1962 Seacraft

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WoodRay
Posts: 531
Joined: 12 Feb 2014, 15:19

Re: 1962 Seacraft

Postby WoodRay » 07 Mar 2014, 18:19

bootlegger wrote:You could run a scavenge line sucking around the thrust. You should still get oil around it then.
I dont think the carnk splashing in the oil caused your problems.
They have been setting up the engines like that for years.
You could turn the engine around and run a z drive. That solves your worry of the crankshaft and will also make it real easy to freshwater cool it.
Off course all this extra stuff adds weight and makes things really complicated with more things to go wrong.


Yeh I'm looking at running a small belt driven gear scavenge pump to draw oil from the rear low point and pumping it back up to the front near the pick up.
I most cases the original set up would have been average at the best but the variable with this one is the dipstick and marked low and full levels that the engine has been running at. The dipstick isn't the original one and has been marked with a very high oil level that causes the timing gear end to be flooded with oil. In my trade as a mechanic I have seen over full oil levels on engines cause various problems such as high vibration, high oil consumption, high fuel consumption, low power, oil aeration causing low oil pressure issues, etc. I remember a few years ago trying to find the cause of a vibration in a Denning Coach. The vibe would shake the hole bus on long its length at any speed above 50kph. To much oil in the engine was the problem with the counterweights bashing through the oil. It was a rear engine bus and you could feel the vibe in the steering wheel!
I don't really want to re-engineer the boat with different drives or by turning the engine around so I'm trying the simplest fix to the problem without changing too much. Originality with a few mods is the go.
I've also just about nutted out the conversion to heat exchanger cooling and think it'll work well and will be compact enough to still fit under the cover.

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WoodRay
Posts: 531
Joined: 12 Feb 2014, 15:19

Re: 1962 Seacraft

Postby WoodRay » 07 Mar 2014, 18:22

Alan wrote:
WoodRay wrote:
screwit wrote:Just remember if you want to restore it back to original , Seacraft had there own conversion cast up for the grey and the red. having there name on it .
If it was fitted out buy seacraft it would have it on the conversion and no dog clutch.
I would stay with the red even by placing a 149 decal on the rocker cover to keep it some where near right for the boat. but if you do go grey keep the red just in case.


Thanks Screwit for the info.
By any chance would you or would you know of any other members that would have any pictures of the Seacraft Grey conversion set up or components.

Cheers

This is an old pic of the seacraft thrust housing and water pump pulley, not sure about the exhaust this one is a Tawco

postlong2a.jpg


Alan.


Thanks heaps for the picture Alan. Cheers.

Damo
Posts: 177
Joined: 01 Nov 2012, 11:01

Re: 1962 Seacraft

Postby Damo » 08 Mar 2014, 10:35

Hey Craig, With respect to your oil level and the crank proximity mine too was running in oil!!!! My oil pick-up sat just above the main bearing height which meant that the crank was continually running in oil which as we all know isn't conducive to RPM. I opted to go to an external oil pick-up system as used in the old speedway cars and to also modify my sump so as I could also lower the oil pick-up considerably and get the oil away from the crank. In doing this I have created a mini sump all of its own of which should guarantee me a consistent reliable oil supply. I have attached some picks as this may be of some interest for you. I am also running an early Tawco dogbox as I think I read you are also, Cheers
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WoodRay
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Joined: 12 Feb 2014, 15:19

Re: 1962 Seacraft

Postby WoodRay » 08 Mar 2014, 14:10

G'day Damo,

your conversion looks the goods. I did see that outside pick up arrangement the other day. It looks to be a good idea and would also be good for an access point to prime the engine prior to start up. Sadly I don't have the room under my sump to do similar due to ribs. You look to be blessed with a rather flat bilge or your engine is higher up than mine. What type of boat is yours in?
I'm running all later Seacraft gear (direct drive).
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Cheers.

Damo
Posts: 177
Joined: 01 Nov 2012, 11:01

Re: 1962 Seacraft

Postby Damo » 08 Mar 2014, 15:44

Yeah I am lucky to have a flat bottom minus ribs ( as per pic ) , don't know what brand of boat it is but the general conciseness is its based around the Boesch design and built in a back yard somewhere!!!! :? Looking at your sump and ribs i would possibly do 1 of two things, I would either scallop out the ribs to half there height and profile ali or s/s plates and sandwich the rib and screw or bolt either side so as to no lose any strength. I would then modify your sump using some 50mm or 75mm thin wall tube cut in half and fabed into your sump so as to give you a common level not the two or three that it currently is. The other idea is to weld fittings into the sump and run a balance tube to connect front , middle and back sections of your sump. You could drill a hole through your rib and run this through it which would probably be easier although not as good. Just my thoughts Craig, Cheers!!
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bootlegger
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Re: 1962 Seacraft

Postby bootlegger » 08 Mar 2014, 18:52

I d really think twice about cutting out frames to make room for sumps etc.
The boat cops a hiding right at that spot when you are going through rollers.
That launch alfra had the same treatment.
The bottom was litterally hanging by a thread.
I dont have a solution for your sump but dont start hacking into the hull.
Its been running fne like that for fifty years.

Damo
Posts: 177
Joined: 01 Nov 2012, 11:01

Re: 1962 Seacraft

Postby Damo » 08 Mar 2014, 22:04

Agreed if you don't install the comp plates but once installed that area is actually as strong or stronger than previous , this is an acceptable method of strengthening and has been used for eons in the building industry and the like ,just my thoughts guys but I would have no reservations doing this myself , cheers

Wildwoody1
Posts: 153
Joined: 24 Dec 2013, 18:47

Re: 1962 Seacraft

Postby Wildwoody1 » 09 Mar 2014, 10:19

The pick showing bearing damage is interesting. Were all Rods like this or only the one at the drive end of the crank ? If drive end only, appears to be possibly due to improper thrust bearing adjustment. Harmonics transmitted to the crank from the prop can cause lack of oil and bearings go away as shown.Simple to set up ,simpler to get it wrong if you do not know what to do correctly.

Wildwoody1

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WoodRay
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Re: 1962 Seacraft

Postby WoodRay » 09 Mar 2014, 19:27

I wont be cutting into the hull, removing ribs or whatever. There just isn't room to lower the sump at the rear to make any effective capacity at that end for the pick up. Dave I'm still a bit miffed why think its been running fine for 50 years. This one hasn't. Sure if you want to ignore what is really going on inside the engine then I guess its fine to most. What you don't see wont hurt you attitude if you like. Like you I have a trade, and I know mine. I also know that what comes from the manufacture is not always right. I've seen heavy diesel engines destroyed time and time again that have a suffered a symptom that no one could diagnose. People blamed outside influences whilst stating that it's been like that for years and its (the machine) has always done this. Real findings revealed that one engine in particular was never set up correctly in the machine from the day it was manufactured and was released from the factory. I've also seen engines returned on a recall after subsequent failures found that 15 engine crankshafts were never hardened correctly prior to fitment. This was some 10 years after the initial release of the engine in the states!
The red motor fitted is not the original and the sump mods already done don't quite suit the lay of the hull and the ribs. One rib has been chamfered for another engine type, not this one. I'd say maybe the original set up with the Grey was probably better angled than this one. I've even found that the shaft angle has been changed as the gland location is about an 1" forward from where it was originally.
Either way, when you run an engine on an extreme angle then induce surge into the oil system your going to cause issues, seen or unseen.
Wildwoody, all the bearings were down to copper or pretty close. No2 cylinder was the worst. Water in the oil and aeration looks to be the major cause here. I'm not discounting vibration being a major contributor either. I think vibration is bad from the start considering the prop is driven off the front of the crank and there is no harmonic balancer either. Having the crank smacking in the oil certainly will make it much worse! I cant see how a poorly adjusted thrust would have caused it. The bearing looked in good nick, shims were ok, and the cranks main thrusts showed little to no wear.
I've decided after a lot of research to run a small 12v continuous duty scavenge pump that will draw oil from the thrust end of the sump and send it to the pick up end via a small de-aeration tank. I'll leave the sump as is, including the trap door set up. This should clear the oil flood at the timing gear end, the thrust should still be well lubricated from the timing gear supply and a drilling. If the pump fails the system will fall back to the way it was so I shouldn't screw the engine in the process. I'm also going to put extra bosses/valves/hoses at the sump low points so I can use the 12v pump to draw all the oil out from the 3 low points when I do a oil change (another downfall of the sump set up - you can only suck the oil out from one end of the engine which leaves heaps of old oil down the timing gear end).
Thanks everyone for their input with this.

Wildwoody1
Posts: 153
Joined: 24 Dec 2013, 18:47

Re: 1962 Seacraft

Postby Wildwoody1 » 09 Mar 2014, 22:22

The adjustment to the thrust setup is done via the flanges ability to slide forward and backward on the snout of the crank within the drive housing. If there is not sufficient movement the the harmonic vibrations are transmitted in the end of the crank which in turn forces the oil out of the bearing space. The problem is most often caused by attaching the flange to the crank with too short a bolt or packing the bolt with washers to achieve a tight fit. Some drives overcome this by fitting a slip yoke in the drive line attached to universal joints.
It does not matter what you do to a sump if the thrust adjustments are not correct the oil will be squeezed out and failure will occur. It also does not matter which end of a crank the drive is taken from the end results are the same , predictable and expensive.

Wildwoody1


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