Please help with thoughts/suggestions/experiences: >Finally got my bracket project out this weekend. In summary this is my first venture into a complete Buick V8 resto / racer. The two passes I made felt like the converter was holding her back. While on the transbrake I could only get it to flash to about 2000 RPM. -- Couldn't break an ET of 15 secs or over 100MPH. :ball: In idle it sounds responsive. Under any load it dogs. The motor itself is proven and had run a best of 10.79 at about 125 MPH in a similar weight and chassis set-up car (3700 lbs). We figured it's about 600HP (no dyno to validate) When getting my parts together I called Coan for their advice. They suggested a 4500 -4800 stall 9", Max Performance. I gave them the cam specs and the info above. So that's what I bought. Is there anything else I can do / troubleshoot before I think about pulling the converter?? Is it likely that Coan would send something this tight with the info I provided? Combo: 30 over , 430 worked heads, t/a sp1 intake, 970 holley (850 -4150 reworked to flow at 970. TH400 worked w/ a trans brake, a ford 9" w/ 4:10 gear running 28x10.5W M/T slicks. MSD ignition and distributer. 30-34 degrees timing. >>Looking to make sure I don't overlook any easy fixes first! Thanks! John
I kinda doubt it. I've got two of their convertors...a nine-inch I just got and an eight-inch I've been running for years. They both came in at 5600 rpm on the trans brake just like ordered. I can't see them being that far off unless maybe they shipped the wrong one by accident!! Stranger things have happened , I guess! Good Luck.
Doug, A new balancer was installed sometime after the motor was assembled. 34 degrees as shown on the balancer is advanced to the point where she won't start after I shut it down. 30-32 dgree seem to be O.K. We suspect it may be 10 degrees off. If we are set to far ahead in timing, could that be the problem (or part of it)? with my stall? Thanks, John
John It's hard to really do anything speculate w/o being there to see and hear what it is doing. You say w/o a load on it the motor sounds OK? If the timing is way off,yes that could have an effect. Set the motor to TDC and see where the timing tab 0* lines up vs.0* on the balancer. Was the cam degreed? You definately can't trust the keyway on the timing chain sets. Really silly,but easy to overlook when you've done this much on a car.......Is it getting full throttle? And one more item. Is the trans new?Might want to look at,and smell the fluid. Keep working,As soon as you as you get a good full pass,you'll forget the misery. PS with the 4.10's,you should get a 30'' tall slick under there.
Gary. First and foremost >> Congrats on the 9.64. That's a great accomplishment.<< The cam had 3 degrees put into it, based on the previous owners experiences. They thought to have picked up maybe a tenth. I just checked TDC. I had my finger on the number one plug hole until it blew off... and checked the dist rotor lined up with the #1 plug. It shows +10 to + 11 on the Romac Balancer. Does that mean my 30 - 32 degrees was really 41 - 43 advanced? > We tried to duplicate a previous proven combo so I could get a baseline and work from there. Some Differences: >Carb: Old = 1050 Dom on 2" riser. New 4150 / 970 on 1/2" riser Jetting 90 square on both Dom and 4150. >Convertor: Old = B&M 9" holeshot. New = Coan 9" >Rear: Old = 12 bolt, ladder bar 4:10. New = Ford 9" ladder bar, coil over, 4:10. Trans is new TH400 , however same set-up by same builder. You're a bit scary on your thoughts regarding throttle. The Lokar cable didn't like the stock square hole bracket and loosened up on the first pass. We also had to T-shoot down a loose roller rocker set-screw (carb was reverbing fuel up through it). We must have missed it when setting the valve lash. On the trans fluid: I have a temp gauge for the trans with the sender mounted near the cooler. I was a little surprised to not see it get hotter than 110 degrees after a pass. o No: Some other notes. I was more organized on the second pass. I did a decent burnout but wasn't able to get it up on the tires. I screwed up the launch (second time ever on a brake), but afterwards, stayed in it. Shiftpoints were set to 5800. 1st to second was O.K. Second to third broke up badly. She was popping and then backfired before I hit 5600 RPM. Regarding the tires. I had problems fitting the 28X10.5Ws (11.5 patch). We rolled the quarters in and what a difference. Once I "John Force" these into oblivion we'll try a set of 30's. Thanks again for the help. John
John, when you say it won't go over 2000 on the tranny brake, is it because the engine is missing or running rough, or it 's running smooth and sounds good, just won't go over 2000 rpm? I really can't see a 9 inch converter not going over 2000 rpm, but , even if the converter were wrong , and way too tight, the only thing I would expect is that you would 60 foot like a dog, but once the car got out and up on the power band, it should pull strong and mph like a banshi. Sounds to me like you are having some sort of engine problems. Jim Burek P.A.E. ENTERPRISES
Ran the motor and noticed that during throttle, fuel looked to still be coming up from the carburator. Popped off the valve covers... 3 separate rockers are loose and backed off at the set screws (TD roller rockers). 1 half of 1 spring lock (not retainer) is sitting in the head valley. They are backed off at least 1/2 inch from were the lash was adjusted. One rocker had been found loose earlier in the day yesterday. We tightened it, re-set the lash, and then went back around every one to ensure no others had gotten loose. Any ideas? On at least one valve, the tip looks to be ate up abit at the bottom end where it would rest against the lock/retainer. How could this happen? Anyways>> Looks like the heads are coming off John
Update: Two pushrods bent. One valve tip sheered. Two valve locks cracked (now have three pieces). Called Coan to validate original order. They had all the prior info and show the converter was a 4000 - 4500 piece and that it is unlikely it bogged the motor so bad to cause this type of problem. The rollers (not new) are going to T&D for inspection. They never heard anything like this. Any comments as what/how the pushrods could spin the set-screws back out?? I'm relatively sure that the loosening of the set screws along with me staying in it on the pass is what initiated the resulting valvetrain failures. Valve springs have 1.4375 outside diameter (not sure of brand, have to find my ppwk) and seem to have very little clearance in respect to the rockers. Cold valve lash was set to .024". What else would cause the pushrods to spin out the set-screws? Indication of an oiling problem through the pushrods? Everything seemed "wet" and never saw a noticable drop in pressure o No:
piston to valve clearance did you change any thing like head gaskits or mill the heads more if so did you ever check piston to valve clearances or was the valve spings ever check for coil binding was size lift cam are you running?it sound like a clearance issues on the valve train.
Nope. No changes such as cam, milling or different type/size of head gaskets. The motor has been set up the same for years with regular refreshes by those familiar with it. I did not check the valve springs for coil binding. I have to check my ppwk and the previous owner, however those too should have stayed the same (type/specs) prior to the refresh. They will certainly be checked/doublechecked the next go around. >>Live and Learn... That's what's stumping us. This set-up was nothing new and was intended to be relatively "troublefree" The previous owner stepped up to a new combo and has been there with me the whole duration of the project.
