8 valve head conversion

I have not been able to find the info that I wanted to share regarding the 8 valve head. It is somewhere in that place that I am told is my house. Anyway, there is a gentleman that is based in the Houston, Tx area that had actually worked out many of the problems withan 8 valver. He had completed the drawings and had actually made chips toward the project. He had determined that a dual overhead cam setup was the only way to approach this and also determined that Suzuki GS/GSXR components were the way to go. More after market parts than a small block Chevy (right). I know that I did have digital images @ one point. It certainly looked no worst than the pushrod attempt.

Any one recall this gent ?

Not me. But while on the subject: "If" the Norton breathed better with is 4 valves ,it would have produced a bit more power. But as this was going to be near the Max rev limit , other factors would prevent more RPM ...so "other factors" would prevent staggering More HP, Having to Detune the cam for realiabilty did not help.
Joe from andover is proberly correct....

The structual limits of the 1947 base design would require re-engineering of the rest of the engine to get any dependable benefit. We love our old bikes. I think we are suffering from the same syndrome that the flathead V8 hot rodders often develop. You can build the ultimate flathead for a king's ransom, or accomplish the same performance end with an engine salvaged from a later model wreck. Still, great recreation to build these projects in our minds. Much more expensive to actually get to the bragging rights stage.
Rj

These o.h.v.s are just a passing phase , the Side Valve will return . . . . . . :lol:

Yeah right side knockers are makin a come back for sure!



gas gas trials engine 2011.

rotorwrinch said:

I have not been able to find the info that I wanted to share regarding the 8 valve head. It is somewhere in that place that I am told is my house. Anyway, there is a gentleman that is based in the Houston, Tx area that had actually worked out many of the problems withan 8 valver. He had completed the drawings and had actually made chips toward the project. He had determined that a dual overhead cam setup was the only way to approach this and also determined that Suzuki GS/GSXR components were the way to go. More after market parts than a small block Chevy (right). I know that I did have digital images @ one point. It certainly looked no worst than the pushrod attempt.

Any one recall this gent ?

Click to expand...

That was Mike Chaplinsky. I haven't talke to Mike for a couple years, but I have copies of his drawings in .dwg format. I'll see if I can convert them to something most viewers can open, and post them, as soon as I can manage it.

Ken

Matt Spencer said:

These o.h.v.s are just a passing phase , the Side Valve will return . . . . . . :lol:

Click to expand...

Did I miss something ? Have they been away ?

Huh tossing power head tradition aside for coil springs eh.
Why not retain under slung cam then lop off the upper head to fit Y rockers to 2 valves each then cast up a cover.

One neat ovhc drive I've never seen in production is a small crank shaft gear with 2 pushrod like dual connecting rods attached like another crankshaft to cam above. Seen video of metal model turning up a blur, sorta like a sewing machine guts peddling like crazy.

Here's a head insight view to ponder on

lcrken said:

rotorwrinch said:

I have not been able to find the info that I wanted to share regarding the 8 valve head. It is somewhere in that place that I am told is my house. Anyway, there is a gentleman that is based in the Houston, Tx area that had actually worked out many of the problems withan 8 valver. He had completed the drawings and had actually made chips toward the project. He had determined that a dual overhead cam setup was the only way to approach this and also determined that Suzuki GS/GSXR components were the way to go. More after market parts than a small block Chevy (right). I know that I did have digital images @ one point. It certainly looked no worst than the pushrod attempt.

Any one recall this gent ?

Click to expand...

That was Mike Chaplinsky. I haven't talke to Mike for a couple years, but I have copies of his drawings in .dwg format. I'll see if I can convert them to something most viewers can open, and post them, as soon as I can manage it.

Ken

Click to expand...

It looks like I've lost the drawings. I think I lost them during one of the computer upgrades I've done since I got them somewhere around 2000. All I can do is summarize what Mike was working on.

He started with the idea of converting the stock head to a 3-valve design, keeping the regular Commando push rods, but making new rockers with a forked one for the intakes. He did some drawings and ran the idea past a local speed shop guy who modified 4-cylinder bike heads for drag racing by fitting a combustion chamber insert ("skull") into the head. Mike was thinking about something like that for the 3-valve. Somehwere along the way, it turned into an 8 valve design. When the local guy, who had done a lot of GSXR heads, looked at the dimensions, he pointed out that if Mike went to a DOHC design, he could pretty much just copy the design from a GSXR. That was the last drawing I had, but I don't think it ever went much further. Mike experienced some business setbacks, and had to re-arrange his priorities. I've lost track of him since, so I don't know if he ever got back to the project.

At that point, it would have been pretty similar to the 8-valve DOHC conversion for the Commando that Merlin Engineering developed back in 1980 or thereabouts. It eventually worked pretty well, but just didn't look like a Commando engine any more.

Ken

lcrken said:

At that point, it would have been pretty similar to the 8-valve DOHC conversion for the Commando that Merlin Engineering developed back in 1980 or thereabouts. It eventually worked pretty well, but just didn't look like a Commando engine any more.
Ken

Click to expand...

Tell more about this Merlin 8 valve version ?
Any details anywhere ?

8 valve variants coming out of the woodwork. ?
Classic bike recently had some sketchy details of a BRM version that Dennis Poore /Nortons commissioned in the 1970s, but came to nothing.

Theres a stupid ford CVH development of the pushrod engine . not really underhead cam .
But the cams under the rockers between the valves . sohc . in centre , rockers over going out to valves .

Only problems the Pushrod Predecessor seems to have more rpm potential .

The Two Valve set up and valve gear arnt the limiting factor in rpm's in a Commando . Other than maybe the Followers .

No rpm figures or these one piece crankshaft race machines ? ? :wink:

( were a bit worried here , Triumph used a one piece crank back 59 , theres nothing new about the idea . )

Its not necessarily rpm you are chasing with 4 valve heads, its breathing.
Some of these fancier 4 valve setups make more low down torque than a well known brand of Big Twin engine.

And if the Piper 8 valve head makes 74 hp plonked onto a stock (?) 850, as much as the best race (750) setup, thats pretty impressive ?? Except we don't know the details...

It would also need to be sustainable hp, not some flash-reading that evaporates as it gets hot.

Talking off ' flash readings ' . a device set up for optimum output will generally go through a few phaseing cycles
in the mechanisms . Therefore the output after half a minut or more may be somewhat differant from ' putting it there '
at a certain rpm's .
Noteably the dvice may have to work through the series of phases to achive the optimum pressure cycling configuration .

Believe it or not .

As in , some things'll whistle up to max , and stop . Some things'l jusut keep winding up quitely ( :lol: :shock: )
when you get there. Well , not actually QUITELY , except in manner .

RIGHt , the 4 valve . All these B.M.E.P.s presumably generate the output . But there NOT whats breaking the Crankshafts ? ? ?
What is then , the irregular rotational velocitie & causes .

(as a aside , the Torsional DAMPENER on straight sixes is of some intrest . Alledgedlly the torsional forces in those and straight eights will tear the crank apart , without the ' Torsional Dampener ' Which is a Dampening FLYWHEEL . Vis ,

Turkey Raceing the Mighty 265 3 speed ( manual ) Charger . " The Flywheel came off. I tried better bolts . I Tried Dowleing .
I tried Bigger Bolts . I tried Bigger Bolts And Dowleing . It Came Off . I almost tried welding it on .Tried Shrink Fit .
& other things .

Tried a 350 Chev Race Harmonic Balancer .It Worked . Even with Standard Bots ( to the Flywheel ) .Didnt Come Off . )

Therefore I summise that a Remote Flywheel ( in Part ) in the manner of , or even Just Flogging one . A GOOD QUALITY
aftermarket Harmonic Balancer , affixed about there . Where the oil goes in , or adjacent the sprocket , could well transform a few issues . If were lucky . and an old iron flywheel wasnt obsolecent with the Sopwith Camel . ? ?

OBVIOUSLY for a ' Bench Test ' it wouldnt be to hard to nail one on adjacent the sprocket .Just need a trench dug on the raceing line for ground Clearance . :lol:

Rohan said:

lcrken said:

At that point, it would have been pretty similar to the 8-valve DOHC conversion for the Commando that Merlin Engineering developed back in 1980 or thereabouts. It eventually worked pretty well, but just didn't look like a Commando engine any more.
Ken

Click to expand...

Tell more about this Merlin 8 valve version ?
Any details anywhere ?

8 valve variants coming out of the woodwork. ?
Classic bike recently had some sketchy details of a BRM version that Dennis Poore /Nortons commissioned in the 1970s, but came to nothing.

Click to expand...

I don't have any pictures handy, Rohan. I recall reading about it and seeing some pictures in one of the bike magazines back in the '80s. It was a pretty big lump. Roy Bacon has a brief mention of it in his book "Norton Twins", but no pics. It was developed by John Baker and Alan Hardcastle, the principals of Merlin Engineering, for use in their Wasp framed motocross sidecar outfit. They ran it as a 920 cc engine. It used a dummy camshaft that continued through on the drive side to a pulley and toothed belt drive to the camshaft pulleys. It had a positive oil feed to the top end, and drained back through external lines. I recall seeing a complete 920 engine with the Merlin head for sale in England in listed in the classified section of MCN back in the '80s, and was tempted to see if I could buy it and have it shipped over, but someone else snapped it up. As mentioned in the Piper article above, Les Emory and Pete Lovell ran a 920 engine with the Merlin head in a road racer for a while. That's all the additional info I have.

Ken

Thanks for the info Ken, always interesting to hear whats been about before.
Sounds like there have been a few versions of 8 valves then.....

Anyone wanting 8 valve heads, well I've had my ear to the ground and found 2 for sale! More info to come so watch this space!

Thought about this long and hard as its a unique opportunity own a bit of Norton history and make for a serious project!
So this is what I found out
NOT CHEAP but you get in the package Norton/Piper developed- 2 x 8 valve heads - early version and late
version. The later version has re-designed rocker supports [maybe the factory
found a problem and altered accordingly] rockers,spindles,pushrods,inlet
manifolds and a 750 short stroke/850 cylinder barrel i.e. 77mm bore. Pistons are Omega, alot too heavy, forged would be better!These heads of course, will not fit a standard barrel due to the different configuration. So this was unsuitable for my 920 Offset special. In Mick's opinion, the valve springs are far too strong which probably caused the original problems at factory.
Yep they've been in Mick Hemmings storage for at least 20 years with that in mind!!!!!!!!!!!!!
This Norton historic/nostalgia package is up for grabs at £3,500.
I hate world depressed grain prices otherwise they'd be in my shed for another project!?
If you want them call Mick Hemmings!
FOXY

Foxy said:

Thought about this long and hard as its a unique opportunity own a bit of Norton history and make for a serious project!
So this is what I found out
NOT CHEAP but you get in the package Norton/Piper developed- 2 x 8 valve heads - early version and late
version. The later version has re-designed rocker supports [maybe the factory
found a problem and altered accordingly] rockers,spindles,pushrods,inlet
manifolds and a 750 short stroke/850 cylinder barrel i.e. 77mm bore. Pistons are Omega, alot too heavy, forged would be better!These heads of course, will not fit a standard barrel due to the different configuration. So this was unsuitable for my 920 Offset special. In Mick's opinion, the valve springs are far too strong which probably caused the original problems at factory.
Yep they've been in Mick Hemmings storage for at least 20 years with that in mind!!!!!!!!!!!!!
This Norton historic/nostalgia package is up for grabs at £3,500.
I hate world depressed grain prices otherwise they'd be in my shed for another project!?
If you want them call Mick Hemmings!
FOXY

Click to expand...

Carnt see anyone falling over in the rush!

So if these heads will not fit a std barrel, do they come with the required barrels. ?
Or if not, how do you go getting said barrels ??

Expensive shelf ornaments otherwise....

Gday Rohan, as stated in my post "and a 750 short stroke/850 cylinder barrel i.e. 77mm bore." So its the whole package, heads and a barrel to suit.
Foxy