as I didn't disturb the cover mounting plate bolts.
MJ

[cburger]

Must have a good feeling of satisfaction on a job well done.

[Capt.Fred]

Hi there Mike Turner,
Also,
An item that I havn't seen on this forum is a the necessity of a flexible coupling between the drive shaft and the transmission. This is especially important if you have flexible motor mounts. This will avoid engine vibration from dislodging your engine rear seal or bearing.

[Masterjuicer]

Indeed. Took me a few days to get around to doing the job but I'm pleased that so far there are no leaks. It's amazing what a few drips of oil can do to the bilges BTW, I attempted to up load pictures - can you see any?
MJ
Actually, I'll try to up load the pix again

[MikeTurner]

I finished my timing cover replacement as well. Pretty much a bolt-together operation. As MJ says, the gasket is sensitive - I overtightened and when the job was all over had a small ooze of oil on one corner of the cover. I also think I may have slightly warped the new cover when first fitting it, it hung up on an alternator support bracket. I'd recommend removing the bracket before trying to refit the cover. Adjusting bolt tensions didn't help in my case (that's why I think it's warped), a dab of Permatex cleared it up.

I bought a 1 1/2" socket to remove the front pulley, only to discover that the nut was hardly tightened at all. Torqued as recommended when replaced. FYI if anyone has trouble finding a properly sized socket locally (I did at first), most of the auto parts stores have then or can get them. Discount stores also carry a low-cost wrench/spanner in 1 1/2" size in their trailer section, used to tighten nuts on trailer hitch balls.

The front crankcase seal must be carefully pressed into place, I did it with the timing cover off. Once everything was reassembled I ran the engine briefly without the crankcase pulley attached to check for leaks, only to learn that the front seal doesn't seat properly unless the pulley is in place - one I put it in place, no seal leak.

On the raw water pump alignment, I rented the special alignment tool (since I was replacing the timing cover I knew I'd have to remove the pump mounts) but found I couldn't use it. Turns out the 4.108 used two raw water pumps, Jabsco and Sherwood. MJ's photos show his engine uses the Jabsco, and it has the adaptor plate between the base of the pump and the timing cover. This is the plate that needs alignment, the central hole in the plate is just big enough for the pump key to pass thru and so must be perfectly aligned with the timing gear key.

My engine uses the Sherwood pump, which has a wider base flange than does the Jabsco pump. This flange takes the place of the adaptor plate, and so there's no central hole to align. I did do the alternate alignment procedure described in the owners' manual (turn the engine over a few times before tightening down the bolts holding the pump).

I installed a new raw water pump, the old one will be rebuilt and maintained as a spare.

So far in about 2 hours of test runs under load at the dock everything is running well with no leaks. I'll continue to monitor as I begin to run the boat under cruising conditions out on the water.

Biggest engine job I've every tackled. Appreciate the tips I got here.