At what point is a lifter bore brace required? Im building a 455 with an aggressive solid flat tappet, 375LBS open pressure, 258@.050, .625''. I have run the same cam is a pontiac, no brace with no problems. They have 3 lifter bores that are thinner than the buick. Let me know what you guys think. Thanks, J
I wouldn't worry about it. I run about the same springs with a cam that is slightly larger than that with no lifter girdle. It would be a little unusual to break a lifter bore with a flat tappet cam. Yes, it's possible, but it would have to be a pretty fast ramp cam and basically a roller spring. Have fun.
If you want to get fancy, you can run the new BBC behive spring that is a drop-in for the Buick if you have 11/32 valves. It is about the same weight loss as going to Titainium valves so you can either run more rpm or go lighter on the seat pressure.
I know, I know.....get rid of the roller. What does someone like you even understand about needing a roller? Ya got 2000 HP with alky injection and a big puffer on the top. The rest of us who want to make big power need our big rollers! Understand? We NEED them!! LOL! :laugh:
Now Doug has roller envy. My roller is bigger than your roller. Just put a little boost to it and take the roller out. once you go boost you will never go back.:laugh: :laugh:
I actually have a set of those springs around from another project. But I have 3/8 Buick style valves.
Bobb, I know you advise aganist rollers, but with all the concern over wiping out cam lobes and oil additives, I'm think of going to one to not have to worry about losing a cam. I just put a new cam from Scott Brown in my car over the winter and got the lifters from him with the oil hole in the face and have not had a problem, but I'm still running the Shell Diesel oil. I would like to go back to the lighter weight Mobil 1 but running a little scared. I know it takes more spring to overcome the weight of the rollers but what is the least you can get by with and run 6800? Thanks JIM
Depends on the cam profile, weight of the valve train, and rocker arm ratio. The more aggressive the lobe, or the hevier the valve train the more spring you will need. The cam Im running is an EXTREMELY aggressive lobe for an .842 lifter, combined with heavy 3/8 valves. I have to run at least 375-400lbs open pressure. Thats why Im worried about lifter bore breakage.
Jim there are a couple oils that still have additives Valvoline make a real race oil (not VR1) it comes in 6 quart cases the 20-50 is part #851 I think, they make it in lighter stuff and in synthetic also. I just put Brad Penn oil in the blower car it is the old Kendall green oil semi synthetic. I am running on the intake side with beehives 185 on the seat and 425 open without oiling lifters. On all my N/A stuff I run the oiling lifters and seat pressure is set at 165 and 375 to 400. And to be honest I haven't ever had an issue with a cam going away. I have lost one do to oil break down from gas in the oil but that stick had run for two years with no issue before it happened. I have broke a couple into pieces because the lifter bore cam out of one and I broke a crank and causing all kinds of carnage on one As far as rollers go if you are going to put a small one in for wear issue then you can get away with a light spring set-up which will help with block life but I just don't see a reason for them a good custom can run with a roller at the RPM's we run these to. We did some testing a few years ago and decide for the 10 HP extra it was worth on that combo it wasn't worth the hassle. There is some power in a roller but none of us are really in need of one the heads up classes have been slowed down so no need to ring every ounce of power out of a car it just makes them less street able. there are more issue with rollers than some people realize extra wear on pars because of the springs (rockers guides etc.) and I have seen more than my share of Chevy’s eat it because the lifter broke it happens all the time. I guess some guy's swear by them and I have no issue with them running them but when they break stuff I always hear. Don't say it I know, why are we running them I just smile and go to the next round.
Hi Jarret I Live in Brighton,CO. We have done some Sold Lift Buick Motors Bobb Makley makes cents. He has a AfterMarket block Now doesn't have these Problems anymore with his Stuff. The Only BDB out and running in a Car. I am going to have to start looking at the Brand X Blocks Give me a call Jarret 720-217-7859 Jeff
If your running iron heads you prob dont need to lift the valve open that much,unless the've been ported by the best even well ported irons start to get turbulent by.550 lift on the intakes and flow backs off.also a study was done some time ago i think by pee-gee perf. and a slightly less aggressive ramp was found to perform a little better they think do to better valve train stability
I have TA STG1 Aluminum heads. Stock valves, flow 330cfm @ .600'', 23x on the exhaughst. I know. The iron heads have good low lift flow. Thats probably why they work well with a mild ramp. I can get more flow out of iron heads up to .400'' than the aluminum. These are 212@.300-vs 222 iron. 265@.400''- vs 268 iron.
