Engine and Transmission Tech

Ok, I'll stop jacking the cam post so we talk rocker assemblies here. Since it was my semi-baked plan on this stuff... I'll be the Guinie Pig? Just ordered set of (16) KMJ brand ,pn. PC 2342 at $180. description: 7075 ext. alum., No heat treat/hardness spec.,straight shaft mounted(.562") dia., 1.6/1 ratio, with no off-set. 90 day warr.-LOL. "IF" this works-out....they might sell with-out un-needed harware, like shafts,bolts, base plates, for a "volume" price. I'll try this set-up against Manley Stg I Buick V6 valves, 1.775/1.5", late rover heads and serious mech. roller. Hang-on gang, it might get bumpy! roverman

Cool. What's the stock shaft dia. for the Buick/Rover. Anybody?

Is it this set?

[www.kmjent.com]

.812"/11/16

It appears there is an offset on the pushrod end.. this pic is from Woodys wedgeshop catalog..

Nic, that's the set. I'm tryin to change order to .16" l/r off-sets. Anyone know off-sets for "Wedge Shops"? Healthy Thanksgiving one and all, roverman.

I'm on my way out the door, but I happened to be passing through the garage and took a moment to compare the Ford y-block (292) rocker to the Olds rocker. It looks close enough to merit more investigation.

Obviously, the Olds is offset, but the Buick might be closer.

There is a company who makes custom rockers for the y-block. Rocker Arm Specialties? Also, Dove. The dimensions of the Y-block rocker are close enough that I think they could be adapted without drama.

So Art, what's your plan for the SBC rockers? Custom shafts and stands?

Things keep going back and forth with cams, lifters and rocker arms. This was tackled and perfected back in the TR8 racing days from 1978 to 1981. Group 44, Ken Slagle, & Huffaker all ran roller cams & crane roller rocker arms with excellent success. The only incident I am aware of was a broken rocker arm in 1980 Sebring with one of the two Group 44 TR8s. There are alternatives but this stuff worked and the engine I had bought had a roller cam in it and then was removed but the vavle train was retained. This eneinge could go back to a roller at any time!

Mike and all, thanks for response. Rocker ratio on your set-up? Cliff, yes, A2 drill blank ,.562" dia.,heat treated to approx58"c",solid, tied to internal boss/end of head and "fat" stands allowed by .16" off-set. My thoughts are, why go to studded if oem. shaft mount system is doable? Mike, My Huffaker came with Engle roller cam and "Volvo"rockers, and they really "scrubbed" and rocked the lash caps,(Ti valves). I haven't received the "KMJ's" yet, we'll see how they stack up.roverman.

Mike -

How are the heads set up to accept the Crane Roller Rockers? From your picture, it looks like they use two studs per shaft/pair of rockers with rod guides as well. I'm trying to envision how the heads would have been modified for the studs... Or is each pair secured via the existing hole for the stock rocker pillar/shaft bolts? Doesn't seem like that would be near strong enough...

Just for S&G I googled up Yella Terra shaft rockers for the Rover 3.5 and 3.9... They do make rockers and full rocker shaft setups.

I cruised a couple of AU sites and this is what I came up with..

Part # YT 6000 Shaft rockers use your own shafts and stands.. $991 USD



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Part # 6305 Full shaft and rocker system $2286.90 USD




The price is scary.. the images are interesting.



Edited 3 time(s). Last edit at 11/29/2009 08:24PM by hoffbug.

The bottom plate is bolted to the head in the stock rocker arm holes. From there the steel plate is threaded for each roller rocker arm. Pretty simple and so far there has never been an issue. This set up is about 10 years old with the hydralic flat tappet and roller cams.

Wow, It's enough to make one consider a Rotary, roverman.

A couple of things Ive noticed..

The Yella Terra rockers utilize a base plate that allows for the ends of the shafts to be supported... Supporting the ends of the shafts has been available through the aftermarket for stock shafts for some time..



It also appears from the photos that the Realsteel F-85 heads have some sort of end support on the shafts.. This I cannot verify have never seen them in person.


The T&D units and the customized T&D unit from the wegdeshop do not... But rely on a stronger gun drilled shaft instead.

One thing you can say for that bottom Yella Terra, the shaft isn't going anywhere. Nice solution to the shaft breakage issue.

Those are like the gussets I bought from D&D.



Edited 1 time(s). Last edit at 11/30/2009 09:17PM by NixVegaGT.

At $2286.90, it's a tuff question...break the bank or maybe a shaft? Maybe the name should be, "GreenTerra", roverman.

Ok, "KMJ" rockers being "drop shipped" from 40mi. away, shipped today. Ordered on 11/25? I just don't "get" the new math.I await with agonizing anticipation/frustration,etc. roverman.

What sort of RPM's are you guys thinking about, if a rev limit of say 6500RPM then the standard rocker system with end supports and tubular spacers to reduce friction is quite adequate and very cost effective.

What ever you do if running a high lift cam, a reduction in rocker pillar height by 60thou to correct rocker gear geometry is important and will require custom or adjustable pushrods, the adjustables still need reducing in length by 2-3mm. depending on what machining has been done to the decks and heads and your choice of tin or composite head gaskets.

I believe Yella Terra do two types of set up, the basic one is just the rockers which fit on the standard Rover shafts and with end support pillars are a lot cheaper than the set up shown above, but still expensive for the limited gains unless you are looking at a 7500 RPM+ screamer engine.

Kevin.

The rpm capabilities/requirements should be based on the cylinder heads and exhaust. Those are the 2 factors that from my experience with the Rover V8 and Rover heads relate. The TR8 with the 4-2-1 headers and rover early, late and buick 300 heads die off @ 6,200rpms no matter your lift or duration. Its the headers and heads combination. The set up that works well and uses roller rockers is the Buick 340 heads and 4-1 headers large and long primary tubes. Thats when you go past 6,200 rpms. Even Group 44 admitted the Road & Track article with the power/rpms rating of thier engines was lower than published. They did go passed 6,200rpms but it was a lot of exotic parts and big bore 4-1 headers. So here is the question......roller rockers when do you really need a set? What are the plans for the engine; heads, cam, valves, etc to justify the roller rockers? My engine for the price which was awesome and irresistable so do I really need them....why not keep what works and it is set up for a roller cam too!

My opinion, for what it's worth, is that a roller cam would be nice for peace of mind regarding oil selection. Other than that, just because the new engines are being built with them and with roller rockers is no reason to jump on the band wagon. They should last longer so that's a factor but the original parts were usually good for over 100K miles so more than double the cost isn't justified there. That leaves high lift and high rpm operation, but as long as valve lift is under 1/2 inch and redline is under 7 grand I can't see the need. The stock valvetrain will handle that with no more than stiffer valve springs. My first 215, built in the early 80's ran the hottest hydraulic Comp Cams stick available at the time, and regularly went to 7K with stock heads (Buick). Now granted I was running a 600 Holley (650 to begin with) and good headers (1-1/2" x 32" primaries equal length within 1/4") and it was never dyno'd, but I'm telling you it sure didn't FEEL like power was dropping off over 6K.

Personally, I think for high rpm use there is something to be gained by the use of a larger carb. True, the low rpm, idle, gas mileage and driveability goes to pot, but on the top end there is a noticeable advantage. Of course, I don't expect everyone to agree with me.

Jim