Jeep Strokers

I had my machinist take a look at my engine issues today, but he had no real insight into it.

However he did notice one thing. He said my valve train was noisy past 2000 RPM and said that it sounded like the lifters were bleeding down at RPM. I did think my valve train was a bit noisy, but thought it was the combination of the cam and roller rockers. He said it was still too noisy for that. He suggested going to a higher viscosity oil and see if it gets quieter. I am currently running Valvoline VR1 10w30. He also suggested if there is no difference with the heavier oil to tighten the preload. Oil pressure is good, ~20 at idle ~60 while up in the RPMs.

The lifters I am using are the Comp standard lifters, not anything special like anti pump lifters.

Basing it on his theory that the oil was thining out too much and being pushed out of the lifters I did a test. After he left I let the engine sit for a few hours. The oil was no longer hot. I started the engine let it run a minute then rev'd it to 3000 RPM. The valve train was actually significantly quieter.

I also called comp cams and they said that their XE cams are pretty noisy cams, but couldn't get any info out of her exactly what makes them so noisy. The only thing she could recommend is warrantying them (don't think it is worth it because the valve train always sounded the same on all the engines even with different lifters) or adjusting the preload tighter. I have the preload set at .030", and she said the lifters require .040"-.060". Factory spec is .030"-.060" iirc, and Harland Sharp recommends .020" pre load...

Any ideas what is going on?

If letting your engine cool down a bit quites it up that leads me to believe it is a viscosity related issue. Maybe high oil temps? Are you running an oil cooler?

I run the 68-231-4 cam also, and its nosier then stock.

esspecially at medium rpms. I run 15w40 oil, never tried 20w50 but its pretty warm climate here.

its in the engine for at least 10K km's.

Jeep4xb4u wrote:If letting your engine cool down a bit quites it up that leads me to believe it is a viscosity related issue. Maybe high oil temps? Are you running an oil cooler?

No oil cooler and the engine runs right around 210*. I don't have an oil temp gauge.

I don't like the idea of running 20w50, the engine shouldn't need it. Maybe the comp cam injectors just aren't that good? Maybe more preload? I thought these things were suppose to pump up at high RPMs.

That comp cam is probably noisy because of the faster ramps closing the valves shut...kinda like slamming a door. I am sure my engle cam will be the same. Did you check your pushrod length? I was really surprised at how short my pushrods are...Almost .300 shorter than stock. I checked them several times by using a black magic marker to paint the top of the valve stems and the turing the engine over to see where the roller is contacting.

Pushrod length is good, but doesn't really matter that much as they are adjustable directly above the push rod, not at the pivot point. I would agree the 68-231-4 is noisy, but what worries me is that it is significantly quieter when the oil is cold and thicker.

So.. what should I try first? Turn the preload up to .40" (.030" now) or go with a heavier oil? I know VR1 comes in a 20w50

Did you groove your lifter bores? If so, maybe thats letting the thinner oil bleed out of the lifters ? I would try the thicker oil. With the outside temps being so high right now, I don't think it will hurt anything. I am running the 20w50 VR1 in my stock 4.0 right now. It has silenced my ticking a bit.

Yes, they are grooved, but wouldn't the oil pressure go low then? At RPM they do still spray plenty of oil up through the push rod.

I had a few other ideas on this.

Maybe the roller rockers give too easy of a path for the oil to leave the lifter? Its pretty much a straight shot through and open hole in the top of the rocker adjuster nut. The how to fix that? Some kind of restricted push rod? Different lifters that meter the oil better?

Perhaps an oil cooler?

Maybe a high volume oil pump (don't really like this idea)?

Also, my machinist was adamant about running 20w50 in the engine from the beginning. The engine was blue printed, so the clearances are stock. I under stand where he is coming from, but he is a bit old school.

I have the 232-4 cam in my 4.0 presently and it started out pretty noisy also running 10-40. It just didn't sound like all of the clatter was going to be reliable down the road. After reading all the zinc issues with SM rated oil, I ended up switching to Rotella 15-40 and I was very surprised at how much quieter the valvetrain was. I also brought my spring pressures down closer to stock (80lbs seat and 240lbs open) and that make a noticeable drop in noise. This cam is still alive going on 59K miles!

dwg86 wrote:That comp cam is probably noisy because of the faster ramps closing the valves shut...kinda like slamming a door.

Yes. That, combined with heavier valve springs, is what causes the valvetrain noise even if the lifter preload is correct. Higher viscosity oil might dampen down the noise a bit.

Oil change seems to be easier and faster than changing preload, and it can't hurt, so I also vote for that sollution. And I believe 30 oil is a bit too thin for every stroker, especially for the summer. I would definitely recommend some nice 40 oil. I personally run 0W40 on stock 4.0 and 5W50 on a stroker (this 50 is a little overkill, but that was just for the first oil change, later I'll change it for 0W40 also)

I tried using the 20w50 today with no results. It actually made it sound worse at idle. And the idle pressure never dropped below 35 psi at idle and it felt like it lost power.

I made a few videos, a bit hard to hear over the fan though.

http://jeep.blackonyx.net/stroker/vids/rev1.mov
http://jeep.blackonyx.net/stroker/vids/rev2.mov
http://jeep.blackonyx.net/stroker/vids/hsrockers.mov

Very little, if any of the sound can be heard in the vehicle while driving.

So, I swapped out the 20w50 for the 10w30 again. Also, I originally had the preload set at .020" then increased it to .030" with no change in the noise.

Maybe its just the aggressive cam combined with the roller rockers and the heavier valve springs. I have used either teh 68-231-4 or 68-232-1 in all the strokers and the only time I heard anything different was when Titan tried to sneak that crane cam buy me... but it was damn quiet. Even the exhaust was quiet. Until it failed.

Hey,
This is the same problem I'm having with my 4.7 I have concluded it's the same issues. High spring rate, Lunati cam with steep ramp profile, and warmer weather. It was still a bit noisy even when the temps were in the 40's. Runs good though, aside from A/F tuning still needed. I've been runnin' 10/30. Haven't tried the heavier oils yet, but I think it's just part of the combo of parts.

T~

Anyone know of a way to tell if they are bleeding down for sure?