Solid lifters on Hyd cam

[gregaba]

I was watching a engine masters show and they did a dyno test on a engine with a hyd cam using solid lifters. The dyno showed a 3 fpt increase and an 11 horsepower increase and a real smooth power band compared to the hyd lifters.
This was on a roller cam and not a flat tappet cam.
The one thing that confused me was when they set the lash I think I heard that they set it at 2 thousands.
That seems kind of small to me.
Has anyone tried this and if so how do you like it?
Greg

[blykins]

Lash is totally different because the hydraulic cam lobe does not have a lash ramp built into it. 

Putting solids on a hyd is a band-aid.  There's really no reason to do it unless you're trying to get around some kind of rule.   The reason they made more horsepower is just because the lifter/valvetrain system wasn't optimized. 

The caveat is that there are some lobes that are designed to take both solid and hydraulic lifters.  But it's intentional, not a band-aid shot in the dark. 

[mbrunson427]

I watched it as well... the only thing I took from it is that you could put a set of solids in and see how close to optimized your hydraulic valvetrain is. It's probably a very small group of people that fall into the category of needing to check their hydraulic roller valvetrain to make sure they're squeezing 99% of the hp out of it.

Very interesting though!!

[gregaba]

Thanks for the reply's
I just find stuff like this interesting. I wouldn't do it for 11 Hp unless I had a full race engine but I like to read about experiments.
This kind of stuff reminds me of in the late 60's when my dads racing friends would put 428 sleeves in their 427's and race them in the stock classes at the drags as a 428 CJ stock classes.
Greg   

[Falcon67]

Related - What's the professional opinion on running solid rollers on a hydro roller cam.  As in, the budget only allows for so much at one time LOL.  The hydros in the 351C tends to get funky around 6500.  Howards brand.  I have their pressurized solid rollers in the 393C and they seem to be working real well.

[Joe-JDC]

As I mentioned in another post, back when the first 5.0 engines came out with hydraulic roller lifters, the shop I was working with specialized in the Mustang 5.0, and I converted my "86 Mustang GT to a 5.8 stroker with EFI and mass air in '87.  I still have the handheld Crane programmer to monitor the timing and fuel parameters as you drive.  I was probably the very first one of those conversions at the time, and I worked with Crane Cams to find a hydraulic roller cam suitable for the 351W conversion in my GT, and they cut 7 camshafts for experimental use and I bought three for the shop and myself.  I asked the specialist at Crane Cams if we could run solid roller lifters on those camshafts to try to get them to rev to 7000 or so rpm, and he came back the with answer to set the lash at .004" hot.  I still have two of those camshafts running in strokers, one with 14 psi boost after 30 years.  One was run with hydraulic roller lifters, and spit out a lifter wheel, but was able to salvage the crank, rods, and block.  The camshaft was toast.  Joe-JDC

[gt350hr]

 A solid roller profile is a little "softer" off of the base circle so the lifters don't get "hammered" with the extra lash they use. A hydraulic roller takes advantage of the roller wheel always being in contact with the lobe so it doesn't hammer and is a bit more aggressive. Changing to a solid roller and tight lash picks up some power because of the more aggressive lobe off of the base circle. As Brent said the  "major" cam companies have explored this and offer complete lines of custom "tight lash" lobes and they make more power than a solid roller on a hydraulic profile.
   As a side note Ford Racing has a small block ( for factory roller blocks) hydraulic roller with a ceramic ( light weight) check ball and with about 150 seat pressure  it will rev safely to 7,000 or a bit more. I have them in my 408W and proved it on the engine dyno. 465 hp @ 6,000 with "regular" lifters and 110 on the seat. Changed to the "R" lifters and springs with 150 on the seat  gave 480 @ 6600 and was still not "pumping up" @ 7,000 but the power was slowly fading.
   Randy