Anyone here have problems with TA orangecrush headgaskets. I have a 12.5:1 stage 2(street eliminator) 455. I have blown Victor, Fel-Pro, and now TA orangecrush headgaskets. I'm begining to think that I dont have a big enough camshaft for the compression. The camshaft is an old Lunati SP-4. 540-550 lift 253-266 duration @0.050 with a 110 lobe center. I've got TA 1.65 roller rockers. The last time I checked cranking compression(previous headgasket problem) it was in the high 250psi range. I'm thinking a cam with a more narrow lobe center to bleed off cylinder pressure might help. I have an old GS 105 cam I might switch to.o No:
Hi Guys, Jeff....Two questions for you..you are sure that both the block deck and head deck surfaces are completely flat and true? Also...I hope you didn't/don't fall for the BS hype that most of these head gasket manufactures put out claiming "No Retorque Required" as this is total crap in my book.:Smarty: Ok, here's what I have to offer... From my experience I've had Fel Pro's hold up to 15.47:1 compression ratio (measured, but basicly 15 1/2 to 1 if you like to round up:grin: ) and peg a compression gauge at 300psi cranking with a TA 608 Hydraulic (bad thing is that this engine itself did not hold up, it was one I built back in the early-mid 90's)! The TA 608 is 258*I and 272*E @.050 on a 108 and .632"I/.639"E lifts w/1.70 rockers. This was with Stage3 heads, TA SP-2 & 1050 Dommy. O-ringing of the block (and I had no receiver grooves in the heads either) and mulitiple and once again, I repeat....multiple (at least 5 times) re-torquing of the stud nuts. You are using head studs and not bolts right?o No: As well as the extra (4) along the bottom of the deck? Now your 250+ cranking compression says that your cam is a little too small for your application. You should have around 220psi to be optimum. More and the cam's too small, less and the cam's too big. Hope this helps & I'm sure others will more than likely have more to add. I'm always up for more extended learning!:TU:
Yes, the block deck and head surfaces are true. I'm using TA undercut head studs, and the extra 4 studs. the engine was together for a few years before the head gaskets let go this time. We retorqued the nut after initial startup. but only once. Thanks for the info JEFF.
The "Orange Crush" head gaskets need to be re-torqed multiple times PRIOR to firing the engine. And usually do not need re-torque after. See our instruction sheet for cylinder heads/head gaskets for details. Dave
Did build a 461 Buick for a friend about a yr. and a half ago. Did use orange crush and followed the TA instructions to a tee (iron heads 12.5 -1) and they have been fine. Cam at .050 is about 245-250 on a 112. I did use arp lube on ALL threads and washers. Thanks Milan
We will have a set of the new T/A 3 piece gaskets going on a 13-1 methanol engine in a couple weeks. I've never seen a head gasket that looks like these.
Update on the new TA head gaskets. Our engine is together and racing. So far so good. 13.25-1 methanol 462 on a 95 degree day for 25 laps plus heat race and trophy dash. Worked perfect.
What type of parts breakage would occur if the cranking compression is over 250 psi? My next engine will be about 12.5 to 1 with JE flat tops and the cam will be .520 lift and 234* and 244* duration from a Reed cam.
I don't know of any breakage that could occur, But detonation could be a problem.Camshaft duration is only part of the equation, lobe seperation is also a major part. Wider lobe centers create more cylinder pressure.
Closer lobe centers will raise your cranking compression since it brings the intake centerline closer to TDC which closes the intake valve sooner on the compression stroke. If you want to lower you cranking compression you can go to a wider l/c cam with the same duration or go to a larger cam with the same l/c as you have now or just retard the cam you have but no farther than straight up. Any way you decide to do it, you need a later closing moment on the intake valve to get the pressure down.
I agree with Buicks4speed, I have right about 9.7 measured compression and a old poston 105A cam with 105 lobe center or lobe spread as I like to call it, I don't have my card in front of me to give intake closing but my low comp motor warmed up will make about 200 -210 on a guage. I don't remember were I read it but it was a bunch of tech stuff on cams and this story said that intake closeing is the most importent of the specs as to compression, early closeing, more cranking compression, later closeing, less compression. Tom
I always thought a closer L/C made less cylinder pressure because of the valve overlap bleeding off cylinder pressure. o No:
Jeff, Could it maybe be detonation? Too little octane, too much timing, hotspots in the chamber, unequal fuel distribution, etc? How do the top half of the rod-bearings look? Figured I'd toss that out there... Ramin
It could possibly be detonation. I use mostly race gas(at least 105 octane) but in a pinch have used a pump/race gas mix. I run the timing @ 34* total. I smoothed all the sharp edges on the pistons & in the combustion chambers. My intake manifold(T/A sp-1) has been port equalized. I did have worn throttle shafts on my old carb(serious vacuum leak).
Stage 2 heads like single pattern camshafts. This is my reason for wanting to run my GS 105 camshaft. It is close to a single pattern cam(same lift int. & exh.). I read an old GSXtra article in which a guy was running 10.40's with this cam in a GS with cast iron stage 2 heads.
105 cam That would be Great Scat,its the 105 with stock iron stg 2's,loves the single pattern cam and is only 11.2 to 1 compression,car weighs 3200# without my fat a** in it,has over 800 passes on it in "scat" and "thumper" runs 10.40's like clock work and has gone 10.28 in good air. gary
I wonder if I could run near those times with my GS 105 cam. My goal is to run 120 mph. in the 1/4 before changing from my sp-4.
