Engine and Transmission Tech

Looks like our "threads", are getting twisted? Jim's talkin why flat tappets in "rockers" and Nic's bespeakin rods in the "rollers". I'm about to get confused. One way to enhance street-use power is to improve "lift/flow under the curve", meaning heads with good low lift flow and open the valves faster. Faster in flat tappet Buick/Rover,sbc is limited by smallish .842" dia of lifter. OEM. didn't go to hyd. rollers because they "like" to spend $'s needlessly. Longevity, reduced emissions and better performance are some of the reasons. Limiting a Merlin,TA or Wilcat head to under .500" lift and 7k redline may prove counter productive compared to a skilled roller set-up. In my experience around OEM. 215's, the best thing a flat tappet cam did was go flat! Fortunately, our oils, "with zink", have improved since then. Long live Diversity University, roverman.

As Art says, it's 'area under the curve' that helps build torque. Since flow in the ports of stock heads seem to hit an inflection point in the .400/.450 lift range, improvements below those lifts will help with performance. Also, with the faster ramp rates possible (and better low-lift flow) with roller lifters, overlap can be reduced and LSA can be widened.

This helps with electronic fuel injection, and for those of us who live in areas where emissions are tested, this helps with emissions.

To recap and make sure I'm on the same page, it's Chevy 3.1L 60^ V6 roller lifters and dog-bones. What was the retainer/spider? Looks like it bolts down, so it might be a stock Buick v6 part. getting two and cutting/splicing them should work, right? And, obviously, all this stuff will work on 215's, 3.5, 3.9, 4.0, 4.2, 4.6, 300ci, 340ci, and probably 350ci.

Paul and all, Yes it must be Buick V6, as to what years? (2) V6 retainers/spiders, overlapping?-maybe. As to why example used chev 3.1L vs. Buick? In leiu of sheet metal conversion, I shall investigate alternatives, including if 3.1L is identicle to sbc hyd. roller. Anybody know if 350 Buick and late V6 use larger base circle on cam? Thanks, roverman.

I have been following this thread and read all 9 pages on the V6 roller conversion. It uses the dog bones and retainer from 86-88 Buick V6 roller engine. The Chevy V8 lifters are too tall. The 3100-3400 (3.1 and 3.4) rollers are the perfect height and same diameter as the Buick and Chevy V8. The Turbo Buick V6 3.1 roller thread says it works with the stock base circle for Buick V6 (1.234) . Also move the spider mounting bolts a little to avoid the oil gallery. Here is a picture of that and a picture of a SBC with the 60 degree 3.1 lifters from a Corvette forum.





Edited 2 time(s). Last edit at 12/03/2009 03:30PM by mgb260.

I guess twisted enthusiasts just can't help making twisted threads.... but isn't that what threads are? Twisted I mean?... anyway,
On my scat rods, which were capscrew type, the shoulders interfered with the cam lobes. The upper shoulder and one capscrew had to be trimmed to clear.



On the bottom, they hit the pan and I will need a pan spacer or girdle plate there, about 1/4" thick. Someone on the Buick board has started working on a cad file but may not get it done by the time I need it.

From Kurt's old article on the D&D 300 based 340 stroker it looks like the same issues came up, along with the need to trim the piston skirts. With the BOPR based build I'd guess it'd be about the same, and the shorter rod might mean more of the shoulder would have to be trimmed. The stock 350 rods used a capscrew type rod bolt which gave more clearance at the cam I believe.

Paul's comments make sense. Enough to justify the extra cost though? That's the part that is hard to say. For me, no. For others of you maybe so. But then, I'm not hampered by reliance on atmospheric pressure to do the cylinder filling so as usual I'm off on some tangent that only has a little relevance to the mainstream. Consider this though, if you plan to put a whole lot of miles on the engine, when the time comes to rebuild you will probably be able to reuse your roller gear with minimal servicing whereas the flat tappet cam, lifters and rockers will probably need replaced or rebushed. So that's another advantage worth considering.

Jim

That's a good point about longevity. I've spent a bit extra on lifters with little oil holes on the lobes because of the aggressive cam I'm using. The reality is it's not gonna last. That's $350 down the drain just for the cam.

So the cap screw rods you guys were talking about have the holes threaded. Huh. Make sense.

HEY! You brought up the VW rods first, Art. LOL!


Whatever happens you've got to admit this is fun, right??

Something we haven't discussed, aluminum as a lifter bore material vs. ci. We know ci. is superior as a wear surface, right. How many of us check "exact" clearance, lifter/bore? We know oil requirement will increase to "square" of clearance increase. I'm thinkin that alum. bore that has a flat tappet, rotating and sliding will likely wear faster than a roller? Nic, please don't fret that the roller set-up weighs 31.7 oz. more.roverman.

Hello pro-roller people. 48 lifters on-the way. Still no "rockers". Waiting on cam quote. rollin on a ...........roverman.

Awesome. Are those the Buick 3.1 roller lifters from 86-88? Did you order them new?

Paul and all, Yes, thanks to this forum and to those that keep it real. One of the next steps will be what "masters", Doug Herbert has. "Dog bones and retainers" also available for good prices. Paul, you have your desirable cam spec's. yet? roverman.

Art,

IO/IC/lift:15°/67°/0.283
EO/EC/Lift: 65°/21°/0.283
Duration int/exh: 266°/266°

These were based on Ford 5.0 cam specs. I think this has a LSA of 112.

Whoa! I was looking at the picture of the Chevy block with the roller lifters. The glyptal painted valley looked similar to the Chevy engine I have for my 55 Chevy, but I was assuming that it was a 305 or 350 roller block. Then I noticed the steam holes. It's a 400 (which means it's non-roller) like my small block. So, some of the parts are retro-fitted.

I'll have find out more about what parts they used. Looks like a pretty slick installation.

3100 and 3400 FWD and 2.2 four cylinder Chevy,also used in other GM cars for the rollers. The spider and dogbones from 86-88 Buick 3.8 roller FWD engine on older RWD turbo 3.8.The spider and dogbones in the Chevy are factory newer Chevy retro fitted on 400 .



Edited 2 time(s). Last edit at 12/06/2009 08:32AM by mgb260.

Wide Open Throttle (WOT-TECH V6 Performance) sells the small V6 lifters with LS springs installed for high lift cams and stiff valve springs. Supposed to be twice as stiff as the stock lifter springs.They sell just the heavier springs for $29.95 for 12, I imagine you could get 16 from them. More stabilty at high RPM,anti-pump up?.




Edited 2 time(s). Last edit at 12/07/2009 12:23AM by mgb260.

Sounds like a decent price. I'll be investigating beehive/ovate springs too. The higher mass of the roller lifter makes 'heavier' springs necessary, but beehive springs avoid spring harmonics and you can get away with lighter springs. Considering the relatively smaller base circle of the Buick/Rover cam, seems like lighter springs are a good idea to help with cam life.

I wonder if that's why Olds used beehive spring on their 215?

Latest Supercharged Buick V6(Series 3) has Beehive springs. Supposed to be good to .480 lift.

Actually, I think the first "beehive", in real production, (some antique engines used a similar design), for GM, may have been the Olds 394". I believe slightly pre-dated the 215. I have a theory, un-proven, that a 1.6 rocker ratio will return the push rod side of the valve train, easier than a 1.5, all else being equal. IE., harder for same parts to open/easier to close. I find it "entertaining" that Comps Cams was blowing, "orfice smoke rings", by claiming "they" invented the beehive. Ok, spring on far right is stock MGB valve spring?-explains the "tilt".Not that long ago, I bought my 1st. set of beehives from Comp Cams, $57.They sure got "pricey" since then! Doug Herbert is still diggin for a quote for roller cams. Rollin On A Riv.....roverman.

Roverman, All those springs are the small springs inside hydraulic roller lifters. The 2 left small and large are V6 the 2 right LS7-mucho stiffer. I was thinking the newer beehives might work on the Rover. On another thread I have a picture of Mopar 318-360 shaft mount rockers that may be modified to work.



Edited 1 time(s). Last edit at 12/07/2009 08:42PM by mgb260.

British Car Conversions also sell the upgrade LS internal springs for the small V6 roller lifters. A guy on the J body forum also recomends replacing the internal wire clip with a 5/8" internal snap ring. The mods would be good for 7000+ RPM. Are you guys doing the roller lifter swap planning on overlapping two 86-88 Buick V6 spiders. I presently have neither a 215 or Rover,but have over the years had 215's,Buick V6's,Buick 300 and 350 V8's. I am interested in the strokers also because in my opinon the 215 was just too small.



Edited 2 time(s). Last edit at 12/14/2009 06:10PM by mgb260.

Jim and clan, My 1st. set will be,gutted/converted to mech. I would "definately" go with the circlip for serious roller work. I just don't believe I will need more than oem., to do the job, in a racing Rover eng. I have Buick V6 "dogbones" on the way and will pursue the Buick V6 hold-down arangement, perhaps spliced/welded. We shall see. roverman.