Rocker Arms: Any; High Performance & Lighter?

[el jedi]

Aloha Guzzi'landia,

Does anyone know of, heard of, or seen: Light Weight High Performance Rocker Arms for round fins?
(Heck, even square fins while I'm asking)

Why: I'm in the middle of my "Pre-planning" Rebuild of my Lemans I motor. Over the years I have done almost
everything there is that you can do (right or wrong) to make a 76 Guzzi Hot Rod. And one thing I've always thought
that would be awesome, performance wise, would be some nice, light weight, Rocker Arms; Things that move up and down all
day long between 2500 to 6000 rpm's should be light as possible in a perfect world.

Its a shot in the dark I know, but. Anyone?

Mahalo,
el jedi

 

[GTM®]

Davido, the only ones I am aware of are modified stock rocker arms that have rollers added. It's questioned in another thread here. I'd say I wouldn't want to trade off reliability for lighter weight in a street motor (or race motor for that matter), but if you're really ambitious, you could probably find a CNC machinist/hot rod shop to do some for you at a cost. If you go that route, be sure to post about it.

 

[rolf j]

FWIW, tuning-guru Dr.Jens Hofmann at Dynotec in Germany is strongly opposed to lightening anything in the Guzzi valvetrain. He even puts in steel pushrods in exchange of the original alu ones in the highly tuned engines. Hofmann can show considerable success in tuning&racing Guzzis (AND making them reliable!) in Europe.

 

[geodoc]

I seem to dimly recall something I heard in conversation with perhaps Charley Cole or perhaps Mike Rich or perhaps somebody else that "rollerizing" the rockers was to be approached with caution on account of it's removal of the oil flow restriction that you have with the stock bushing configuration. This apparently drops the oil pressure upstream at the fwd. cam journal and maybe even the fwd. main bearing.

I remember seeing pictures of Gordon & Rick's MG Cycle race bike and it had roller bearing rockers. Give them a call. Also, Charley Cole was reliably spinning that unit of his to 10K - recall he said he used steel pushrods.

GD

 

[chris a]

There also used to be some rockers available in germany/switzerland with a roller foot actuating against the valve.Expensive and to my knowledge no longer available but Stein Dinse may know where to source them .

 

[Tonerjockey]

I am not sure if the roller rockers are lighter than normal ones. They probably provide less friction, longer valve life? Less power loss?

These have been around for a while and now are living at my place. They have a roller tip, brass sleeve on rocker pin, and bearing shims replacing the wave washers.

I have a set of bearings to replace the inside bushing but havn't begun that yet .... gotta thimk about the ramifications of that.

These were on Porco Rosso last season, but I was experiencing so many issues at that time that I removed them during troubleshooting and never reinstalled.

I installed the bearing shims that replace the wave washer a few seasons ago on the racer and they seem to work OK. I can't say there is any power enhancement (my focus in LSR) but I still leave them in. They don't have any wear marks yet so I am expecting no bad influence.

The bearing shims are STUPID EXPENSIVE locally (Schweingeld in German) so I wanna continue to use them as long as they are already paid for if you get my drift.

Anyone know who GSO or GSD is?

Alex

 

[jr1967]

You could try to source Titanium adjusting screws and nuts, I have seen them around somewhere. Another option is to see where the rockers touch the valves(on the 'hammer' side) and grind away all excess material on either side of the wear marks. The hammers are wider than the valve stems so there is excess material there. I've done this mod before, and no you don't feel the difference, they actually work fine as is..... :lol:
Cheers, JR

 

[Chris R]

The performance gains by reducing weight south of the valves is really minimal - on the rockers we are talking about maybe 50 RPM max (I might be wildly optimistic here) if your do the maths. Here is a case where a plain bearing is the best bet - roller bearings are not really meant for reversing loads and when they do fail they spit hardened metal through the engine. The roller tip may look promising but in reality I suspect that it locks solid when loaded just giving you a much more radiused tip.

You have to remember that the roller rockers that NASCAR uses are replacing really really crappy pressed steel rockers that flop and bend all over the place on really really big engines so their value amounts to a measurable increase. The original guzzi rocker is well designed.

Reducing whip in the valve train is more productive and most tuners have found going to steel pushrods gives a slight advantage. I haven't measured so can't comment but trust the people who tell me it does.

Locking the valve train solid with gears does not produce any measurable increase in HP in my experience (I did measure on a dyno) and may or may not be reliable.

Titanium valves and collars will help more but require proper engineering - the guides and seats have to be right - and have to be replaced on a scheduled basis - expensive for a slight increase in Revability. Titanium is not the panacea people think - it is light, strong and good with heat BUT it galls easily, hates all other metals and is rather elastic. Use with caution and a great deal of thought and input from a proper engineering company like Del West.

Roller tappets may have a performance angle as the head geometry greatly restricts the amount of cam one can use. That being said you can really get a lot of initial acceleration out of a flat tappet. Find a friendly cam grinder with the latest software and figure out if the idea has any merit.

If you really need to rev and want an engineering challenge than explore pneumatic valves ala F1 that let the valve train rev pretty much to the limit of the conrods and/or combustion chamber burn time.

Of course the ultimate solution is to buy a modern bike that will make three times the horsepower out of the box but you probably don't want to hear that!

Ta,

Chris R

 

[el jedi]

Mahalo guyz,

Big-time good advices being thrownout here, Mahalo. You guys pretty much nipped that one in the back-side for me, which is good, cause now I'll finally get a desent nights sleep instead of designing rockers in my head.

Reguarding push-rods, I'm 100% with ya on haven good ones with no flex... went with Chromoly ones years back, and they've been priceless and worth thier weight in gold: Handle big Cams and ya can Rev all ya want.

Someone mentioned something about Needle bearings and them possibly exploding... That scares me, cause I applied this theory to my last rebuild (replaces the wave washer), havent had a problem yet, but not looking for one either. Has this happened to any one?? And by using them, would one be causing less oil to make it down stream; Cam Journl and Mainbearing??

Jurjentatsma, you mentioned grindging the extra metal off them hammers on the Rocker Arms, like this idea, and will have to look into it further. How would one go about making sure they stay balanced/intunned, as one grinds away metal??

Going Modern for BHP: On those days, thats what my Ghezzi Brian is for: A Hundered and Thirty plus Horses get laid down quick where the rubber meets the hard-stuff, all the while weighing 25 pounds short of 400 all wet n ready...
But thats not the case with my 76 Lemans, its more of a quest of final "Dream Mods" after years of Hot Roding my Cafe girl, purely in the name of Hot Roding to the fullest "SoCal" style... Zen and the Art of Guzzi-Roding with a little Ace Cafe thrown in the mix.

Mahalo, keep'em coming boyz, loven it, we're on to something good. Aloha.
el jedi

 

[Chris R]

If you replaced the wavy washers with needle bearings I wouldn't worry too much - they are not loaded very much and are unlikely to die. Replacing the main rocker bearing is another matter - this was a standard go faster trick done by tuners like Bruno Scola. I think the gains are non-existent for a lot of effort and bother. Better to spend your time on the flow bench and dyno frankly.

As to whether putting in needle bearings reduces the flow - no. Needle bearings need less oil than a plain bearing and so in NASCAR the use of needle bearings allows them to stick a flow restrictor reducing the top end oiling/increasing bottom end oiling.No flow restrictor and the flow is pretty much the same. Also the fancy roller rockers direct the oil at the springs better than the stock stamped units which is what you really need the oil for - the springs generate an amazing amount of heat.

I see no problem grinding the end off any excess metal - just avoid sharp edges. If I was going racing I would have them shot peened.
Ta,

 

[el jedi]

Mahalo Chris,

Thats what I needed hear... was kind of worried about them Needle Bearings, now I'm not
(though its been awhile, and I dont have them in front of me, I'm wondering if I put them on both sides of the Rockers,
I kind of remember doing that with Matt Capri help at Southbay Triumph, I'll know better once I get back over to the Mainland to start this rebuild ging again).

Heads are Ported, Flowed from my exhaust all the way to my 41 Delo's, even Reshaped/Grinded in the cylinder dome
(Not that I'd recommend the later to future builders unless there going for extreme Racing results).
Bigger Valves, seats, and new Valve guides. Like everyone else back in the ninties, I dual plugged them
as well... but after many years of living with them, not sure if "Dualing" is needed once ya have gone to them
high output Dyna Coils, E.I. and High Compression Pistons anyways.
Not gonna change them back, but not sure if I'd push them on Guzzi builders in the future.
Whats your take on dual plugging old round-fins for the next generation Hot-Rod builders???

Rocker Arms: Gonna look into that further, cause I like the theory. Gonna see if theres a shop out there that
could do it in a "Balanced & Smoth" way. You referred to having them "Shot Peened", not familar with that,
is that like Bead/Walnut Blasting? Kind of guessing I'm way off on that one, lol.

Again, Mahalo for the cool stuff and advice... Look forward to hearing more of your thoughts. Aloha
el jedi

 

[Chris R]

If you are running a lot of compression and the fuel in your area is not hot then I definitely recommend twin plugging (as well as getting the squish as close as possible). This, of course, is predicated on recurving the distributor to suit. I found I could know of 6 degrees of advance which indicates it is helping alot. I have never found a hotter spark to get rid of detonation and I did play with plasma systems for a while (waste of time).

Shot peening is not bead blasting - the shot is metal and basically pounds the surface removing all stress raiser and greatly extending the fatigue life. You can't just fire up your blast cabinet with some metal shot - this is an exacting process. You have to take it to a company like Peen-rite and tell them to do it to the applicable milspec. Polishing does much the same thing but not as effectively. This is standard practice in the aerospace biz and F1 brigade so if you live in socal you should find someone no problem.

 

[el jedi]

Mahalo Chris,
Yeah, I was running way to much compression (Like 13plus to 1), which will be part of this rebuild, lowering that compression.
Shooting for low to mid 11's on this build, and at the same time increasing my Squish factor... if all my math works out,
which it should, they always say "3" a charm, lol. Six percent, wow??? I've almost always played in this area when ever first getting the bike to idle after rebuilds, but have never stuck with it... I'll add it to my bag of tricks to try, Mahalo.

I'm with ya on spark to, I've tried soooo many high out put plugs, and even larger high performance spark plug wires, No Dice.
They seem to just fire the way their going to fire, no more, no less. Its all about the timing and squish. Gas over here in Kauai is about the same as Cali, but they add ethal for salt... which will be a new thing to deal with when that day comes.

On the Shot Peening, is that something ya'd do post grinding the extra metal off them hammers?
And in theory, it sounds like the proccess "Its-self" would reduce some un-needed weight as well, correct?
I still have some SoCal connections, so I'll see what shop/shops they like, but I'm gonna try and track down
Peen-Rite right now on the net.

Big time Mahalo again Chris, Aloha for now.
el jedi

 

[el jedi]

Aloha Chris,

Answered that last one myself after checking out some sites: Stronger, not lighter.

And still sounds like a very smart idea, will do, Mahalo.
el jedi

 

[guzzibob]

About twin plugging, my T3 is twin plugged & as far as I can tell that did little to nothing. However, this is a very nearly stock T3 used strictly in the street. General consensus is that the large valve/Le Mans heads benefit the most from this because of the tortured shape of the combustion chamber, the small valve heads like on my T3-with their much more reasonably shaped combustion chamber the least if any. Was told same personally by Dr John Wittner himself back in the day. I believe his original endurance racer used small valve heads as they got the best overall results that way. If head/piston dome modified, well than I guess it depends.

 

[Chris R]

Shot peening does not remove material it just compresses the surface.

And yes twin plugging a T-3 isn't going to help much unless you up the compression a lot. Detonation on those engines is not a real problem. I also agree that the small valve is not a bad place to start for serious porting work; the problem with the guzzi intake is the small radius and the small valve gives you some metal to play with. I have put the mid-valve and the small valve head on the flow bench and the small valve makes more air from the factory. So the performance gain of the Lemon comes from greater compression, more aggressive cam and timing and carbs.

Ta,

Chris R

 

[el jedi]

True that chris on the porting, I'm in the middle of helping my buddy J.Bales modify his newly aquired T-3
via emails and here. And am pretty much walking him through the proccess of getting that T-3 to Lemans specs.
And porting is a must (he's on the fence whether to Dual plug or not), as well as more lift and longer der of a Cam profile.
He's looking at going with one of them 950 kit that are out there, with a higher Compression. You have any personnel prefference of whom's to go with?? (I went with Augustini years ago... But thier a serious pain to deal with over the years)

On my Lemans, I went bigger valves on both intake and exhaust (like every one back in the Doctor John & Raceco days).
Courious though about your theory of "Smaller" valves, not on my engine (its to late), but to know down the road for some future build and or with my buudies bike.

Also, I've got these 41mm Delo's on mine from a factory racing Ducati (40's are normally the biggest).
On my buddies bike/build... Being that all T3's were pretty choked up, what size Carbs should he be looking for to give T-3 more Lungs??? 36'ers??? Want to have that squared away before he goes off to porting, that way he can send in the manifolds at the same time so its one smooth run for them Pumpers to the valve opening.

Off to the grind (work), so I'll check back with ya, Mahalo and Aloha.
el jedi

 

[guzzibob]

About which size carbs to use, all I can tell you is that my otherwise mostly near stock T3 has 32 PHF's mounted, which compared to stock 30 VHBs had a very dramatic positive effect on mid to top performance with no cost down low, both before & after I went 850 to 1000 or so cc. That said, lots of T3s, G5s etc out there with 36's since those are more common & easier to mount, generally to reported good result. On my big valve 1000S, the stock 40 PHFs seem like plenty, if not maybe a little too much for street usage, & the mid valve 1000S comes with 36s, again in street trim. Tonerjocky tried 32's to very good effect I think on his V7 (750 cc) based race bike & I think also tried 36s on it, maybe he can give you some input.

 

[Chris R]

36's are about right. If you have to choose between mid throttle response and WOT Hp pick mid throttle response everytime. 40's most would say are a bit big and have lazy part throttle response.

Porting without a flowbench is - if you are paying for it- a scam and if you are not paying for it unlikely to produce the gains you imagine. Air is not intuitive. Making everything smooth and shiny does not make more air - indeed you can move a peice of wire with a bent tip around in the airstream and sometimes drammatically improve flow. Same goes with valves and valve guides - I have seen flow go down by replace larger stemmed guides with smaller ones and the same with replacing small valves with big ones.

You don't need a calibrated flowbench as you are not racing anyone else's - just a vacuum cleaner motor and a simple manometer is all you need to tell you if your modifications are going in the right direction. It is very important to mount the head on the barrels you are going to use.

That being said, opening the inlet to match the 36mm carb will produce results with or without the flowbench.

All the nicasils are made by Gilardoni - it doesn't really matter where you buy them. I think piston wise you only have two choices: the low compression SP/T3 piston and the high compression Lemans Piston. The lemans head is sunk 2mm deeper so piston to head contact needs to be checked.

I myself have always had a good experience with Agostini's - Alic is a delightful (& beautiful) lady! MG have always been straight and knowledgeable to me.

Chris R

 

[el jedi]

Aloha Guzzi Bob !!!

Been way to long, and great to hear ya chime in, its been way tooo long since a gathering with
my Socal boyz and good campfire drink... Hoping to come out that way soon, just 3000 miles of ocean in the way these days.
I'll check around deeper on Carb specs and benifits, but most likely I'll point Jay in the direction of 36ers, just cause there
easy to find and mount as you said. Mahalo and much Aloha.

el jedi