Kerrdogg

Cam talk, as some of you might have read I have a 2011 GS 6 speed MT. Recently I did some upgrades to gain power from the car, one that didn’t work well was the cam. I chose to go with the Spinmonster tried and true 230/ 234 cam, the car was tuned and there was no real power gain until 5200 rpm, then the power slowly built up to 6300 rpm where it peaked at 28 hp gain and 368 rwhp on a Mustang Dyno. I did not have headers at the time so some long tubes were installed along with an 3” x-pipe and a take off ZO6 exhaust, the power responded well in the midrange with 35-40 rwhp gains but at the peak
the gain had calmed down a bit to total of 389 rwhp. I did not tackle the cam install but I decided to jump in and pull things apart and I am glad I did. I sent the cam to a neutral party and had it checked, I had someone much smarter than myself read the results and there were a few things wrong but nothing major enough to cause the lack of power.

Here is a list of all the mods,

OBX 1-7/8 header and 3” xpipe
ZO6 mufflers
Ported intake & TB
Cam
TR6 plugs
Vararam
160* thermostat
Tune
Meziere water pump not installed yet

Note: When I purchased the cam I was told to use 7.425 pushrods as the base circle was smaller, I purchased them from a site sponsor and they were installed, at the time of disassembly I measured them and came up with 7.440 what is interesting is in talking to two different but well known cam companies I am being told to run stock length pushrods, so did the extra .040 cause a power loss?

I called the cam grinder and explained the situation, he pulled up my serial number and said the cam was ground correct, says they cam dr every custom ground cam they cut now and save the file. He did not like the grind design and said the LS3 needs a wider split to make power, I told him that lots of people used this cam and made great power, he was surprised and recommended a cam cut on LSR lobes, 227/243 .614/.624 113.

An engine builder friend hooked me up with another cam company, spoke to their LS engine expert and he agreed that the lobe separation was too tight, suggested 14 degrees between the numbers and then gave me a grind that they just dynoed with success that specs at 226/240 .624 .624 114 (cam card really looks like 114 +3.5).

So, anyone running a big split cam that is extremely streetable and make good power, I thought the cam I had was well mannered, Justin with his Pat G speced 230/238 has made great power and he says it’s daily drivable. Chris liked his Pat G cam that was really close to Justin’s but had a failure of some sort and took the opportunity to go with a larger cam that made more power but lost drivability. Think the pushrod length could have caused a 40-50 hp problem?

??????

old motorhead

Me thinks you have other issues. All the cams mentioned should be capable of making within a few hp of the other. If the p'rod length was off enough to cause a hundred hp loss, I think you'd notice it. Way too long and the valves wouldn't close. Way too short and it would sound like sheet. You have the parts to make sweet music. Something's not right. Ain't the cam.

Joe_G

Interested to hear opinions here.

I'd have thought with the shorter pushrods you'd have a lot more ticking noise than you did. It sounded fine when I saw you.

Kerrdogg

Old- I agree, according to Comp and Crane it's ground close enough to make power, strange neither like the grind even though its proven here (well in every one elses car) to work.


JOE- The pushrods were .040 longer, 7.440, ticking noise wasn't bad at first after some track passes it seemed to get worse, then the headers went on and it was really noticeable, that is why it got parked and torn down. I am just wondering if they could be long enough to bottom out the lifter, when you want to make power you run things loose, these weren't, could that cause a big loss in power?

Joe_G

Sorry I read that wrong. Seems that wouldn't matter that much but something caused it. Were the pushrods bent?

old motorhead

I had a 226/234 114lsa and a 232/234 112lsa in my LS3 before going f/i. Both made in the 475 rwhp range (actually 465 with 4:10 gears). No way I'm believing that increasing the exhaust duration 10 degrees in either one of those grinds would yield huge results. A few hp maybe. The 50 you're looking for....no way.

corvette4595

Did the 112 lsa cam idle a lot rougher?

old motorhead

Yes, made more torque too (25 or 30). Also peaked at 5800rpm. The 114lsa cam was smoother and peaked around 6300 if memory serves. The 114lsa cam was more well mannered too.

CTD

When you removed the cam, did you check the timing? Not dot to dot, actually measure the ICL & all the rest.

I'm going to guess maybe not, so might possibly have issue with the timing set or crank gear index.

JUIC3D

Everything I have read says that LS3s do not benefit from wide splits and while I'm sure the guys at Comp know a thing or two, I doubt they're at the track often enough to test the different designs.

Like we spoke about earlier, I think your cam choice is right on, but something else is obviously off--it might be time to check the timing gear set and do some measurements to be certain the cam goes in correctly.

I didn't check mine and threw it in dot to dot and so far it seems to be working just fine so I'm curious to find out what exactly is wrong with yours.

Can you post the cam doctor report along with the cam card from Comp?

Joe_G

This has been my contention all along...seems to me the cam was installed retarded, perhaps on a faulty gear set or an adjustable gear set installed incorrectly.

Joe_G

Pretty sure Comp uses engine dyno software and actual engine dynos when creating camshaft profiles. From what I've seen, the software is amazingly accurate these days.

Kerrdogg

When we pulled it apart we couldn't see the bottom gear due to the extra wide oil pump and the fact that it doesn't seem to want and come out so we set the engine to TDC using a homemade piston stop and degree wheel, the timing gear for the cam was aiming straight down so...

The guy that installed the cam has done 40 or so in the past few years, I didn't like some of he install finds that I have shared but he was caught with his pants down and tried to get it done vs calling me and getting the correct parts.

Justin, I don't have a scanner but I'll email you a few things in a moment.

Taking the weekend off from car stuff, hope to get it figured out so I can use the three day weekend to get it put back together next week.

JUIC3D

Ya, I don't doubt that they do.
Can the engine dyno mimic daily driving characteristics though? I might be uninformed but I wouldn't think their computers have the capability to simulate part throttle driving, habits, etc.

old motorhead

I think it depends on who you talk to at Comp. They told me one of their off the shelf blower grinds would have excellent manners. Damn thing was huge. Computer might "show" it to be quite mild. It might have had excellent manners in a 454, but no way in an LS3.

CTD

so........? other than dot to dot to is correct? That does "not" tell the cam is timed correctly.

Kerrdogg

Correct, at that point in time we were just making sure it was installed at TDC, there is no adjustment in the factory timing pieces and the chain wasn't installed a tooth off.

Still baffled, the push rod thing has me the most concerned, if they are actually .040 longer than necessary could it hurt anything and could in cause that much of a loss.

Kerrdogg

I'm looking for what you made, plus what you would gain with the extra parts I have over what you did not a mysterious extra 50 rwhp. Your car made 475 rwhp, now add a ported intake and TB and a Meziere water pump, should see close to 500 rwhp, works for me, but it didn't, that is where I am lost.

Kerrdogg

Little update, pushrods are marked 7.425 and measure 7.440, when I spoke to the rep for the co that made them I was told that that reading is correct, the ball depth adds to the pushrod length.

Spoke to both cam guys again and was told the reason why some cam designers request the extra pushrod length over stock is to compensate for the ramp speed of the cam, there is plenty of cushion left so they use it to make sure the valve train tracks correctly.

After listening to Comp, they offered to grind a cam for me at a discounted rate since my cam was ground a bit off, the price they quoted me was $40 higher than what I paid for the original cam grind through a friends shop, I passed. Spoke to the guy at Crane and he offered to cut me a deal on the cam they just got done testing on the dyno so I went with that, should have the cam here Monday. This is a grind that they tested on a ls3 crate engine that picked up 73 hp and still has good street manners (5 degrees over lap & intake valve closing at 43.5 degrees).

All the rest of the parts are here including the ATI balancer (nice piece) and the Meziere water pump, plan on spending a few hours a night over the next week getting it buttoned up.

JUIC3D

What are the specs of the cam? I think you said it was 234/242 or something which would be 8* overlap, no?