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MG MGA - Engine break

I need feedback about the best way to start my freshly rebuilt motor in my MGA .

What kind of oil used to break the engine , how many miles i have to run with it and after that is synthetic oils are good for our old engines .

I want to do the right ting first .

All tips are welcome .

Thank's

Jules
MGA MK II 1962
Jules Desbiens

Jules. There is much information on this in the MGB archives, which you might wish to check out.

My own procedure, based on Peter Burgess' recommendations is to make sure all of the coolant lines are tight and the system full of coolant.

Make sure the oil is to the "max" mark on the dipstick.

Disconnect the wire from the coil to the distributor at the coil.

Turn the engine over, on the starter, for 20 seconds. Let the starter rest for 15 seconds. Repeat, up to three times, as necessary to begin to show oil pressure. Go and have a beer and smoke your pipe (a traditional French-Canadian occupation). If you are a non-smoker/non-drinker, wait at least one half hour for oil to drain down.

Remove the dipstick, wipe it clean and re-insert it. Remove it and check the oil level. It should be down by the amount necessary to fill the oil filter. Top up the oil to the "max" mark on the dipstick.

Start the engine. If at all possible, have an assistant do this. Hold the engine rpms at 2,000 to 2,500, varying them from time to time, for a period of 20 minutes. If you have to do this by yourself, start the engine, run it up to 2,000 rpm and allow it to run for about one minute. Then, adjust one of the throttle screws until the engine will maintain 2,000 rpm. You can bump it up, by hand, a couple of times during the run in period.

Check for problems. Leaking coolant and blown out "freeze plugs" are the two main problems, the latter quite dramatic.

Run the engine for 20 minutes. If there is a problem, immediately stop the engine, correct the problem, and start again. I use a stop watch for this.

At the end of the 20 minute run in, drain the oil. Replace the oil and the oil filter with fresh supplies. While the oil is draining out, let it drain as much as possible, remove the rocker arm cover, check the torque on the cylinder head, in proper order, then, reset the valves as necessary. Re-install the sump plug. (Once, I poured three quarts of oil into the sump, checked the level on the dipstick--none, and realized I had not re-installed the plug. Good learning experience.)

If you can still find non-detergent oil in Canada (hard to find here in the US), use SAE 30 oil for the first 1,000 miles. Then, change the oil and filter and refill the engine with whatever oil you decide to use. I use the Castrol 20W-50 oil myself because the synthetic oils tend to leak more. The synthetics will hold up much better in extended usage and will flow better in very cold weather. But, I change my oil and filter every 3K miles and it seldom freezes here. Hence, I do not need the more expensive oils with their problems of leaking from our older engines.

If you cannot find the non-detergent oil, use the Castrol 20-50 and realize it will take the engine longer to "break in". About 10,000 miles in my experience before the rings are fully "seated"--i.e. worn in to perfectly fit the bores.

My opinion is that the cylinder head should be retorqued after initial run in, at 250 miles, at 500 miles and at 1,000 miles. After that, the head should have the torque checked annually. Again, much information on this in the archives.

Les
Les Bengtson

Les ,

Many thank's for your precious informations . I will follow that with care .

Again , thank you .

Jules .
MGA 1600 MKII 1962
Jules Desbiens

Hi Jules. It is very important that your camshaft and lifters are coated with Moly based assembly lubricant before startup. If you used something other than moly based lubricant to assemble your engine, then I would pour moly some based assembly lube down the pushrod holes, and onto the lifters and camshaft before attempting to start the engine. The camshaft lobes and lifters are under high loading on initial startup, and require moly based lubricant to prevent serious damage (premature wear) to those parts. Cheers, Glenn
Glenn

Glenn. I would not dispute you as I use a molibdynum disulfide (sp?) based assembly lube myself when rebuilding engines. However, the various "moly" products are somewhat new, only coming into use in the late 1960s. Prior to that time, we used a coating of STP oil additive on such parts. All of those engines, and the ones built before without any of these special lubricants, seemed to work quite well for many years.

Thus, I use the modern products myself. But, I cannot guarantee that they are really needed.

Les
Les Bengtson

Hi Les. Like you, I used only STP as an assembly lubricant for many years, before moly based products were available. But on disassembly of many of those engines, EXTREME camshaft lobe and lifter bottom wear was quite obvious. The camshaft and lifters are apparently only surface hardened. So if an extreme pressure lubricant such as moly is not used, it is likely that the high loading on the parts during break in will prematurely wear the camshaft lobes and lifter bottoms. Once these parts begin to wear, they continue to do so, and at an accelerated rate because of the the softer underlying unhardened metal. I am certainly no expert, but believe all this to be true from personal experience. One of the camshaft manufacturers,( I forget which one) has a website blurb that discusses the critical importance of using extreme pressure (moly based) lubricant on all valve train components. If memory serves, I think this same camshaft manufacturer strictly requires the use of Moly based lube on it's camshafts, otherwise the camshaft warranty becomes void.
On the engines that I have rebuilt using moly based lubricant, valve train wear has been minimal in comparison to those assembled with STP or gear oil. Perhaps other folks could comment on their experiences regarding moly based lubes VS other compounds? Cheers! GLenn
Glenn


From the Crane Camshaft website. Lengthy but interesting:



Reasons and Causes for Cam Failure


Cam failure is rarely caused by the cam itself. The only things we can control during manufacture pertaining to cam lobe wear are lobe taper, lobe hardness and surface finish. Of all the damaged cams we have checked over the years, more than 99.99 percent have been manufactured correctly. Some people have the misconception that it is common for a cast iron flat tappet cam to occasionally have a soft lobe. We have yet to see a cast iron flat tappet cam that had a soft lobe.

When the cast core is made at the casting foundry, all the lobes are flame hardened. That process hardens all the lobes to a depth below the barrel of the core. That depth of hardness allows the finish cam grinder to finish grind the cam lobes with a Rockwell hardness above 50Rc. The generally accepted hardness on a finished cast cam should be between 48Rc to 58Rc.

All of the finished cams that we have checked are always above 50Rc hardness on the lobes. Many outside factors, or a combination of factors, can cause cam failures. We will list some of the factors we have determined that may cause camshaft failure.

1. Lobe wear
A) Incorrect break-in lubricant.
Use only the Moly Paste, Part Number 99002-1 that is included with the cam. This Moly Paste must be applied to every cam lobe surface, and to the bottom of every lifter face of all flat tappet cams. Roller tappet cams only require engine oil to be applied to the lifters and cam. Also, apply the Moly Paste to the distributor gears on the cam and distributor for all camshafts. For extra protection, an anti-wear additive should be added, such as Crane Super Lube, Part Number 99003-1.

NOTE: Do not use synthetic oil during the break-in period. It is not recommended to use any type of oil restrictors to the lifter galley, or use windage trays, baffles,or plug any oil return holes in the valley. Oil has a two-fold purpose, not only to lubricate, but to draw the heat away from whatever it comes in contact with. The cam needs oil splash from the crankcase, and oil run-back from the top of the engine to help draw the heat away. Without this oil flow, all the heat generated at the cam is transferred to the lifter, which can contribute to it's early demise.

B) Correct break-in procedure.
After the correct break-in lubricant is applied to the cam and lifters, fill the crankcase with fresh non-synthetic oil. Prime the oil system with a priming tool and an electric drill so that all oil passages and the oil filter are full of oil. Pre-set the ignition timing and prime the fuel system. Fill the cooling system. Start the engine. The engine should start quickly and run between 1500 and 3000 rpm.

If the engine will not start, don't continue to crank for long periods, as that is very detrimental to the life of the cam. Check for the cause and correct. The engine should quickly start and be run between 1500 to 3000 rpm. Vary the rpm up and down in this rpm range during the first 15 to 20 minutes, (do not run the engine at a steady rpm). During this break-in time, verify that the pushrods are rotating, as this will show that the lifters are also rotating. If the lifters don't rotate, the cam lobe and lifter will fail. Sometimes you may need to help spin the pushrod to start the rotation process during this break-in procedure.

(a) Note: Lifter rotation is created by a taper ground on the cam lobe and the convex shape of the face of the flat tappet lifter. Also in some cases, the lobe is slightly offset from the center of the lifter bore in the block. If the linear spacing of the lifter bores in the block is not to the correct factory specifications, or the angle of the lifter bore is not 90 degrees to the centerline of the cam, the lifter may not rotate.

Even if the engine you’re rebuilding had 100,000 miles on it and the cam you removed had no badly worn lobes, this still doesn't mean that your block is made correctly. It just means that the break in procedure caused everything to work correctly. Be careful to watch the pushrods during break in to verify lifter rotation. Don't assume everything will work correctly the second time.

(b) Note: Always use new lifters on a new flat tappet cam. If you are removing a good used flat tappet cam and lifters and are planning to use them again in the same (or another) engine, you must keep the lifters in order as to what lobe of the cam they were on. The lifter breaks-in to the specific lobe it is mated with and it can't be changed. If the used lifters get mixed up, you should discard them and install a new set of lifters and break the cam in again as you would on a new cam and lifters. You can use new lifters on a good used cam, but never try to use used lifters on a new cam.

(c) Note: Roller tappet cams don’t require any break-in. You can use roller lifters over again on a new cam if they are in good condition. There will be, of course, no lifter or pushrod rotation with the use of a roller tappet cam.

C) Spring pressure
Normal recommended spring seat pressure for most mild street-type flat tappet cams is between 85 to 105 lbs. More radical street and race applications may use valve spring seat pressure between 105 to 130 lbs. For street hydraulic roller cams, seat pressure should range from 105 to 140 lb. Spring seat pressure for mechanical street roller cams should not exceed 150 lb. Race roller cams with high lift and spring pressure are not recommended for street use, because of a lack of oil splash onto the cam at low speed running to help cool the cam and lubricate the lifters. This high spring pressure causes the heat created at the cam to be transferred to the roller wheel, resulting in its early failure. Any springs that may be used must be assembled to the manufacturer’s recommended height. Never install springs without verifying the correct assembled height and pressures.

NOTE: Increased spring pressure from a spring change and/or increased valve lift can hinder lifter rotation during cam break-in. We have found that decreasing spring pressure during the break-in period will be a great help. This can be accomplished by using a shorter ratio rocker arm to lower the valve lift; and/ or removing the inner spring, during the cam break-in time, if dual springs are being used.

D) Mechanical interference.
There are many factors that can cause mechanical interference.

(1) Spring coil bind: This is when all of the coils of the spring (outside, inside or flat damper) contact each other before the full lift of the valve. We recommend that the spring you are using be capable of traveling at least .060" more than the valve lift of the cam from its assembled height.

(2) Retainer to seal/ valve guide boss interference. You need at least .060" clearance between the bottom of the retainer and the seal or the top of the valve guide when the valve is at full lift.

(3) Valve to piston interference: this occurs when a change in cam specs. (i.e.; lift, duration or centerline) is enough to cause this mechanical interference. Also: increased valve size, surfacing the block and/or cylinder head may cause this problem. If you have any doubt, piston to valve clearance should be checked. Minimum recommended clearance: .080" intake and .100" exhaust.

(4) Rocker arm slot to stud interference: As you increase valve lift, the rocker arm swings farther on its axis. Therefore the slot in the bottom of the rocker arm may run out of travel, and the end of the slot will contact the stud and stop the movement of the rocker arm. The slot in the rocker arm must be able to travel at least .060" more than the full lift of the valve. Some engine families, like small block Chevrolet, have stamped steel rocker arms available in long and extra long slot versions for this purpose.

2) Distributor gear wear.
The main cause for distributor gear wear is the use of high volume or high-pressure oil pumps. We don’t recommend the use of these types of oil pumps. If you do run these types of oil pumps, you can expect short life of the cam and distributor gears, especially for low speed running, in street type applications. If you must run these types of oil pumps, you can increase the life of the gears by adding more oil flow over the gear area to help cool off the point of contact.

NOTE: distributors that have end play adjustment (up and down movement of distributor shaft and gear), Maintain a maximum of .010" end play, to help prevent premature wear.

3) Camshaft end play.
Some engines have a thrust plate to control the forward and backward movement of the cam. The recommended end play on these types of engines is between .003" to .008". Many factors may cause this end play to be changed. When installing a new cam, timing gears, or thrust plates, be sure to verify end play after the cam bolts are torqued to factory specs. If the end play is excessive, it will cause the cam to move back in the block, causing the side of the lobe to contact an adjacent lifter.

4) Broken dowel pins or keys.
The dowel pin or Woodruff key does not drive the cam; the torque of the timing gear bolt, or bolts, against the front of the cam drives the cam. Some reasons for the dowel pin or key failing are: Bolts not being torqued to correct specs; Incorrect bolts of a lower grade being used; Stretching and losing torque; Not using the correct hardened washer that may distort and cause torque of the bolt to change; LocTite not being used; Or some interference with the cam and lifters or connecting rods causing the cam to stop rotation.

5) Broken cam
A broken cam is usually caused by the cam being hit by a connecting rod, or other rotating parts of the engine coming loose and hitting the cam. When this happens, the cam will usually break in more than two-pieces. Sometimes the cam will break in two pieces after a short time of use because of a crack or fracture in the cam due to rough handling during shipping, or some time before installation. If a cam becomes cracked or fractured due to rough handling, it will generally not be straight.

Most people will not have any means of checking cam straightness. As a general rule, if you can install the cam in the engine and install the timing gear, the cam should turn freely with just your finger pressure. There should not be any drag or resistance in turning the cam. This free turning of the cam is assuming that if new cam bearings were installed, they were the correct parts and they were installed correctly.

NOTE: When removing a used cam that may be worn, you may have difficulty turning or removing it. This may not mean that the cam is cracked or fractured. The heat generated at the cam during the failure of the cam lobe, and/or lifter, will distort the cam and cause it not to be straight any more


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Glenn

Glenn. As I noted, I only assemble engines with a moly assembly lube now. The only one I have had to disassemble (hose to oil cooler split at highway speed, pumping out the oil before it got into the oil system) showed no cam/tappet/ rocker arm wear. But, this was a relatively low milage engine at the time of the incident. On my current crop of cars, I will not know whether the moly engine assembly compound has helped, or not, for many years. Its use is, however, a standard item amoung the better engine rebuilders. Hence, I use it myself and tend to believe the information you posted on the cam lobe wear, without the use of the moly, may be true.

But, I have no personal proof of it, just a belief. I have not had the opportunity to tear down an engine I rebuild 30 years ago--back in the STP days. Nor, have I had an opportunity to tear down an engine I rebuild 20 years ago back when LubriPlate was the common choice for engine rebuilders. Since you seem to have such an opportunity, and considering your general level of expertise, I would tend to believe that your experience is correct and accurately related.

Back when I did my first engine rebuild, about 1968 or early 69, I found that, at 62K miles, the block cylinders had a decided lip at the upper end where the piston rings had not touched. Today, when I pull apart an engine run with the modern oils, I find little, if any, detectable wear to the cylinder bores. Obviously, lubrication technology has made some very large advances over the last 40 years and we should all take advantage of it.

Les
Les Bengtson

Hi Les. I agree about oil technology having improved greatly. When I rebuilt my MGA engine 2 years ago, the cylinders were completely unworn, after almost 25 years of use! I was able to simply hone the cylinders, and install new rings on the old pistons. Talk about an inexpensive rebuild! I have been using synthetic oil for many years now, and it seems to really stop or greatly minimize wear of moving parts. I also use synthetic oil in my transmission, and use synthtic grease in all the grease fittings. Cheers. Glenn
Glenn

Glenn,
Thanks for an excellent article. I have rebuilt many engines and have always used the camshaft manufacturer's lube, and have never had any problems with the cams. I especially appreciate the section regarding verification of the pushrod turning, as I normally haven't checked that, although years ago I did. It is one of those little things nobody notices because nobody has had problems, I think.
Regarding the validity of the manufacturer's recommendations, we have to remember that the manufacturer places the cams under extreme testing, simulating thousands of miles in weeks. They have a much better idea of what does and doesn't work than we do.
I have just started(with my present vehicle) using synthetics, so I cannot speak this way or that way, but standard oils are, as Les stated, so much better than in years past that I know good oil will protect our LBCs long after we are around.
mike parker

Mike and Glenn. Well said. For those of us old enough to remember the modern oils are a marvel.

Mike. As to the "long after we are around", this is the main point. I have been driving these cars since graduating from High School back in 1968. I have passed my love of these cars on to my daughters. (One of whom just completed a 900 mile trip in her 77B to introduce her fiance to her aged maternal grandmother. Now, I only have to worry about the trip back.)

I should hope that the love of fine British cars will be passed on to their children. To anyone who has studied the history of the MG Marque, there is a special flavor in keeping these cars on the road and in daily use.

Les
Les Bengtson

This thread was discussed between 13/03/2006 and 14/03/2006

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