1. SQ4 Oil-ways Cleaning

2. Fitting neoprene corks to petrol taps

3. 1938-1948 SQ 4 manual

4. Square 4 Head stud installation and Torque

5. How to remove a Mk1 Sq4 head without removing the rockers

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SQ4 oil-way cleaning

Blocked oilways in Sq4s that have been stored or have had infrequent oil changes.
The following tell how and why to remove the sludge that blocks the crankshaft oilways in Sq4s. They were posted as e-mails but the wealth of experience and technical information is so great that I saved them here.
Summary
Sludge builds up in the crankshaft unless the oil is changed every 500-700 miles. Sludge progressively starves the connecting rod bearings of oil. Because the #4 rod bearing is the last in line to get oil, it will be the first to seize, breaking the rod and punching a hole in the crankcase. The sludge will be present unless oil changes have always been very frequent, consequently more than half of Sq4s have seized a rod bearing. The presence of sludge cannot be detected without opening the crankcase, and it is so hard that it cannot be flushed out with solvent. The cranks must be removed and the sludge drilled out.
Note: A related issue is metal fatigue in Sq4 connecting rods. I have been on a ride with a recently rebuilt Sq4 where one of the con-rods failed due to fatigue. In 2012 the UK club had a run of Sq4 connecting rods remanufactured by an American company (Carrillo?) to solve the metal fatigue problem. They are available through the AOMCC and Draganfly.
From: TERRY B.
The sludge in my crankshaft (1955 Sq4) was the consistency of black concrete. There is no
solvent that would dissolve it in my opinion. I had to buy an extended length bit and use an
electric drill to remove it. Then lots of flushing with solvent. Any one who starts a Sq up after
extended storage without cleaning the oilways is looking for trouble and a big repair bill. I am
now restoring a second Sq 4 (1939 Sq4) and the oilways are plugged just like the last one.
From: TERRY C.
Following the recent oil passage and sludge trap comments, I opened the sludge traps on one of my "spare" front crankshafts and found the following. Predictably the sludge had impacted in the gallery in front of the two countersink screws, so hard it needed drilling out. Then I found that the gallery through the centre of the crankshaft is drilled to 5/32" (3,9mm). The hole
appears to be original with an offset in the centre of about 1mm where the holes don't quite line up. It does not look to have been tampered with. The feed hole to the number one big end bearing is 3/32" (2.4mm) but the feed hole to number four bigend is melted shut. The centre of the main gallery at the offset junction of the holes was blocked solid and needed hammering out with a thin rod. The supply hole in the main journal at number one is 7/32" (5,5mm). The crank has a "Y" stamped on one bigend casting if that means anything to anybody. Incedentally, the material that was blocking the gallery appears to be grit or sand based plus oil, with a few very small metal particles. total amount would probable fill two plastic valve caps. When the rod let go, it left some healthy dents in the crank; about 1.5mm deep.
From: Chuck W.
I’ll try and explain what I’ve learned about this Sq 4 engine. I have kept records on most all of the 63 Sq 4 engines that I have re-done since 1959. This includes all the engines from 1937 to 59. I have never got into the cammys for a complete overhaul.
I believe I said in a previous mail that approx. 60 percent of all Sq. 4,s have thrown a rod or two in their service. Of the 63 that I have done , 37 of them had a rod seize and most of them made a big hole out the bottom. In most all cases it was either #3 or #4 rod that seized. More so on # 4 since it is the last to get oil. Never the rods fault. It was from the oil passage through
the crank that got plugged solid from dirty oil, other metal or an engine that did not run for long periods and varnish, gum, and condensation formed into a solid that took a drill to drill it out. Early engines did not have a step from being drilled from both ends, which can break a drill if it hangs up. Later MK twos all had that step.
Some engines had thick loose sludge but most were caked solid. Engines that had run with frequent oil changes were in pretty good shape. My 56 MK 2 I bought new and when I first took It apart at 46,000 miles was clean. Again at 77,000 miles was still clean but I changed oil every 500-700 miles. The oil gets diluted very soon in this engine, as is very obvious. I never added
a filter because I could see that the original pump was not sufficient to push 50 wt oil through it when cold. The new Morgo pump will do a good job of it, but I still change oil before it gets too dirty.
I drill out the cranks then fray the end of a large clutch cable and drag it back and forth through the hole then flush with high pressure cleaning fluid and MEK, Acetone or Lacquer thinner. The screws in each end of the cranks can be difficult to loosen but a couple of good taps with a stubby screw driver will shock the metal enough to help out. Some engines froze because of the oil pump stoppage.(stripped worm drive, gears locked up from debris, or poor maintenance on the pump). The pump cannot push oil through plugged cranks. It delivers under pressure to the areas that are required, (main bushings on right side,
over-head oil line, areas that have clearance) and that oil drains to the sump where the screen is located, then is scavenged back to the tank by the scavenge gears. When the crank oil passages are plugged , you will never know it until the rod seizes from lack of oil. As I’ve said many times, an engine will run fine at low RPM from splash oil getting to the sides of the rod
bearings, but when at higher RPM and engine load there has to be oil fed to the journals under pressure. When they are plugged they don’t get sufficient oil.  Return oil to the tank does not tell you that the rod journals are getting sufficient oil.
All it tells you is that the pump is operating and is scavenging oil from the bottom of the engine. I do not have an original pump on any of my Sq 4s, I went to the Morgo pump. When I used the original pump, I pulled the oil cap on every engine start to check for pump operation, because the pump drive usually strips on eng. start, or froze after shut down.    Oil filter is a good route to go with the Morgo pump, but oil isn’t that expensive to change more often. This is pretty lengthy but maybe it will help some. The engine does have some troubles but can be a joy to operate and show.

 

FITTING NEOPRENE PETROL TAP SEALS

These “Corks” have been made from ethanol proof Neoprene and will provide a superior seal in even worn taps. They will have to be fettled to suit your tap as taps wear by varying degrees.

   Remove the old cork by slicing it lengthwise and fit the new one by also slicing lengthwise using a sharp knife. As the “cork” is a tight fit in the housing it will close up and seal ok. Careful inspection will show that the ‘Cork’ is slightly tapered and the smaller end should enter the housing first, a little oil will assist entry.

If the plunder is too tight, remove material along the length of the slit using emery paper or a file placed in the gap and remove a small amount at a time. Keep trying the plunger in the tap; the aim is to be as tight as possible without needing to use pliers to pull it out again. Make sure that the small retaining screw does not bottom on the plunger. There is advantage to reaming the tap if it is badly worn.

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Sq4 Manual 1929-1948 click on link to see an original Ariel Manual

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Sq4 Mk2 Manual Click on the link to see original Manual

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Sq4 Head Stud Installation and Torque - contact the club for a PDF outlining the ins and outs of achieving a good Mk1 head lock down. Believe us when we say you should get this dicument before attempting a Mk1 Stud and head Installation.

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How to remove a Mk1 head with rockers in place

Courtesy Gui Dory UK Ariel Club)

By the way, one can disassemble and assemble the head with the rockers in place. After the 3rd time I had to do it, I came up with it, and it saves disassembling and assembling the rockers every time.

On disassembly, one has to lift the head from the barrel by an inch or so. Then one pushes the pushrods all the way down into the bottom of the rocker boxes. This should give enough room to turn the rocker inwards and past the pushrod cups until they are nearly vertical. Then one can pull the pushrods up past the rockers and out. And after that the head is free to pull it off the engine.

Reassembly is basically the opposite. I lay the head on the barrel, just past the first few threads of the studs and then place all the pushrods in, letting them hang on the bottom of the rocker boxes by their cups. Then rotate the rockers back to horizontal, and proceed to lower the head all the way down. One has to carefully check that all the pushrods really engage into their respective cam followers, but much easier and quicker than having to take out the four rocker shafts and rockers and all the other bits.

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