still have no idea what it could be

[Lt1_8U]

hey guys i am still at a loss as to what my problem could be still. went outside to start my car it started rough then died started it back up and went maybe 200 ft and the rockers started clacking so i shut it off and pulled the valve covers then started it and saw i had to oil up top. i put cleaners through it, new thinner oil and i have 65 lbs of pressure which i checked on a mechanical guage. i pulled the intake and all my lifters pushrods and rockers are fine as well as the girdle which holds the lifters in. the oil pump shaft is fine that runs off the cam. im about ready to pull the motor and tear it apart. its a 96 lt1 trickflow 21* heads cc306 cam ls7 lifters stock length pushrods 1.55 roller rockers. this motor was freshened up with new everything about 5000 miles ago it was built, it has been running for a year without problem now this. if anyone has any insight on what i should do or has had this problem i would be grateful. i was told by the shop that did it that possibly one of the caps above the cam came out but to check that i will need to pull my whole front of the engine apart and if it isnt that it would suck to waste all that time. thanks in advance guys:cry:

[greenformula92]

are the rockers still in proper adjustment, my cousin had a motor built about a year ago for his truck and the rockers keep coming out of adjustment....just a thought

[WildBillyT]

Whose rockers are you running?

[Pampered-Z]

Can you put the car on Ramps and listenfrom under the car. Make sre its no somethig low in the rotating assembly? I thought I had a bad lifter, tune out my crank wasmaking conact with the scrapper.

If your sure you lifters are getting noisey the nI would pull it apart before you do any real serious damage.

Even if a cam bearing didn't walk, you will want to pull the mains ad make sure the bearings are good. Eating a bearing makes a mess of your inernals - Trust me!

[sweetbmxrider]

FYI my ls7's are noisier than ****. I'm going to swap them out at some point.

[Blackbirdws6]

Maybe verify the timing chain didn't skip for whatever reason ?

[Lt1_8U]

i have ls7 lifters and comp cams roller rockers, i had checked the rockers and they were all fine. and the lifters hadnt made noise prior to this before. right now i have the intake and all the electric off and im getting ready to pull it and start taking it apart to see what could possibly be the problem. i was told that another possibility is one of the plugs above the cam may have popped out... i will keep this updated, im leaving for a week tomorrow so it will be when i return, gotta love it:mrgreen:

thanks for the replies I am just getting frustrated because its a pretty new build and i went new with everything and its been a year and im having problems already

[crainholio]

FYI my ls7's are noisier than ****. I'm going to swap them out at some point.

Melling lifters for relatively low $, Morel link-bar for the higher $ sure thing.

[sweetbmxrider]

Yeah, I am most likely going with morel link-bars. Thanks.

[Blacdout96]

Sweet, let me know when you are getting rid of the LS7's, I may be in the market for my engine if the price is good.....

[sweetbmxrider]

They will be priced to gtfoutta my life

[Lt1_8U]

update pulled everything off the motor and all oil galley plugs are fine and i see nothing wrong, i guess now i will take the pan off and checkthe bearings. this blows, i dont understand how something could have happened off of a bad start. i have 65 lbs of pressure but no oil up top

[Lt1_8U]

well i took the motor out and put it on a stand and stripped in all down and today i dropped the pan, boy did i find something wrong. one of my piston rods snapped in two. i suppose i had a misfire and the cylinder detonated and just split the rod

[sweetbmxrider]

Snapped a rod?!? Wow! Pics of carnage! I'm guessing factory rods?

[Lt1_8U]

yessir, ill take a pic tomorrow when i take it out. it was running fine then i started it one morning and (fart noise) it crapped out on me. yep stock rods

[Blackbirdws6]

Wow that sucks but glad you found the issue. In for pics...

[Lt1_8U]

me too, it was bothering me that i didnt know what it was, just means time to upgrade:lol: i should be out around 5ish so ill take the heads off and ill take the piston out and snap some pics for you guys

[Blackbirdws6]

Time to make the wallet hurt!

http://27.media.tumblr.com/tumblr_lj4ar8bWdD1qzwd45o1_500.jpg

[Lt1_8U]

hahah yes, do you think its possible to keep this build at a solid 2,500? with the rotating assembly im planning on spending around 1,300 on a eagle kit, i dont have the green for compstar and all that. and to bore the block and machine it.

btw Carnage as promised!

http://i183.photobucket.com/albums/x94/69novaguy/0824112103.jpg

[Blackbirdws6]

If you keep the stock crank then it should be doable for $2,500. I believe my pistons were around $800 and the rods a little less. Get the good stuff.

[sweetbmxrider]

Nice carnage. Honestly I would want to spend more now than more + more later.

[Lt1_8U]

thats true, good point. i might as well wait and build it to handle a lot. you guys think a forged roatating assembly kit from like eagle or scat isnt good? a 383 kit was like 1,800 for forged

[WayFast84]

I've heard mixed reviews about eagle.. since this isn't a racer why not lower the boost and go with the stock crank? do you plan on getting a new rear?

[Lt1_8U]

I've heard mixed reviews about eagle.. since this isn't a racer why not lower the boost and go with the stock crank? do you plan on getting a new rear?

i already have a moser 12 bolt with 33 spline axles:mrgreen: i want to price everything out and see how much the difference is. i'm reading a lot now into builds and different combinations, im fairly new to this because my last build was just stock bottom end, just arp bolts and trickflow heads and cc306camshaft. i just thought a complete kit would be easier than having to find out all the measurements i need and find things that work together to make the 383. am i over thinking this? lol

[Blackbirdws6]

i already have a moser 12 bolt with 33 spline axles:mrgreen: i want to price everything out and see how much the difference is. i'm reading a lot now into builds and different combinations, im fairly new to this because my last build was just stock bottom end, just arp bolts and trickflow heads and cc306camshaft. i just thought a complete kit would be easier than having to find out all the measurements i need and find things that work together to make the 383. am i over thinking this? lol

The only thing to really be concerned about are bearing clearances and such. A reputable machine/engine shop should be able to mic out everything and recommend what bearings and such to purchase to make everything work well together. Obviously it makes sense to double check this during assembly. Again, the stock crank is known to take some pretty good abuse so I would focus on a good rod and piston. There are plenty of 355s making very good power on boost.

[sweetbmxrider]

You will also want to get a piston that brings your scr down enough to safely run the boost level you are looking at. A kit may or may not have what you need.

[Lt1_8U]

im going to try to get to my machine shop this weekend if my car doesnt get blown away:lol: ill speak with him on what he can do. your right sweetbmx, i was looking at kits and most of them make like 11.5:1 compression, my motor is stock compression but i definitely want to make it around 9.5:1, whats the most compression an engine should be runnign with boost?

[WildBillyT]

whats the most compression an engine should be runnign with boost?

That's not a question with an easy answer. The basic one? "It depends".

[sweetbmxrider]

Yeah, exactly. There's a good bit of math to building a motor. Do you know what size the combustion chambers are in the heads?

[Lt1_8U]

they are 54cc

[Lt1_8U]

That's not a question with an easy answer. The basic one? "It depends".

that is a good point, would a better question be, is it safer to run a lower compression ratio with a boosted motor? example 10:1 would be (safer) than 10.5:1

[Blackbirdws6]

That's a loaded question but speaking for what you are doing, shoot for a 9.0 to 9.5 SCR. You can get there with a -20 to -31cc dished piston. Mines right around a 9.0 SCR with the -31cc piston and the same combustion chamber size. If you don't plan on much more boost, JE makes a nice off-the-shelf -22cc extreme duty piston for boosted applications.

[Lt1_8U]

thats a great site with all the info and pistons thanks. now i saw that they have a 383 with -33cc bore is 4.030 and the rod length is 5.7. now the stock rod length on a 350 smallblock is 5.7 so whats the difference if i go with the 383 pistons that are the same but have a 6.0 length? i would imagine that involves a lot more machine work and that would make it a stroker?

[Blackbirdws6]

thats a great site with all the info and pistons thanks. now i saw that they have a 383 with -33cc bore is 4.030 and the rod length is 5.7. now the stock rod length on a 350 smallblock is 5.7 so whats the difference if i go with the 383 pistons that are the same but have a 6.0 length? i would imagine that involves a lot more machine work and that would make it a stroker?

A 5.7 rod will move pin down on the piston, giving you more "meat". The stroke is dependent upon the crankshaft so for the 383, you would go with a 3.75".

For a 383, the machine shop is going to bore the cylinders and clearance the block for the longer stroke of the crankshaft. They should check and do a lot more but thats the basics.

I really think that you need to stick with a 355 build as it will reduce your cost, machine work, parts costs, etc and still leave you with a car ready for boost and plenty of power. Stock crank, forged compstar rods, forged JE/Diamond/Mahle 2618 material piston, good rings, and a cam suited for a blower.

[Lt1_8U]

oh gotcha, thats true a 355 sounds a lot cheaper and easier to do. i have to get my block checked out to see if there was any damage, the only damage i saw was at the bottom of the bore it has a small chip in it. i have to see if they will sleeve the cylinder or fill it. i also want to have the head vacuum tested on the side where the rod broke.

[Lt1_8U]

http://www.competitionproducts.com/Compstar-4340-Forged-H-Beam-Rods-Chev-SB-LJ-5700/productinfo/CSA5700DS2A2AH/

http://www.jepistons.com/ShoppingCart.aspx?CartItemAdded=Product+Was+Added+ To+Your+Cart.

do i just choose the rod based on the length? being 5.7 so its stock length just forged. and also i was curious if there had to be any machine work to the block or crank for these new rods? i know the block needs to be bored

[Pampered-Z]

If you do a search there was a good decussion some time ago and rod lenght and the effect it has on TDC/BDC = Piston dwell, directing force down the rod, cylinder wall stress etc.

The crank throw remains the same, the lenght of the rod will effect piston design to properly locate the wrist pin and provide clearace to th crank throws. You cannot use a longer/short rod to effect compression. a 5.7" rod requires one desing, a 6.0" another.

If you eally want to get into it, You can buy some books about building a SBC (another search that would yeild a good listing ), Yurick and Lingenfelter are two that I have referenced allot, so you understand the effects of rods, and also the designs, H-Beam, I-Beam etc. weight locatin Rod vrs Pistion, Rod lenght effect on Torque vrs RPM, And after all that reading,

But I will say that rod lenght doesn't have a clear one is bette then the other, many builders differ on opinion.

[Lt1_8U]

If you do a search there was a good decussion some time ago and rod lenght and the effect it has on TDC/BDC = Piston dwell, directing force down the rod, cylinder wall stress etc.

The crank throw remains the same, the lenght of the rod will effect piston design to properly locate the wrist pin and provide clearace to th crank throws. You cannot use a longer/short rod to effect compression. a 5.7" rod requires one desing, a 6.0" another.

If you eally want to get into it, You can buy some books about building a SBC (another search that would yeild a good listing ), Yurick and Lingenfelter are two that I have referenced allot, so you understand the effects of rods, and also the designs, H-Beam, I-Beam etc. weight locatin Rod vrs Pistion, Rod lenght effect on Torque vrs RPM, And after all that reading,

But I will say that rod lenght doesn't have a clear one is bette then the other, many builders differ on opinion.

thanks for the info, i just went out and purchased a builders book and i found one that my dad had and im comparing the old school ways to what we have now, i spoke with my machine shop and he gave me some tips as well but all in all it looks like machine work to the block including bearings and putting the pins in the pistons, having them balanced and blueprinted with run me about 650.00