How much ZDDP do I need?

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Not sure if there is a hard number or not, but I need to know what kind of oil I should be looking for.

I put a bigger cam in a 305 for my plow truck and upgraded the springs accordingly

It is a hydraulic flat tappet cam with 260/260 advertised duration 204/204 @ 0.050" lift. It has .427" lift at the valve.

The springs are 358lbs/inch. They have 125lbs on the seat and just shy of 300 lbs at lift with this cam.

So the cam isn't wildly aggressive, but moderately so (with regard to cam intensity, not duration). The springs aren't "bone crushing" but they are quite a bit more than stock.

What should I be looking at for oil? I'd like to stay with a 5w30 because this is a winter rig, so that makes it harder.

From what I've found, 800ppm is inadequate for these spring pressures. But I don't need a race oil with 2000ppm either.

Any ideas where I need to be for ZDDP?
 
A well worn flat tappet doesn't need huge amounts of Zddp, but a little extra won't hurt anyway.
Probably the best choice for it is Shell Rotella 10W-30, it's gasoline rated, and being a HDEO it has a healthy dose of Zddp, well above 1000ppm, in the 1200-1400ppm range iirc.
 
5-40 may be a light for an older Chevy V-8.. Even if rebuilt the bearing clearance are looser than modern stuff.. Of course it depends how cold it gets where you are .....As mentioned ,less is required once it well broken in, but Chevy Gen 1 engines were never known for long cam life so .generally speaking, 1200 on ZDDP is safe.. I use Rotella 10-30 T4 in my older 4.0 flat tappet Jeeps.. Low temps here are about zero F...cranks over just fine...
 
Moly not zddp.

If you want both, a co in L.A. used to blend synthetic oil for snowblowers that had lots of moly and zddp. Ran that in a Toyota in the mid 2000's and it was steller!



Summer? 25w40 Marine oil or 4T motorbike oil - equivalent and better than API SH in what you need.
 
I am guessing you DID NOT follow the advice of the cam manufacturer when you chose those springs....

That cam is MILD, stock springs are fine!
Why did you go with such ridiculous springs?
 
Originally Posted By: Linctex
I am guessing you DID NOT follow the advice of the cam manufacturer when you chose those springs....

That cam is MILD, stock springs are fine!
Why did you go with such ridiculous springs?


It is a summit cam and I used the springs they recommended. It wasn't until well after I had them installed that I realized they were a lot more spring than really needed. I just went with what they said and didn't even question it.

The actual over the nose pressure is 277 lbs at .427 as calculated.

The engine is a 1990 and had about 36,000 miles on it. Was spotless inside when I opened it up. 150hp is about right. This cam has about 20 degrees more duration and almost .050 more lift on the intake side compared to the stock cam. That's why changed it. Just needed a little more everything everywhere.

I found some amsoil diesel graded 5w30 which has about 1300 ppm of zinc, which I feel pretty good about, but it's not cheap so looking for alternative.
 
From my past experience,220 pounds open, 100 pounds on the seat is fine...it's a few hours of work to change them without pulling the heads....I think in the long run you'll be better off....
 
Originally Posted By: fuzzysig
does zddp protect anything else besides cams and rockers?

It does not do anything to the rockers.
ZDDP ( Zincdialkyldithiophosphate = Zinc and Phosphorous ) is designed to react chemically to high friction areas which produce heat and creating a film between those parts, specially to keep the followers and cam lobs from tearing eachother apart when in boundary lubrication ( low revs idling ).
Flat tappet camshafts in overhead valve Vee engines are just prone to wear, the camshaft in these engines is not pressure fed, all the oil it gets is the oil that the crankshaft throws around the crankcase.
That is why when breaking in a flat tappet cam you are advised to immediately bring the revs up to 2000-4000 rpm, the higher the engine speed the more oil the camshaft recieves.
 
Originally Posted By: meborder
Originally Posted By: Linctex
I am guessing you DID NOT follow the advice of the cam manufacturer when you chose those springs....

That cam is MILD, stock springs are fine!
Why did you go with such ridiculous springs?


It is a summit cam and I used the springs they recommended. It wasn't until well after I had them installed that I realized they were a lot more spring than really needed. I just went with what they said and didn't even question it.

The actual over the nose pressure is 277 lbs at .427 as calculated.

The engine is a 1990 and had about 36,000 miles on it. Was spotless inside when I opened it up. 150hp is about right. This cam has about 20 degrees more duration and almost .050 more lift on the intake side compared to the stock cam. That's why changed it. Just needed a little more everything everywhere.

I found some amsoil diesel graded 5w30 which has about 1300 ppm of zinc, which I feel pretty good about, but it's not cheap so looking for alternative.


That would be AMSoil HDD, which is a good oil.
Or AMSoil Z-Rod is one that has high zddp, but I'm not sure it's available in 5w30.
Redline 5w30.
Valvoline VR1 10w30 is a conventional oil with high zddp, so it will be cheaper than the boutique synthetics.
I'd shy away from Rotella T5. It's not high zddp.
I think you need 1200 ppm of Phosphorous as a safe starting point.
Did you use any kind of assembly lube with high zddp when you installed the cam?
 
Originally Posted By: A_Harman
Originally Posted By: meborder
Originally Posted By: Linctex
I am guessing you DID NOT follow the advice of the cam manufacturer when you chose those springs....

That cam is MILD, stock springs are fine!
Why did you go with such ridiculous springs?


It is a summit cam and I used the springs they recommended. It wasn't until well after I had them installed that I realized they were a lot more spring than really needed. I just went with what they said and didn't even question it.

The actual over the nose pressure is 277 lbs at .427 as calculated.

The engine is a 1990 and had about 36,000 miles on it. Was spotless inside when I opened it up. 150hp is about right. This cam has about 20 degrees more duration and almost .050 more lift on the intake side compared to the stock cam. That's why changed it. Just needed a little more everything everywhere.

I found some amsoil diesel graded 5w30 which has about 1300 ppm of zinc, which I feel pretty good about, but it's not cheap so looking for alternative.


That would be AMSoil HDD, which is a good oil.
Or AMSoil Z-Rod is one that has high zddp, but I'm not sure it's available in 5w30.
Redline 5w30.
Valvoline VR1 10w30 is a conventional oil with high zddp, so it will be cheaper than the boutique synthetics.
I'd shy away from Rotella T5. It's not high zddp.
I think you need 1200 ppm of Phosphorous as a safe starting point.
Did you use any kind of assembly lube with high zddp when you installed the cam?


I did. I used the zinc-rich assembly paste on the lobes and lifters face during assembly. I also broke it in at high idle for 15 min with amsoil break in oil which is 2000+ppm zddp. I still have the break in oil in the sump. It probably has 30-45 min of run time on the motor, most of which is at a very fast idle.
 
The Euro oils often have more ZDDP than typical ILSAC oils which are often 800 ppm or less.

M1 0W40 is listed at 1100 ppm zinc. That's a good step up in ZDDP and with ample winter cold starting ability. It's right at the thin end of the 40 grade oils in terms of viscosity, close to a thick 30 grade.

Just another option for you.

BTW I'm using semi-synthetic Penrite oil with 1200ppm zinc right now, just because....
 
Last edited:
Originally Posted By: Truckedup
From my past experience,220 pounds open, 100 pounds on the seat is fine...it's a few hours of work to change them without pulling the heads....I think in the long run you'll be better off....


I agree 100%

High spring pressures = short cam life (regardless of oil)

Always always always always always always has that been true.
 
Your going to pull the rocker studs out of the heads if they are pressed in with those springs.
 
If it was my engine I'd use 3 qt's of M1 H/M 0/20 and 2 qt's of Lucas Hot Rod & Classic Hi-Performance motor oil SAE 10W-40, or even a 50/50 mix. That 60/40 mix will give you over 1100 ZDDP and a good bit of Moly.
Take a look at this post from BITOG
https://www.bobistheoilguy.com/forums/ub...Car_VOA_Study__
and here is the numbers for those 10 oils
https://onedrive.live.com/?authkey=%21AHKKfKJ3E11RU1E&cid=FD59A041A3808BD5&id=FD59A041A3808BD5%211416&parId=FD59A041A3808BD5%21207&o=OneUp

ROD
 
So, a correction on the spring rates.

The rate is more like 107/260 or 96/250 depending on which installed height you go by.

I mistakenly assumed the installed height listed would be the installed height for my valves, but that isn't the case. They had a shorter installed height listed to get the 125 seat pressure. So that's my bad. Going by the specs listed on the summit page, it should be 250 on the nose. If you go by the installed height listed on their q&a ir comes up to 260 on tye nose, but i think they just has a typo.

Regardless, much more livable than originally thought.

Also I checked on the amsoil I bought, and it is the series 3000 oil. Supposed to be their 25,000 mile product.

There is a distributor in the area that sells the brad pen oil, but I don't know if they carry the 5w30. Most guys use this for racing and 5w30 wouldn't be very popular for them. If they have it, they sell for about $5/qt according to my one racer friend. So that might be an option if I don't have to order a ton of it at one time.
 
You're wasting money using a boutique oil in a 1990 305 Chevy SBC (coming from someone that has owned several).
 
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