Dyno day, the good and the bad....

Well, today was a beautiful day here in NC! Oh yeah, and I made it back to the dyno, this time with more bearing clearance. The good news...almost every pull gave slightly better numbers, all seems to be well and good!!!

Last outing, back in October, resulted in 509 HP and 532 TQ. Now, I would have been very happy with that... just so the engine didn't hurt itself. This time clearances were opened up some and compression was upped slightly. I went from 10.13 to 10.3:1 static compression.

I was very happy to see 515 HP from 5100 rpm to 6100 rpms where we shut it down... we made 525 HP from 5200 rpm to 5800 rpms. Torque was up as well from the previous outing, 545+ ft-lbs from 4100 rpm to 4700 rpms.

:beers2: :beers2: :beers2: :beers2: :beers2:

 

Congrats! Very nice numbers.
So what all was needed to recover the engine?

 

Nice work thats great #'s you put down have fun with it.
Jamie

 

Thanks for the comments guys.

I know this is a long thread so here is a quick summery:

It's been a long road getting this thing back together. When my daughter Jennifer had to stay another two semesters at ECU I had to put things on hold. During that time Bert, a good friend of mine, mentioned he had the parts to build a flow bench and they had been sitting in his garage for years. I said "heck, lets build it.... It took quite some learning but we did it, I've been storing it for him now for at least a year :laugh:

Now I had "ported" these `73 small valve heads before in ~2002, I did not really know what I was doing. Had them flowed and found ~258 int. and 157 exh. I ran 12.2s at 109 with them, so I guess it turned out good.

With the newly built flow bench I had to chance to spend quality time in the garage. I made pitot tubes, an acrylic head fixture, a couple of valve spring fixtures, replace bearings in vacuum motors, calibrate the flow bench with orifice plates, sleeve (2) head bolt holes, raise the intake ports, play with epoxy, repair the newly cracked flow bench and pay someone to braze an exhaust port. I'm sure you get the picture....but, after all that with Stage 1 valves I got ~273 int. and 178 exh. Was it all worth it...No...but I'm glad I did it.

Before the October dyno I unshrouding my chambers for the bigger valves using an old Felpro Blue gasket I had as a guide. When I received the thinner head gasket I found it had a significantly smaller bore. :blast: I knew this would not work, it extended into the chamber, so I had to go with a new (thicker) Felpro gasket. After October's dyno, spinning two rods, the block went back to the shop. This time I made it clear that it was imperative to increase the clearances. They also align honed the block, and decked the block another .015 to get my compression and quench back to where I wanted it.

My clearances are now .0024 - .0025 on the rods (was ~.002) and .0026 to .0028 on the mains (was ~.002). Side clearance is now .016", up from .009-.012 range. I think this was the main problem all along; my old clearances were too tight. My oil pressure is somewhat lower than before but still o.k. I think. I went from 70 psi @ 6K to 62 psi @ 6K. I have a regulator but have yet to change the adjustment.

Ive got to get this thing running, Ive got a lot of driving to catch up on.

 

Thanks for the summary! :TU:
What is left to get it driving other than heading out on the road? I guess putting the engine back in would be step one? ou:

 

Couple of other upgrades like TH-400 (done), quick ratio steering box (being installed today), measure for and order a new new driveshaft (coming weekends), and a new set of solid pushrods (likely after it's on the road). Now If I can just remember where everything is and where it goes....:idea2:

 

I just went back over your combo you made this power with the same SB cam if so im even more impressed.How much timing was best?This was a job verry well done.:TU:
Jamie

 

Yes, the same cam. Let me broke out my notes......

This cam measured slightly different than the October cam (had two bad lifters) with 233.5 / 248.1 at .050 with .537"/.530" lift with 1.6 rockers. Advertised duration was 285.8 / 304.7, on 112 LSA installed at 107.8 deg. ICL. Dynamic compression calculates to be 7.91 with 10.43 static compression and a quench of .039". Best timing on the dyno turned out to be 34 - 35 total, I started with 32 and worked up. I'm not sure if the incremental improvements were due to timing or the rings sealing, but each time I bumped it HP went up slightly. I will likely run 33 to 34 on the street to be safe.

I have a question:
We had EGT's on cylinders 1 & 3 and an A/F sensors in each collector (M/T Scavenger). I'm running the SP-1 and Holley 4781. My drivers side cylinders are more lean and the EGT for #3 was ~60 degrees higher than #1. Can I address the more lean condition on the drivers side with the Holley (don't want to port the intake)? We discussed staggered jetting to equalize the A/F, we later found a "Little Issue" discussed below. Which side of the carb. would you jet up to richen the drivers side? My dyno guy said the opposite side tends to cross feed to the other bank, may be Chevy experience talking here? I also was wondering if shifting the carb. towards one side would help?

I do not have adjustable air bleeds but we did drill out all four to help reduce the trend to more rich on the upper rpm's. We drilled .004 bigger on the front and .005" bigger on the back to get them square (.029"/.029"). This helped a little, but the fuel curve still tends to get a little richer after 5300 rpms.

"Little Issue"....we took the plates off the 4781 and found that on the rear plate one of the emulsion passages on the passenger side was buggered up. Maybe this contributed to the A/F difference from pass to driver? Regardless I need to replace the rear plate.

Jetting is currently 79 square with 55 PV. Man this is fun......Thanks!

 

Thx 4 sharing all your info i can never get enough it just keeps me pondering all the #'s as 4 your lean cylinder its not my strong point tuning carbs ( i get help).Good luck with it and here' to a long lasting BBB.I also run 34 for timing it made the most (15hp) more from 5000 to 6000 over the 31 i was running.Pls keep us updated as you go take care
Jamie

 

Craig,

Congratulations !!! I know you have been through alot with this build where alot of people would have thrown in the towel and walked away. Your perserverance in keeping a Buick motor in-between the frame rails of your ride is commendable. I wish you the best of luck and now its time to :3gears:

Take Care,

 

First drive to work today :bglasses:

I've got 15 psi of vacumm at 1000 rpms, much better than before (12).
Man this PTC converter is loose with 3200 stall, this thing should really be strong off the line...guess I'll need to learn how to launch it all over again. Come on spring-time!

 

Congrats on getting the motor back and running.

I've said it before but I'm going to say it again that my decision to get Jim to build my engine makes me feel a lot happier.