8.1l whippled WONT START rebuilt motor
 

ok so i have just finished rebuilding my motor and now i cant get it to start. had a low voltage code (ground wire) fixed that now i cant get it to start at all.

i have now checked 2 dif cylinders and i am not getting over 100lbs of compression in the engine. also found a nice little fact that the fireing order for a 01 is different from a 02 but summit says that the cam works from 01-07?

ugh multiple companys multiple answers.. comp cams says its the valve springs need to be changed from stock to COMP Cams 911-16.. machine shop said i shouldnt have presoaked the lifters in oil. summit says they will refund my money if i return the cam.. wtf i just want a answer as to why i halfto back off the retaining nuts on my rockers to get any compression above 0.. raylar roller rockers and his special locknuts

I have no idea why you wouldn't pre-soak your lifters in oil.
Pushrods too long holding the valves open maybe?

new lifters, stock pushrods with 250k on them from original motor. only things we are thinking now is that it needs a relearn for the crank sensor, and the camshaft may have been ground wrong.. i have a merc cam im thinking of putting in

Let us know what you figure out.

well i have several cylinders with GOOD compression 160+ and some that wont go above 30-60 so what we can conclude is that the valves arnt seating properly. valve grinding compound was used to get a seal and aparently it didnt do good enough so 175 at the machine shop and ill see if that takes care of it

Bummer!

yea your telling me

Do what? what cam shaft did you put in it? me personally i would chuck those stock push rods in the trash. I forgot the details of your motor what did you do to it.

You can email me direct
edward.coss@gmail.com

.060 over, cbb wr270 hr14 camshaft. ported heads/ intake. front mount intercooler.
still gotta buy the springs to go with the cam acording to comp cams. 611-16
oh yea roller rockers from raylar with there special little hold down nuts.

i was concerned the firing order for the cam was that of a 01 because i had found a warning from jasper saying the 01 firing order was the same as the older gen 454. talking to comp cams directly they say it has the newer firing order.

woops 911-16 for the springs

Same firing order as the LS motors?

1-8-7-2-6-5-4-3 2002 and up is this 2001 1-8-4-3-6-5-7-2.. this is acording to jasper

Interesting. I didn't realize they changed the big block firing order also.

yea the 496 is a interesting monster

Hate learning that stuff the hard way. :(

yupper

Did you get the heads back and installed yet?

na had a kids bday party to go to yesterday. should have them back by mid week

pulled the heads.. yup several valves wernt completly sealed. about 1/4 inch on the valve waasnt sealed by just enough to not work

OMFG wasnt expecting the call from the machine shop today saying "well we cleaned the heads and well your not gonna belive it but". yes what am i not gonna belive "They are both cracked all the way to the combustion chamber". SON OF A......... bought those heads 2 years ago so i cant even go after the person who sold them to me

Wow that REALLY sucks! Are they repairable or a total loss?

Damn man! How much are heads for those engines? And are they stock?

stock heads. had bought the set for 400 as a spare set. they were clean and mine were well nasty so i wanted to use them. oh well machine shop is gonna clean my old ones up

Great! Are your old heads ported or anything?

nope guese i halfto do that when i get them back here

so lets see.. got the heads from the machine shop and installed.. now there is no spark on any cylinder??? i have a hand held programer that i can see im getting 90-130 rpms while cranking, 5 degree of advance on my timing, and i know i my temp sensor is reading 80 degrees also. fuel injectors are all working just no spark??? im lost

wow wow really i hate GM... there was ONE blue ground wire by the front right side of the block not attached that stopped it from sparking.. wtf no codes ever went off

So you're good to go now?

yea jumpered it last night and got gooood spark so if i get the time today after work im gonna hook it all up properly and get her started so i can do a brake in

Sweet! Sounds like its about time to burn rubber.

Man that was one hell of a battle to get the thing fired up.


Glad you got it all sorted out

ill get a video up this weekend when i get it all buttoned up and feel like laying some rubber on the neighbors driveway.. gonna be funny when they see the marks :D