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Using Hydraulic Lifters with Solid Lifter Cam

15K views 22 replies 9 participants last post by  kennybis 
#1 ·
Just curious what experience anyone has running hydraulic lifters on a solid lifter cam.

Basically I have a solid lifter cam that works very well but I figured out that I don't really need solid lifters since I shift the engine at 6500 rpm and have the rev limiter at 6700. Primarily I'm looking to reduce the rocker noise and maintenance for periodic adjustments. I plan to use very high quality hydraulic lifters.

Cam is a Comp Cam street grind with low lash - 248/242 deg duration @.050" and has .640 lift using 1.7 rockers.

I know it will work at least for sometime but I'm concerned about the long term durabiity. If you are not familiar with my car, it's not unusual for me to drive it many miles to the track so I'm concerned about durability.

Thanks.
 
#2 ·
I would think the biggest thing is the hyd.lifters will make the cam seem much larger than with the solids.Instead of the lash ramps just taking up clearance in the valvetrain it will begin lifting the valve at that point.It will make the seat to seat timing act like a larger cam.
 
#5 ·
in that particular scenario the lobe design itself would bust shit up. springs would be the least of the worries. the flatty/roller camshaft ramps are not even close to being compatible.

randy, i dont know if the lobes would be similar enough to pull that off or not. i know for a fact it works the other way roller to solid i just never saw enough improvement to justify the 300+ bucks spent.
 
#6 ·
in that particular scenario the lobe design itself would bust shit up. springs would be the least of the worries. the flatty/roller camshaft ramps are not even close to being compatible.

randy, i dont know if the lobes would be similar enough to pull that off or not. i know for a fact it works the other way roller to solid i just never saw enough improvement to justify the 300+ bucks spent.
Yeah, even though it was going from solid rollers to hydraulic rollers, I thought about it and decided to just get a hydraulic roller cam. I had a spec'd hydraulic cam design before that ran virtually the same number as the current solid so I decided to go back to hydraulic so I don't have to worry about setting valves anymore plus the tick-tick noise.
 
#8 ·
Randy.... theres no need for your motor to have a reverse split camhaft in it. Not with the twins.

There are some lobe designs from comp that can use either lifter.... but odds are on yours the ramps accelleration rates are too high and itll collapse a hydraulic lifter.

Id love to work something up for ya if youre interested.
 
#9 ·
Randy.... theres no need for your motor to have a reverse split camhaft in it. Not with the twins.

There are some lobe designs from comp that can use either lifter.... but odds are on yours the ramps accelleration rates are too high and itll collapse a hydraulic lifter.

Id love to work something up for ya if youre interested.
Thanks LilJohn for the info. Honestly, you may be right about the camshaft (it is a Comp Cam) but I'm trying to make things simple and keep everything as they are. I'm simply going to go back to the hydraulic design I had in the engine previously which had virtually the same performance and mileage - a proven design with my combination. The mechanical roller was an "experiment" which showed my that the previous hydraulic roller cam was actually doing quite well - less spring pressure, less maintenance and quieter operation.

Perhaps I could improve performance slightly by testing different cams but honestly, the car weighs 3550lbs, goes 8.40-8.50s and gets almost 18 mpg with both the mechanical roller and the previous hydraulic roller cam - shifting at 6500. I have competitors with cars weighing 200lbs less, bigger cams shifting at 7500, TFS R-box, same boost, etc. that ET the same as I do but at a few more MPH. I'm pleased with my combo already and I'm limited in the resources necessary to try new things right now.

The original posted question is actually a moot point. After getting back from this last trip I ran a compression check and had something going on in the engine so I pulled it yesterday and disassembled it today. Found a bad lifter and wiped lobe - first time I ever had a problem like this in this engine. Don't know if the lobe or the lifter roller went first but their both history. These were high end roller lifters so I suspect the lobe. Hopefully by going back to a hydraulic with less spring rates I won't have this problem again. Fortunately the engine needed to be refreshed so I'm just going to go through it and and make everything fresh.

Now what I need badly is information on a good machine shop in central Tennessee that can hone a block and turn a crank.
 
#22 ·
Didn't really work better with the solid rollers vs the hydraulic rollers, not enough RPM in my combination to need the solid rollers. I shift at 6500 and have a rev limit set at 6700. I was using ford OEM lifters prior and really didn't pick up anything using the solid lifter setup.

I would say if your combo is set to run over 7000 then solid lifters would start to be a better choice.
 
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