BritishV8 Forum

Art, I understand that after about .400" of valve lift the BOPR ports don't increase their flow by much. I've seen that inflection on Ford Y-block heads and Studebaker V8 heads. So the trick is to maximize low-lift flow to get the port flowing that much sooner (I think). With the roller lifters the valve timing can actually be shortened and still have a very good Area Under the Curve (AUC).

The down-side with roller cams would have to be reversion. Maybe that's why you always see factory HiPo roller cam engines using long intake runner tuning (TPI Chevy, SEFI Ford 5.0L, SEFI Ford 7.5L); it's probably because of the wicked air pressure pulses from snapping the valves open so quickly. The long runners would isolate the other cylinders from 'seeing' the pulses, and carbs have a bad time with tuning when the reversion is severe. But I'm not an expert on this by any stretch - I'm just guessing.

So, between increasing the intake valve size a bit, pocket porting the intake ports, removing any abrupt angles in both ports, and a roller cam, we can get big improvements in low RPM torque and still have ok power in the mid-range.

I'm modeling my specs on the Ford 5.0 SEFI HO engine because I drive one and it's got very nice low-RPM torque, excellent fuel economy at highway speeds, and uses electronic port fuel injection. The 4.0 that I got has port fuel injection.

I think the stock 5.0 cam has something like 114 or 115^ LSA. But the 5.0 has short rods (5.09" on a 3.0" stroke). With the low rod ratio, the piston gets to the top of its travel later and the exhaust and intake events are naturally closer, resulting in more reversion from exhaust pressure. Also, with a wide LSA, valve overlap is reduced and less fuel escapes during overlap, which improves economy and reduces emissions.

The rod ratio is higher on stock BOPR engines. My Olds has a 2.8" stroke and a 5.66" rod and the piston spends more time near the head during overlap, so blow-down will end sooner and reversion will be reduced, so I'm assuming that I can pull the LSA in a little tighter, to 112, to pick up some more mid-range torque. The Rover 4.0 has an even longer rod and it will have even less sensitivity to LSA and overlap.

But I'm only taking a swag at these numbers. I'm completely open to suggestions about valve timing suggestions. My goal is for a daily-driver friendly engine in a LBC with a 5 speed.

I have an Olds 215, a Rover 4.0, and I also have a Rover 4.2 crank that I might put into the Olds. Engine sizes will all be in the 3.5 to 4.0L range. The Olds heads have the valves centered in the cylinder better than the Buick-based heads, so the shrouding issue is different there, but it might not make much difference in my application.

Ok, So we got Nic,Paul and Art interested. Ian, anybody? roverman.

Art, I would be but I have a custom grind in my 340 that is yet to be tested and crank clearance in this motor is critical so I'll have to pass this time around. But I do hope it becomes available as a regular part. Better check with the boys over on the Buick board. Some of them may buy in, and if they could get them with the 350 journal sizes several of the 350 guys would I'm sure now that the TA heads are almost done.

Jim

Jim, Thanks for response and I understand. Only response I got for V8 Buick folks was for LS 1  pattern on 350 sbc's. As I see it, those folks already have resonably priced cams from TA. I think it's a good thing to have more than one supplier of a particular type of cam. I suspect more people will, "come on board", once"others" provide concrete results. Thanks, roverman.

I'm ordering #8620 mat. blanks, tommorrow. Paul Menton will have (5),completed cams, should anyone be interested.  roverman.

Art, I haven't yet come up with a ramp rate for the cams. I'm thinking that because the base circle is relatively small, and because the lifer bores are cast aluminum, I'd be looking at something that's lower than the typical Ford Windsor or Chevy SB ramp rates.

I was going to mine the Buick V6 site for potential information about cam specs, but searches of the web on terms such as 'cam ramp rate', 'cam lift rate', etc. never did produce any numeric values, only references to the subject as an abstract concept.

BTW, our friend who is building a turbo V8 Triumph might be interested in a cam with zero overlap and a wide (114 -117) LSA. Seems like a roller cam would be perfect for a turbo application.

Art..
 Is there a master catalog of ramp profiles for us to look at?

Paul and Tony, I'll ask Fri. bout lift rates and what "masters", they have in-stock. Good new is, as round lobe blanks, only thing final is "flange/no flange".For obvious reasons, we want to keep base circle as large as possible,while achieving enough lobe lift, and smaller than bearing #4. I "assume", you-guys,  have found a swinging deal on double roller chain drive for "no flange" Rover ?        Rollin on a riv.....   roverman.

Do you need any funds? Let me know.

Nic, thanks, but no thanks. Just buy a cam when your ready. Paul and all, I put a deposit in, to build (10) blanks, (6)flangeless and (4) with(215 style).I want to use 2.0" dia. on flange and a Rover retainer plate. If someone has a problem with this...tell me NOW. Contreras is  going to spec. an oem. sbf. roller cam coming into shop, prior to being ground-hotter. "Rollin on a riv."....roverman.

I would be/am interested in a cam for a TT 300, but I am currently laid off until April so no big $$ 'til then. Prolly a wide-ish LSA and no overlap... Would definately need setup for dist. drive.

By "using the rover retainer" do you mean a "thrust plate"?

If a stock thrust plate could be bolted to a 300 sbb, that would be awesome.. better than using a thrust button. I'm assuming that would work with a stock style 215-350 timing set?

Now, the "noseless" ones, would that be like the front end of a Turbo 6 roller cam?

(10 pages is a lot to read)


OH, I am sure THIS has been discussed before as well but.. Can the cam bearing journals all be bored out safely to 350 SBB size, to take advantage of TA's advanced bearings?

Art, outstanding work so far.

I lost a little free time when my SO went to the ER for a MI. IANAC (Cardiologist), but three trips with no real diagnosis tells me we're still in the dark ages of medical practice. All's well, so I'm back to work on projects like carpeting one of my rental units, and prepping an engine for a shiny new cam.

Paul

Thanks Paul. It's true, I joke a lot, but I have a serious passion for these engines ! Because of this forum and the and the working gene-pool, Rover just might become, "the lead dog", for a while, at least for some of us.  Wesley,#1, retainer = thrust plate. #2,215" style flange will be machined to take "thrust plate", but use is not mandatory. I have not attempted use of plate conversion on non oem. blocks.#3, I would "sonic test", areas of concern, around bearing tunnels for installing "350" bearings. A little "romance" for a "lot" of work. You would need a "one-off" cam be made,(expensive) ! The stock bearings can be re-drilled and rotated, if not available from TA/etc. This procedure is well defined in several Buick V6 books. Were I to go, off-the-deep-end, for cam bearings, I'd go to needles,  even "more" work. Onward, roverman.

For needle bearings you'd have to greatly restrict oil flow to the cam bearings. Otherwise oil pressure would plummet.

Jim

Jim, yes indeed. They need precious little compared to inserts. Were I to... I think, use machined outer housing/fractured, like modern con-rods and needles would run directly on 8620 cam, with undercut journals, mostly surrounding the needles and reducing "bleed-off. This would also reduce outside of housing for less "tunnel"boring. As a side note, Chevrolet experimented with needle bearings, on the sbc., for mains/rods. For the very reason you mentioned, Jim, they had too much volume required and "bleed-off". These might be handy on a "Coates" headded, sbc. Motor #1 blew-up at around 16,700 rpm. Reportedly #2, lived at 16,500 ! Anyone who has had heard a "Spintron", valve train dyno, at full gallup, can appreciate the "hellacious" forces of impact, with poppet valves. I believe, easily  70+% of all, professionally prepaired,  racing motor , catasrophic failures, "start" in the valve train.Further I believe, the future of the piston/recip. motor, lies with slide valve technology. Time will tell. roverman.

Prices quoted are for min. qty. of (10), each style nose, ie. flanged or flangeless. NO mix and match. Max of (2) different profiles in 10 cam lot or extra $'s. Regards, roverman.

If I were forced to choose between nose or noseless, I'd choose noseless. Although the cost will be relatively reasonable, I think swapping in a roller cam is going to be popular with the type of builder who wants to spend a little extra on an engine and a few goodies to get a peppy solution.

And I'd be fine with a choice between two profiles; first would be emissions/computer/efi compatible (relatively wide LSA, 112-114, and low overlap - maximize torque at 3750 RPM) , and the second is something sporty but streetable for a carbed engine (narrower LSA, 108-110, max torque at 4500 RPM).

Again, I'd model the first cam on something like the Ford 5.0 H.O. roller from 1989. Max lift to be compatible with stock valve gear (lift in the .420" range?). The dream is to swap out the cam gear on an otherwise stock 4.0/4.6 engine and see an improvement in torque throughout the RPM range.

The second cam would require valve work to increase max lift.

If the crowd wants the nose, then we're looking at slightly sportier profiles because we're dealing with a crowd who is doing more to tune their engines and wants more power (grunt, grunt. Rewire it for more power.) In that case, I'd be wanting something streetable for all my cams.

That sounds practical. I'd think the first LSA should be more toward 112º IMO. Maybe make the second one with some more aggressive lift. Over 500. Just pitching out ideas. I'll buy the second one. LOL!

Remember hydraulic and solid lifters have different ramps also.

Jim, Old drag racing trick, run mechanical lifters on a hyd. cam,(no clearance ramps). Drags only!  roverman.

Clan, until I get a "yes" for (10) of either, their on hold. roverman.

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WOW, Kragen quoted(Cloyes) $449.! Did I miss something here? Should be close in price to early? I want to machine "late set" to fit sbc. nose. Anybody?  roverman.

Art, Is that for a roller timing chain? I recently picked one up on eBay from a seller named BullDog or BadDog (or BadBullDog, or something.) I'll update when I get home from work, but it was reasonable.

I've gotten some nice roller stuff from an Oz supplier named Master something. (No, not baiter.) Availability varies.

Edit: RollMaster. Some of their stuff uses high quality German parts.

Paul,Thanks, I'll keep diggin. If your "up" for (5) flangeless cam blanks, I'll consumate the order. "if" I can mod the late Rover roller set,(machinable), I'll also attempt optional use of dizzy gear. roverman.