Roller Cams - are they possible? UPDATED w/pics

[AzCoupe]

I've done a lot of research on roller cams in the past few months, to see if they can be installed in the US sixes. The answer is YES, but there were a few problems to overcome.

The first problem is roller core availability, since they are not produced. There are major differences in lobe profiles, thus making it impossible to grind a roller profile on a stock core. That being said, I've been working with the company that produces cores for Clay Smith Cams, and after a little prodding, they agreed to produce a roller core for FSPP. However, it should be noted that they will be more expensive due to the limited number required (standard run is 2000 cores). Problem one solved.

Installing roller lifters appears to be the other major problem, as they normally require tie bars. It would be difficult (at best) to install a pair of roller lifters into a US block with the tie bars inplace, but with a few modifications to the block, it is possible. However, we began looking at other possibilities and discovered that this is not necessary. We are working with Jesel and have come up with a design that eliminates the tie bars altogether. A special lifter is required, as well as machining the lifter bores, but it eliminates the use of tie bars. Problem two solved.

The last problem is the easiest to solve. There are no roller profiles established for inline six applications. Clay Smith Cams is currently developing new roller profiles, which will be suited to inline six applications. This will probably require new master profiles, which are expensive, so we will limit them to the most popular setups. However, we will be offering three or four profiles designed around the new aluminum head. Problem three solved.

Now, back to the lifters, as I'm sure you are wondering how we plan to eliminate the tie bars. Jesel already produces the required lifters; they just never intended them to be used in an inline six application. That's not surprising is it?

The lifters have a tiny knob that sticks out the side of the lifter. They are available in two styles, with a rounded end or a square end. To install them in the block you need to do one of two things. Machine a grove in the lifer bore which uses the round end, or re-machine the lifter bore (to a larger diameter) to accept a special brass lifter guide which uses the square end. The brass guides are manufactured with a groove that works with cams up to .500 lift (at the lobe), which is more than we would ever need. I'll see if I can get some pics of the lifters and guides posted.

The ones on their website have keyways as opposed to the peg style they showed us at PRI ??? Same concept. They are also very pricey at $175 per hole. Guess you could use the keyway lifters on the one and six cylinders, and standard tie bar lifters on the other four to save a few bucks.

 

[Asa]

i wondered why something like that wasn't done, to align the lifters i mean
it just sorta made sense to me

 

[xctasy]

The log, 2V/ME/SP non cross flow have water conduit risers to the head right beside the lifter gallery. (The true right of the engine).

This prevents the tie rod being linked to make six pairs.

Lifters No 1 and 12 at each end of the cylinders is fully encased, and the normal small block V6 or V8 Ford, GM, AMC or Chrysler aftermarket lifters can't fit without a bunch of metal work. For lifters 2 and 3, 4 and 5, 6 and 7 , 8 and 9, 10 and 11, you can use the stock small block Ford roller lifter with a custom made tie rod which has the stock 144-200-250 I6 spacing.

The real problem with this is that the only way to fit tie-rods to those outer lifters is to die grind or bore the structural gussets out. Argentine racers do it, but its very time consuming, and it is a major on a non cross flow engine.

With the Aussie X-flows, Ford made a design change to the water condit risers. They are on the the true left of the engine, the other side to the non cross flow.

It's real easy to fit six tied together roller lifters into the block with no modifactions at all. This was done in 1990 by Mr Spence at Crow cams Australia.

If people are making billet core cams, then the same stock can be used for cross flow as for the non cross flow. The lobes have to be 360 degree to the require maximum lift, so FSPP would then have control over cores made in America and be able to supply them all over the world for X-flows as well as non X-flows. Anyone making one line of roller cams without an ablity to change game plans will mis out on a huge market.


Since it is so hard to make the stock 144/170/188/200/221/250 block take a roller cam, its far better to redo the 12 bores of the lifters with a brass sleave. This is how all the NASCAR guys do it, and its cheaper to ream out a lifter bore than ramchine a groove.


Lastly, the time is right for Carbon fibre pushrods. The roller cam profile can basically model any late model OHC cam profile on a log head engine block!. With 1.6:1 lifters, you can run the roller cam profile like it is a modern 1.8 or 2:1 OHC cam profile, ie, a Workalike Ohc profile. The real performance gain is in the off the ramps timing and not having a flexiable drive train. Dropping the noahs ark tube or cast pushrods and using carbon fibre with your cam masters will result in a huge gain.


Advantages are

a) Working clearance can be reduced by 5 thou.

b) They dampen noise out as well as a hydraulic lifter does.

c) they transmit very little vibration and stop valve train surge.

d) They do not damage the engine when they fail.

e) They weigh half of most steel pushrods

f) there bending load is almost twice that of a steel rod, and they don't fail explosively.

The British were doing fibre pusrods in the late 1980's for APT Parts in California.Capter 11, pages 303 to 316 explain all the advantages of fibre rods and belt drives. Roller cams are just the begining!

http://www.aptfast.com/APT_Parts/Books/ ... 1_info.htm

Regarding the fibre pushrods, there were only a small amout of takers. I believe Windsor ESC in England were making them with cut off metal bases and super stiff carbon grahite fibre trunks. Back then, the quality assurance process was a little difficult on them, with 1 in 16 of the pushrods failing in service. I don't think aftermarket pushrods fail that mutch, but if they do, they take a roller rocker or lifter or cam with them. Since the carbon fibre rods never take out an engine or rocker gear like metal ones do, then there is more scope for making them 100%. Batch building them, and runing them them on a test rig will allow 100% sucess. If they survive 30 minutes on a test engine at the worst operating range, then they should ever fail in service.

Having no ramp on a cam and being able to run 4 thou clearancres rather than 25 thou will make a huge difference to performance!

Top marks on getting Jessel into the picture. Most aftermarket makers realy on high price, low volume to survive. All production economics improve exponetailly when you make more than 11 items per week or about 500 units a year on on a 45 week plant utlisation. That is the plant break-even for most manufactured goods.

Truth is the quality improves as you start to produce more volume. Jessel need our patronage to make sure there belt drives and valve gear stuff gets used.

Since the little I6 is so avaliable, then your risks are very low.

 

[Thad]

OK, you are talking about the SBF-6.
Didn't I read somewhere that the Argies had an adaptation for roller lifters in their racing Falcons.

As far as the BBF-6 there is Crane hydraulic roller lifters and cam.

 

[xafalcongs]

I'm game for both a roller cam AND carbon fiber pushrods. I have a XF Falcon X-flow so if you can get Smith to grind your cams to work in a X-flow, I'll buy one. Will you take custom grind orders?

--J

 

[addo]

I think Crow did some roller crossflow grinds. Email them and see.

 

[80broncoman]

Foundry+ Roller cam These two don't really belong together. Cast steel cams were used in the 60's. I have seen real life examples, and I've seen why its no longer done that way.
I'd stick with 8620 material for Rollercams.

 

[AzCoupe]

Foundry+ Roller cam These two don't really belong together

How true. I've been working with so many foundry's lateley, that I automaticly enter it without thinking. Thanks, correction made "company".

Deano, you hit it right on. Those are the precise problems, both with the block, and just about word for word what Jesel had to say when we were discussing it with them. We were also looking inot the possiblities of using removable tie bars, so they could be dropped into the front and rear pairs. It may have been possible, but would have required a special tool and a contortionist to pull it off.

Jesel also agreed the best way was to use the guides, but warned the the machine shop must be very cautious when boring out the lifter bores. Paying extra attention to boring them perfectly parallel, or is it perpendicular? At any rate, any top quality shop should be able to handle the job. Jesel stocks both items on the shelf.

I'll mention your thoughts on the cam cores, so they can be used in X/F engines too. Great idea. Never even crossed my mind.

 

[xctasy]

Another 1 million potential customers never hurt a good cam core. Heatseaker made some billet cams back in 1990, as did Crowcams, but there was a micro recession in America, Australia back then, and the market died out.

Since all the billets I've seen are 360 degree lobe, and you have to cut a tooth for the cam drive, then Crow and maybe Chevy Off Road and Marine (COME) in Australia might help out taking X-flow cores. I know that Crow cams has to market in a very knowledgable manner to beat the cheaper 'white box' cams. Sam Blumstein at COME has relatives in the US, and he's a sharp MBA business man too. Most of his inventory is from US suppliers which are closer to the OEM side of the manufactuting scale, where the quality is. JP in Australia have made tight quality limits the means of selling less expensive materials in there world class cam chain sets, and this puts them closer to the action because they can make them in volume without rework.

That's the old A-series engine and Detroit Engineering secrete. Use a lower grade material and run a better production process to make it a goer. That's why aluminum engines have cost GM a bundle over the years, yet Ford spits out quad cam engines on the same tools since 1989.

Another point, the steeper the rocker ratio, the lower your machining costs. An X-flow runs a 1.73:1 lifter, but Chevy have 1.8:1 lifters for there LS V8's. Once you've got a roller cam for the non cross flow, you will save money on machining if you dedicate the design to just the 1.6 high lift rocker ratios.

I'd be interested in if the FE guys are going to steeper lifter ratios. Even though its a 48 year old design, Edlebrock and the aftermarket still seam to be spendng a heck of a lot of money on 390/406/427/428 heads. Perhaps its the fact that trucks were running it till the late 70's, and that they are smaller than the Lima block, but it still amazes me that there were so few hot FE engines made, yet the aftermarket still has crap loads of really trick gear for it.


To me, if you were looking at using, say, the 1.76:1 FE roller rockers and shaft dimensions, plus the roller cam profiles, on your 200 and 250 I6's, there may be a way to, um, 'use' the features on the table for that engine. Wouldn't it be neat to be able to sell some real volume rockers to the I6 guys, and save the costs on the roller csm by making it a full package?