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Author Topic:   Engine Break in, Procedure ?
Kromulous
Member
posted June 10, 2004 07:24 AM
Could someone tell me the proper way to break in a race engine. Building our first one now 355, 6" ROD, 12 to 1, roller cam (double springs 200# seat pressure), and 3/8's pushrods with guide plates. 23* Dart Pro 1 heads 215cc runners, 2.05 / 1.60 valves (SS).

Just to be through it has a 4340 Eagle crank, H series Clevitte bearings, Eagle Rods, Wiseco pistons, Plasma rings. Also it has Howrds billet caps in 2 3 & 4, in a Stock block. 750 CFM 4150 Holley, and a Mallory Distributor & box.

Also want to mention, it has a Melling oil pump, and the upper end oil flow has been restricted.

I've read that you should set the timing low, and pre pump up the motor. If someone could give me a good run down of the pre set up and break in procedure it would be mucho appreciated.

Spent all the moola i got on this engine and dont want to screw it up LOL. Plus its my first attempt at building a race engine.

Not sure if all that info above was needed, but thought it couldnt hurt.

[This message has been edited by Kromulous (edited June 10, 2004).]

dirtbuster
Member
posted June 10, 2004 08:13 AM
well with a roller its a lot simpler. You dont have to worry so much about tearing up the cam on breakin. I would get everything ready to go, prime the engine by driving the oil pump with a drill. Then set your distributor as close to your timing as you can get. Get the carb ready prime it and fire away. Keep a timing light handy to adjust after she fires if it needs it. Then let her run for awhile to build some heat and break in rings.


Raz_900
Member
posted June 10, 2004 08:31 AM
Ya, even though it's a roller cam, run it around 1500-2500 (varying) for about 20 minutes. The cylinder walls need the oil splash for the rings to break in and not wear out. Timing shouldn't much matter unless it overheats (if it does, you probably have a vacuum leak or sumthing).

Shut it down, let it cool about 30-60 minutes, change oil and filter. Run it moderately easy up and down the street or for warmups, little harder for first race, change oil and filter again, then have at it.


racer038
Member
posted June 10, 2004 09:32 AM
I would also talk to the maker of your valve springs. There are some engine builders that recommend a couple of heat cycles for the springs. I am following this procedure (for better or worse) a) Pre lube with drill and old distributor shaft. Start motor. Check for fuel leaks. Have timing light handy and set timing conservatively. Run engine for 20 minutes varying 2000 - 2400 RPM. Let engine cool, checking plugs. Run engine again for 20 minutes at 2000-2400 RPM. Shut down, change oil and filter. Remember to use the same fuel octane you plan on racing. Don't run pump gas, just because it's in the garage and not the track. My 2 cents.


Kromulous
Member
posted June 10, 2004 10:08 AM
It ok to run race gas to break in, then switch to alcohol later? or should i just run the alky right from the get go?

Also what oil? start out on synthetic or fossil oils? I've read to where some break in on a high detergent straight 30 weight and then switch it out for more of a racing oil, this accurate?

Thanks for all the pointers so far.

Raz_900
Member
posted June 10, 2004 10:41 AM
Dino oil for breaking, then synth after a race or 3. Did you measure the bearing clearances? Bearing clearances and oil pump capacity determine the weight oil required. If the bearings are on the tight side, a lighter oil is needed. Loose side and 20w50 or straight 60 weight might be needed to keep pressure up. Thick oil in tight clearances is just as bad as thin oil in loose clearances.

Personally, I think the HD SAE 30 or 40 is an old wives tale on breakin. If you need high detergent in a brandie new motor...ahh..???? It should be clean already.

I don't see any problem with running alky out of the gate. Just make sure it's not rich and poluting the oil with alky/water.

dirtbuster
Member
posted June 10, 2004 10:54 AM
Actually it would be better to breakin on gas then switch to alky if you have a carb to do it. The gas will build more heat and rings will seat better.

As for oil id reccomend dino oil for breakin. Then switch to syn. Have heard you can run syn from the start on roller motors but i think conventional would help the rings in a little better. As for weight it depends on the rest of you combo but 20w50 would work fine. 10w40 would be alright in the shop probably. Id be careful going to light on the track without an oil cooler because the thinner oil may not be able to support the loads on it once it gets hot. Synthetic can run lighter and not hurt anything. Either way (but especially with conventional) make sure the engine is up to temp before hitting the track and racing.

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