Oil recommendation 350 crate w/ flat tappet cam

[Islandvic]

This spring I am going to replace the engine in my '95 GMC K1500 .

I may buy this stock GM Goodwrench crate replacement engine.

This engine is a direct replacement for TBI trucks.

The engine is low on HP, so I was going to pocket port the heads, and install a better but mild cam such as this one , among other bolt on goodies.

The replacement engine has a flat tappet cam. The truck has no catalytic converters, so I can run any kind of oil.

What type of oil would you recommend? I have heard that flat tappet engines need additive levels that current SM oils lack.

How would Maxlife Syn 10-30 with VSOP work? Rotella Syn 5-40 is available also the Wal-Mart. SLOB that I have read about is only available in all Spanish Labeling at a Dollar Store.


Your thoughts, opinions, and experiences welcome.

Thanks.

 

[MGregoir]

High pressure valve springs on flat tappet cams are the bigger issue, in most typical applications it is not such a major issue. The main problems with flat tappet cams have been high performance, aggressively built engines, rather than conventional flat-tappet camshaft engines which SM is back-specced for.

If you are really worried, use a CI-4 or CI-4+ rated HDEO. Higher additive level for ZDDP, but unless you have high pressure valve springs on a really high lift cam you might be looking at a non-problem. Part of the testing for the SM rated oils is running in a Buick V6 with a flat tappet cam at 3600 rpm putting out a continuous (not peak) 125 horsepower. The performance level of that crate engine is really not far off of that.

There are camshaft break-in supplements out there, so one of those for your first oil run might be the better bet.

 

[chet2]

does not GM sell some kind of oil additive for new engines?

 

[RWEST]

Use lots of that moly lube stuff that comes with the cam, and GM EOS supplement or Crane's break-in lube (Crane Super Lube, Part Number 99003-1) and read this http://www.cranecams.com/?show=faq&id=1 .

I use nothing later than CI-4+ in all my flat tappet stuff, but that's just me. SOMETHING's wiping out all those cams we keep hearing about. Until proven otherwise, I'm blaming reduced ZDDP levels.

 

[Slick 55]

Rotella T 10w30 would be ideal.

 

[Rock_Hudstone]

Originally Posted By: MGregoir
The main problems with flat tappet cams have been high performance, aggressively built engines, rather than conventional flat-tappet camshaft engines which SM is back-specced for.
but unless you have high pressure valve springs on a really high lift cam you might be looking at a non-problem. \

On the contrary, even stock valve springs on a pushrod engines can develop very high pressures over the nose of the cam lobe. Moreover, SAE papers as far back as the 1970's suggest a safe ZDDP level of 1200 ppm for flat tappet cams.

However, in a way high performance engines could be considered the "canary in the coal mine" for depleted ZDDP levels as numerous unexplained premature camshaft failures were experienced by reputable engine builders following proper break-in procedures.
Whereas an stock high mileage motor having the same problem would most likely be written off as simply worn out with little further investigation.

I'd used nothing less than a heavy-duty diesel motor oil in flat tappet engine, or full synthetic Mobil 1 15w-50, as well as adding a bottle of GM E.O.S. to the crankcase for the intial start up.

 

[Chris142]

Originally Posted By: Rock_Hudstone

I'd used nothing less than a heavy-duty diesel motor oil in flat tappet engine, or full synthetic Mobil 1 15w-50, as well as adding a bottle of GM E.O.S. to the crankcase for the intial start up.


Yup. Personally I would run one of the big 3 diesel oils and either some EOS or SLOB during the cam break in. Make sure that you prime the oil system before you start it and as soon as it starts and gets oil pressure run it up to 2000 rpm for 30 minutes. Keeping an eye on the coolant temp and oil pressure guages.

I would run it 200-300 miles and dump the oil and filter. Put more diesel oil in it and some more slob if you have it and run that 2k or so and drain it. Be ok to go to regular SM oil now IMO.

 

[Steve S]

Get a roller cam $$$

 

[Merkava_4]

Originally Posted By: Rock_Hudstone
SAE papers as far back as the 1970's suggest a safe ZDDP level of 1200 ppm for flat tappet cams.


That's the answer right there.

 

[Islandvic]

SteveS. I agree but my wallet does not about the roller cam.

Does Shell Rotella Syn 5-40 have sufficient ZDDP levels?

Does the current Valvoline Syn Oil Treatment have boosted ZDDP levels?

Thanks,

More comments welcome.

 

[RWEST]

Quote:
Does Shell Rotella Syn 5-40 have sufficient ZDDP levels?

Here's a recent VOA on CI-4+/SL - still has good zinc/phos numbers. https://bobistheoilguy.com/forums/threads/voa-rotella-t-synthetic-5w-40-ci-4-sl.82778/

And, based on a used oil analysis at 90 hours (equivalent to probably 3,000 miles or so, I'd guess) in my J-D diesel, it's still holding up well.

There are rumors that Rotella T Synthetic 5w40 is being re-formulated to CJ-4, which may, in time, be proven okay. In the meantime, I'm scarfing up all of it in CI-4+ I can find.