Very excited, first start after rebuild!

[grisoni]

All the info is for pushrod engines, the lil Fiat motor gets plenty lube on the cams, you'll do no harm but I doubt it makes a lick of difference..



( Failure to run the motor at 2500 rpm or higher (alternating 500/1000 rpm up and down) to allow the crank and rod big ends to throw oil onto the cam, for a minimum of 20 minutes.

Warning Warning: No idling! The motor should not be run at less than 2500 rpm for a minimum of 20 minutes. If a problem develops, shut the motor down and fix it, then resume break-in. The main sources of camshaft lubrication is oil thrown off of the rods and crankshaft, drain back from the oil rings and oil blowing around inside the crankcase (this is known as "windage"). At idle, the crank isn't spinning fast enough to provide sufficient oil splash to the camshaft/lifters for proper break in protection. )


All the info is for pushrod engines, the lil Fiat motor gets plenty lube on the cams

[So Cal Mark]

lol, so your theory is that Fiat cams don't/can't go flat?

[zachmac]

I am so happy for you all that you've been able to engage in this spirited discussion of break in methods. Anyone got any answer to my other questions in the original post?

[timinator]

All the info is for pushrod engines, the lil Fiat motor gets plenty lube on the cams

The standard for testing motor oil used to be done by dyno runs on 2.3l Pinto OHC engines. The 2.3l is known for cam failures and it has a hollow camshaft with oiling directly to the lobe. As Mark stated he has lots of flat Fiat cams to prove just being bathed in oil is no guarantee of proper lubricity.

If you don't believe that the industry standard for engine break-in with modern day oil is required then don't follow it.

[So Cal Mark]

never in my life have I experienced people advising against preparation. Oh well, it's your motor, abuse it all you want

[DieselSpider]

Are we talking special precautions for newly installed performance aftermarket cams with stiffer dual valve springs, etc or even OEM with the standard valve springs and such?

[zachmac]

As Mark said, you all can do whatever you like to your engine. I DID use lots of assembly lube with additives and I DID bring it right to 2000 rpm and idle it there for about 20 minutes once I fixed the oil leak. I don't get this whole thread as why would you NOT take the simple precaution of a 20 to 30 minute 1800 to 2000 rpm break in at initial start? After all, I haven't seen anyone arguing doing so would hurt? But Google will find you many, many arguments that not doing so might; including tech articles on almost all the cam manufacturer sites.

Yes they are mostly talking about big block Chevies and high lift cams, etc. But REALLY? You can't be bothered to spend twenty minutes of engine run time to possible ensure an extended engine life?

As far as I am concerned this thread is dead.

[So Cal Mark]

to revisit your initial issues;
I'm not familiar with the cams you're using, so I don't know their specs. But I'd start out with cam timing straight up and experiment with it after the motor tune is fairly sorted out. You'll find a bit more initial advance will help with our older mechanical advance ignition. With perf cams I've used up to 15btdc initial timing. The idf tuning guide we have posted is a good starting point for your carbs as far as jetting

[bradartigue]

never in my life have I experienced people advising against preparation. Oh well, it's your motor, abuse it all you want

Don't confuse attempts to understand with a lack of precaution.

Must be winter somewhere, this place is grumpy.

[So Cal Mark]

I didn't see many attempts to understand, mainly dismissals of advice

[grisoni]

I meant no disrespect, nor do I care how one does break in a motor, I just pointed to the fact that one could glaze the cylinders vs. cam lobes going flat. I think on these little anemic Fiats neither would be an issue.

If I inadvertently stirred somebody's oatmeal I apologize

[timinator]

I meant no disrespect, nor do I care how one does break in a motor, I just pointed to the fact that one could glaze the cylinders vs. cam lobes going flat.

I can't remember the last time anyone I know glazed a cylinder wall. Since plateau honing is done by almost any machine shop these days seating rings is really effortless. Light load and excessive idling of new engines is usually the cause of glazing. So 20 minutes at 2000 rpm and drive the car normally and glazing can only be caused by overly rich mixture.

I saw the reference to airplanes so I guess you think there is a similarity between chromed or ceramic coated cylinder walls and a Fiat cast iron block. Doesn't fly.(Pun intended) Cams start going flat instantly. Call up a cam manufacture and ask them about the BAD old days when ZDDP was first removed from oil. Nobody knew why everybodies cams were going flat. Now they know why and Mark is trying to educate Fiat owners so they can enjoy their cars.

Got to go now my oatmeal is ready.

[bradartigue]

I didn't see many attempts to understand, mainly dismissals of advice

The general frustration I read is with the answers - it may be advice, but just saying "because every aftermarket cam manufacturer says to do it" isn't answering the question of why. The initial explanations given deal with non-FIATs, then airplane engines. I was waiting for someone to throw in how to break in a steam engine. You have to get half way through this thread before the "advice" given is even explained with sufficient information to justify the procedure.

Enthusiasts are curious people; feed the curiosity, don't dismiss it.

[azruss]

My interest in this conversation is curiosity as i have never heard of breaking in a cam. I know the shims are hardened to a very high rockwell and have never seen one with any wear. So that leaves the cam lobe. If cams are too hard, then they are brittle. I'm thinking the break-in period is designed to harden the lobe tip through the constant banging on the shim.

[DieselSpider]

It seems to conflict with piston ring seating instructions held to by Hastings and others though. Initial warm up to operating temp at 1,500 rpm (fast idle), retourque and then warm up and ten times accelerate hard from 30 to 50 mph as the object is to apply a load to the engine for short periods of time and in rapid succession soon after engine warm up. This action thrusts the piston rings against the cylinder wall with increased pressure and results in accelerated ring seating. Drive vehicle normally but avoid sustained high speed during the first 100 miles.

Back in the day a competition cam and rocker set would usually not be installed until after the rings had been seated and run in using a break in cam/old cam.

The old way appears to satisfy the needs of both the rings and the cams.