Engine break-in run.

[Oiluj]

Just finished a 290 mile drive in my 240Z to finish breaking-in the engine today.

Travelled from the San Francisco peninsula and picked-up a buddy in the east bay, about 70 miles away.

The second stop was at Rebello Racing in Antioch where my engine was rebuilt. Showed the completed car to Dave Rebello, so he could see his 2.7 upgrade installed. Dave complimented me on the car and pointed out that my harmonic balancer has the beginning of a wobble. Nothing to be concerned about, but he suggested it be replaced down the road. He also suggested that rebuilding the distributor could improve how the engine runs on pump gas.

We filled the tank and crossed the San Joaquin river over Antioch bridge into the delta proper. The SF delta is full of winding levee roads with a 10 to 20 foot drop on either side. On one side is water, the other drops down to farm fields or orchards. Safe speeds on these roads ranged from 25 to 70 mph with all kinds of road conditions.

We passed through several small delta towns, Isleton, Locke and Courtland, making a few stops at delta resorts for refreshments and lunch. We made it almost all the way to Sacramento, traveling the back roads.

After dropping-off my buddy, I got caught in rush hour traffic for about 90 minutes on the way home. I travelled a total of about 20 miles in stop & go / very slow& go traffic. Even with the heavy stop & go traffic, the car still got 23.4 mpg. Better than I expected! Without all the stop & go traffic, I’m sure it would have easily exceeded 24 mpg.

I still have a squeak under the floor in the differential area. As I have changed the u-joints in the half-shafts, I’m thinking it may be the diff mount, a loose exhaust hanger or the exhaust pipe rubbing somewhere. I’ll take a closer look next weekend.

Now that the engine has over 500 miles on it, this weekend I’ll change the oil, re-torque the head and manifold bolts. Sorry, no pics. I forgot to charge my camera battery...

[Travel'n Man]

Julio-

Did Dave do any head work for you? If so, can you tell me what your specs were and if your happy with the work.

Thanks in advance. I'm getting ready to order a head with cam from Dave next week.

[Oiluj]

Yes. He did what they call a "touring" head with a stage 3 cam. The combustion chambers are reworked and on my e-88 head the valves were enlarged to fit the 280 valves.

If I recall, the cam is .480 / .280. Idle is a bit rough, but it really revs fast! I'm very satisfied with Dave's work. He's an expert on tweaking the L-series engines.

[Oiluj]

Even with the heavy stop & go traffic, the car still got 23.4 mpg. Better than I expected! Without all the stop & go traffic, I’m sure it would have easily exceeded 24 mpg.

Was curious, so today I did a 50 mile freeway drive. Stayed between 65 and 75 mph and she got 25.6 mpg! Now I'm wondering what she'll do with the 5-speed!

[ozconnection]

He also suggested that rebuilding the distributor could improve how the engine runs on pump gas.

After dropping-off my buddy, I got caught in rush hour traffic for about 90 minutes on the way home. I travelled a total of about 20 miles in stop & go / very slow& go traffic. Even with the heavy stop & go traffic, the car still got 23.4 mpg. Better than I expected! Without all the stop & go traffic, I’m sure it would have easily exceeded 24 mpg.

Sounds to me that your new engine it's running nicely!

Does you engine ping? Does it get lousy economy? Does it start nicely and settle quickly to a nice and smooth idle? Does it have good throttle response? Does it make good power? (yes, I know its a fresh engine)

Can you see where I'm going with this? How much 'better' can you get things with what I assume to be a stock distributor? Sounds to me like all is well there, spend your time and money on a better balancer, a defective one will cost you a lot more than a 'defective' dizzy. Wobbly balancer...now that doesn't sound very reliable....at all.

Just my 2 cents

Cheers

[Travel'n Man]

Julio-

Can you detail your engine break-in for me. My rebuild is getting close and Rebello Racing is shipping my head at the end of this week. I have already saved some threads to read up on but wanted to know how yours is going. Dave Rebello told me to keep a load on the engine (with the brakes) and maintain RPM's at around 2500 - 3500 until the brakes got hot. Then normal driving with frequent oil changes.

He also recommended a 50-50 mx of oil:

50% Pennzoil GT Racing Oil 20/50

50% Motorcraft 5w/30 Synthetic Blend

I was going to change at 50 - 100 - 500 - 750 - 1000 and then normal mileage along with filter ( I will not complete this until next driving season as fall is closing in on us in the Western-N.C. mountains.

Any tips?

Thanks in advance!

[Oiluj]

Mitchell,

I can't claim any expert knowledge when it comes to breaking-in engines, but here's what has worked for me.

Change oil at 100 and 500 miles. Used the oil Dave put in it for the 1st 100 miles. Probably the blend he recommended to you. Then went with Castrol 10-30 for the remainder of the break-in.

Initial start-up break-in was done on Dave's dyno. I done the brake loading thing he described in the past. After that, I just tried to keep the engine from remaining at a constant load or rmp for an extended period of time. That's why my initial drives were up & down hills and on curvy roads with plenty of speed changes. Also, I endevored to keep the rpms below 5800 for the first 100 miles.

Seemed to work well for me. Had a few puffs of smoke in the first 20 miles, then nothing. Engine uses no oil and oil is still looking clean.

Now that I have over 500 miles on the engine, I have to decide if I'm going with a synthetic oil or sticking with Castrol 10-30.

[Inf]

Nice, sounds like you did what my mechanic advised me to do during break-in.

I know people come on here and argue about synthetic vs. regular oil all the time, but I'm definitely going back to regular 10W-30 when it's time to change. I went to synthetic right after 500 miles, and I started to get some small leaks above the oil filter at the head gasket, and around the front cover. It's not a fast leak, I've driven probably 1800 miles and the oil is still above the max line on the dipstick (and still looking clean). It just turned keeping the engine bay and garage floor clean into a losing battle.

If your engine work is anything like the rest of your car I've seen on this forum, your build is hopefully a lot tighter and well executed than mine, so hopefully you won't have those problems if you decide on synthetic.