Let's summarize where we're at.
We spent beaucoup $$$ getting an engine rebuilt so it would run the same or worse than it did when I bought it with a huge exhaust leak, 212K miles, a nearly non-working turbo (very, very little boost), and stock exhaust. The shop I'd been using is telling me this is how these turbos run. Repeatedly.
At lower RPMs at 4.5 PSI boost (more than when I bought it), it ran worse than when I bought it. It really had not run better, and would hardly do 80, just a smidge better than before I brought it in.
Some sleuthing around and learning had me convinced the cam was retarded. The shop had "checked" and said it wasn't off a tooth. Errr, but was it retarded?
I'd sent off the dyno chart to a slew of shops in the San Diego area, with the offer to bring them my problem if they could tell me what it was. I got a lot of interesting responses, but only a couple diagnosed it as likely a cam retardation problem or possibly an overly aggressive cam (all focused on peak power). Most others wanted to throw more ignition timing at it. Errr, the dyno shop already did that folks!
Convinced it was the cam, I ordered one from DOA Racing. It had a lot of great reviews all over the place.
Since I was tired of spending $$, and it was just a cam, I decided to do it myself. Sure, I'd likely get it reimbursed by "The Shop", but "likely" might involved court this time, and I really wanted to tear into this thing myself.
Scott, my ultra-cool mechanically inclined neighbor came over. He has a 350hp VW-motored buggy and used to rebuild and maintain 16 cylinder methane-powered engines. Not a bad guy to have in your camp. I'm no slouch, having rebuilt a couple motors and trannies, etc., but it's not something I do every day. :)
Before installing the cam, I degree'd the existing cam. It showed about 7 degrees retarded. Yeouch!
The Crane Stage II cam is not a turbo cam. And, as I'd mentioned, I found enough complaints about lack of power and running rich for the Crane Stage II cam in normally aspirated applications, I was just happy to get it out. I really, really resist spending money chasing problems without having confidence the $$ being spent will solve the issue. I really did my homework on this one, and I was feeling good. Not always a good sign! LOL
Input from folks was that a 105 degree centerline cam in an automatic wasn't exactly a good match. Now, granted, the AT is not intended to be in there for too much longer, but whatever - once the truck is running down the road, AT or MT doesn't matter. And saying this one didn't run down the road none too good was being generous.
The new cam from DOA Racing is a 110 degree centerline.
When I held both cams up (Crane Stage II, supposedly, and the DOA 270) with the dowel pins at 12:00 the Crane's lobes were further counterclockwise than the DOA's. There's that 5 degree difference... Maybe more.
Old Cam specs from my invoice: New Cam specs
Cam specs Int Exh (SWAG from the writing on the box)
Valve lift: .429 .442 .432
Cam lift: .275 .283 .271
Duration (SAE)
Valve lash .012 .012
Centerline 105 105 110
Spread 110
Timing events @ 0.050
Duration 224 234 226
Rocker ratio: 1.56 Same (same rockers)
Nice cam comparison site (does not include the DOA cam):
http://home.comcast.net/~jonmarkstewart/cam.htm
This was probably the easiest cam I've ever done. The only reason it took as long as it did is that I was messing around with the degree wheel and finding where the original cam was phased. I loosely followed these directions. I was worried about the head gasket, but I had quite a few people, including some really respected names in Toyotas, tell me as long as I didn't break the seal, I was good.
Years ago, I replaced a head on my mom's 22RE, and I remember that sucker was sealed pretty well to the block, so I got over it and bit the bullet!.
I installed the new cam, slathered in cam lube, and degree'd it. It came out to 3 degrees retarded. None of the degree wheel stuff was touched in between cams. I'm wondering if the Cranes are being misdrilled...
After the initial valve adjustment, it was... The Moment of Truth!
I'm used to Chevy's where the distributor spins 360 while you get it started, then you adjust it as needed so the wires and/or vacuum advance (for oldies) points where you want 'em to AFTER you break in the cam/motor. On the Toy, the distributor has a limited swing and you need to stop, pull the cap (2 small bolts), pull the retaining bolt, rotate it, replace the cap, replace the bolt, and see how you did.
It took me three tries to get the distributor where I wanted it. :)
The first time, I had the ignition timing way off and when I cranked it over, it fired as one of the pistons tried to come up, nearly stalling the poor starter. D'oh!
Off with the cap, pull and rotate the distributor a bit, try again. It started. Checked the timing and it was still way off. I had to pull the distributor one more time to get it where I wanted and so it would time well. I set it to factory specs (jumper the check pins!), 5 degrees BTDC, for now. It's going to a shop to get tuned on the dyno, so I'm not too worried about that part right now.
After 20 minutes for breakin, I let it cool down a bit while I cleaned up and put most of the tools away. If you put them all away, you'll need to get them out again. It's just the way it works. ;-)
The first thing I noticed was that it fired RIGHT up. That was an improvement.
It idled much more smoothly. That was an improvement. Especially given the solid motor mounts
At idle, it no longer felt like it wanted to die. That was an improvement
I got in it and went to back up. When it leapt backwards, I started giggling like a schoolgirl. That was a huge improvement.
On the road, it made boost before I reached the STOP sign. That's 3 houses in suburbia. That was a definite improvement, especially considering I wasn't trying. After all, it had a new cam for cripes sake!
On the main road, I realized I was effectively driving a new truck. Holeee Carp! I've never had a single, relatively cheap performance mod make such a tangible difference. And this was with the cam 3 degrees retarded still!
The old truck was a danger to pull out into traffic.
This one throws itself out there in comparison. It's not scary anymore, that's for sure.
The old truck would absolutely NOT spin a tire in dirt from a dead stop (with puny stock 225s no less!).
The new one throws dirt merrily. Then the turbo kicks in and it gets a little angry as it throws dirt. LOL
You all saw the dyno chart I posted earlier. The original behaviour makes perfect sense with that graph. I'm excited to see what the chart looks like now!
Several days later, I got to drive it 50 miles to Temecula. There are some hills between here and there on the highway where even SWMBO's 283hp Suburban wants to shift out of OD. Not the 4Runner, nopers. OD the whole way (Econo mode).
Before, 80 had the poor thing working its guts out (at 4.5psi boost). At 9psi, it still wasn't exactly happy at 80. Now 80 is just some number on the way to a higher number. >:) Time to replace those 10 year old rear tires!!!
In summation, this is the best money I ever spent on a performance mod. It probably wouldn't have been so phenomenal a difference if the Crane cam hadn't been such the wrong choice for this application. But I'm definitely high on DOA camshafts right now!
Next up, taking it to the new shop to get tuned and see what else is Not Quite Right...
Toyota Survey
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