Harlyman
Member
Stock cam about tune was able to increase timing by at least 15 deg through 2000 rpm to 3000 rpm. But listen for pinging
So your seat of the pants gains were RRs PLUS tune, right?
They have a rather limited lifespan compared to stock rockers correct? Like 20-30k? I almost got some harlans but didn't for that reasonYes, bearing failures at both the fulcrum and roller tip, common in mopar v-8 applications, not so much in Jeeps just based on volume of installation
Don't forget, the change in ratio changed the effective cam profile. So his seat-of-the-pants feel was from a change in effective cam profile, a change in tune and timing.
Full roller rockers would net no significant power differences in something making the power of a 4.0. IIRC the guys on engine masters showed no power change from a stamp steel rocker vs full roller rocker on a 500 hp engine. Also
Don't forget, the change in ratio changed the effective cam profile. So his seat-of-the-pants feel was from a change in effective cam profile, a change in tune and timing.
Different platforms have different results. Some gains can be had simply from a lack of deflection in the stock stamped rockers at higher rpms in some applications. I think I remember seeing a 4.0 dyno shoot out showing just that somewhere. I'll see if I can dig it up.Full roller rockers would net no significant power differences in something making the power of a 4.0. IIRC the guys on engine masters showed no power change from a stamp steel rocker vs full roller rocker on a 500 hp engine.
Just finished installing a set of Harland Sharp roller rocker arms. Here is a comparison vs stock.
Can’t tell if there’s any power increase but engine is definitely quieter and seems smoother although that may be because of the sound.
Also like to give a shout out to Harland Sharp. I dropped one of the rocker fulcrums somewhere in the engine bay and just could not find it. Called them and they had two sent to me in a few days no charge!
View attachment 267215
I didn’t check just went ahead and cut the baffle out and no clearance problems.
As long as this thread got brought back from the dead, our 4.0L's are non-interference, so this shouldn't ever happen.Everything from noises to valves kissing pistons in the chamber of love
I put in the 1.7 couple years ago. You’ll need an aftermarket valve cover for clearance. There’s a lot on the Jeep Strokers forum about them.
Just finished installing a set of Harland Sharp roller rocker arms. Here is a comparison vs stock.
Can’t tell if there’s any power increase but engine is definitely quieter and seems smoother although that may be because of the sound.
Also like to give a shout out to Harland Sharp. I dropped one of the rocker fulcrums somewhere in the engine bay and just could not find it. Called them and they had two sent to me in a few days no charge!
View attachment 267215
I'm going to concur they DO bring engine noise down a bit.
Mine went in as part of an engine overhaul where many new parts (OEM and After-Market) got installed, so I can't pinpoint which ones may have positively affected what or to what extent... But on the whole, I basically have a new 4.0L powerplant in a 20-year-old jeep.
There are different opinions on pairing valve cover options:
1. Get a taller after-market one.
2. Cut out the top baffle plate inside the stock cover to accommodate the HS rockers' height.
3. Rubber mallet the top plate to pick up the tink bit of clearence you'll need to keep the OEM cover.
I cut my out the top baffle plate but have since leaned that this will probably send oil into the PCV system. Any thoughts out there? In hindsight, I think the rubber mallet may have been the the best low-tech option, but would incur a lot of trial and error.
There are different opinions on pairing valve cover options:
1. Get a taller after-market one.
2. Cut out the top baffle plate inside the stock cover to accommodate the HS rockers' height.
3. Rubber mallet the top plate to pick up the tink bit of clearence you'll need to keep the OEM cover.
I cut my out the top baffle plate but have since leaned that this will probably send oil into the PCV system. Any thoughts out there? In hindsight, I think the rubber mallet may have been the the best low-tech option, but would incur a lot of trial and error.
4.0l harland sharp Roller rockers were a hard no for me. They don't last anywhere near as long from what I've gathered.I have stock rockers with 200k on them in great shape with my comp cam.
Yes my research says about 50,000 mi. In a V-8. I’m doing Less rpm so probably more. My TJ is a 2004 I bought new. It has 78,000 now. And I put 3000mi on it in the last 5 years. So they will never make it to 50,000. But I will say the 1.7 do make a difference.