Ok, so I located new copper and unions for the coolant lines that run over my left front airbox, the one with the nasty little hole in it. I cut out the old copper so that I now have clear access to the hole for repair (I'm going to try to weld a plate over it) and I drained out the antifreeze.
Now my question is, definitively and for sure, is the coolant for an 8v71 regular auto coolant or 50/50 or???
-Dave
Dave use only ethylene glycol based antifreeze it can be 50/50 or straight antifreeze with distilled water.also use a pre charged antifreeze if you can locate it in your area
C&J Bus Repair recommends adding SCA only as indicated by test strips. They recommend not using precharged coolant and not using coolant filters that add SCA. The charged coolant filters can add SCA too fast or too slow. Regular testing with the strips is what they recommend.
I personally think the precharged coolant is okay if you want to pay for it, but you still need to test and have SCA available, so why bother? I added some 12 gallons of coolant to my bus last year. I thought I would need to add a pint or more of SCA, but testing showed it only needed a few ounces.
The 8V-71 is a dry sleeve (thats the determining factor) and you can use the regular car stuff. I added additives that I found out later that I didn't need. There is lots and lots of confusion out there on this topic.
HTH,
Laryn
Ummm......what is SCA?? :)
My knowledge is based on the Detroit Series 60 and the Ford Powerstroke diesel engines. I thought all Detroit Diesel engines required SCAs. My apologies for leading anyone astray.
SCAs are supplemental cooling additives. They are necessary for some diesel engines so the coolant doesn't eat through the cylinder walls. High mileage Ford trucks with diesel engines are known for getting holes in the cylinder walls if coolant is not changed regularly and the SCAs maintained.
laryn,you are correct about the 8v71 being dry liners but it has the same material used in the head seals, water pump seal and any other place that water comes in contact with the engine as the 92 series and to take the confusion out just follow your DD specs in the manual
By the way, for anyone else who ends up needing to change out the copper lines in their MCI (maybe others?), they are 3/4" o.d tube not to be mistaken for 3/4" i.d copper pipe. Tube is measured by o.d and pipe is measured by i.d.
I also spliced in a section of tube in my air line running down the tunnel and through a frame member and was leaking from chafing on the frame. Unions, 3/4" tube and a new grommet and all done!
This may be common knowledge to some but it wasn't to me, I had to learn it like so much else I'm learning as I go on this beast.
Paladin,
Keep sharing. You didn't waste my time....this or any other of your posts.
Thanks,
John
You do not need to add SCA's to an 8V71 like you do to an 8V92 which does require it because of its design. With modern wet sleeved diesel engine designs, you have to use SCA's. If you want to, and it makes you feel good, it will not hurt an 8V71. You will just spend money you don't need to. I have SCA's in mine, but I thought at one time I had to have it, now I know more about it. TomC is knowledgeable about this stuff and hopefully we will hear from him soon. It will cost about $20-$25 to add the SCA's, so it's not a huge expense if you want to add it.
The main concern about liners and which type of antifreeze/SCA's to use comes from cavitation. Higher hp wet sleeved engines will have a greater tendancey to have the problem of cavatation. These high hp engines require better, and more efficient heat transfer, that is one of the reasons why they use a wet sleeve design. If you already know the difference between a wet liner vs. dry liner, then you can see why this is not really an issue with the 8V71.
From TheDieselStop.Com (http://www.thedieselstop.com/contents/getitems.php3?Cavitation%20Analysis):
What is cavitation? One of our diesel experts offered this explanation:
Cavitation is a localized low pressure zone that forms adjacent to the outer wall of the cylinder. It is caused by by the flexing of the cylinder wall due to the high cylinder pressures experienced in diesel engine ignition. Gasoline engines don't typically get this failure mode due to lower cylinder pressures during ignition. Basically what happens is the cylinder wall quickly expands due to ignition then returns to its original geometry. This expansion of the cylinder wall is more pronounced as you increase the demand for power. Bascially when you increase your demand for power you are pumping more fuel into the cylinder. If you have a turbo charged unit you are also increasing air charge. This increase in fuel and air causes a more violent ignition which further increases cylinder pressures and thus increases the flexing of the cylinder wall. This fast cylinder wall movement causes a low pressure zone to be created in the coolant adjacent to the cylinder wall. When this pressure zone drops below the vapor pressure point (temperature, coolant ratio, and additive dependant) a vapor bubble is formed. When this low pressure zone returns to a high pressure zone, the vapor bubble collapses, causing an implosion, or pitting phenomena on the cylinder wall (like hitting the surface with a microscopic ball peen hammer). If left unchecked, it will eventually eat all the way through the cylinder wall.
The next question is probably What do I do to prevent cavitation?
The answer is simple, add the appropriate coolant additive at 15,000 mile intervals and perform a complete coolant change every 30,000. By following these procedures, you'll never have a coolant-related failure. The additives include Ford's FW-16 (replacement for the older FW-15), Fleetguard's DCA4, Penray's Pencool, and others. A new alternative is to use Cat and Fleetguard's new extended life coolant. It is impregnated with the proper additive and mixed to the proper antifreeze/water combination at the factory. You simply pour it in.
How does it work? would be the next question.
In conventional coolant the additive called SCA or Supplemental Coolant Additive adds a sacrificial layer to the cylinder wall so that the cavitation action will act against it instead of against the metal cylinder wall. Keeping additive levels maintained will keep this sacrificial layer in optimum condition.
In extended life coolants the carboxylate molecule is a long chained molecule and it is in constant flux of being attached and detached to the cylinder wall. This action and length of the carboxylate molecule absorbs the cavitation action and does not allow the metal of the cylinder wall to be impacted.
Another good link from Expert Diesel:
http://www.expertdiesel.com/cavitation.htm
Good old Prestone mixed 50/50 with distilled water will work great. That's all I've ever used in all my trucks-the important thing is to test for acidity periodically. Although, as stated before, since a 71 series is a dry liner, the engine has alot of cast iron to go through, and cast iron just doesn't rust all that easily compared to the steel of the 92 series, Cummins ISC or larger, Caterpillar C9 or larger, International DT466, etc. Good Luck, TomC
Laryn, a good post but if you think 71 series don't have a problem with cavitation your wrong this is just one of the reasons the 71 series have to be bored and over size liners installed at rebuild is to remove the hot spots in the block caused by cavitation. Me I will pay the $15.00 a gal for the correct and recommend antifreeze good insurance for a $20,000 engine.
TomC a 92 series has 11" tall liner that only 2" at the top comes in contact with the coolant to cool the top of the piston unlike a 71 series that cools by oil from the bottom and I don't know what the formula is in prestone antifreeze because I have never used it but if works for you great
This is all I will say about the subject for the ones that are confused is to read the 5 pages about coolant,filters and additives in your DD manual
QuoteLaryn, a good post but if you think 71 series don't have a problem with cavitation your wrong
Mike,
I feel safe to say as a general rule they don't and in the type of service these engines are seeing in a bus conversion it's incredibly unlikely if never. If it was something of a problem with the 8V71 there would be a lot more talk of it. There always seems to be a lot of confusion out there on this topic and I had to do my research before I felt comfortable in knowing that it's not a requirement for the 8V71. But like you said, for $15 plus dollars why worry about it.
QuoteThis is all I will say about the subject for the ones that are confused is to read the 5 pages about coolant, filters and additives in your DD manual
The manual I have (V-71 Highway Vehicle Service Manual 1971) only has two pages dedicated to the filters and additives. Where can I go to read what you are referencing or can you possibly give more info? My manual discusses scale, ph, and corrosion inhibitors. Additives in regular antifreeze cover that without any additional SCA's. Do not take my inquiry as questioning what you have posted. I am here to learn and would like to know more about your understanding of the topic. Please elaborate.
Laryn
This is more than just interesting. I heard a long time ago that the 8V71 did just fine with auto grade anti freeze. So many times, in fact, that i believe it. There are things I am hearing that are NEWS but that doesn't mean anything definite considering my knowledge base. One is that the SCA's improve the "standard" auto grade AF so you can use it in a *V92. I think that is wrong....what about the "low silicone" content spec? You can't remove something by adding another is my problem. Also, if I understand this, a 71 doesn't require SCA's because it is low power. So if I aftercool and turbo and intercool my 8 V 71 up to 425 HP I will have to switch over to the V92 spec coolant? Now, I am serious about this being a question......I am not poking at anybody. I feel like I am floundering here and I miss the accepted experts chiming in.
Thanks,
John
Laryn (and others) -
Here you go, right from the horse's mouth, so to speak:
http://www.detroitdiesel.com/support/on-highway/manuals/Lubricants_Fuels_Coolants/7se298.pdf
FWIW & HTH. . .
;)
Great link Russ. It is getting late, and was only able to give it a glance; therefore, I might find more details during a later and more through read. This is a 2002 publication and it gives the reason for not using conventional automotive antifreeze is due to high silicate or possible phosphates that were used at that time (4-16) and because it offers no liner pitting protection (4-9). From reading the side of the newer automotive antifreezes the formulation has changed to a non-silicate formula. I have been in several truck shops over the past year and they sell the same stuff in a jug for trucks that one can get for cars at any local parts store. The difference being they will also sell the SCA's to add to it and the test kits to check it. All of the antifreeze listed in the dd manual on the supplied chart is "fully formulated antifreeze" and the DDC Power cool does contain nitrites that are added to "inhibit cast iron corrosion and cavitation".
Having read several old manuals and publications, and because of this post, going back and rereading some, I have noticed that nowhere is it mentioned to add any additives to prevent cavation. I am lead to believe that cavatation was either not well understood then, or because of the design and/or low hp engines, it was not an issue and therefore wasn't addressed. I would also think it would be wise to obviously use the most recent publication available, and if the new standard is to use SCA's in all engines, then that is what one should do. I also need to add that apparently the 8V71 will run a long time without SCA's and have no ill effects due the many testimonials that "old time" mechanics have given. As I have stated earlier, I have it in my bus, but I wouldn't loose any sleep over it if I didn't. Everyone that has an interest in this needs to educate themselves and do what they feel is in their best interest.
Phew! I am running out of time and steam tonight but I have read a few articles that I want to follow up on regarding the new automotive formulation. It seems that some might meet the requirements for the fully formulated recommendation. I have a tile floor to install tomorrow in the laundry room and I had better move on for now. Maybe someone else could follow up on this.
As I remember reading the 4104 manual recently the only anti-freeze recommended is the plain old ethylene glycol type used in autos.
The filters discussed in the manual are mostly for keeping debris out of the circulation.
The additives discussed in the manual are to replace the anti corrosion additives normally included in AF which wears out in 6 mo to a year. The freeze protection part of AF does not wear out but the anti-corrosion additive does.
From reading the manual my interpretation is that regular AF will protect any series 71 DD all it needs to be protected.
Cavitation of pumps knowledge has been around as long as rotating pumps. Probably the first knowledge of cavitation was developed when ships first started using propellers which is a really big problem.
Gus, the big ole Scenicruiser manual I have says to not use the water filter when using AF, it says to block it off.
I do know that for years Greyhound did not run AF, they kept them running and had instuctions for the drivers to drain them if the motor quit in the cold!
For what it's worth.
Ok guys i will take one more shot at this topic there is two designs of the 8v71 engine the old and the newer.The old one had the oval inspection covers and had no coolant around the cylinder walls this engine was redsigned in the 70s because the top half would move and cause liner problems.The new design has smaller inspection ports and the cylinder walls are surrounded by coolant by far the better engine.All I am trying to tell you is a manual written in the 50s,60s and early 70s may not apply to the engine you have in your bus as most of the old style 8v71 are not around anymore but a few are Happy New Year everyone
Quotethere is two designs of the 8v71 engine the old and the newer
I didn't know that.
Thanks,
Laryn
2stk,
Very good info, I didn't know that either!