Thanks Everyone!! I'm going to try to answer all of your questions...
JackFish":3jnwci45 said:
I'm confused, is the head already shaved, if so, how much?
And is that why you've installed shims under the rockers? You can get shorter pushrods to compensate for that.
What head gasket is being used?
Head was shaved to 55cc chambers. Block was decked leaving pistons .005" in the hole. New .030" over pistons had smaller dish ~5cc. I asked the engine builder to shave the head to achieve a CR 9.0-9.1. He cc'd the chambers as he cut to achieve 55cc chambers. He told me the compressed thickness of the head gasket would be .042". The JY head I used cc'd out to 60cc initially so I think it already had a clean up pass on it. All of the numbers were given to me by the engine builder(Bruce) who did all of the machining. He is very well respected around here for his experience in building race engines for Sprint, Late Models, and Pulling Truck engines. He was extremely helpful and let me hang out in his shop while he did some of my work so I could learn/understand exactly what was being done.
Using David's CR calculator on his site, this puts me right at 9.1:1. He said that since he hadn't built a 200-6 before, he would not feel comfortable putting an engine with this much work in it together w/out checking the geometry. I was initially going to rely on the lifters to collapse, but then called Mike at CI and he said he wouldn't put an engine together w/out checking it either so I admitted my ignorance to Bruce and asked him to check it for me as I'm still in school and don't have a garage/proper tools.
wsa111":3jnwci45 said:
Stephen, putting the 1.6 adjustable rockers in you will also need pushrods designed for the adjustables.
I hope you are going to purchase the roller tip 1.6 rockers.
Your advertised duration will not change but the duration @.050 will probably jump to 210 degrees & the lift as you stated.
You will notice a definate improvement in performance.
I would remove the shims you have under the rocker stands, cause the adjustable rockers should compensate enough. Bill
Bill,
I plan on saving money until I can get the roller tipped rockers. I don't think I'm going to spring for the full roller rockers as I don't want to pull the head and block the oil port in the top of the block. I didn't think about the duration at .050" changing, thanks, that's good to know. And yep, I would remove the shims and use the adj. on the rockers to take care of that.
CZLN6":3jnwci45 said:
Howdy Bck Stephen and all:
This sounds like a nice build. Bill nailed your questions and concerns about the 1.6:1 rockers. He's been there and done that.
I'm still a little concerned with what head gasket you plan to use?
Do you plan to put a back-cut on the intake valves? It is a cheap and effective upgrade. Similiar, in effect, to high lift rockers.
I'm assuming that you have hydraulic lifters.
The adjustible feature of the rockers will allow you to optimize geometry, maximize cam potential and minimize lifter pump up at high rpms. I would concur with the suggestion to not shim up the rocker stands as it puts additional strain on the stability of the rocker shaft. Since you will need new pushrods specific to adjustible rockers that's the place to get the geometry right. The adjustible feature of the rockers will also offer some correction.
Increased lift effects torque and HP throught the rpm range and has only a slight effect on where peak HP and torque fall. Increased duration raises peak RPM and torque, lowers cylinder pressure and engine vacuum. It also usually decreases HP and torque at the lower end of the rpm range.
The question for you is more specific. If you're building for a street engine, increased lift is the way to go. If you're building for the track, more duration may be the answer. What is your goal?
Adios, David
David,
Head gasket has compressed thickness of .042". Intake valves were backcut, I don't have the precise angle, but they were backcut. The lifters are hydraulic, as you assumed, sorry I forgot to add that detail.
This engine is assembled, in the car, and it's driving!!!! It has substantially more power and torque. I'm waiting on some jets to get here from Italy for my HW 5200 so that I can rejet it. It's way way lean.
She's a daily driver, I may take it to the track just to see what it does, but I don't plan on changing my 2.83:1 rearend unless I do a T5 swap so low end power/torque is key. I really liked my gas mileage before this engine swap(27 highway was awesome) and I'm thinking I should be close with the H/W and other economy mods.
My goal, you ask, is to STOP BEING CUT OFF BY '87 COROLLAS WHEN I'M TRYING TO GET ON THE FREEWAY. It was like a slap in the face everytime I would try to maneuver on the freeway and rustbuckets were taking the lane I needed. My car is 95% original(the rear seat belts had the Ford baggies on them when I bought the car...COOL!!!) On another note, the vacuum lost from more duration would not bother me if the transmission continued to shift correctly, I'm not going to add power brakes because the manual brakes keeps my sisters from driving my car.
EDIT: I plan to put headers/high flow muffler on this engine before the 1.6 rockers. I have an extremely quiet replacement muffler and stock manifold now. I feel like the exhaust is limiting me the most right now. Agree/Disagree?
Joe, JackFish, rbohm, Bill, David,
Thank You All
Your insight and replies are very helpful as always and I would probably be up the creek without a paddle without this forum.
Thanks again,
Stephen
