i just finished building my lt1 385

<eagle 4340 crank, forged eagle i-beams rods, srp .040 over pistons, keyed crank hub, gm extreme duty roller chain, 224/230 .502 .510 cam, comp r lifters, stock push rods ported heads, 11.0:1 compression,fully balanced, sotck oil pan massaged to clear crank, stock windage tray, melling hv oil pump with stock pick up, brand new opti, msd wires new ac plugs,stock coil(msd needs to be installed), stock injectors (30#'s on the way),aeromotive fpr @60psi, stock fuel pump(255lph walbro on the way),stock pcm tuning(have program but have not flashed pcm yet),new map, descreened maf,still running egr and air pump...i think thats covers it, if i left anything out just ask>

any way heres my problem. first off i have a knock from the bottom end, quieted down after pan was clearanced but still there. my thoughts are that crank is hitting the windage tray but that seems to easy. the oil clearances were in spec on mains and rods the only thing i noticed was that the balancer wobbles<had trouble putting on hub> other problem is that just off idle the enige bogs down. it drops from 700rpm at idle to about 375 when the throttle is opened. tps seems to be functionig correctly as well as maf and map<map readings are a little high 3.5v@ idle but i think possibly due to new cam> when rpm drops maf g/s drop as well, spark advance jumps to 254 degrees!!! injector pw goes from 6.1ms at idle to 7.0 ms integrator is at about 130 all the time block learn is 160 at idle and 130 at problem. any ideas please help

 

All of the LT1 sstroker guys hang out on "LT1 Tech"... so that is where you are most likely to get an answer.

Moving to LT1 Tech.....

 

nobody has any ideas?

 

Can you log this?

 

What did you do for main studs? If you got ARP studs then a windage tray wont fit, i fopund that out the hard way. thats why im running without a tray now... The bogging right off of idle will probibly go away with PCM tuning and the balancer..... tell me you pressed (not hammered) it on....

 

Did you check to see if the pan still cleared after you bolted it down. I had to dremel out a small area near the lip of the pan on one side that a rod bolt was hitting when bolted down. (It didnt hit till I bolted down the pan)

 

no i did not hammer it on i used a long 7/16 fine thread bolt a washer and the bearing out of a harmonic balancer installer kit. if you know of a better way please let me know! or if you know where i can get the kent moore tool that would be even better!

i did recheck the pan(i put it on with out clearancing it so i had to pull it to make it clear after the engine was installed it did not make contact when turned over by hand) before you were able to put your hang on the bottom of the pan and feel it making contact now you cant. i guess i just need to pull it again and pull the tray to check if there is any sign of contact.

im waiting on a friend of mine to download the program to my pcm and the injectors should be here today or tomorrow along with a new hub so hopefully that'll do it. if any one out there has any otyher input it would gbe greatly appreciated

thanx!!!

one more thing could miss adjusted valves cause the engine to bog down? just a thought let me know

 

Why would you bump the fuel pressure to 60psi without programming for it? In theory, that should cause it to run pig rich, and bottom out (108) the long term fuel corrections, but instead, you've got the maximum allowable extra fuel being added at idle by the long terms (160). Something isn't right. Smell the oil for fuel.... could be dumping so much fuel in that the oil is being washed off the cylinder walls and you are diluting the oil.

Also sounds like you may have a bad engine or PCM ground with the data jumping all over like that.

 

th fp set at 60psi did not affect the readings at all. i had hoped it would because of the lean condition my thoughts were to help richen it up some until the programming and injectors were installed. i will be pulling the pan on sat. so i will definitely take a look at the oil.