prjctSILVERKNIGHTy2k

ok so i just finished up my cam swap. this is the specs on my cam and springs:


cam: .580/.590
288/294
236/242 @ 050
114 lsa


springs: 1.290"/.885" OD
1.055/.650" ID
130 lbs @ 1.800" -valve closed, spring instralled height
320 lbs @ .600" lift (1.200")
345 @ .640" lift (1.160")
max lift- .640"
rate- 313 lbs
average coil bind @ 1.090"
higher pressures than comp 26915 springs



Now heres my problem. On first startup try we heard a loud grinding noise from the front of the motor before it started cranking right. When i got the timing cover off before the old cam came out the timing chain had some slack in it. It had the same amount when i got the new cam in. I had the dots on the crank and cam pulley aligned perfect. I have a strong feeling that the chain skipped off the teeth on the first try. Now when you crank it, it cranks fine but all it does is little pops and occasional big backfires as it cranks. It wont even fire. All i can get out of it is the popping during cranking. Now i think its just the timing chain skipped off, but my buddy thinks that my injectors are wayyyyy too small for the cam and its not even getting enough fuel to fire. HELPPPPP!


Thanks

bongva

iTrader: (7)

i think your buddy is wrong LOL.

But yea i agree with you, sounds like its not in time.

MM98

iTrader: (13)

Might also double check and make sure your coil packs are on the correct sides.. Sounds silly, but the car won't fire if they're not.

19ls1ta99

iTrader: (2)

Your buddy sounds like he dont know what hes talking about,pull the cover back off you got a timing problem

prjctSILVERKNIGHTy2k

thank god. I dont have money for injectors right now. lol
He said that the stock ones will be maxed out and still not enough for my cam.
I'm gonna try switching the coil packs first and try it and if it doesnt fire i'll tear it back down to the chain.


How do you adjust the tension on the timing chain? I dont think theres supposed to be that much slack in it..

FreebirdWS6

You can buy another chain or got the best bang for your buck and ger a dual roller timing chain set!

SOMbitch

iTrader: (8)

These motors don't have tensioners except for some of the VERY early ones. I saw a guy on the vette forums that modified a Gen IV TC damper and put on his LS1.

Some play in a stock chain is normal. I would pull the TC cover off and make sure you are dot to dot and go from there.



Edit: Here I am not too lazy today>>>> http://forums.corvetteforum.com/auto...ls1-block.html

JohnnyBz28

iTrader: (12)

As far as the injectors go, I just did a cam and heads.

Cam 225/229 .580/.590 114+4 LSA

My stock 28lb injectors were at 110% duty cycle. Anything over 80% duty cycle is really stressing the injectors. You might want to look into injectors soon lol


edit: I swapped out to Ford Green Top 42lb injectors

Mike454SS

iTrader: (4)

All other problems aside, your stock injectors will run WAY WAY WAY more engine than you have enough to fire it up, idle it, and even drive it around town...AND even to go full throttle at low RPM...I'll be very very very surprised if you need more injector below 4000 or even 4500 RPM...so worry about them later, troubleshoot your problem first, get the engine running, then look at your potential fuel system issues.

the_merv

iTrader: (88)

I'd re-check everything..the LS2 Chain is a good upgrade.

Ya that's definately crazy..lol..I switch mine all the time and I don't have any problems.

Whoever told you that kick 'em in the dick for me..

Pocket

iTrader: (22)

Agreed, this is incorrect. Coil connectors interchange. The only way he 'might' be able to get something switched is if he pulled the coil harness off the bracket and theres no reason to do that and even if he did, the harness only has enough length to fit one way

1969mach1

sound like your 180* out, pull the front of the motor back down and remove the timing cover, also remove the valve covers. make sure its still dot to dot, these timing chains on these LS motors have slack, IT'S OK, even the expensive doubble roller chains have slack.
If its not lined up dot to dot and I mean DEAD ON, then get it there. some times the crank sproket is hard to see the dot but its there. If it is DEAD ON dot to dot you my have to degree in the cam, which will mean you will need to remove the drivers head. But first make sure the cam was not install 180 out. You should have lined the dots up befor removing the old cam this way you know is it good. alot of guy have a problem of tearing it all down and pulling the old cam out with out lineing up the dots. once the cam is out they spin the motor over till the #1 piston is up and then it's a 50/50 change of it being right or 180 out.

by the way if it were just a tooth off in either direction it would still run but it would run like total ****, spit'n and spudering. But if its not running at all and popping throught the intake, it's 180* out.

Good Luck

1969mach1

right!!!

Sales2@Texas-speed

iTrader: (5)

Next time you get into one of these, try something. Line 'em up dot to dot, turn the crank 360º, and see where the cam dot is. It'll be at 12:00 high just like the crank gear dot...the PCM sorts out whether it's intake or exhaust stroke every time you start the car, so it doesn't matter if you try to get 180º out, it's still going to start as long as it's not off a tooth!

1969mach1

learn something new every day!!!


Thanks Matt

kmracer

iTrader: (1)

theres something else going on, timing chains dont skip. if there was ALOT of slack, it could throw off the timing, but nothing more than a few degrees. it'd still start. run like ****? yes. another thing is, if you lined it up dot to dot, it came out the same way. if the chain had all this slack, it wouldnt have run before you swapped the cam either, the timing would have been off the same amount.

crankshaft position sensor?

devious

iTrader: (1)

if theres a load on the valve train then there will be some sack on the chain, and tight on the other side, can u send a pic with the timing cover off?

Intimidator02SS

Did you reinstall the camshaft retainer plate? Maybe the camshaft is floating to far forward causing the cam sensor to not read right, or your lifters are hitting 2 lobes versus 1??? Could explain the grinding sound from front of motor while cranking??

XtraCajunSS

iTrader: (2)

If you installed that cam 1 tooth off, you may have bent valves... P to V on that cam could be tight depending on how its ground. If you installed it off, it could have caused piston to valve contact.

As stated above, you REALLY need to check cam timing...

Shane

slamminjim

iTrader: (6)

I bet your engine is out of time. The grinding noise you heard was the cam hitting the valves. You need to check the timing. My bet is you have cute little eyebrows on your pistons now.