Engine and Transmission Tech

When I put a Buick crank (215) in an Olds block with a 6" 327 rod and a 305 SBC piston, I luckily have .007 deck clearance. Now, I can adjust needed deck clearance by trimming the band around the dome of the piston. Hopefully, the compression ratio will work out as well.

Larry, what chamber size are you using?
With a 3.8" bore and a .040" head gasket the 300 heads give about 10.6:1 so you should be close if using the same chamber size. With smaller chamber heads it'll be high.

Jim

The heads are 3.9-4.0 LR, with small chambers. The head gasket is 0. Bore is std. 305 (3.736). The dish on the TRW forged pistons is fairly large, so the ratio will hopefully be adjustable enough. Looking for something around 9.5-1. (turbos and water/alcohol injection)

The dish size will be important. If you are going to cut the piston you might want to make the dish deeper. It'll have a bigger effect and you won't lose your squish.

Jim.

I, too am a squish guy. The more of the mixture you can hem up, the quicker and more thoroughly you can burn it. But I also like compression. Trimming the top of the piston also effectively moves the top ring up, which is good. These particular heads have the sparkplug very near the center of the chamber, which is very good. Need to find sparkplugs with long extended tips. I want to do everything possible to decrease spark advance.

What octane ? DCR, without boost, to be ? Maximum air inlet temp ? MSD/etc boost retard with knock sensor loop ? With Cometic gaskets, you can "tune" the squish height. Flanged liners ? Cheers, roverman.

93 octane, DCR DK, temp at air cleaner or intake manifold? MSD? No head gasket, no flanged liners. Planning to use LS type ecm to have maximum controllability.

"Boosted" air temp, is most important, and "chilled". Wideband O2 sensor, a plus. flyingwedge.

Wideband o2 is a must. I intend to monitor all phases of operation. Alcohol/water injection (foggers) will be used partially to lower intake air charge. monitors for iat, exhaust pressure, exhaust gas temp, boost, etc. If necessary, I will use radiator type intercoolers, but I had rather not.

How about rocker arms? What is available in roller type, etc. Looks like the head would lend itself to many options.

If you can find KenneBell V6 rockers-maybe. YellaTerra, very pricey ! TA available. Volvo B18, adjustable steel, no rollers, are very durable,(search this forum). roverman.

TA? Pardon my ignorance.

> How about rocker arms? What is available in roller type, etc. Looks like the head would lend itself to many options.

The ones I run on the Buick 300 heads are from Ted @ TSI, part number #TRV8RR, $425 per set:

[www.tsimportedautomotive.com]

They are Harland Sharp aluminum rocker arms with roller tips that have been machined to fit the Rover/Buick stands. The fulcrums have oilite bronze bushings and are compatible with stock rockershafts and stands. The rockers force feed oil to the tip and pushrod. They have adjustable pushrod sockets but require a different end on the pushrod compared to the stock pushrods. That's no big deal for me since I need custom length pushrods anyway. The stock rocker stand bolts have a round shoulder that interferes with the rocker arm bodies and will need to be turned down 20 thousands for clearance. The rocker arm bodies are wider than stock so the stock rocker shaft springs are compressed more. That increases the friction so you'd want to shorten the springs and put shims between the springs and rocker arms so the springs don't wear on the rocker arms. Another route would be to use aluminum spacers instead of springs. The roller rocker set-up on my 427 Ford side-oiler stroker is set-up that way. I also used a set of end stands from D&D. Their standard version doesn't fit but they machined a couple of sets to fit the wider roller rockers. I haven't checked valve cover clearance (valve cover spacers may be needed). I purchased new rocker shafts from one of the Land Rover sources as the usual sources were out.

Woody Cooper also sells a roller rocker (IIRC from T&D) set up for $1,265.00:

[www.thewedgeshopstore.com]

I'm told T&D makes a 1.70:1 ratio rocker using the .812" shafts.

TA Performance has also introduced a roller rocker set up:

[v8buick.com]

Part number TA 1309 but price was TBD when I checked several months back.

Yella Terra in Australia used to also list a set:

[www.yellaterra.com.au]

The GM 215 race heads I had were milled to accept stud mounted SBC roller rockers. Dave Nelson at Joe Sherman Racing Engines
did something similar for a Buick 300 stroker engine:

[www.hotrod.com]

Basically the studs screw into a 6061-T6 extruded aluminum plate which is then mounted to the head using the original rocker
shaft mounting holes. Nelson said he planned to sell a kit for this via Joe Sherman Racing.

Dan Jones

Thanks for the info, Dan. I was looking at the heads today, and thinking about doing something similar to the last option. My situation is that I am a machinist in an automotive machine shop. Std. auto stuff plus lathe, mills, tig, mig, etc. I had rather build stuff than buy it. We also have hundreds of engine cores, etc.

This is the engine that I spoke to you about cam design. I am getting a little closer to having the necessary info together.

Larry, the stud conversion done on the SBB and posted on the V8Buick website had a problem with snapping the mounting bolts off and I don't think that was ever resolved. I'd tend to shy away from that option. It is inherently less rigid than a shaft.

Jim

I wonder what kind of spring spec they were using. Using beehive, ovate springs should lower the stud or shaft load significantly. Maybe 7075 plate, maybe ARP studs to mount plate? Maybe? Maybe?

The problem is the four 5/16" bolts you're holding the plate down with and the leverage generated by the distance between the bolts and the tips of the pushrods. If you think about it, even the best grade 8 bolts aren't up to that task. It is true that the rocker shaft also uses four 5/16" bolts, but the pedestals and the length of the bolts greatly change the way the stresses are applied. And a pure stud rocker head like the SBC has 8 studs. Even then, for higher RPM work builders add stiffening bars above the rockers.

I see no real advantage to a stud rocker head, and see a shaft rocker head converted to studs as a grave misunderstanding of how the two systems work.

Jim

Jim, you are 100 0/0 correct. Shafts should always be better than studs. However, I would use much larger bolts than 5/16".

My performance work has always been stud related, so I am much more knowledgeable in that area. I can make shafts, pedestals, etc. I need to do research on shaft mounted rockers. There should be quite an assortment of stuff for 3800 Buick engines.

I checked my heads today and they have 3/8" bolts for the rocker stands, easily increased to 7/16" or even 1/2". Also looked at 3.1 Chevy valve spring. Looks like they might be useful. Beehive, ovate wire, and about the right length. 80# @ 1.640" and 230# @ 1.260" and 270# at .500" lift. Also learned that 3800 does not have shaft rockers.

What is the original rocker ratio? Looks like the LS1 rockers might be useful.

Larry, The problem is the 3/8" threads pull out of the aluminum head. Timesert steel insert and 7/16" stud and you won't have a problem. Alex's Parts has SBC/Vortec Beehives pretty cheap 1.75 install height, the 3.1 are shorter than what most use with longer stem valves(like 2.3 Ford or 3.4 Chevy V6). The Hot Rod magazine 300 Buick stroker used SBC self guided after market roller rockers. Stock Buick/Rover ratio is supposed to be 1.6 but checks out about 1.55.

Ok, so Buick shaft mounted-then ? They break shafts, using the little mounting bolts. 7/16", even worse. RV8 co's supply "stradle supports", for the ends of the shafts. The Volvo set-up is "very" sturdy", including the shafts, with a section collar, in the middle. These came on my Huffaker GT 1/TR8, and it lived at 8,000 rpm., with mech. roller cam. FWIW., roverman.