Sort of a new message - re a long-running topic ... Guzzi 4 valve heads

[ohiorider]

Wonder what the power deficit would have been had Guzzi simply designed a 4 valve head with each set of valves ( a set being two intakes or two exhausts) actuated by a pushrod and forked rocker arm system, using the single cam located in the block, instead of the current 8v high-cam design?

I believe a German company, owned by Mike Krauser, designed 4 valve heads for the old BMW airheads that utilized the cam in block and existing pushrod to do that.  However, I don't have any info on what power gains were achieved.

[oldbike54]

 My understanding is that the largest gains in a 4 valve vs 2 valve head are in the midrange . Certainly a 4 valve design with lighter components allows for higher RPM's , but that is a side effect . The Krauser 4 valve beemer heads were worth about 4 HP at 5K if memory serves . Triumph experimented with 4 valve chambers designed by Cosworth in pushrod twins , unfortunately the castings were so porous they were not a success , although they did provide some benefit at 4500 Revs .

  Dusty

[Bisbonian]

My Yamaha Road Star Warrior had a design like you mention.

It seemed to work well even though that engine red lined at 5500 rpm.

[mwrenn]

Moto Guzzi was pretty ingenious with the small blocks, starting with the Imola II, then continuing with the much maligned Lario.  They both used the existing two valve cam, with a set of intakes and a set of exhausts just as you described.  Fortunately this lends itself quite well to later small blocks being modified to run with four valves.  I have seen a power and torque increase across the board with my conversion. I think just over a 40% increase in RWHP. 
Anyhow, I attached some pictures you might find enlightening.

[ohiorider]

That is interesting to me (any maybe anyone who doesn't know Guzzi has already done this.)  Thanks for the info.  I'm relatively new to Guzzi (2008 1200 Sport), and find this kind of info really good!

[jacksonracingcomau]

  Triumph experimented with 4 valve chambers designed by Cosworth in pushrod twins , unfortunately the castings were so porous they were not a success , although they did provide some benefit at 4500 Revs .

  Dusty

Harry Weslake not Cosworth
Full engines still available from Dave Nourish (Nourish on covers, not Weslake as orig )
The conversion for unit Triumphs was paid for by Rickman (Rickman on rocker covers)
Factory TSS (finned only rocker covers) was the one with porous heads but real problem was Margaret Thatcher, the co-op went into liquidation in August 83, bikes had hardly started production.
Quite a few Weslake / Nourish engines about here + some unit Triumphs with the top end only, haven't seen a factory TSS for years

[oldbike54]

Harry Weslake not Cosworth
Full engines still available from Dave Nourish (Nourish on covers, not Weslake as orig )
The conversion for unit Triumphs was paid for by Rickman (Rickman on rocker covers)
Factory TSS (finned only rocker covers) was the one with porous heads but real problem was Margaret Thatcher, the co-op went into liquidation in August 83, bikes had hardly started production.
Quite a few Weslake / Nourish engines about here + some unit Triumphs with the top end only, haven't seen a factory TSS for years

 Yeah , Weslake . I almost purchased a TSS , really glad that didn't happen . Have lost touch with the whole Brit bike culture over the last several years , but back in the day I bled BRG .

  Dusty

[Murray]

I believe a German company, owned by Mike Krauser, designed 4 valve heads for the old BMW airheads that utilized the cam in block and existing pushrod to do that.  However, I don't have any info on what power gains were achieved.

Krauser heads were also available for Guzzi's the newer "hi cam" motors are a clean sheet design when given that, the question why would you engineer what essentially is a stop gap measure.

[ohiorider]

Krauser heads were also available for Guzzi's the newer "hi cam" motors are a clean sheet design when given that, the question why would you engineer what essentially is a stop gap measure.

My thought was ..... Guzzi is a tiny mfg in the total scheme of motorcycle manufacturing.  They sell (what?) 5000-7000 machines a year, of which possibly half are big blocks.  Maybe a stop gap measure, if it was indeed a stop gap measure, would have been ok if the engineering $$ had been applied elsewhere to improve other aspects of Guzzi's operations ....  distribution, sales, dealer support, and warranty.

[canuguzzi]

My thought was ..... Guzzi is a tiny mfg in the total scheme of motorcycle manufacturing.  They sell (what?) 5000-7000 machines a year, of which possibly half are big blocks.  Maybe a stop gap measure, if it was indeed a stop gap measure, would have been ok if the engineering $$ had been applied elsewhere to improve other aspects of Guzzi's operations ....  distribution, sales, dealer support, and warranty.

Bingo! There was nothing wring with the first Gen Norge that refinement couldn't address, postpone the 8V and really do it right.

With the resources put into quality assurance, dealer/customer support and such, they wouldn't be selling 7k units, they'd sell 30,000. Then resources would be available to make the next 20 year engine.

Imagine top tier quality control, better suspensions, all the figment near perfect, wiring straightened out and so forth. Cruise and such available as options from the factory and working spot in.

Sales would skyrocket, new buyers would not hesitate and by now you'd be able to get that new engined MG that took no prisoners.

[Chuck in Indiana]

I hear the wind blow.  When I first became addicted to Guzzis, the "message boards" had the same "if only Guzzi would" threads.
The more things change, the more they stay the same. <shrug>

[Vasco DG]

I've known a couple of folks who had the aftermarket 4V Pushrod heads and they were fraught with problems. Most related to the valve spring pressure. They used twin springs per valve, might even of just doubled up on the 2-Valve springs from memory. They collapsed pushrods and buggered cams often.


KCS was I think the mob who made them.

Pete

[mwrenn]

Found this picture online of a couple of LeMans IIIs with the KCS heads.