I am looking for advise on firing up my fully rebuilt L72 engine. The builder says that due to the solid lifter cam i should bring it right up to 1700 rpm for 20 min to ensure proper lubrication to the cam. should i pull the dist and pre prime? or will the assembly lube be sufficiant until the pessure builds up. should i check the timing before i start it? if yes, how? it has a fully rebuilt TI system, are they prone to any glitches on fire up? i am very anxious about firing it the first time and not being able to maintain this rpm until every thing is adjusted. due to the amount on money i have in this engine i want to do it right. if any one has any input on do's and don'ts i am all ears (or should i say eyes?) bill
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Re: firing up a fresh L72 engine
Using a pre-oiler is a good idea, but not absolutely necessary if the engine was recently assembled with assembly lube on the cam, lifters, and valvetrain mating surfaces. If you do use a pre-oiler rotate the engine several revolutions while the pre-oiler is turning the oil pump.
Static time it by placing the balancer notch at the proper initial timing point on the timing tab. Then rotate the dist. housing until the rotating pole piece tips are just past (clockwise) the stationary pole piece tips. This should place the initial timing within a degree or two of spec, which will enable the engine to start.
If you used a quality camshaft that has Parkerized lobes and OE or OE equivalent valve springs, a cam breaking is not necessary (GM didn't do a cam breakin on OE engines), but it's not a bad idea either.
The engine should start fast if you fill the carb with a syringe through the bowl vents. Fill slowly until you see fuel dribble out the venturi discharge nozzeles.
Pump the throttle to the floor a couple of times and check that the choke valve is fully closed. Wait a couple of minutes to let the liquid fuel in the manifold evaporate, then crank it. If everything is in order and you follow the above procedure, it should start right up.
Best valvetrain (and engine) life is ensured by the use of API CI-4 or CJ-4 motor oil. (Check archives if you don't understand this.) Also add a bottle of GM EOS. Since the solids in assembly lube will tend to plug the oil filter, change it after the initial cam breakin procedure. Change the filter again at 500 miles, but leave the original oil and EOS in the engine.
Do a complete oil and filter change again at 1000-1500 miles and continue to use CI-4 or CJ-4 motor oil.
Current API SM oil for modern spark igntiion engines IS NOT A GOOD FORMULATION FOR VINTAGE ENGINE REGARDLESS OF THE BASE STOCK - SYNTHETIC OR MINERAL OIL!
Duke -
Re: firing up a fresh L72 engine
Bill,
Last summer, we started a L36 with TI after a rebuild. You should preprime the motor with distributor out. Put the #1 piston at TDC to static set the timing. Use the timing mark for reference for exact positioning. The distributor rotor should point somewhere toward the front passenger side of the car if you have the distributor positioned correctly. Re-install the distributor and leave the clamp snug, but not tight, so you can rotate the distributor as necessary. The rotor should be under or close to the #1 plug wire.
With TI, never turn the motor over with the coil wire disconnected. That could damage it. I always disconnect the wiring at the transducer to turn the motor over without starting. I suggest you turn the motor over until you get fuel pressure to make sure there are no serious gas leaks. I also try to get get oil pressure. Water leaks are not as serious.
Then, plug the transducer in and see what you got. If you get her going with no serious leaks, hold her like the builder said. And one more thing, have fire extinguisher nearby. It never hurts!
Good luckComment
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Re: firing up a fresh L72 engine
Duke,
Will you elaborate on GM EOS? What is it and what does EOS stand for?
Thanks and best regards,
GeneComment
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Re: firing up a fresh L72 engine
I believe EOS stands for Engine Oil Supplement. Regardless, I went thru this last winter... just go to the Chevy dealer and ask for a 4 oz. bottle of it. Tell them you're firing up a rebuilt old engine for the first time. They'll know what it is. Also, I believe Duke or others have posted in the past that the EOS is to be used for the first oil in the engine, but should not be used for subsequent oil changes.Comment
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Re: firing up a fresh L72 engine
Gene,
EOS stands for Engine Oil Supplement, an oil additive recommended for initial startup and run for new engines.
As Duke states, use API CI-4 or CJ-4 motor oil, Rotella is one brand (recommended for diesel engines) with EOS. There have been extensive discussions here about oil formulation and why you should use diesel oil. They are worth the read and could save you a lot of money.
VerleComment
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Re: firing up a fresh L72 engine
Verle,
Thank you for answering my question. I believe that my engine builder put Rotella in the engine after assembly. I have not started it the first time. Before I do so, I'll clarify what oil he used.
If he installed Rotella, should I add GM EOS or is it redundent and unnecessary?
Best regards,
GeneComment
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Re: firing up a fresh L72 engine
Engine Oil Supplement. It's rich in ZDDP anti-wear additive and is specifically sold for new engine break-in. It's been around for over 30 years.
DukeComment
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Re: firing up a fresh L72 engine
Like I said, use CI-4 or CJ-4 oil AND EOS for the initial oil fill. When you change the initial oil fill (after the two recommended filter changes) there is no need to use EOS or thereafter. Continue to use CI-4 or CJ-4 oil.
DukeComment
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Re: firing up a fresh L72 engine
Bill, The 66 requires a groove in the rear journel of the cam for oil flow. Some replacment cams do not come with this groove. It can be machined in if the engine builder is aware of the need. If you're not sure it would be good to check with him before cranking it over.Comment
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GM Part Number 1052367
The last bottle I bought was PN 1052367 (16 fluid onces). In fact, I think Joe Lucia posted that part number here.
Use of the entire 16 once bottle may be debatible...it appears the intended use of the product may have changed over the years. The label now says E.O.S. Assembly Lubricant, and the directions on the back of the bottle indicate pouring it over the bearings and camshaft before installation, down the lifter bores, and coating the cylinder bores.
The label also has an interesting disclamer: "GM RECOMMENDS E.O.S. ASSEMBLY LUBRICANT ONLY FOR THE SPECIFIC PURPOSES LISTED ABOVE. GM DOES NOT RECOMMEND THE USE OF THIS OR ANY PRODUCT AS AN ADDITIVE TO ENGINE OIL." It sounds like to me someone may have managed to stop up their filter with it, and blamed GM for their problem.Comment
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Re: firing up a fresh L72 engine
Duke...is there a noteable difference between GM EOS and say STP?? Thx FrankComment
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Re: firing up a fresh L72 engine
I would not draw ANY comparison between EOS and STP. GM is not in the business of selling snake oil.
Using EOS as an assembly lube is fine, but a molydisulfide assembly grease will cling better to valvetrain wear surfaces. Okay to use EOS on bearings, pistons/rings, and cylinder walls. Then just pour the rest onto the lifters and rockers before you install the manfold and valve covers.
GM DOES NOT RECOMMEND EOS AFTER BREAK-IN, and there is absolutely no need to continue using it if you use HD diesel engine oil. EOS' heavy does of additives like ZDDP can rapidly build up spark plug and chamber deposits if use is continuous and can degrade catalysts on catalyst equipped engines.
DukeComment
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Re: firing up a fresh L72 engine
Thx Duke I will abide by your advice, however I have used "Power Punch" for years in assembyling engines with a lot of success. I always considered EOS, STP, and Power Punch the same. But I know you know chemistry more than I do. I used "Power Punch" and "Isky Lube" for years with no problems...Regards FrankComment
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Re: firing up a fresh L72 engine
what weight APICI4/CJ4?Comment
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