What is this and where does it mount?

[ccoon520]

So while attempting to adjust my shift linkage I found this zip tied onto the exhaust. It appears to be part of the trim or tilt system. Does anyone know where this mounts so I can get it properly installed?

Motor is a 76-79 Ford 351W.
Thanks for any help.

 

[Bondo]

Ayuh,.... That's the reverse lock for the outdrive, 'n mounts on the shift plate,....

 

[ccoon520]

Ok thanks. I'll go see what I can find in the book on how to install it. I had no idea what it was so didn't know where to start.

 

[ccoon520]

Ok I need some additional help with this (or maybe just another hint). I scoured the books that I have the internet, this forum and still cannot seem to find how to mount this to the shift plate.

 

[achris]

Ok. Just read another thread of yours, and I think I know what the problem might be...

You have a 70s era engine, and they came with an MC1 drive (and transom plates). That era trim pump (Presolite) didn't have internal reverse lock capability, so that valve (reverse lock valve) was in the hydraulic circuit and closed when the control cable for gears was slid to REVERSE. That prevented the thrust from the prop in reverse pulling the drive up and forcing trim fluid back in the reservoir. The Oildyne pumps (used on later models) are valved internally for reverse lock, so the valve was deleted, as was its mounting point.

I noted you have a Alpha One drive. Not sure how it's all set up because the engine flywheel cover mounting points have a different spacing between the MC1 transom plate (14") and the later transom plate (1982 and on), which have a 10" spacing. If you have an Oildyne pump, you can remove the valve from the circuit... And as it's sitting away from any way to activate it, it's likely no longer needed.

Chris...........
(I'd still love to know who you have a later transom assembly and a Ford engine mounted to it)

 

[ccoon520]

Ok. Just read another thread of yours, and I think I know what the problem might be...

You have a 70s era engine, and they came with an MC1 drive (and transom plates). That era trim pump (Presolite) didn't have internal reverse lock capability, so that valve (reverse lock valve) was in the hydraulic circuit and closed when the control cable for gears was slid to REVERSE. That prevented the thrust from the prop in reverse pulling the drive up and forcing trim fluid back in the reservoir. The Oildyne pumps (used on later models) are valved internally for reverse lock, so the valve was deleted, as was its mounting point.

I noted you have a Alpha One drive. Not sure how it's all set up because the engine flywheel cover mounting points have a different spacing between the MC1 transom plate (14") and the later transom plate (1982 and on), which have a 10" spacing. If you have an Oildyne pump, you can remove the valve from the circuit... And as it's sitting away from any way to activate it, it's likely no longer needed.

Chris...........
(I'd still love to know who you have a later transom assembly and a Ford engine mounted to it)

I doubt that it has the newer oildyne trim pump in it as everything looks to be original, but I will check just in case (because let's be honest if the pump was replaced in 1990 with the new style it would be over 30 years old at this point so would look older anyway). If it has the older Presolite pump though, do you know where on the shift plate this mechanism would mount? I cannot seem to find a logical bolt up location and cannot seem to find any diagrams either on its specific location.

The engine and transom assemblies are original to the boat. The boat was built in 76 according to the HIN, I will have to check the title when I get it but it may have sold in 79 so it was sold as a 79 (this is done a lot with tractors that don't come out with new model years like cars all the time), or maybe it was just a typo from the seller.

 

[kenny nunez]

Since you still have the original Prestolite system does the drive rise up when you shift to reverse? The blue wires from the Micro switch are supposed to prevent the pump from running in the up direction. If the pump tries to raise the drive while the valve is in the reverse mode and the Micro switch was by passed then the rams will explode. There is 3000 PSI in the up hydraulic circuit and 800 PSI on the down circuit.
Move the vent hoses out of the way and take a picture of the shift linkage plate and then we can see where the valve needs to be mounted.

 

[ccoon520]

Since you still have the original Prestolite system does the drive rise up when you shift to reverse? The blue wires from the Micro switch are supposed to prevent the pump from running in the up direction. If the pump tries to raise the drive while the valve is in the reverse mode and the Micro switch was by passed then the rams will explode. There is 3000 PSI in the up hydraulic circuit and 800 PSI on the down circuit.
Move the vent hoses out of the way and take a picture of the shift linkage plate and then we can see where the valve needs to be mounted.

I'll take pictures of the shift plate and pump when I get home. I do not know if the outdrive lifts when in reverse because I haven't gotten it in the water yet and I want to have my i's dotted and t's crossed as much as possible before load testing the boat.

 

[bbook83]

Here is how my 1974 4 cylinder is set up. Note the valve is independently mounted on the transom and the lockout switch is on the transom mount assembly. A few years ago, I had the engine and all mechanical gear out of the boat and rebuilt the transom from the inside. I screwed the reverse lockout valve to the transom close to where it had been from pictures and according to the the length of the hydraulic lines and wires and it it works as it should. Heed the warnings from the experts on here about the hydraulic pressure. I jumped the wires on the trim solenoid while the shifter was in reverse and literally exploded one cylinder.

 

[achris]

.... If the pump tries to raise the drive while the valve is in the reverse mode and the Micro switch was by passed then the rams will explode.

Rubbish!

There is 3000 PSI in the up hydraulic circuit and 800 PSI on the down circuit.

You clearly don't understand hydraulics very well. Pumps produce FLOW, not pressure. Pressure is created by restricting that flow, and within a pump is a pressure relief so the pressure will not rise beyond the design point. Or in the case of a ram, the load acting on the end of the rod that is opposing extension.

That 3,000 psi is only seen when there is enough load on the ram to generate that pressure. And that's all based around the area of the piston. If the piston is 50mm diameter, then the load on the end of the ram would need to be around 4,300kg (that's on each ram) to produce 3,000psi. If all they are doing is lifting the drive while the boat's on trailer, then the pressure in the system (until the drive reaches full up and the system loads up) will only ever reach about 50psi...

As for down, the same rules for pressure calculations applies, but you have to remove the area of the piston rod form the area of the piston to find the area acted on by the hydraulic fluid.

The rams are capable of withstanding internal pressures far in excess of the UP pressure of 3,000psi. If they weren't, rams would explode every time you reach full UP and kept your finger on the button....

Chris.........

 

[kenny nunez]

Question, have you ever rebuilt the Prestolite style hydraulic rams? Then you know about the thin outer housing.
If someone jumps the up solenoid while the drive is shifted to reverse the rams will explode if it has the early style lock valve.
The last generation of the Prestolite pumps had a reverse lock built in which eliminated the need for the lever style lock valve.
I must agree on what you are saying as far as hydraulic theory and my lack of.
I have seen Prestolite systems build up over 3000PSI while the boat was on the trailer in the sun with the drive raised resulting in blown out hydraulic hoses.
I reference to your first post.
MC1 transom plate /flywheel housing mounting points are 9.5“- 9/916” and not 10”. This dimension is still the same even with the Alpha 2. The flywheel housings for the V8s had holes for Ford and Chevrolet bolt patterns until the late 70s. 1971 was the first year for the V8 MC1 packages. The dimension was narrowed for the “Y” pipe exhaust. So while not practical, and with some “back yard yankee hot rod” engineering it is still possible to mount a Ford engine to a Alpha 2 with the early style flywheel housing.
Back in the 70s the Mercruiser school spent a lot of the time on the Prestolite tilt trim trouble shooting and the shift system. We had to learn how to use the hydraulic test kit which resembled a Freon charging manifold. With it then the valves in the pump could be adjusted.
Needless to say the Oildyne system saves a lot of headaches over the Prestolite.

 

[achris]

Question, have you ever rebuilt the Prestolite style hydraulic rams? Then you know about the thin outer housing.

As a former dealer yes, rebuilt many. If you think the outer tube has 3,000psi applied to it, then it sounds like you haven't done any! And yes the OUTER housing is thin, but the outer housing is only for the DOWN circuit, and the relief opens at 800psi. The only thing that has 3,000psi applied to it is the INNER tube, which is much thicker. Also yes in the sun the oil will heat up and if the drive has been tilted right up, the pressure IN THE INNER TUBE ONLY will build up, but only to 3,000psi. Once it reaches 3,000psi the relief valve in the pump will open. In the thinner outer tube, the DOWN circuit relief is set at 800psi, and it will open at that pressure. That's how hydraulic circuits work!

Also, go measure an MC1 inner transom plate mounting spacing, it's 14" my friend, not 10" (or 9-1/2, or 9-9/16), 14"..... And the Ford and GM flywheel housing are VERY VERY different, one will not bolt up to the other!

Chris.....

 

[kenny nunez]

4.3 V6 flywheel housing. The same dimension for all V style engines from 1971 to current Alpha In line models also.
Some Ford model flywheel covers had 2 sets of dowel pins for use with Chevrolet engines.

 

[achris]

4.3 V6 flywheel housing. The same dimension for all V style engines from 1971 to current Alpha In line models also.

No, they aren't.

Here's a composite picture of an MC1 inner plate and an Alpha One inner plate. I've made it easy so you don't have to think about it too hard. CLEARLY you can see the different rear mounting points (also sometimes called 'ears') have very different spacing...



And no, there was NEVER a flywheel housing that fitted both a Ford and a GM engine, never.

Chris.....

 

[ccoon520]

Sorry for the delay weather and my schedule got in the way of me being able to get pictures. So back on topic. I have attached pictures of the shift plate as well as the trim pump. Is this a Prestolite or Oildyne system?

If it is a Prestolite does anyone see any obvious mounting location that I am just missing?

 

[achris]

That is a Prestolite pump. I did notice the shift plate lever has 'ALPHA' cast on it. That is a new style plate, and were never designed to have a reverse lock valve on them.

Here's how the valve would have been mounted originally.


Notice the shape of the lever that's designed to be mounted ON the valve. As the control cable pushes the lever to reverse the valve closes, and hydraulic fluid can't flow, stopping the drive from 'kicking up'. It also trips a switch (not visible in this picture) that stops the UP circuit being run while in reverse.

Next time you're out on the water, open the throttle in reverse and see if the drive does kick up. If it doesn't, someone has replaced the original Presolite pump (without internal reverse locking) to one with.

I'd also be interested if you could post a photo of the gimbal housing and drive, and the inner transom plate, viewing the engine flywheel cover and the mountings. Also, could you measure the mounting bolts centre to centre? I have a theory on how you could have a later MC1 (about 1975 to 1982) inner transom plate and an 'Alpha One' gimbal housing (1983+)... That way you'd be able to use a Ford engine (with the wider mounts) and a later (1983+) gimbal housing.

Chris........

 

[ccoon520]

That is a Prestolite pump. I did notice the shift plate lever has 'ALPHA' cast on it. That is a new style plate, and were never designed to have a reverse lock valve on them.

Here's how the valve would have been mounted originally.
View attachment 339484

Notice the shape of the lever that's designed to be mounted ON the valve. As the control cable pushes the lever to reverse the valve closes, and hydraulic fluid can't flow, stopping the drive from 'kicking up'. It also trips a switch (not visible in this picture) that stops the UP circuit being run while in reverse.

Next time you're out on the water, open the throttle in reverse and see if the drive does kick up. If it doesn't, someone has replaced the original Presolite pump (without internal reverse locking) to one with.

I'd also be interested if you could post a photo of the gimbal housing and drive, and the inner transom plate, viewing the engine flywheel cover and the mountings. Also, could you measure the mounting bolts centre to centre? I have a theory on how you could have a later MC1 (about 1975 to 1982) inner transom plate and an 'Alpha One' gimbal housing (1983+)... That way you'd be able to use a Ford engine (with the wider mounts) and a later (1983+) gimbal housing.

Chris........

If I shift the unit into revers out of water and try to pull out on the cylinders to see if they move will that be adequate or does it need more load?

Also, I would bet that I just called the wrong drive out and that I actually have an MC-1. The sticker is worn off the outdrive so I made assumptions on what was attached based off information I could find online. I do have pictures of the external stuff but trying to get a picture of the flywheel for curiosities sake I'll have to say no for now. I'd like to get the thing put together and in the water first.

 

[achris]

If I shift the unit into revers out of water and try to pull out on the cylinders to see if they move will that be adequate or does it need more load?

Yes, it'll need more force than you can exert.

Also, I would bet that I just called the wrong drive out and that I actually have an MC-1. The sticker is worn off the outdrive so I made assumptions on what was attached based off information I could find online. I do have pictures of the external stuff but trying to get a picture of the flywheel for curiosities sake I'll have to say no for now. I'd like to get the thing put together and in the water first.

Cool.

 

[ccoon520]

Here's how the valve would have been mounted originally.
View attachment 339484

Notice the shape of the lever that's designed to be mounted ON the valve. As the control cable pushes the lever to reverse the valve closes, and hydraulic fluid can't flow, stopping the drive from 'kicking up'. It also trips a switch (not visible in this picture) that stops the UP circuit being run while in reverse.

Also is there a place where I can purchase that shift plate lever and change out the current one, or do I just have to upgrade the trim pump to one with the reverse lock valve integrated into it?

 

[kenny nunez]

I have been searching around for Prestolite pumps and the later style block that has the reverse lock incorporated. Unfortunately every place I have looked it is NLA. I am sure there is one somewhere.
Finding a complete pump will work but the block on the bottom has to have 2, 3/16”inverted flare fitting receivers. The one that you have has a pipe thread female where the clear line attaches. In other words do not purchase a pump on line if they do not show the bottom of the pump.
I think I may have found one on a site called Bloody Decks. There is a pump showing which I am pretty sure is the one you need.
If you find the pump you need you may have enough length of the high pressure hose from the reverse lock valve to fit into the down pressure side of the pump or with a 3/16” inverted flare union just a short length of steel tubing with the flare fittings.

Try to contact them. Where are you located?