Engine and Transmission Tech

I was looking at more of a racey motor, but have now re-visited my expectations and would like to target a lower HP to keep the standard 3.9 pistons, and achieve a broader power band, making for an easier driving machine.

I've already pocketed the pistons, decked the block to raise the CR (should be around 10.5:1 plus/minus depending what I decide to do with the heads).

Engine will be used in an endurance race series.

Heads will be ported, have bullet guides, DW500 1.630" (41.4mm) and DW501 1.400" (35.6mm) 3-angle valves. I've already pocketed for whatever springs I could possibly need.

Running aftermarket injection through the 3,9 plenum with larger TB and shortened trumpets.

I have a set of SD1 Vitesse Volvo adjustable rockers I can use should I choose solid lifters.

Please share your recommendations for a camshaft - and if hydraulic or mechanical.
If Hydraulic, I'm assuming that I should look to the anti-pump up versions rather than the OE lifter?

I should also add, I'm using the later serpentine front cover, so oil pressure/volume shouldn't be an issue.

Crower 50232 with their Camsaver hydraulic lifters. Get an adjustable pushrod to figure proper pushrod length.

Thanks Jim, This does seem to be a popular choice stateside.

These say "redline 5000 rpm" ? That seems a little low; maybe its assuming standard timing. I'd have thought an engine of that advertised duration would have revved harder than that?

Any chance you can run a desktop dyno sim to advise what looks like the best results?

Dave, I think Crower's redline is really the powerband. Their cams have 4 degrees advance built in. With your higher compression I would retard it 4 degrees. I have a copy of a real dyno with the 50233 that has 247HP in a 3.9.




Edited 4 time(s). Last edit at 03/02/2021 07:33PM by mgb260.

That on an engine dyno, Jim? I would think it would take a fairly radical 3.9 with a bigger cam to get that at the wheels.

Carl, yep. At the flywheel.

"Endurance Racing", as-in 12-24 hours ? Best to read of trials and tribulations in this forum, with wet sump, racing RV8's.
Realistic rpm range ? Small mains/rods ? Cross bolted ? 240 hp. at rear wheels ? Flowed the heads ? Allowed a roller cam ?
Cool Case/ Tuftride the crank ? Good Luck, Art.

I got about that hp out of a 215 with a big carb and equal length headers, running the biggest hydraulic cam Comp ever made for the SBB (no longer available) and a 7K redline. After about 20K miles I cracked a piston and spun a bearing but it was great fun until then. OEM Hi-Po pistons, that 7 grand eventually did them in.

Jim

Art,
240hp flywheel. Even 220hp flywheel would be competitive and still plenty of "fun"
I'm liking this cam; the more research I'm doing...
Will be small 3.9 small journal, the usual prep to the mains for improved oiling, serpentine front cover for plenty of oil, wet winged sump, heads as good as possible, mapped injection and ignition. Using the standard serp full height cap, but none Cross-bolted block. If cooling looks to be an issue, I'll immediately jump on a pierburg CWA200 pump and TinyCWA controller as Ive had good experiences with them.

Quote:

I have a copy of a real dyno with the 50233 that has 247HP in a 3.9.

You also mentioned the 50232 cam, Jim Just wanted to get clarification that this dyno sheet was with the bigger 50233 cam? I figure it, was looking at the top end.

Carl, I meant the 50233. The 50232 is a little milder.

You did say 50233 on the dyno sheet post. Just wanted to be sure.

I have had a new 50232 to put in a 3.9 for years. Never did. My Buick 215 never quit screaming. I do like that dyno chart above. Shame it's not RWHP. :)

"full height cap", bolt bosses above pan rail ? If so, I would drill and tap. Air flow is free hp. ! Allowed 300" or aftermarket heads ?

Dave, I ran a Real Steel Tornado (?) hydraulic cam in my 4.6 litre engine. It was actually a Comp Cams grind. I have the Comp spec sheet somewhere, it has the Comp grind number. It might be another option since you are in the States.

"Crower Cam Saver" Do they pray for the undersize base circles ?

Art, They cut a little groove lengthwise on the lifter to put more oil on the lobe. Might lose 1-2 psi oil pressure. They also replace the wire clip with a C clip.




Edited 1 time(s). Last edit at 03/22/2021 07:39PM by mgb260.

I would like a small edm. hole in center of lifter , better.
Not to to derale your cam thoughts, Dave, have you considered a roller, solid or hydraulic ? Dan Jones,( this forum), has a cam core and I still have
some,( round lobe). Perhaps you and he could agree on a profile ? I have new gm. short-body lifters. Can be converted to mech., if need.
Art.

Hey Art,
For me, just getting on the track is key. Heaven knows, a 50232 is about as easy to drive as anyone could want, so that's what Ill be running on the main and backup motor until I get the chassis dialed in. I can always change it later, but that's my plan for now.

Cheers,

Wonder what the fuel consumption difference would be between a 50232 vs a 50230?