Broken rocker shaft - recommendations, please
- Thread starter lyonsd
- Start date
lyonsd
Active Member
- Joined
- May 24, 2001
Mods, in case you can't see sig.
'87 GN
GN1 stroker
RCJ oil pan with crank scraper
RCJ block girdle
Champion CNC ported iron heads
206 roller cam
Terry Houston downpipe & hi-flow cat (Jet-Hot coated)
Precision upper intake plenum (65mm)
Jay Jackson modified 62/65mm OEM throttle body
RJC Airflow Distribution Power Plate
Jay Carter Variable Timing 93 octane street chip
Walbro GSS307 255 lph fuel pump
Accufab adjustable fuel pressure regulator
MSD 50lb injectors
SMC Alcohol injection
160º thermostat
GN1 Aluminum 3-row radiator
Dual SPAL fans 1360 cfm each
Art Carr 200 4R Pan Kit with magnetic drain plug
Eaton Posi
Art Carr Shift Kit
T/A Rear End Girdle
Poly motor mounts (both sides)
Lower rear control arms
'87 GN
GN1 stroker
RCJ oil pan with crank scraper
RCJ block girdle
Champion CNC ported iron heads
206 roller cam
Terry Houston downpipe & hi-flow cat (Jet-Hot coated)
Precision upper intake plenum (65mm)
Jay Jackson modified 62/65mm OEM throttle body
RJC Airflow Distribution Power Plate
Jay Carter Variable Timing 93 octane street chip
Walbro GSS307 255 lph fuel pump
Accufab adjustable fuel pressure regulator
MSD 50lb injectors
SMC Alcohol injection
160º thermostat
GN1 Aluminum 3-row radiator
Dual SPAL fans 1360 cfm each
Art Carr 200 4R Pan Kit with magnetic drain plug
Eaton Posi
Art Carr Shift Kit
T/A Rear End Girdle
Poly motor mounts (both sides)
Lower rear control arms
3.8L V-8 eater
Well-Known Member
- Joined
- Jul 22, 2006
That's a nice set up you have!! I'm assuming you have stock rocker shafts if so your build is worthy of some roller rockers.....If your broke like I'am or have other needs buy a set of heavy duty "stock style" rocker shafts and also use the shaft braces...I have both on my car....TA performance sells em and they are a reputable vendor..
turbofabricator
Well-Known Member
- Joined
- Mar 7, 2004
With a 206 roller I would suggest 1.65 ratio to bump the lift a bit.
mikestertwo
Well-Known Member
- Joined
- Sep 13, 2006
+1 Just get a set off heavy duty shafts and don't overtighten them.sorry but for a 12.8 et car RRs are a waste of $$$
I have used them on customers cars where they didn't want to bother adjusting them.. or getting bigger valve covers .. Lazy guys that just go racing
turbofabricator
Well-Known Member
- Joined
- Mar 7, 2004
And for guys that like to buy 12 different lengths of push rods so they can hit the lifter pre-load spot on.I have used them on customers cars where they didn't want to bother adjusting them.. or getting bigger valve covers .. Lazy guys that just go racing
With the original posters listed mods, roller rockers would be a good upgrade. Probably make a significant power gain due to getting the lifter pre-load right for the first time. Hardened shafts AND adjustable push rods will work, too. (unless you order the exact length push rod needed for each valve.) Correct lifter pre-load makes a significant difference on a turbo Buick. Off by .030" and it'll kill power. many times valve stem heighths are way off, then add thinner head gaskets, decked block, milled head, you have alot of chance to kill lifter pre-load. (.020"-.040") But Dan knows ALL this already. This is for everyone else. (He's been building shaft mounted rocker engines (FE Fords) longer than I have, and I'm NOT calling him old. Ancient, maybe, but not old.)But Dan knows ALL this already. This is for everyone else.
hahahaha... actually looking at a 70 Shelby GT 500 for a driver
Old "blue blood" is trickling in my veins again. ..RR are def the right way to go BUT some won't spend the $$$ and don't want to adjust them. Ok goin out to work on a 66 GT 350
I use the TA hardened shafts and the TA adjustible pushrods. I have used the adjustible pushrods in my big block car. I had them in there for a good 10 years with zero issues. I initially put the RJC rocker braces on, but later took them off since the TA shafts are SO much thicker and the braces are really a band aid for the stock shafts. Here is how I adjusted my pushrods. I set them all at zero preload on the car, then removed them so I could measure the preload I wanted with a set of digital calipers. There is now no doubt in my mind that each valve has the preload set dead nuts on and my motor is surprisingly strong considering my combo. Attention to details like that make a difference when they all add up. here's a pic of the TA shafts vs. OEM ones.
turbofabricator
Well-Known Member
- Joined
- Mar 7, 2004
To adjust the adjustable pushrods I just measure ONE push rod before and after one 360* rotation to measure how much it moves. Then set it to zero and then add the needed preload. Same-O, Same-O. (Japanese for "the same thing") Just faster.
Dan,
My dad had a '66 GT-350H, '69 Boss 429 (with 19K original miles), '65 convertable with Shelby(H) running gear and a '66 convertible with Shelby(H) running gear. (among other cool cars like a '64 GTO convertible, 1918 Buick Touring, 1928 REO {we called it the "REO Speed Wagon"}, 1951 Lincoln a.k.a. the "yellow submarine", Austin Healey, which he road raced when I was an infant) , 1946 Pontiac "Woody Wagon", (2) 1931 Hupmobiles, perfect 1941 Olds, 1928 Ford truck, '69F100 Pick-up w/ a 429 Super Cobra Jet for motivation, 1936 Cadillac LaSalle, 1939 Pontiac (that I drove to school often) 1951 Buick (Straight eight and Dynaflow trans, which was my first ride to school) Ya, I had alot of fun in High School. Now, ALL these cars are gone. (not MY choice, though)
I also use to restore Mustangs for a living prior to racing Unlimited Hydroplanes for a living. Rolls-Royce Griffon Kick-ass V-12's. (2,240 cid or 39 litre's) Then went directly into 3.8 litre Buicks. Ten times SMALLER. Been doin' Buicks since. Would LOVE to build Shelby's again. I really love the old FE Fords, too. But then again, building a turbo'd LSX for my son's (right hand drive) RX-7 is alot of fun, too. Odd-ball stuff is alot more fun than '69 Camaro's. Geeze I wish we lived closer together. Our spouses would HATE that though, I'm sure.
My favorite car that my Dad had was the 1952 Henway. Nothing like that anymore.
Dan,
My dad had a '66 GT-350H, '69 Boss 429 (with 19K original miles), '65 convertable with Shelby(H) running gear and a '66 convertible with Shelby(H) running gear. (among other cool cars like a '64 GTO convertible, 1918 Buick Touring, 1928 REO {we called it the "REO Speed Wagon"}, 1951 Lincoln a.k.a. the "yellow submarine", Austin Healey, which he road raced when I was an infant) , 1946 Pontiac "Woody Wagon", (2) 1931 Hupmobiles, perfect 1941 Olds, 1928 Ford truck, '69F100 Pick-up w/ a 429 Super Cobra Jet for motivation, 1936 Cadillac LaSalle, 1939 Pontiac (that I drove to school often) 1951 Buick (Straight eight and Dynaflow trans, which was my first ride to school) Ya, I had alot of fun in High School. Now, ALL these cars are gone. (not MY choice, though)
I also use to restore Mustangs for a living prior to racing Unlimited Hydroplanes for a living. Rolls-Royce Griffon Kick-ass V-12's. (2,240 cid or 39 litre's) Then went directly into 3.8 litre Buicks. Ten times SMALLER. Been doin' Buicks since. Would LOVE to build Shelby's again. I really love the old FE Fords, too. But then again, building a turbo'd LSX for my son's (right hand drive) RX-7 is alot of fun, too. Odd-ball stuff is alot more fun than '69 Camaro's. Geeze I wish we lived closer together. Our spouses would HATE that though, I'm sure.
My favorite car that my Dad had was the 1952 Henway. Nothing like that anymore.
I thought about doing that, but I found it a bit awkward to get to all of them in the car. I didn't have that warm and fuzzy feeling that I really turned it what I wanted and if it reversed a little when I tightened the nut. I said screw it and did it the long way. At least I don't have to guess if it's right.
turbofabricator
Well-Known Member
- Joined
- Mar 7, 2004
Yep.....Adjusting them with the engine IN the car is a PAIN for sure. Your way WOULD be easier if the engine is in the car. And getting the lock nuts tight really takes a high quality wrench (Snap-On) or the open ends flex too much. (3/8")
Considering you've gone big with all your other engine components it makes sense. I wonder why he recommended stock ratio for you. What turbo and stall do you have? also, what plans do you have with that motor out of curiosity? You've put a ton of work into it. It would be a shame not to push it hard.
lyonsd
Active Member
- Joined
- May 24, 2001
Well, most of my mods are the result of breaking something and replacing it with something better.
The heads and cam came about because the car overheated, I wiped the stock cam, and seized a valve in the heads. Instead of machining and repairing them, I bought the Champions. And the next size bigger cam - 206.
The stroker came about for the same reason - car overheated, and a scorched the rings and bearings. I decided that since I had to have a rebuild, may as well install a stroker.
I still have stock turbo, intercooler and exhaust.
I'm not going to wait for the turbo to crap out before getting a new one. I hope to get a nice bb turbo and converter good for ~600 hp or so. But I've spent a shitload on this car recently, and I don't know when I'll be buying a new turbo.
Until then, I need to see if I can increase the boost on the stock turbo and get deeper into the 12s.
The common 206/206 roller is a 9 sec cam. Running 1.55 rockers with springs that provide 135lbs on the seat and 380-400lbs open will allow you to run up to 5900rpm/30psi with no valve float. Running the 1.65 ratio would need a little more spring pressure to be able to do the same. It would take better heads to even see anything with more lift on this application anyway. You won't be anywhere near 5600 rpm with this until you throw a turbo on there and turn it way up.
I keep forgetting that the roller cams are good for much more HP compared to a flat tappet with the same duration due to the quick ramp up rate. It takes a much bigger flat tappet to handle those types of numbers. I guess 1.55 is perfect for your setup.
