40ci mercury reed cage question

[rabbitears2]

I need to replace the reed cages in my 44ci mercury engine(750cc) I have a 40ci mercury with reed cages in it. Will the reed cages in the 40ci work in the 44ci? Any info would be helpful. Thanks.

[PRO-MOTIONRACING]

Yes, but I have seen cages with large or small openings

[ZUL8TR]

I need to replace the reed cages in my 44ci mercury engine(750cc) I have a 40ci mercury with reed cages in it. Will the reed cages in the 40ci work in the 44ci? Any info would be helpful. Thanks.

The outer diameter of the cages are the same and the lock bolt in the same location and will fit, but there may be differences in the size of the reed port opening as Pro-MotionRacing notes. Also check the carb opening. What is the problem with the present cages? The 44 uses aluminum and the 40 ci uses brass. Brass better if you get a match. Also note the inner passages of the cage, some are more restrictive that others.

Inspect the condition of the cage and block locator pin holes they tend to get loose and that's not good, if the block pin holes are loose they need to be fixed.

Contact Jerry Weinandt at Tridant Racing he may have some cages and knows the 44 and has lots of tips for the 44..

tridentracing@new.rr.com

[trident]

For the record, its Wienandt. Yes, that is my shop e-mail, but I'll be down for a couple days, back online later in the week. Happy to help you then. Be careful not to use a two cylinder brass cage, like a MK25, as those have the bolt holes located off from the four cylinder version. Get it all together and the hole is half a bolt width off... Oops.

[ZUL8TR]

excuse please, Wienandt got it.

[trident]

I have on hand, early Aluminum cages, late Aluminum cages (44XS style with the 1 5/16" openings and plastic pins), 1" opening brass reedcages and the big brass reedcages, 1 7/32" openings with big carb holes and labyrinth seals. For Mod, I prefer the big brass ones , with a lot of cutting, grinding and retrofit of the plastic pins (which never fail), but that all gets expensive. The 44XS type big Aluminum cages with plastic pins are lots cheaper, as they don't need much... put your choice of reeds and stops on and go... Replace as needed.

Jerry

[Dave M]

Brass better if you get a match.

Why are the brass ones better ? Please explain. Are the openings the same ? Do they flow better than the aluminum ? Curious as to the reasoning behind the conclusion.

[ZUL8TR]

Why are the brass ones better ? Please explain. Are the openings the same ? Do they flow better than the aluminum ? Curious as to the reasoning behind the conclusion.

Strictly from a strength standpoint they brass is stronger than aluminum and it has better fatigue strength and is harder (see link below), also there can be combinations of iron, aluminum, silicon and manganese, copper, etc (see link below) in the brass to make the brass more corrosion resistant and enhance other properties. The brass cage is a dissimilar metal compared to the cast aluminum and perhaps corrosion was reduced by adding other metals, but it appears to not matter in the oil and fuel mix (it might with the E fuel?). From a flow standpoint some of the brass cages were better sand cast units and had better internal passages than other brass cages and some received factory hand finishing, some of the 20H brass cages had drilled internal passages. As Jerry notes above the reed openings on the late aluminum ones like in the 25ss and the 44xs were the largest at 5/8" x 1-5/8" compared to brass at 5/8" x 1-7/32" (Merc 30H &55H). The 20H had 5/8" x 1" brass. The reed opening comparison does not tell all there is about the cage flow capacity, the internal passages could be the most restrictive part of the cage especially flowing from the front to the rear reeds. A flow bench test would be interesting to see the cage flow differences with the reeds in place flapping at 7000+ up and downs a minute.

Quincy used brass for his mod motors for the strength, but made them thicker (H. Brinkman).

From a cost standpoint the aluminum is cheaper to make.

Here is a summary of properties of cast metals:

http://www.paceind.com/die-casting-1...ing_properties

There is probably more to the brass vs aluminum cages.

[trident]

And brass / bronze (the exact alloy varied) is a better bearing material in addition to being stronger... Remember the crank in a four doesn't just spin, but tries to whip around in a kind of squashed hourglass shaped pattern, pivoting in the needle bearing Center Main. It pounds the aluminum cages out of round on the ID faster.


All these cages benefit from fine tuning, careful grinding, flowing and shaping, etc.

BTW, the 40H cages were drilled, like 20H cages, but without the needle bearing insert.

Early 1" Brass Mk 30 and Mk 55 cages had small carb holes and a smooth bore... easy to add labyrinth seal cuts with a lathe.

Last 1" cages had the labyrinth seal and large carb holes... think Mk58

The early cast 1" cages with the large cored passage around the crank have the reed petal pattern layed out differently from all the later versions, a detriment to my thinking

Lots of versions.

I have most on hand. What do you need?

Jerry

[Dave M]

Interesting. I have flow benched them and understand the flow aspects. From my findings, they all need tweaked. It is also important to remember other restrictions within the engine that affect how the fuel flows through. Especially on a Mod engine with pipes. I don't think I have ever seen reed cages that were corroded to the point of being unusable, even when they have been sitting out for years in the junk yard. I imagine if one is on the coast exposed to salt air or salt water it could be different. I don't think the E Fuels will bother them much, if at all. But that is just my opinion. So far for the last several years I have not noticed any differences in Reed Cage corrosiveness (is that a word?) using the E Fuels. The biggest complaint I have on factory cages are the fact the bolts you put into them from outside the front cover. Those holes seem to fatigue at a higher rate than I would like and allow it to spin.


Thanks for the links, will see if I can read and interpret them at some point.

[ZUL8TR]

I suppose you didn't do any flow testing with the reeds in place as they operate?

[ram95]

I applaud every one of you who are interested in what Carl Kiekhaefer and Brunswick have produced, especially in the reed-cage department. There is so much to be known and understood. And, there are racers/builders who generously share their knowledge. This discussion is exactly what racing is about (at least in my book.. which I have yet to write). However, with tongue-in-cheek, and as the guy who makes the RAM50 ( Tohatsu 42.5cu in) D-Stock APBA motor I think your dollars and time can be better spent. BUT... that is only my opinion. And, I express my thoughts here, probably to my own detriment, as I would like to sell a few more race engine packages.... meaning RAM50's.

But again, I certainly respect every one of you who wants to know the details and over the past 40 years there is plenty of material to discuss, so ROCK ON!!

Alex - Richmond Aero Marine
Home of the RAM50
207-737-4570