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Assembly lube and break-in for Triumph engines

Most of the cam grinders supply assembly lube paste with their cams. We can supply tubes of Moly paste for under 10.00 a tube made by "Lubromolly" a German company. "HRL" used to supply it. There are a lot of different suppliers. they are probably all ok as long as the contain Molybdenum di Sulfide as the primary extreme pressure additive. We try to use this past on all iron to iron (cam & lifters) or steel to steel (rocker arm tip to the end of the valve stem, that are subjected to very high contact pressures and rubbing contact any time the engine has been freshly assembled, but especially when the parts are new and have never run together. For the rest of the engine, crank, rod bearings, piston to pin, rings, piston skirts, rod bush to pin, rocker shaft to rocker arms, oil pump, timing chain and tensioner, cam bearings and journals, front and rear seals, & so on, we think it is appropriate to use oil.

Good 50 weight racing oil fortified with a liquid Moly supplement is what we use. We make it up by mixing a 50/50 mix of the engine oil with a good liquid engine oil supplement that contains a high amount of Moly. I do not have an exhaustive list of suppliers, but "Mr Moly" & "Slip", are two that I have used over the years with good success. It may be that in this application, the Moly may not make any difference, but that what is important is the liberal application of high quality 50 weight Racing oil. The 50 SAE oil will not drain away in storage, (unless it is for a very long time). It may be that the Moly just makes me feel good by its' presents! Using assembly lube paste where there are bearings (ie. actual bearing material like on a typical rod bearing) can destroy the bearing upon startup. The paste can be thick enough do to this. "Don't ask me how I know this!"

A lot of "production engine rebuilders" use thin, lightweight bearing assembly grease on bearings in engines that might be "on the self" for a long time before they are used. "Lubriplate" makes an assembly lube grease that is lightweight and white in color for this purpose. It has a good reputation. I have never used it for this purpose. All the engines we do are usually put in service within a short time after they are assembled. The purpose of the Lubriplate assembly grease is to insure that the there is lubrication on all of the bearing surfaces if the engine has been in storage for over months or a year after it was assembled.

PS Moly as an anti-friction, extreme pressure additive really works. Years ago we did a valve job on an air cooler VW. Just after putting the engine back into the car I drove it over Highway 17 past San Jose to Hayward.The first 30 miles I took it easy, below 55 mph. Then I speeded up to 65 mph on the flat in San Jose, 2 or 3 minutes at that speed and the #1 Exhaust valve would stick in the guide & the pushrod would fall out of position in the rocker arm. Probably excess heat. times I freed up the valve and put the pushrod back in position, each time 3 or minutes at 65 mph, the same thing happened. In Hayward I put in a bottle of "slip" Moly engine oil additive. 75 mph all the way back to Santa Cruz. The valve never stuck again. This was a permanent fix. The Moly really does "plate on" to the surface of the metals and creates a sacrificial sliding surface of molecules that prevents metal to metal contact.

Greg Solow

If everything in an engine is in good shape & there are no problems with fit, finish and lubrication, then the critical areas during breaking are the iron to iron or steel to steel surfaces that are lubricated by the oil film and not by Hydrostatic lubrication. The main, rod, & cam bearings are never really supposed to touch the cam or crank as there is a separating film of oil that is captured and forced into the space by the oil pump. The cam and lifters, the valve stem tips to the rocker arms, the rings against the cylinder walls, the Timing chain, sprockets and tensioner are the critical areas in a TR-4 type engine.

The cam wants the engine to go fast enough to keep oil splashing on it and to keep the surface speed of the lifter on the cam high enough, but not to high, during the first 15 to 20 minutes of operation, especially. The rings want enough gas pressure above the top ring to keep the ring pressed against the cylinder wall so it will "wear in" both the wall and the ring face. Again it wants enough oil to keep it lubricated and cool, but not to much speed until the surfaces have begun to "mate" with one another.

We always break in with Chevron Delo, Brad Penn, or Torco, which we continue to race with. We run at about 2200 rpm for the first 15 to 20 minutes, then shut down, retorque the head, adjust the valves, look for plenty of oil on the top of the head. If we are at the track, we then run 2 or 3 laps at up the 4,000 rpm using about 2/3 of WOT, then go up 500 rpm every two laps or so to 6,000 at WOT after about 20 to 25 minutes of running. What is most important is that the oil and water temperatures remain stable. It is also good to decelerate from 4,000 down to 3,000 with the throttle completely closed to create high vacuum in the cylinders during the first couple of laps (make sure there is no one behind you when you do this!), to draw oil up into the ring belt and cool off the rings during their initial breakin under load.

By the end of the 2nd session, everything should be well broken in. Adjust the valves hot, right off of the track so clearances are as close as possible to the 'running" condition and temperature. Sometime in the middle of the 2'nd session, it is good to do a "clean cut" and coast into the pits to look at the spark plugs and make sure there are no signs of detonation. These usually manifest themselves as tiny black speckles like black pepper on the clean white ceramic of the spark plug insulator. If you see any of this, retard the timing & or richen the mixture.

Greg Solow






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