oil pump alignment

[natemoore]

Okay. Is this an attempt by Mercruiser to sell another $50 tool (91-148220)?

I asked my boat mechanic friend if he had one. He said they never used one. I also remember a member of this forum saying the same thing.

It seems the play built into the distributor shaft would account for any slight misalignment (you can't really move the oil pump around that much anyway).

How do you non-specialty tool diy'ers do it? Align the oil pump, that is.

 

[mikeneal]

Re: oil pump alignment

What engine? I am not sure I understand your question. You have dist out and looking to align the oil pump? I have used a large flat blade screw driver.

 

[Bt Doctur]

Re: oil pump alignment

I think he has the 470-488 type. What you can do is install the dist first, then install the oil pump on the hex drive, then tighten oil pump mounting bolts.Otherwise if the alignment is off you will snap the oil pump hex shaft.

 

[natemoore]

Re: oil pump alignment

What engine? I am not sure I understand your question. You have dist out and looking to align the oil pump? I have used a large flat blade screw driver.

My signature has all my vital statistics. My engine is on a stand. I'm installing a new oil pump. I have in the past used the distributor itself to align the oil pump on automobile engines.

If everyone on this forum would follow me on Twitter, you'd all know exactly where I was at every step of this project.

The tool is actually $63 plus shipping. If they had those at Lowes or Home Depot, I'd buy it, use it, decide I didn't like it very much, then go get a refund.

 

[Bt Doctur]

Re: oil pump alignment

Whats a "Twitter"?

 

[natemoore]

Re: oil pump alignment

I think he has the 470-488 type. What you can do is install the dist first, then install the oil pump on the hex drive, then tighten oil pump mounting bolts.Otherwise if the alignment is off you will snap the oil pump hex shaft.

I toyed with this idea last night. The play in the hex shaft basically allowed me to move the oil pump around freely within the confines of the bolt holes, so this left a little uncertainty as to whether is was centered or in a bind or whatnot.

As I lie awake in bed this morning at about 4:00 a.m. I thought about this problem some more. The hex shaft has a pretty good amount of play in it, so it needs to be squared up and made stationary, then I could use it as a guide.

A deep socket of the correct size with a flat washer epoxied to its base may do the trick. I can put the distributor in a vise, give it a spin, and if it doesn't wobble, the jig should work.

Or maybe I'll fabricate a gauge out of aluminum flat bar.....

Ideas are appreciated.

 

[natemoore]

Re: oil pump alignment

Whats a "Twitter"?

It's something new for techno-junkies. From what I understand, it basically allows a person to simultaneously text-message a list of people who sign up on their account...it's called "tweeting."

If I had a texting plan on my cell phone, and if everyone on this forum went to twitter.com and signed up on my account, you'd receive on your cell phone, throughout the day, text messages like...

"I'm drinking coffee and installing my cylinder head."

" Damned! I just skinned my knuckles."

"Taking a break right now."

"Trying to align my oil pump."

And to think that someone is probably becoming a billionaire with this idea.

 

[Don S]

Re: oil pump alignment

I knew a guy that rebuilt his own 470 twice, then brought it to us the 3rd time. Both times the hex end of the distributor had broken while running. We used the tool, to check his old pump and it was way off. Compare the price of that tool with shipping, compared to the price of loosing oil pressure at 3500 rpm. Your choice.

 

[natemoore]

Re: oil pump alignment

I knew a guy that rebuilt his own 470 twice, then brought it to us the 3rd time. Both times the hex end of the distributor had broken while running. We used the tool, to check his old pump and it was way off. Compare the price of that tool with shipping, compared to the price of loosing oil pressure at 3500 rpm. Your choice.

That would be the wise and safe thing to do. A real-world anecdote is a good persuader.

 

[jtybt]

Re: oil pump alignment

That's what you get from a merc designed engine. GM has a locating pin built in to locate/align the oil pump.

Unfortunately, Merc marketed and installed that engine on many boats.

 

[natemoore]

Re: oil pump alignment

Well, I only found one place online that even advertised the tool. When I called, they said it was NLA.

Called a couple of local marine repair shops. They both said they have built dozens of 470s without the tool with no incidents.

I also called the owner of Breezeworks, who until recently rebuilt and sold 470's. He said the same thing that I suspected. The play in the shaft is intentionally designed in so that gnat's-*** alignment isn't an issue. If the shaft were rigidly constructed, then alignment would matter much more (however, a rigid distributor shaft also doubles as the alignment tool in that case). He also reported that he has never had any issue with not using the alignment tool.

In science, correlation doesn't prove causation. So the two broken shafts Don mentioned may or may not be related to the non-use of Mercruiser's tool. Whose to say it wasn't a bad batch of aftermarket distributors or not even an attempt to "eyeball" the alignment by the installer?

However, if I can't even get the tool it is a moot point.

So, I'll employ some yankee ingenuity and devise a way to make the axis of the shaft and the axis of the distributor base co-linear, then use some JB Weld to keep it square and rigid, then I'll basically have what Mercuriser used to sell for $75. Yes, the JB Weld will be removed afterward.

Heck, I could probably even turn a suitable tool on my wood lathe if I had a large plastic rod.

This is the best I can do at this point.

 

[natemoore]

Re: oil pump alignment

Here's what I came up with. I made three collars out of Corian material like so: First I squared up my drill press table. Then I drilled three holes in the piece of scrap just slightly smaller than the hex shaft. Then I went almost all the way through again with a bit just slightly larger. This left a lip on the inside of the hole. Then I forced the collars onto the hex shaft. This left the collars snug on the shaft. Then I glued the three collars together.

I used the spring, washer, and steel drill bit stop collar to hold the Corian collars tightly against the gear body. This both squared it up and stiffened it so it could be used as an alignment gauge.

When I mounted the distributor on a vice and spun the shaft, it was not by any means perfectly straight, but I definitely got it to within about .010" to .015", compared to the 0.150" of play it has without the collar. I'll bet I could shove that Merc alignment tool in my block and get that much wiggle (.010 - .015" that is).

When I inserted the distributor into the block, it was stiff enough to move the oil pump to the correct alignment, as opposed to the distributor shaft moving to the pump.

I used an inspection mirror to observe as I slowly inserted and removed the distributor shaft. It looked good to me. So I've put on the oil pan after double and triple-checking all my bolts for the correct torque.