korvette4u

blew the engine totally last fall, there was nothing but air between 3,5,7 cylinder, crank in two pieces,, with that being said:

the new build is {
new rotating bottom end with flat piston
rebuilt corvette alum heads
tpi with rebiult tb..
THE CAM: 206-212 duration with 456 I and 474E -1.6 roller rocker.. CAM is NOT ROLLER,, comp 258H , hyd flat tappet (non roller block).. suppose to work with orginal ECM..as tpi compatable

EGR and waste emmsion all removed , korvette4u air eliminator,installed



THE PROBLEM:
starts runs very ruff.. can not increase rpm. seems to back fire, stubbling!

what been checked:
code check: the only codes set is 32 . that would be becuz no egr, (It ran good before with only code, egr is mssing and sets this code). no other codes..

IAC set to book, set TPS according Book, all sensor connected (tirple checked). vaccums lines plugged where need.

electrical ,, new, plugs, cap, rotor, ignition module and 8.8 wire, accel coil all working!

QUestion:

The block asemble is non roller, the non roller cam selection was made in memic close to orginal spec.

I there a possiblity that the ecm can not handle the cam?

Is there an management system available is run this modfication?

if reprogramming chip. are any modified program available?

completely remove and replace with carberator? what is the easiest way?

I dont care about orginallity just want this to be runner..

Pete K

Sounds like your cam timing, or ignition timing may be off. You did degree the cam to be sure, right?

bjankuski

I agree that your timing may be off (Check all the basics). The cam seems pretty tame and should run fine with the stock tune. The most you would need would be a custom tune with the stock computer.

DarkBlue88

did you put it in bypass mode to set the base timing?

Churchkey

First step: check the compression. You may have a valve adjusted to tight.

korvette4u

took picture of assembl, xhecked timing marks lined up as they are suppose ro be...number one is at TDC when called

korvette4u

YES, disconnect tan blk wire below wiper motor ..to set timing

korvette4u

this is logicial, setting valve cold, zero lash plus 3/4 turn. may be might be to much,, i'll check compresion...

Pete K

If this is what you did, it should be fine. Double check it anyway, as mistakes happen.

If valves are good, and ignition timing and compression are good, you likely have a major vacuum leak (such as the brake booster), crossed plug wires, of cam timing off. dot to dot installation does not ensure all is well. Degreeing the cam comfirms or condems the phasing and parts accuracy.

If you are really unlucky, the new flat tappet cam wiped out on break in. Idle the engine with the valve covers removed and look for rocker arm that are loose, or not moving as much as the others.

korvette4u

no vaccum leaks ! igntion and timing set perfectly.. the valves were too tight.. should any one suggest that 3/4 of turn is TOO miuch I WILL agree!! they are reset to 3/8 turn after zero lash.. idles with notcable cam effect.
cam was oiled very well. with cam break in stuff.. the engine has not seen 1000 rpm. SO i dought if cam is WIPE OUT!

korvette4u

there is a concern..

a new distrubuter has a 3/8" groove around the bottom of the housing. the orginal has a 1/4" groove.. yes there is oil flowing to the rockerS. when i prelube with drill . i got 50 lbs cold ..remember this engine is newly rebuilt. will this cause less oil pressure when hot? i not liking low pressure.. please your comments

the new oil pump is an M55 high volume.

cv67

hasnt seen 1000 rpm? It needs to be run around 1500-2000 rpm +- for about 15-20 min to break in, the oil splashing up on the cam has a lot to to with break in. Not much of that going on at idle. Who knows on that, its just recommended. Have put FT cams in started it up timed it and hit the road right away without a problem either.
Sounds like it may be Ok though.

korvette4u

yup hasnt seen 1000rpm. simply becuz it hasnt run long enough..now

what about the oil pressure question related to the grooves on distributor?

engle1147

Should be fine if you've got 50 psi with only using a drill. Rule of thumb is 10psi per 1000 RPM. If you feel there is a problem down road swap the distributor out.

I highly recommend you reeeaaaaaallllllllly pay attention to what CF member cuisinartvette said about proper non roller cam break in. If you don't you'll kill the cam.

korvette4u

thanks i do that when i get it running.. meanwhile i said it hasnot run any length of time.. and has not seen 1000 rpm. the cam install instruction suggested that being not my first engine rebuild , i am aware..


THE topic was answered the valve preset WAS TO TITE.. done ! thankss