Viterbo Posted September 26, 2016 Report Share Posted September 26, 2016 I read that K engines should use mineral oil and people should avoid synthetic oils. I've been using Shell Helix H7 10W40 (synthetic) in my 5K with no hassle relative to the use of this oil grade apart perhaps some lifters noise. So I was willing to try a mineral oil but some questions appear. Which brand? Which grade (15W40? 20W50?)? Checked the repair manual and it only says "SF grade", which doesn't help that much since almost every oil now is at least SL grade. My 5K was fully rebuilt, I don't have any oil consumption with the 10W40 and already has some mods (compression, flywheel, little head work, etc) and I will fit a camshaft similar to the Kent T124 and bike carbs. I don't know if this changes somehow the oil choice so I leave here this information regarding my engine. Let me hear your opinions and experiences Quote Link to comment Share on other sites More sharing options...
CorollaNut68 Posted December 24, 2016 Report Share Posted December 24, 2016 (edited) I've been running nothing but Castrol GTX 20/50 for 30 years (800,00 miles)and never had any issues. Well...no oil related issues. Sometimes people just make things too complicated. Keep it full and relatively clean. If you've had zero issues with what you're using, no sense in changing. I use thicker because all I want to hear is the exhaust note, and our summers are hot and winters short. Hell the tolerances in these engines are almost in inches. I had one keep running for months. though badly. Didn't have time to mess with it. When I finally parked it and took it apart, there was a crack right down the middle of the cylinders, a crack to the outside of the block seeping water, 3 broken pistons and a matching crack down the head among other things. It was still getting me to work. That was a "factory second" 3K crate engine with a K head on it running 10-1, with stock carby and my special pair of 2-1 headers with dual exhaust. Yep, I'm American, gotta have duals. I'm thinking the block did not pass quality control. Stout as hell and quick for several years before it finally went to pieces. That's the engine i was clocked at 131 mph (210 kph) with. And the stock 4:22 gears. Hahaha radiator went off like a bomb during that run. Blew the whole top off. Should have removed the thermostat. Braided hose held better than the soldered brass. But hey...all of that and no gunk inside from crappy oil! Edited December 24, 2016 by CorollaNut68 Quote Link to comment Share on other sites More sharing options...
ke70dave Posted December 24, 2016 Report Share Posted December 24, 2016 Just remember you can spend more money on 5L of oil than you can buy a replacement k engine! Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted December 24, 2016 Report Share Posted December 24, 2016 Just remember you can spend more money on 5L of oil than you can buy a replacement k engine! that is sad! but true.... I use 15W-40, the 4K, the 4AGE, the SR20 and the 3SGE.. Makes life simple. I've used thicker and thinner oils without any gains. Quote Link to comment Share on other sites More sharing options...
Viterbo Posted December 25, 2016 Author Report Share Posted December 25, 2016 I'm using Shell Helix H7 10w40 (semi-synthetic) and I'm gonna do an oil change soon, I'm gonna try Total Q5000 15w40 mineral. Quote Link to comment Share on other sites More sharing options...
ke70dave Posted December 25, 2016 Report Share Posted December 25, 2016 How are you going to determine if the new oil is better than the old oil? Quote Link to comment Share on other sites More sharing options...
7000rpm Posted December 25, 2016 Report Share Posted December 25, 2016 Has anyone experimented with oils on a k series for track racing use, where the engine is under constant stress? Quote Link to comment Share on other sites More sharing options...
Clapped out Posted December 26, 2016 Report Share Posted December 26, 2016 Has anyone experimented with oils on a k series for track racing use, where the engine is under constant stress? Anything that has zinc is a good start, good for high friction areas like lifters on cam lobes etc. Quote Link to comment Share on other sites More sharing options...
Viterbo Posted December 26, 2016 Author Report Share Posted December 26, 2016 How are you going to determine if the new oil is better than the old oil? I think my hydraulics are going to give me a clue :lolcry: Quote Link to comment Share on other sites More sharing options...
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