Quincy Looper Pics.............

**Mark75H** · 12-20-2004

I've been asking and trying stuff to degum stuck castor resin for 2 years with no satisfactory results. Maybe someone here will have a good suggestion. I tried all kinds of penetrating oils and solvents and most did absolutely nothing. So far I have had the best (but not very good) results with acetone, but be careful, acetone reacts with copper. Anything with copper in its alloy will turn green.

We need to find out what the "active solvents" would be for castor resin. So far the most likely candidate I've found is heat. The research I've done basically says most castor resins go soft below 70º C ..... gotta get out my conversion chart, but at least we know it is less than 212ºF (100ºC). For destroying surface castor resin it looks like strong UV light may be the best candidate.

**Jeff Lytle** · 12-21-2004

We used to use "Fantastic" to cut old castor gum. Soaking old stubborn parts for an hour or 2 really did the trick.

After running, I used to take a juice can and a paint brush and go over the the whole engine with gasoline. It kept them spotless and shiny clean.

**Frank Volker** · 12-21-2004

Steve - Here are a couple of options for the exhaust dividers:

Option 1
======
(1) Remove dividers from the elbows.
(2) Remove sharp edges from machined groove (in elbows) with a small rotary file.
(3) Cut the gasket to fit the remaining empty groove to remove the small flaps that would be in the flow path.
(4) Put dividers in exhaust hole in block (6061 T6 aluminum should work).

Option 2
======
Leave the dividers out of everything unless you're going to be running more than 5 or so races per season. If you elect to do this, very carefully remove the sharp corners from the divider grooves in the block. No heavy grinding, just a small radius. Also, do step (3) above to match gasket to hole.

I tend to favor Option 2. I never did a back-to-back dyno run, but my guess is that the dividers may actually drop top-end hp just a little. Also, once the dividers are removed from the pipes, the divider in the block could conceivably "creep" out of the block and into the remaining groove in the pipe. Hope this helps.

Frank

**Seagull 170** · 12-22-2004

Frank
What's the purpose of the Exhaust divider?
It looks to me that it's just to stop the piston ring/rings catching on the port.
I would think the block dividers are operating in very harsh conditions, at 600 degrees C low silica aluminium would expand quite a lot.
Sorry if this is a dam fool question.
Charles

**Frank Volker** · 12-23-2004

Charles,

Actually, it's a good question.

The main purpose of the divider was to shield the adjacent piston from the direct exhaust blast. If you look at the pix of the D block that switzerbullet posted ( http://www.boatracingfacts.com/forum...tachmentid=590 ), you see that the upper edge of the divider is about 1/8 in. from the water jacket and the bottom edge is less than 1/4 in. from a fuel/air passage, with the back edge against the center rib. Given the good thermal conductivity, I doubt if the divider even reached the annealing temp. I'm not sure of the exact composition of the cast alum. block, but I don't think the differences in cte's was significant at the running temps. My concern with the divider was always one of flow restriction and the wave pattern that it might set up. Plus, it required additional machining and hand fitting operations.

Frank

**Seagull 170** · 12-23-2004

Siamesed exhaust ports, now I understand. I don't think these beasts ever made it to the uk, well not on a permanant basis. So each cylinder's exhaust port exits both sides of the block & to make them one sided would force the block to increase in length. Clever them Americans. Was the divider full length of the pipe? without that the pulse would be weaker?
Charles

**Ron Hill** · 12-23-2004

Harry's B Quincy Looper never seemed much more powerful than our A... We even put Levendusky pistions in her...which we didn't see any change...Didn't seem to have the high RPM's like the A

What was the difference on the dyno between the A and the B...? An did you or do you have any opinion of the two pistons...?

Thanks for your posts.... enjoy them like crazy!!!!

**Frank Volker** · 12-24-2004

Ron,

First off, thanks to you and Ted for building a nice forum here.

Were the FA/FB engines from about the same time frame? I think the FA's of late '66/early '67 were pulling almost as much hp as the earlier FB's. The early loop engines had tons of lo-end torque, but hp rolled off rapidly. For our shop, it meant running 16:21 gears, swinging big wheels with big cups and chewing up lower units on a regular basis. In the AD (After Dyno) years, the peak hp began moving from 8400-8500 into the 92-9500 range. This made finding a decent 1:1 wheel much easier. I'm relying on a bad memory here, but I think in '72 the FA's pulled about 55hp and the FB's about 66hp on straight methanol.

We ran our own pistons, mainly because we were always looking at ring shape, ring pin location, dome configuration, clearance, and ring/cylinder fit. There may have been blanks from different sources, but the machining was usually done at QW.

Frank

**Frank Volker** · 12-24-2004

Charles,

The divider in the exhaust elbow was about 1 in. long or so, as I recall. It's primary purpose in life was to provide a better transition to the pipe diameter than would be possible by chopping off the divider at the cylinder block surface.

Frank