BigEd_98Formula

iTrader: (4)

Been going nuts wondering why my LQ9 Stroker wouldn't fire up and was acting like it was out of time.

Here's the basic specs:
408 LQ9 Stroker
Eagle Forged LS1 Crank 4" Stroke
CamMotion HYD. Roller 249/257 650/650 lift - 114
Comp Gold Alum 1.72 Rockers
Heads Flow 324 Intake and 212 exhaust @ 600 lift
Compression 11.7 to 1
was sold to me with the assumption of around 650 crank HP spun to 6800 rpm.
Planing on 150 Shot of Nitrous
Victor JR with edelbrock elbow
Right now has a 4000 Fuddle with a 2.5STR (way to loose for this setup, its on the list)

LOTS of fuel, Fireballs out of the open headers, general sick sound, fouls all the plugs.

For troubleshooting purposes stock ls1 intake and injectors used

With the help of my friends, and friends at Elma Automotive and J&J Speedshop, the motor was swaped, and troubleshooting went from simple to more in depth.

Pushrod length was adjusted, wiring checked etc.

The front cover removed to discover cam and such all lined up.

STOCK cam swapped in, STARTED right up.

My question, how big of a cam can a 98 PCM support, and/or what needs to be tweaked in the PCM to get it to start. One theory is that its detecting excessive knock and is simply pulling all the timing at startup.

I'm not deadset on this large of a cam because mainly I want to drive this thing, and its needs to drive to the track, and I enjoy cruising more than track time. Not sure how this would handle on the thruway. I've had several suggestions for cams but am trying to gather as much information as I can for my choice.

If the cam has to be changed, the plan will be to spin it to less than 6500 to preserve my built 4l60e, which is another reason I'm considering something smaller to bring the powerband down a bit so I don't have to spin it so high.

This build is on a tight budget so I want to avoid swapping the PCM/Cam to save money on other components I need to finish it up.

mvvette97

iTrader: (18)

your pcm is fine for that cam. tuning should be no big deal though a smaller cam would be alot more driver friendly. Makes me wonder if something is wrong with that other cam. It should start but probably not idle very well till it's tuned. I would go with something in the 226 up to a 230 @.050 to keep it friendly on the roads.

BigEd_98Formula

iTrader: (4)

Is there anything in the PCM I can look at changing to help get it to start prior to a full tune?

brianfromhawaii

iTrader: (3)

timing should be at like 30 degrees at idle lmao... wow thats a big cam... have fun driving that bitch on the street!

LS1-450

iTrader: (33)

Can you post the tune?

DrkPhx

iTrader: (15)

It's really not that big for a stroker motor. Mine has almost the same cam specs and it idles pretty damn good with 25 degrees of timing at idle.

O/P - The 98 PCM is not as robust as the later LS1 PCM's, however it can still handle your setup. It sounds like the tune, however it's hard to say without looking at the tune. I would also be careful about washing out the cylinders with that much fuel getting dumped into the motor.

jmm98LS1

iTrader: (28)

I'm running a very similar cam with less cubes and a '98 pcm, sounds like you haven't done any tuning? Mine idles at 1k rpm with about 24* timing.

Psychopjv

iTrader: (16)

Some tuning was tried but this thing will not fire. It simply sounds like a vehicle where the distributor is 180 out. Car fired right up with a stock cam put in it. So i'm thinking something is off with the grind.

Doc

iTrader: (9)

Some tuning? Sounds like some peanut butter on a PB&J.

JonCR96Z

iTrader: (33)

That's a little much.

2xLS1

iTrader: (25)

I would check the reluctor on the Cam Motion cam to see if it is 180 off. They made some cams for I think Futral with this problem a few years ago. One thing you could have tried with the Cam Motion cam installed is see if it would start with the cam sensor unplugged. These engines will start and run with no cam sensor signal but won't with the wrong signal.

BigEd_98Formula

iTrader: (4)

Thought I would post a reply to this.

Been rocking the motor with a stock cam (C5 vette cam actually and uggh LS1 intake) to just get it out and make sure there were no hidden problems with the motor.

Took it to one track session and eventually did the converter in Pulled hard to around the 330 mark, 1.64 60's with some tire spin, possible wheel yank one run. Low end is phenomenal. Wont lock up anymore and when it does, under load isn't a pleasent sound.

So I'm having a smaller cam speced since I honestly wasn't dead set on a such a big cam mainly because I want to do a lot of driving with this and 4l60e's, built or not, don't like high revving. I will continue to update after the swap.

Also will be having the big cam speced by a cam doctor or similar to make sure it is, what it is and will be posting it up for sale if its "good to go".