Project Boat and Mod motors

[Guest]

Pins

Mike,

When you make horsepower, you start tossing those pins. We had to scrap our best E engine a few years back becasue we could not keep those pins in no matter how hard we tried. It was Dad's best engine and had won many races prior to the wreck. It was wicked fast. He pulled props bigger than my Super E would.

If I could get away with it, I would weld those dang pins in. But there is no way to do that I know of. If the holes get elongated in any way shape or form, you are going to toss them again. Give Eric Vanover a call, he might have a good solution.

Hi Dave,
One thing that we have found is that the clamp up on the read cage is very important in keeping them in place. As the old iron wears the reed block clamp up gets less. One way to fix that is to take .002 off the front cover to provide more clamping force and reduce the load on the pin which is trying to keep the reed block from rotating along with the bolt which is in a clearance hole.

Alan

[blueskyracer]

So that we are all on the same page this is the pin that came out in the photos I show the two still in and the empty hole..It was much more elongated but I squeezed it back together with needle nose pliers.. The pin must be swimming with the fishes in Centralia somewhere with a chunk of ring

[trident]

Pins and wedges...

OK, we seem to have three subjects going, here.

Dunno about the boat. Above my pay grade.

On the reed pins, yes, exactly what is shown in the pix. Make sure the 'stem' of the pin presses in without 'shaving' a ridge to hold it high in the bore. Tiny chamfer on the inner hole helps. Also, be sure the flange on the pin is flush or below grade by a couple thou.

On the rear dowel pin, that pin is essential, first to align on assembly, then to locate and hold shear load vertically and rotationally... I bed my cages with a thin dressing of Loctite 518, to seal and reduce 'rattle' in the bore. If the pin bore is worn, mill, not drill, an oversize hole for an oversized pin. No soft material, here, dowel pin or needle bearing is good. Going deeper in the hole on the block and the cage, with a longer pin, should help stabilize that joint. Please understand these cranks are trying to whip around in an ellipse, just pounding whee out the bearings and cages.

I'd also recommend removing the two large crankcase dowels (heat helps) then lightly draw file with a big, 12" or so, fine cut flat mill bastard, on both halves. All those shiny spots were high spots! See the high spot around each pin. Replace the dowel pins.

Worst case, yes, cut the case surface .002 or .003". More clamping as another writer suggested...

Other key is minimun crankcase sealer, otherwise you float the case cover on a formed in place shim of sealer, now the line bore is out of round and the whole crank train rattles around, wearing everything bigger. See a burnished OD on a cage? Its rattling. Make it stop! I've seen other builders leave a layer of sealer up to .010". It doesn't all squeeze out on torquing the cover.

If anyone needs a writeup on sealer, what and how much, drop me a note, tridentracing@new.rr.com, I'll send you a writeup in e-mail.

Hope this helps.

Jerry

[trident]

Pin hole

Yup, it was Alan who mentioned the clamping. I agree. Alan is also right about the bolt hole is a clearance hole, but the role of that bolt is to clamp. So, clamp it, Loctite it.

KK, those ARE blind holes, until the sides break out... See Mike's pix. Then you have a loose steel pin going through the motor. All kinds of damage results. Broken rings, peppered heads, damaged piston crown, damaged port edge. Even seen the head pushed out from the pin being trapped between piston and head.

Loose steel pin is really quick way to trash a powerhead. The plastic reed pins solved that issue for me, but we must keep the cage in place... I use all the methods from my previous post, depending...

Belt and suspenders.

Hope this helps,

Jerry

[krazy karl]

Ok, now I see what would or could happen. I didn't think about the side breaking out. I would hope that the cages are clamped down real well so that there aren't any verticle forces working on the pins but apparently this isn't always the case.

I have recently been converted to using Ultra Copper in a tube as a sealant. Leaves a very thin film unlike the rest of the Permatex sealants. Also remains pliable so dis-assembly later is not a problem. I worked in a shop that overhauled/restored radial aircraft engines and that is all we used. It was also FAA approved. I don't race a Merc at this time but would like to try a CMOD again at some time.
kk

[blueskyracer]

I guess we have a fine mess.. Thanks for all the words of wisdom and help from everyone.. I will say out here in the sticks we have only junk yard welders and no machinists so we will ponder.. I have a friend coming over to help determine the next move..I am glad I have my new engine or we would be sitting out this year

[Larry M]

You can fix the pin hole without much problem. If you have a drill press it will work. Line up on the hole and drill it out to a bigger size. Then make a pin to fit the hole with a step in it to fit the hole on the reed block. You might need a lathe to make your pin fit good. We have done this repair several times with good results.

Larry Mac

[ZUL8TR]

reed cage pins

Those are the merc reed cage plastic pins I was noting above. They are well retained and stay put. Just follow Tridents advice on modding cages for them.

[trident]

Sealer

KK, for you, but let's give this to everyone...

I had mentioned above, use just the minimum amount of sealer.

The best I've found for our Merc's with a split case is LocTite 518. Hands down, my best sealer, but the trick is not to use too much.

Pasted in below is a write-up I did for the Antiquers, some time back:

Crankcase Sealer… if some is good, more is better, then way too much must be just right.

DON”T DO THAT!

So, you need to seal those machined castings, where there is no paper gasket, on your freshly restored pride and joy… what to use?

This info applies to any motor with a two piece block, like the Mercury’s which have half the crankcase cavity cast into the block and the other half of the crankcase cast into a matching cover. Think Mark 55 and the jillion similar models, 2, 3, 4 and 6 cylinders.

I say ‘matching’ because the cover is matched to the block early in manufacturing process, and a 2 or 3 digit ID number is stamped on both parts, then that assembly is finished machined as one. The really critical operation, here, is the crankshaft linebore and facing off the top and bottom end cap surfaces.

I don’t EVER recommend mismatching covers and blocks. It can be done, but not unless you know exactly what to check, have access to a mill and have a whole pile of covers to choose from… don’t go there.

Sealer: Some is good, more is very bad., but its absolutely critical that this joint be well sealed, otherwise you get a nasty drool of leaking fuel and oil, and in extreme cases, a cylinder can even run lean from a case compression leak.

Back in the day, way back, Mercury used white lead as a sealer. Then we went to various goos, some of which worked fairly well, some not so well. I recall needing to tear down perfectly good running race motors for no other reason than to reseal the case cover, as the sealer would slowly dissolve over several seasons. Must have been really good fuel! Never use RTV Silicone sealer here, as gas breaks that stuff down, BTW.

I recommend LocTite 518 sealer. I put a row of small dots of sealer up and down the mating surface. Then I tap, tap, tap with a fingertip to evenly spread the dots into a uniform, very faint coating. If you can tell its red, you have too much… just a faint pattern of pinkish fingerprints is the goal. If any squeezes out as you torque the cover, you used too much. The danger of too much is a thicker coating will squeeze out at the edges but will leave enough in the gap that the cover is ‘floating’ on a layer of sealer several thousandths thick. (I’ve seen motors, built by others, where this coating was over .010”) This makes the line bore oversize in one direction, no longer round, so now the crankshaft with center main bearing, reed cages, and bearing caps have clearance to rattle around in the line bore. You see that as shiny burnished mating surfaces in badly built motors. What we really want is a perfectly mated metal-to-metal joint with just enough sealer to fill the microscopic imperfection in the mating surfaces to prevent leakage. NO MORE!

The good news is the LocTite sealers, 518, 515, 514, 510, will stay sealed until you mechanically separate the parts. This stuff is an anaerobic resin that cures in the presence of metal and the absence of air. It is fuel proof indefinitely. The different product numbers reflect the hardness and elasticity of the cured product. For our purposes, I’d recommend 518, as the ‘one size fits all’ answer.

Cured LocTite sealer is easily removed with Zip Strip Original formula paint remover, or any similar methylene chloride paint remover based product. Lots of ventilation, then wash. You know
the drill.

Note to HR:

Mike, if you want to move this motor stuff over to a fresh thread, feel free to move my motor posts to wherever they'll do the most good. This started as a boat thread, yah?

Jerry

[krazy karl]

I should have been more specific on the use of Ultra Copper. It most certainly should not be put on with the tube. The best practice is to get a dab on your finger and spread it on the case surface as thin as you can. It should not be put on as a bead, because it will be pushed into the cases, not good as Jerry said. When the cases are dis-assembled you will see that there is almost none of the sealant left and what is there can be easily removed with your finger, it will not harden. I am sure the Locktite products are excellent, I have never used the sealant, only the red, blue and green thread lockers. Ultra Copper shouldn't be counted out, it is an excellent product.

BTW we charged extra to clean up engine cases that had been sealed with products like Yamabond. It took a lot of paint stripper to take that stuff off and also made it difficult to separate cases without damaging cases that cost several thousand dollars if they were even available.
kk

[trident]

Sealer

Yup, I suppose you could use WEST epoxy, but you'd never get it apart...

Just kidding.

The LocTite 518 goes on easy, just don't use too much, stays sealed until you mechanically separate the parts and any tiny residue can be peeled off with your fingernail. It stays slightly flexible. Paint stripper is way faster and less tedious to remove residue... I don't recommend sharp tools, scapers and the like, that leave scratches.

BTW, the major manufacturers use the stuff in production... Mercury silk screens a very thin, faint coating. I've used a small dia. foam roller. Store in a covered plastic box for short term...

If you're doing a lot of assembly work in a short time, a tiny paint roller works well, but it wastes some sealer... my fingerprint method work very well for one motor but even that gets tedious. I used this method all the way up to V-6's BTW. I cheat on those and use two fingers.

Jerry

[Guest]

Beed Blasting Parts

One thing we al must remember is that beed blasting can distort thin and thick parts. If someone agressivly beed blasts a crankcase cover a large compression residual stress is imparted on the outside surface. This stress causes the cover to grow in size and loose its roundness. This case distortions is also one of the main sources of loosing clamping force on the reed block. A better media is baking soda or walnut shells.

Alan

[laddies]

We have had pin holes TIG welded and the block redrilled by a local tool and die man, that ends the problem.

[trident]

Bead Blasting

Geez, Alan. What are you using, marbles?

Fine grit bead, AC, #8, here, at moderate pressure. Inside and outside on all my Championship and Record setting Mod motors. Just clean to bare metal. Then wash, wash, wash.

Yes, blasting the daylights out of thin sections distorts significantly, especially blasting only one side. Too much pressure, too big media will do it.

Then, less aggressive media will cause less trouble.

I'd never use sand on powerhead parts, though it sure takes old paint off swivel brackets, towers and such. Sand cuts, so it leaves a nasty finish. If I use sand for heavy cleanup, I clean the cabinet thoroughly, and follow with beads for final finish.

Moderation, in all things.

Agree with the post about TIG weld and remachine the pin holes. I'd still recommend deeper holes with longer dowel pins, as those are less likely to break out the sides. No loose fit, either. Light press fit in repaired hole, just gently tap the pin in... A hand drill or even a drill press is not precise enough for me. A mill, with a competant (not me) machinist, thank you.

Jerry

[blueskyracer]

The hole is now going to be welded up and redrilled for a longer pin..Saving this motor is important since it is still a standard bore and it was my anniversary present..