Been a long time coming.
The engine has been finished for a few weeks now but had to dodge other builds and scheduling. Beautiful day here today, upper 50's, fall weather, nice and sunny.
I got to the dyno at about 8:45 this morning and it took us about an hour to get it all bolted up and ready to go. We bolted on a Holley 830 to start off with. Engine fired right up, I set the timing to 36°, and we dialed it up to a 2500 rpm break-in rpm and just let it run.
This was a fairly thumpy camshaft, especially for a 352, with about 80 degrees overlap. The 106 LSA doesn't really give a lopey, thumpy idle, but it's more reminiscent of a Cup engine idling. Hard to describe.
After the oil temp and water temp got to where we want, we put a short pull on it to about 5500 rpm. It sounded a little lazy but made 393 hp on the first pull. I went ahead and pulled a spark plug to see where it wanted to be for timing and was shocked to see the porcelain was starting to turn green, which indicates a very hot condition.
Compression ratio came in right at 10.4:1 and I had stuck some Autolite 45's in it. Not a lot of compression and a big fat camshaft, plus we were running some 112 race gas that was still in the fuel cell. The timing mark was almost all the way at the base of the strap, so just to see what would happen (it is a dyno mule after all), I pulled 4 degrees out and we hit it again. Timing mark on the plug moved a hair, but it was still super hot. Dropped 10 hp.
The stupid thing is that I have sets of 124's, AR32's, and AR33's sitting on the shelf, but I didn't bring any of them. So I've got my phone up looking at cross reference charts so I would have some things to ask for when I called the local parts store. The good thing is that the parts store in Buffalo, KY is an old-school store where people actually know stuff. The woman that owns it (yep) answered the phone and I said, "I've got an Autolite 45 plug, do you have a heat index chart for different plugs, because I need something a good bit colder." "She kept me on the line and said, I've got a set of 124's on the shelf." I told her I was on the way.
So $22 later and 3 minutes in plug changes and we fire it back up. I set the timing back to 36° and we put a pull on it. 415 hp. Bingo. Engine still sounded a little lazy but things were looking up. I pulled a plug again, no green porcelain and the timing mark on the strap was on the side it should be on....
We starting making timing changes and it would pick up every time we made a change. The added bonus was that the engine started accelerating a lot better through the pull. No longer sounded lazy. At 42° timing it made 433 hp at 6800 with 405 lb-ft at 4500. At 44° it lost 8 hp, so I put it back to 42.
I had built the 1030 3-barrel carb to take down with me, so we tried that next. Took us several minutes to get it swapped over. We had to change from the 1" Super Sucker to a 1" open spacer due to the rear throttle blade. Got it all bolted up, hit the fuel pump to fill the bowls and gas shot out of the rear vents. I grabbed the nearest hitting stick I could find and pecked the rear bowl in case the float got hung up on the ride down. No cigar. I then lowered the float level to see if it would change anything. No cigar on that one either, so we pulled the rear bowl and found out that the float was mashing up against the metering plate and it wouldn't let it move. I didn't have any floats or parts with me, so that dream quickly faded. I'll try it on the next iteration.
All-in-all, I'm very pleased with this little engine. I know some of you were expecting to see 450-470-500 hp, but to basically have a factory headed 352 with no head work at all aside from a very basic valve job and some small stem valves, making 430-ish hp with just some careful assembly and a big fat cam is pretty cool to me. Remember that this thing is making more than what a 428CJ and a 427MR is rated for. I actually think we would have knocked on 450 hp if we would have let it cool down. The intake manifold was very hot because we were hot lapping the dyno pulls.
I used one of my factory replacement oil pans with oil control baffles, but because of the oil capacity I put an M57B pump in. After the oil and water temps got up to 170-180, it had about 35 lbs of oil pressure at idle and it kept making oil pressure all the way up over 7000 rpm, ending up with about 75 psi at full song. Oil pressure didn't flutter, even with the stand pipes in the lifter valley.
So the thing that was kinda in the back of my mind the entire time was that I was running standard valvetrain hardware on a solid roller with quite a bit of spring pressure. I think I was at somewhere around 670-680 open pressure, with just HD shafts, POP stands/end stands, ARP studs, and my roller tip non-adjustable rockers (more on that in a second). When I was first mocking up the valvetrain with the pushrods, one stand stud wouldn't reach full torque, so when I pulled it back apart I saw that it was starting to pull threads. I went ahead and put a helicoil in that hole on the engine stand, but in the back of my mind, I was wondering if the rest would hold fast, even though they pulled the full 40 lb-ft of torque. I've had rocker studs pull out of aluminum heads on the dyno and it's not fun for anyone involved. Regardless, the valvetrain made it.
Setting up non-adjustable rocker arms with a solid camshaft isn't a walk in the park. It's do-able, but it takes a lot of careful measuring as well as some various length pushrods, some different thickness lash caps, and I even bought some .002" hardened steel shims. At the end of the engine assembly, I had .020"-.021" lash on all 16 valves. I wouldn't recommend this to anyone LOL but I wanted to do it because I wanted to see what my non-adjustable rocker arms would handle and it's a good exercise in engine building measurement techniques to get it all squared away. Props to Smith Brothers pushrods because I told them what I was doing and when I got the pushrods they were all to specified length, +/- about .001". I ended up using 3/8" .145" wall pushrods, 5/16" balls on each end for my rockers, and they were oiling. The oil at the cylinder head feed was completely blocked off and I restricted oil to the each lifter gallery to .125".
In the next few weeks I'll be pulling the intake and heads back off so I can get the heads to Mr. Craine. I'm really curious to see how the pistons fared, as I set the pistons up at .004" out of the hole and used a .041" gasket. The pistons are 1.920" compression height and with .003" piston/wall clearance, there was barely any piston rock at all, so I felt comfortable doing this. I expect to see some clean piston tops and hopefully no witness marks.
I didn't flow the heads after the valve job and 5/16" valve installation. It didn't really matter, I was gonna flog it one way or the other. I'll have Joe flow them as-is and then after the work is done. I'd like to see him pick them up 40-50 numbers. We'll see.
Once the heads are back, I'm going to change to the Harland Sharp adjustable rocker arms with cup adjusters. I'm pretty confident I can use the same pushrods I have that way, but since the valves may move up with a different valve job, I don't want to mess with remeasuring and reconfiguring the non-adjustables again. I have a few other things I'd like to try after the head work is done. I have an FE Power timing cover and adjustable cam gear in the engine right now, so I can try some different cam timing settings.
Here's a video of it at full song:
https://www.youtube.com/watch?v=FyOSLrVkZS4If anyone thinks they made a close guess in the other thread, I'll be taking a look at that shortly.
