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TR2/3/3A Tips for Breaking in a Rebuilt TR3 Engine

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RedTR3

RedTR3

Jedi Trainee
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Need Tips for Breaking in a Rebuilt TR3 Engine

Hopefully in a couple weeks I'll be back on the road...I am sure that the mechanic/machinist will have instructions for breaking in, but I would very much appreciate any knowledge from you guys.

What I will have is new pistons/rings/liners, lifters, cam reground, cam bearings, crank turned to 10/10, line bored block, new head studs, etc.. Head was rebuilt earlier this year.

Thanks for any tips/advice!
 
Kas Kastner, Greg Solow, and several other well-known TR engine builders recommend immediately running the engine for 15-20 minutes at a fast idle (1500-2000 rpm) with NO blipping of the throttle. According to Kas, this allows the critical areas of the cam lobes to work harden and mate to the lifters. Obviously keep a close eye on the engine, checking for leaks, overheating, bad noises, etc. If you have one, directing a fan into the radiator may be a good idea as well.
 
This is one area where I err on the cautious side and use ZDDP or products like GM EOS and a good break in oil from Joe Gibbs or Brad Penn for the getting the engine going. Also, I'm more comfortable with using a shaft to spin up the oil pump to at least get pressure up before the first start up.

Once things are off and running, I would also follow the factory recommendation and retorque the head after 500 miles. Very surprising how much it can loosen up.
 
I'm with Randy, during the initial running, most engine builders suggest using a "break in oil" with high ZDDP levels. Generally, use 100-150 miles of running on the first oil, then change it (and either use more break-in oil, or standard oil with a high ZDDP additive) and go through 500 miles, then change again and just use your preferred oil.

After that initial high idle running to break in the cam, once you're actually driving the car, the standard rules should apply: vary the speed/rpms and avoid wide-open-throttle.

Since TRs are low-stress engines (provided they are below redline ;) ) you shouldn't have much problem.
 
Break in the cam and then drive it like you plan to use it. The only hard rule is not to cruise at a steady RPM, like locking 60mph for hours on the freeway, for at least the first 500 miles. Vary the rpm regularly to ensure everything in the motor stays lubricated.
 
prime the oil system before starting, verify they got the cam bearing in right by watching for oil to spurt through the rocker arms.
 
A friend of mine with a FAST TR4 race car. Has been building race engines for 50 years.

20 minutes at 3000-3500rpm. Let sit overnight. Retorque the head cold. 20 minutes again doing the same. Change oil. Go racing.

How I just did my bike (roller cam):
15 minutes fast idle (just trying to get everything to do a heat cycle). Let sit overnight. Retorque head cold. 1/4 throttle ride up to 60, engine brake down to about 20 (downshifting so it doesn't lug). Do that a few times. Repeat at half throttle and lastly at full throttle. Change oil and done.

You want a good oil with higher amounts of ZDDP regardless. This has been beaten into submission countless times. Try to use a non fully synthetic oil for breaking in. Brad Penn, Joe Gibbs (now called Driven), Amsoil all have specially formulated break-in oils. Might have to mail order it, but just hit the easy button and do that.
 
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