I ran across something I'd never heard before, but it makes perfect sense - Summit Racing (great company - excellent customer service), in their description of the break-in oil I'm using, says that for optimal results, the oil should be heated to 180 degrees F prior to first starting the engine after a rebuild. I can see how this would help circulate the oil quicker to the critical components when starting a rebuilt engine for the first time, and maybe even minimize the lifter-clatter time, although the fact that I used assembly grease on all the critical parts (main, rod, and cam bearings, cam lobes, etc.) should mitigate most initial wear issues.
However, I love this type of thing, so, since I've put so much time, effort, and money into this project, I figure, what the heck, it wouldn't hurt to come up with a way to pre-heat the oil prior to starting the engine for the first time. The question is, how? I've found they sell oil pan heating blankets for this purpose, but that's just way too easy, so I'm wondering about DIY ways to accomplish the same thing. Heat gun? Space heaters aimed at the pan? Put a pot of boiling water on the jack and submerge as much of the pan as possible in the hot water (may be hard to get much of the pan submerged on our slanted engines)? None of these seem like they'd transfer enough heat to the oil to really heat it up much. Any other ideas from the creative folks out there? Thanks.
not sure i like the idea. to avoid leaks, the gaskets and o-rings should heat gradually, and not be subjected to hot oil abruptly like they would if you heated the oil in the pan.
i always start the engine with a lighter oil, or a break in oil, and then change it at 500 miles to a mid viscosity oil, and then change it again at 2000 miles to what i would normally run.
before actually starting the car, i also always pull the plugs, disconnect the coil, and make sure no fuel is running into anything (in our cars you pull the DME relay), and run the starter motor for 30 seconds, 3 or 4 times, taking a 1 minute break in between each run to give the starter a break.
I've got a 120,000 btu space heater for my hanger. I may shoot it at the pan for awhile next time I do this. Sounds like the kind of thing that can't hurt.
In my little bit of research on this topic, it appears that the most common approach is to attach some sort of resistive heater to the bottom of the pan. This should heat the oil gradually, and protect the gaskets from any abrupt heating. Just need to find the most economical way to do this, as I don't feel like spending a lot of money on something that I don't think is all that critical. Just playing, to be honest - I can't resist a little project like this.
And yes, I was definitely planning on cranking the engine with the starter prior to firing it up.
Flash makes some good points. I don't think you need to heat the oil to 180 deg. That temp could have some unintended consequences. But warming some, say like to 100 dF, does make sense.
As to using the starter I have a slightly different ah spin <img src="/forum/images/smilies/968/biggrin.png" class="smilie" alt="" /> . The initial steps I do with plugs out, disconnected coil and DME relay pulled. First I want to turn the crankshaft a turn or two with a wrench by hand to make sure nothing is binding. Then I spin it once a few rotations with the starter, again just to make sure nothing is binding. I don't do this more than once because in this mode you are just spinning things without getting any oil supply or pressure to the bearings, lifters, cams, etc. If it will spin with the starter once without problems, I then reconnect things and start the engine. If I have two bodies, I'll start it and watch the oil pressure gauge while my assistant is watching the engine itself for leaks, fires and stuff.
Just one amateur's technique.
You got an old electric blanket? Wrap up the engine and put it on H for awhile.
remember that the oil thermostat will not allow oil to pass into the cooler until it hits 200 degrees, and once you hit that, it will open up and let that cold oil in there, so whatever you do in the way of pre-heating will have a limited effect. but, by all means, have fun. as i am a nervous nelly with new motors, i'll stick to letting things heat up evenly and gradually, the way they were designed. there is no way to get inside the motor and heat up the metal, so heating the oil sounds like a bad idea to me. but hey, it might work. i can sure see it working on a dry sump system.
let us know what you find out.
lear - interesting. i do the manual spin too, but i spin it with the starter to get the oil moving at only 200rpm. it isn't to build pressure, but the pump is moving, so there is oil flowing, but it's at a non-loading low rpm speed, so it stands a better chance of getting oil to the bearings than starting it right up and immediately putting load on dry bearings.
Yeah, I think the idea is just to allow the oil to get to the metal parts a tad quicker. While it doesn't get terribly cold here in Texas, it can dip into the 20s, so I think it makes sense to warm the oil up a bit before cranking it up (sure to be probably the most nervous moment of my life). I think I'll do some combination of a space heater and a heating blanket.
Did you use assembly oil/grease when rebuilding you engine .
I really do not see any advantage .
waste of time in my opinion .
interesting point. i always used an engine building grease when i built them. however, my current builder refuses to do that on porsche engines, due to their tighter tolerances. he says it actually can cause a starvation problem. since he built this one, i let him do it his way.
[quote name='flash' timestamp='1357144114' post='136940']interesting point. i always used an engine building grease when i built them. however, my current builder refuses to do that on porsche engines, due to their tighter tolerances. he says it actually can cause a starvation problem. since he built this one, i let him do it his way.[/quote]
I agree .
Some parts oil is better and some parts the assembly lube .
An Aluminum pan and engine block will soak up the heat from the oil almost immediately. A light weight oil to me is the way to go. You will be draining it soon to check for any metal particles anyway. My father used cheese cloth to strain the new oil and I have followed suit. I have even used 10-10 turbine oil before with great results as it cleans out all oil passage ways.
Cheers,
Larry
I don't really see that the science supports warming the oil unless you are using a single grade oil. If you are using a multi-viscosity oil, I don't see much of a benifit to heating the oil up first. Due to the nature of the multi-visosity, the viscosity in cenitstokes (?sp) will be close to the same no matter what temp you have the oil at as long as it isn't outside in 0F weather. If it is an attached garage where it's in the 50F range or higher, I wouldn't worry about it.
I do practice the use of assembly lube (gives you a little more protection when surfaces are new to one another especially when the assembly process may have added some microscopic nicks or brusess; adds some extra EP modifers to the mix while they burnish themselves together). Always put a bar on the crank and turn it over by hand, just to make sure it feels right. And then I crank the engine with either the fuel pump off, or the igntion not working just to make sure all the galleys are primed before starting.
Thaks for all the responses. I agree that warming the oil is probably not a make-or-break factor. I was just intrigued by the fact that the descripetion for the oil that I'm using (Joe Gibbs Performance break-in oil, I believe 15W50, from Mike Lindsey's recommendation) specifically recommends warming the oil before the first firing. I think I'll warm it up to some degree, but not spend a lot of money or time on it. And I used assembly lube on the parts where it was recommended. I thought these engines had relatively loose tolerances, which is why Porsche recommended such a relatively high viscosity oil. At least that's what Mike told me.
And yes, I've turned the engine over many dozens of times since the rebuild (most recently when pulling out the flywheel for the fixes Flash has prescribed), and everything is very smooth, and the timing marks line up correctly, so hopefully no disasters will happen, but one never knows...
After a recent rebuild on a old Austin Healey, I took my Motive Pressure bleeder, added two quarts of oil and use it into the oil filter port to pressurize the oiling system before first roll-over or start-up. Not sure on the 968 a location of a good pressure port, just an idea, maybe good for seasonal shutdown periods for northern snow bound 968's also.
There are oil pressure systems like that made for race applications. It is basically a tank with a pressure bladder on one side, and oil on the other which is connected into the lube system of the engine. It has a gate valve in the line, so when the engine is running it will build up pressure in the tank. Once the tank shows system pressure, then the gate valve is closed so as to maintain pressurized oil in the tank (they usually also have a schrader valve on the air side of the bladder so it can be pressurized from an air pump). Before you start the engine, you open the gate valve which sends pressurized oil though the engine. I don't know enough about the systems to know how they deal with the extra volume of oil, until the tank is refilled after the engine starts.
When I lived in Alaska we got 40 watt heating pads from NAPA for $10 and siliconed it onto the oil pan to keep the oil warm over night. This should heat your oil to about 100-140 degrees F depending on oil volume and ambient temps. They plug into standard 120V outlets. Cheap and quick.
Ten bucks, huh? I would do it for that, but I haven't been able to find any heating pads for under $60. I went ahead and aimed a pair of space heaters at my oil pan for a few hours yesterday, and according to my oil temp gauge, got the oil up to 155 deg. Unfortunately, the engine start was a no-go. Not hearing the fuel pump whine, so it's got to be either the DME relay (I have two of them and the fuel pump doesn't make any sound with either of them in place, but that doesn't necessarily rule out the DME relay), or the pump itself. I knew starting an engine that's been disassembled/sitting for nearly two years wouldn't be straightforward...
Like the pressure oil idea. We use to do this on piston aircraft engine when we rebuilt them and I recently did the same when rebuilding the Cummins in my dodge pickup.