Oil for old cars (no cats)

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263
Location
DFW, TX
I've been reading a bit about all of the oil formulation/additive changes due to emissions and such. I have a car that does not have any cats or sensors that could be harmed. Are there any oils which would be better than the API certified oils in this application? Would a motorcycle oil work in this application? I'd be hesitant to use one because they are made to work with the wet clutches and may not be ideal for an auto engine. I do believe that the latest SL oils would still be best, but I'm posting this to be sure.
 
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349
Location
Quebec, Canada
From what I've been reading here in the boards so far - try older oils that do not have the SL API rating. Apparently the API SL has a lower Zinc/Phosphor(?) content as they can ruin the cat converter when burned off. The content percentage cannot be no more than .10%(?) or something like that. This applies to oil viscosities 0W20, 0W30, 5W20, 5W30, & 10W30. 40wt. oils & up such as 5W40 and 10W40 are not restricted with these numbers, I believe. Correct me if I'm wrong guys, Oz
 

MolaKule

Staff member
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21,950
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Iowegia - USA
For older cars, I would use a 10W40 or 15W40 SF or SJ rating. I am assuming here that the older car has larger clearances as well. I do know the SF's had quite a bit of ZDDP's and such.
 
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194
Location
Roxboro, NC
quote:
Originally posted by Chris A: I've been reading a bit about all of the oil formulation/additive changes due to emissions and such. I have a car that does not have any cats or sensors that could be harmed. Are there any oils which would be better than the API certified oils in this application? Would a motorcycle oil work in this application? I'd be hesitant to use one because they are made to work with the wet clutches and may not be ideal for an auto engine. I do believe that the latest SL oils would still be best, but I'm posting this to be sure.
When you say older, how old ? In My 1953 Pontiac straight 8 cyl I run schaeffer's #110 50 wt. but if yours is, let's say 196? then I would use straight 30wt. Don't have time now to explain. David [stretch]
 
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1,874
Location
Ocala, Florida
As David is pointing out, Older cars clearences are such that a multivisocity oil is not desirable, As many have seen only straight grade oils. The shearing of a mutivisocity oil would allow blow by and oil consumption. This aside from the lower antiwear additive is concern for not using a newer oil. Like David said, more later, just wanted to start stiring up things here as I'm know to be good at.
 

Chris A

Thread starter
Messages
263
Location
DFW, TX
The car is a 1969, but I think the engine block is from 1979. It was recently rebuilt and I do think that it does have "loose" clearances. I first ran 10w30 and did not like the oil pressure at idle. I'm currently running 10w40 and it's ok. Since I live in a hot summer climate (Dallas), I was thinking of running a straight weight oil, but I figured that having a multi-visc oil would protect much better at startup. I'll be looking out for the reasoning.
 

MolaKule

Staff member
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21,950
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Iowegia - USA
David, My Dad had a 1951 Buick stright eight, ran 10W40 all the time. [Cheers!] Chris, For older engines I would go with a 15W40 such as Schaeffer's or Amsoil AME.
 

Chris A

Thread starter
Messages
263
Location
DFW, TX
I'm currently running 10w40 syn, but I had bought it a while ago. I'm not sure yet as to if I'm going to continue with a syn oil. I had considered 15w40, but most (all?) of those are deisel oils and I wasn't sure if that would be the best choice for a gas engine.
 
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3,333
Location
Bolivia
My preference is something with a high phos and zinc package, I've used both Delo and a Group I SJ/CH-4 for several years in a lot of older vehicles, both gasoline and diesel. I don't have the mixing tables here, but from what I remember you "proportion" the newer additive packages to get the lower amounts on the older oils. Somewhere I have analysis of SF oils with about 700 ppm of zinc and phos.
 
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1,874
Location
Ocala, Florida
Chris, I concur with Molakules comments about the 15w40 but in addition, you could even use a 20w50 as that engine's design was for straight wt oils and only 30 and 40wts were common at that time, therefore, both the 30 and 40 are thicker than a 20w50 on startup and since you are living in Dallas, I know from personal experience living in Tyler 88 miles east and Arlinton, that summers can get hot. Keep in mind that a thicker oil in an older engine will act like a cusion and not cause the wear as a thinner multigrade oil, so If you do use a multigrade, make sure there is a good barrier additive in place. Also During a cold winter, if using a multigrade, I'd consider dropping back to 15w40. Quite frankly, if it was my car, I would lean more to running a straight wt, but the other options are reasonable. in my 95 ford I use at present the Schaeffers 15w40 which is the new SL for gas and CI rated for diesels. This along with the chevron delo and amsoil have higher barrier lube properties and will provide the protection with what the older cars called for, but I don't know the api's spec's for if it is SL or not. They could answer that better.
 
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700
Location
USA
Bob, How could a 20w-50 be thicker at startup? If it was 100f outside in Texas, The 20w-50 is about 160cst, and the 30w would be about 100cst. Would that make the 30w better at cold starts (90-100f)?
 
Messages
1,874
Location
Ocala, Florida
JonS, theoriticly that might be true except, in reality, a car in 100 deg F temp will not have 100 deg oil. Remember, the hood on the car is exposed to the direct heat, this protects the engine from direct heat from the sun, then the engine insulates the oil from the ambient temp some as well. I just went outside and decided to do a little experiment.. My issuzu p/u, hasn't been used in months. I took my heat raytek minitemp gun, shot temps. On the hood... 97deg on the engine...86 deg(valve cover) opened the oil cap, shot temp on valve train.. 80 deg's. Now that only shows a 17deg drop from outside to inside on top of the motor. This isn't taking into account the wind factor which I suspect may not factor in. Yes, you are right, the current temp in the oil will vary it's starting visocsity due to outside temps and this is one reason that a barrier lube is essential in all oils(including synths) so that this will provide a lube barrier when start ups occur because base oil's will drain off components. So the minor amounts of time difference between the one ver's the other will not be enough to even notice let alone be a problem in hotter temp start ups.
 

Chris A

Thread starter
Messages
263
Location
DFW, TX
I agree with both Bob and JonS. I was looking at the [email protected] to try to get an idea on how the oils would compare at startup. It very rarely gets below 80F here at night, so at most the oil at startup would be 80F. I'll definately go with a multi-vis during the winter month. I'm still a little confused about a couple of things: 1) Wouldn't a 10w30 and a straight 30 act the same at operating temps (>200F) 2) How would looser clearances and a multi-vis oil cause blow-by and consumption? I would think that the blow-by and consumption would occur at the rings. When you talk about clearances, aren't you talking about the bearings? 3) Should I expect to still see oil from a pre SL certification? I've looked and it all pretty much looks like SL oil with a few SJ still laying around.
 

Patman

Staff member
Messages
22,012
Location
Guelph, Ontario
quote:
Originally posted by Chris A: 1) Wouldn't a 10w30 and a straight 30 act the same at operating temps (>200F)
Not necessarily. Ideally they should, but the straight 30 weight is more shear stable, and under duress it won't thin out as easily as a multigrade will.
 
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1,933
Location
Oklahoma
Chris, In my opinion I would use the Pennzoil 10/30 year round with 10 percent Synergen additve. Then let Terry do an analysis to see what is going on. Oil pressure could be do to the thin Synthetic you are using You could easily imo run the straight Pennzoil 30wt in the summer down there. For what is's worth it has a 450 F flash point As Terry has said and I aggree,always looking for a better way to lube a car less expensively,this is what I am doing,the tests will tell the story and will either dispell the rumours of adding a additive that messes up the formulation of a oil or quantify the statemants made prior. This Synergyn is not a run of the mill additve though in my opinion,again,a little more time will tell [ August 11, 2002, 06:37 PM: Message edited by: dragboat ]
 

Chris A

Thread starter
Messages
263
Location
DFW, TX
I've been running dino oil for the first 8k miles on this engine. I'm only running the syn now because I already had it and I don't want to run a xw40 oil in my other cars. My current thinking is to run the 10w30 Pennzoil in the winter (and I'll try synergyn) and then probably go with the straight 30 or the 15w40 during the summer. In the winter, my oil pressure is OK with a xw30 oil, but it gets a little low (<20 psi at idle) when it gets >90* F. I also noticed that the straight weights are a little thicker @200*C than the multi-visc oils are so a striaght 30 may be good.
 

driven2services

Administrator
Messages
0
quote:
Originally posted by Chris A: .... 3) Should I expect to still see oil from a pre SL certification? I've looked and it all pretty much looks like SL oil with a few SJ still laying around.
Shortly before SL became the current standard some oil companies were packaging SL oil into bottles with the SJ label. It exceeded the SJ spec, so why not? (Rhetorical question...don't answer.) They did say SL on the carton. Chevron had this announcement on their web page. Ken
 
Messages
3,333
Location
Bolivia
Standard industry practice is to up the additive and certifications before running out of packaging, or before you can say it on the label. I have lots of CI-4 oil, but it has to say CH-4 until September 5. As long as it is backwards compatible, it is acceptable/standard practice. I once had a customer who insisted on CD oil. Unless my orders were over 50 drums per order, the plant labeled the current product (CG-4) as a CD, and my customer was happy except when the order was over 50 drums and he got real CD, with it's higher evaporation, higher oxidation, and lighter intial color.
 
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