painting an engine ?'s and break-in process

[MaxPower]

OK. Need some pointers/tips for painting an engine block. Specifically, I bought a reman'd motor(ATK) for the Jeep and would like to paint over the black paint that it comes finished in. Lighter colors make it easier to see oil leaks and what not down the road and to make things brighter in the engine bay when working on stuff. So my ? is it OK to just degrease the surface of the finish that is already there of do I have to scuff it(scotch-brite or similar) to get teh absolute best adherence possible? brake cleaner OK to degrease or will that ruin what is already on there? or recommendations?

And as well, what is the procedure for properly breaking-in a new motor? I have read several different trains of thought on this on the internet and would like to hear some more experiences for achieving the very best in ring sealing and optimum power output.... Your thoughts?

[pandemic]

You're going to want to sand it down to get the best possible surface for the paint to adhere to. You also want to make sure to buy high temperature paint and primer. Personally, I'd prime it and then paint it but I don't think it's a requirement.

Composition of the block is also important. If it's an Aluminum block I wouldn't use brake cleaner. Use something that won't eat aluminum. I learned that the hard way :P

I think the best break in procedure would be low revs/low speeds for about 100 miles and be very gentile with it for up to 500 miles. After that it should be pretty much set. Also, depending on block composition, a magnetic oil drain plug could be a plus.

[Exbiker]

All I can offer is what I did in the past. Every V8 car motor we built was broke in hard. Every diesel I owned from new was broke in hard. My big thing was to no hold it to any steady RPM or long idle till after 500 miles. (no cruise control for that mileage)
I never had a motor with excessive oil consumption or premature failure.

[Asmodeus6]

Since the block was already painted it's going to be more difficult than if it wasn't (IMO) I would not use brake cleaner as a degreasing agent either. Mainly because it leaves residue which can be reactivated by wet paint, softening the underlayer and effecting the overall strength of the paint.

You are going to have to either sand it or media blast it. But, I don't like media anywhere near an engine. This includes people carelessly blasting valve covers to powder coat or paint them... I've seen people lose engines because of it.

I would rough it up with sand paper and then wash it down with soapy water. Then rinse with clean water and then acetone. Chances are that if you use thinner it will soften the existing paint. You may be OK with using VERY hot water to rinse it and the heat will help evaporate the water and aid in the drying process. At that point I would use a high temp paint commonly available at an auto parts store. VHT, or any of the heavy ceramic high temp paints. Priming over the existing paint won't likely give you any better adhesion than the original paint. So I wouldn't bother. If they did a good job you'll be ok. If they didn't, you're fucked, and there really isn't any way to fix that aside from getting it all off. (See also; near impossible on an assembled engine)

As far as break in, the key is evacuating the debris from break in as often as possible. If the crank was cut, or they didn't do a great job cleaning the engine after machining, there can be a lot of metal debris circulating in the oil in the beginning. Getting that out of the stream before it impacts moving parts and embeds itself into bearings is paramount to avoiding early failures. The best thing you can do is change your oil and filter OFTEN during the break in period. I don't deal with stock engines or Jeep's. But we break our stuff in hard and flush it out right from the very beginning. Driving it easy is a good way to get mediocre ring seal. In my world, that defeats the purpose of the engine rebuild.

The key is engine braking. Go out and drive the vehicle after it is up to operating temperature and you are SURE there are no fluid leaks or problems. Letting it decelerate in gear from 35-40mph will help to suck the rings into the cylinder walls as vacuum increases and cause the rings to wear in and create a good seal. For us this includes some basic driving, (to double check everything is OK) then light throttle to a moderate rpm, and deceleration. Repeat a few times. Make sure nothing is leaking...
Increase throttle application, and rpm, decelerate... repeat the same process until you are close to your redline. I usually don't tach a car out on it's maiden voyage or go WOT - the point is engine braking here and heavy vacuum. But I do bring it within 1000 rpm or so depending on what engine I am dealing with.

At this point we change the oil AND filter. And check for debris and signs of component failure. If we're OK. I recommend driving as you normally would (but with the power turned down. --- this has more to do with the cars I deal with... not so much a jeep...) This gives things like clutches and such time to break in as well. If it's A/T - not a concern.

But with BRIEF oil change intervals. 100miles 250miles... and then 500miles. With OIL and FILTER being changed. This is the point where we drop the pan and shake everything down. It's either going to run at this point - or it should have already exploded / bad build. With this oil change regimen your oil should be free from particulate by the 3rd change. I recommend switching over to your preffered synthetic at about 1000 miles if you use it. By then you are ready to rock... and when we start tuning the car back to it's desired power level. (again does not apply to you.)

For the average car - or Jeep. I would still change the oil as frequently as you can bring yourself to. Buy cheap oil, and just dump it a lot. But use good filters. Don't go buy a bunch of mobil 1 oil and filters and pour it down the drain. You can usually get Wix or even OEM filters for a fair price - just don't use the cheap ass Bosch or STP filters... they won't handle the smaller particles and will just pass them right through back into your engine.

Which will end up embedded in your brand new bearings...

But whatever you do, do not go put-put around like a grandma and then wonder why your ring seal won't pass a leak down test at 1000 miles... you obviously do not want to abuse the car/engine. But you DO need to get your foot into it enough to get the rings to seal. Every motor / car is different, and they all like different things. YMMV.

I deal in turbo 4 cylinder stuff. Predominantly Mitsu. And they can be particular / picky motors if you don't play by the rules.

Your Jeep's I6 should be more forgiving. They are good engines.

[wis bang]

As far as break in, the key is evacuating the debris from break in as often as possible.

The best thing you can do is change your oil and filter OFTEN during the break in period.

Driving it easy is a good way to get mediocre ring seal. In my world, that defeats the purpose of the engine rebuild.

The key is engine braking. Go out and drive the vehicle after it is up to operating temperature and you are SURE there are no fluid leaks or problems. Letting it decelerate in gear from 35-40mph will help to suck the rings into the cylinder walls as vacuum increases and cause the rings to wear in and create a good seal. For us this includes some basic driving, (to double check everything is OK) then light throttle to a moderate rpm, and deceleration. Repeat a few times. Make sure nothing is leaking...
Increase throttle application, and rpm, decelerate... repeat the same process until you are close to your redline. I usually don't tach a car out on it's maiden voyage or go WOT - the point is engine braking here and heavy vacuum. But I do bring it within 1000 rpm or so depending on what engine I am dealing with.

My GM Performance crate engine came w/ similar instructions but said to not go over 3/4ths throttle for the first 500 miles. The recomended no prolonged idling or fixed throttle positions and then acelerate to 40 and coast back down to around 10 MPH numerous times to seat the rings. the quoted poster is correct that the vacuum of engine braking wears in the rings.

Near the shop where I installed the engine was a long straight road in an industrial area so there was no traffic on Sunday allowing me to speed up and coast down numerous times. Running a new engine 'wears in' the front/top of the rings where the engine braking does the back/bottom making the seal effective. Don't abuse it but use it and coast alot.

First oil change should be the first week/500 miles whichever comes first. Start w/ conventional dino oil then change to synth after the first or 2nd change. I recomend Mobil 1 or Royal Purple if you have deep pockets. Jeeps can spend a lot of time off road at low speeds and Mobil 1 won't sludge up.

Always change the filter when you change the oil. Avoid Fram filters. They ae junk.

[4XLT]

wire brush the paint thats on it... take a scotch bright pad and run over it with that for a little bit,, clean it with mineral sprits, make sure its clean and oil free..

tape everything off you dont want painted then get a good quality engine heat paint of whatever color you want, paint it with 2-3 thin coats....

break in
me personally all i ever did was drive it, try to stay off the highways for a while run the engine through the rpm range as best you can from idle up to 4k rpm should be fine, you dont want to rev it too much.. check the oil often while putting hte first 2-300 miles on it.

change the oil/filter, go over everything making sure its all tight and where it shoudl be... ie: wires,hoses,bolts,plugs...after that just run it, but dont beat on it till you have about 2k miles on it...

[redeye202]

All I can offer is what I did in the past. Every V8 car motor we built was broke in hard. Every diesel I owned from new was broke in hard. My big thing was to no hold it to any steady RPM or long idle till after 500 miles. (no cruise control for that mileage)
I never had a motor with excessive oil consumption or premature failure.

x2 on what ^^^^^^ said.

[LDMF]

Two Guys Garage had a show on this past weekend that included painting a block. I looked around their website but didn't have any luck finding the episode. But maybe if you are more patient you can find it. I would think it would be worth your time to see. They were using duplicolor paint. www.twoguysgarage.com.

[stevieb92]

Since the block was already painted it's going to be more difficult than if it wasn't (IMO) I would not use brake cleaner as a degreasing agent either. Mainly because it leaves residue which can be reactivated by wet paint, softening the underlayer and effecting the overall strength of the paint.

You are going to have to either sand it or media blast it. But, I don't like media anywhere near an engine. This includes people carelessly blasting valve covers to powder coat or paint them... I've seen people lose engines because of it.

I would rough it up with sand paper and then wash it down with soapy water. Then rinse with clean water and then acetone. Chances are that if you use thinner it will soften the existing paint. You may be OK with using VERY hot water to rinse it and the heat will help evaporate the water and aid in the drying process. At that point I would use a high temp paint commonly available at an auto parts store. VHT, or any of the heavy ceramic high temp paints. Priming over the existing paint won't likely give you any better adhesion than the original paint. So I wouldn't bother. If they did a good job you'll be ok. If they didn't, you're fucked, and there really isn't any way to fix that aside from getting it all off. (See also; near impossible on an assembled engine)

As far as break in, the key is evacuating the debris from break in as often as possible. If the crank was cut, or they didn't do a great job cleaning the engine after machining, there can be a lot of metal debris circulating in the oil in the beginning. Getting that out of the stream before it impacts moving parts and embeds itself into bearings is paramount to avoiding early failures. The best thing you can do is change your oil and filter OFTEN during the break in period. I don't deal with stock engines or Jeep's. But we break our stuff in hard and flush it out right from the very beginning. Driving it easy is a good way to get mediocre ring seal. In my world, that defeats the purpose of the engine rebuild.

The key is engine braking. Go out and drive the vehicle after it is up to operating temperature and you are SURE there are no fluid leaks or problems. Letting it decelerate in gear from 35-40mph will help to suck the rings into the cylinder walls as vacuum increases and cause the rings to wear in and create a good seal. For us this includes some basic driving, (to double check everything is OK) then light throttle to a moderate rpm, and deceleration. Repeat a few times. Make sure nothing is leaking...
Increase throttle application, and rpm, decelerate... repeat the same process until you are close to your redline. I usually don't tach a car out on it's maiden voyage or go WOT - the point is engine braking here and heavy vacuum. But I do bring it within 1000 rpm or so depending on what engine I am dealing with.

At this point we change the oil AND filter. And check for debris and signs of component failure. If we're OK. I recommend driving as you normally would (but with the power turned down. --- this has more to do with the cars I deal with... not so much a jeep...) This gives things like clutches and such time to break in as well. If it's A/T - not a concern.

But with BRIEF oil change intervals. 100miles 250miles... and then 500miles. With OIL and FILTER being changed. This is the point where we drop the pan and shake everything down. It's either going to run at this point - or it should have already exploded / bad build. With this oil change regimen your oil should be free from particulate by the 3rd change. I recommend switching over to your preffered synthetic at about 1000 miles if you use it. By then you are ready to rock... and when we start tuning the car back to it's desired power level. (again does not apply to you.)

For the average car - or Jeep. I would still change the oil as frequently as you can bring yourself to. Buy cheap oil, and just dump it a lot. But use good filters. Don't go buy a bunch of mobil 1 oil and filters and pour it down the drain. You can usually get Wix or even OEM filters for a fair price - just don't use the cheap ass Bosch or STP filters... they won't handle the smaller particles and will just pass them right through back into your engine.

Which will end up embedded in your brand new bearings...

But whatever you do, do not go put-put around like a grandma and then wonder why your ring seal won't pass a leak down test at 1000 miles... you obviously do not want to abuse the car/engine. But you DO need to get your foot into it enough to get the rings to seal. Every motor / car is different, and they all like different things. YMMV.

I deal in turbo 4 cylinder stuff. Predominantly Mitsu. And they can be particular / picky motors if you don't play by the rules.

Your Jeep's I6 should be more forgiving. They are good engines.

X2 on the above. Plus, one of these can't hurt to install.

http://www.shopfiltermag.com/

[Azzy]

My GM Performance crate engine came w/ similar instructions but said to not go over 3/4ths throttle for the first 500 miles. The recomended no prolonged idling or fixed throttle positions and then acelerate to 40 and coast back down to around 10 MPH numerous times to seat the rings. the quoted poster is correct that the vacuum of engine braking wears in the rings.

Near the shop where I installed the engine was a long straight road in an industrial area so there was no traffic on Sunday allowing me to speed up and coast down numerous times. Running a new engine 'wears in' the front/top of the rings where the engine braking does the back/bottom making the seal effective. Don't abuse it but use it and coast alot.

First oil change should be the first week/500 miles whichever comes first. Start w/ conventional dino oil then change to synth after the first or 2nd change. I recomend Mobil 1 or Royal Purple if you have deep pockets. Jeeps can spend a lot of time off road at low speeds and Mobil 1 won't sludge up.

Always change the filter when you change the oil. Avoid Fram filters. They ae junk.

the studies and tests I have read (for motorcycles... some of us are more adept at swallowing BS than the average car owner) show that the 2 best oils out there are Mobile 1 synth, and Castrol GTX for dino. Most of the fancy top shelf oils are either worse off in durability, or just rebranded oil from one of the major producers.

In something that you are not racing or running under insane conditions, why spend 2x the cash to get no return? If you just like bragging about the money you dole out, find a charity