Lumarus

Ok i may be dumb here n overlooking something simple or so. Idk, but i am some what newbie on mechanic work. Just recently built my own engine and installed it in my car. Im having a lil issue. Im also knew to this site so i hope im posting this in the rite forum. Im sure ive come to the rite site tho lol. Lots of info on here, been reading for the past 2 hours on here. but anywho here goes:

First off a lil background: -MY car is a t-top 1982 z28 , ive taken a running 1989 TBI 350 bored to 355, took a running 1997 vortec 350 and installed its vortec heads, push rods and roller lifters in my 89 355. installed a mild ProTek cam ((280/290 degree Advanced Duration, 214/224 Duration @ .050", .295/.310 Cam Lift, .443/.465 Valve Lift with 122 Seperation)) put dual pressure valve springs in. Max lift .500. Put on Vortec edelbrock intake, and 600 edelbrock carb. Has a street fire HEI distributor with vaccum advance. Behind the motor is a t-5 5speed tranny, and then factory limited slip rear end.

Second, My issue: -Ok this motor still has less than 50miles on it. It backfires thro the exhaust sometimes and RARELY it backfires lightly thro intake. i was told that was normal. -_-; normal to backfire thro intake? ive check pushrods, there all fine, ive replaced Plugs Multi times cuz they fowl out after a few days of running the car. Thought i was getting too much gas. i had a 750 carb on so i replaced it with a new 600 carb. and 2inch spacer. still fowl out after a while. I have an electric inline fuel pump that puts out 7psi max. i have fuel pressure regulator that i leave set at 4 1/2. If i put it on 2 it wont idle, so i set it on 4 1/2. The regulator only goes to 5 1/2. the carb is adjusted to factory settings. I have vaccum advance hooked up to driver side port on carb for vaccume all the time. i wana believe my timing is set rite but im not 100%. a mechanic i trust went by ear when adjusting the distributor. said he set it just a hair above TBC for advance timeing. Also my car has low throttle response! If i start it it fires rite up no hesitation. idles fine, but if i throw my foot into the gas it bogs down then piks up with a vibrating missfire. Sometimes bogs down n dies. But if slowly put my foot into the gas it reves up no problem.

Third: Wat dah eff? any thoughts on my backfiring issure or my slow throttle response? ive checked for vaccum leaks, had several different people look at it. I have had it at a shop but i got burned out on waiting 3 months for the idiots to get to my car, and then tell me they broke my door handle n i gota pay them to fix it, and they charged me 250$ to fix my clutch pedal and put grease in my tranny! said ill just fix it myself. ...if i can. Im wondering if maybe my timing is wrong, vaccum advance is all wrong, or if my NEW distributor is faulty. cuz the vacc adcance canister is sumwat loose. it dont move up or down but if u push it side to side it moves like a 1/16 inch. not sure if thats normal or wat. anythoughts or suggestions may help.

Fourth: Just for kicks wat kinda HP do you think this motor may produce. (the closest dyno to me is over 200miles away in Dallas) Also Note that i have Shorty headers with header insulation wrap, No clutch fan its electric, Long neck water pump and serpentine belt system, No AC. My guesstimation whould be (Keepin fingers crossed) 350-400HP???

affliction1

sounds like ur timings off have it timed or retime it,what fuel 87 or 93 on hp id say around 350 ish

InfernalVortex

iTrader: (4)

For a general shakedown to get a new build going, I would just ignore vacuum advance. Keep it simple, eliminate possibilities for vacuum leaks.

Get a vacuum gauge and a compression gauge and a timing light. Between those 3 things you should be able to find something to help you get your car running well.

Did you get new plug wires? Are the terminals on the boots making good contact with your plugs?

TreeFiddy

What he said.

This is a huge blinking red light - what mech doesn't use at least a timing light? Sounds like it's set way retarded, would cause the backfiring and no power. Get a light and do it right! 36 deg by 3000 rpm - do a search, plenty of posts about it.

BTW, that's not a flat tappet cam with roller lifters, is it?

Lumarus

...whoops. nobody told me that crap. yes it is a flat tappet cam and i put in roller lifters. like i said "newbie here". Ive read online that i can be done but not suggested, loss of power n gas. So what should i do now? remove my intake and replace rollers with flat lifters n replace push rods? i also put on the dual valve springs. there max is .500. is that gona be to much pressure for flat lifters?

TreeFiddy

I've never seen the results of that, but it can't be good. FT cam lobes are ground with a slight chamfer front-back, to spin the lifters. Roller cams, the lobes are 90 deg flat to provide a flat surface to roll on, and the lifters must not spin. So you'll have rollers digging one edge into the cam lobe and carving grooves, and trying to spin.

When you say dual valve springs, do you mean true dual springs, or just a single spring with the damper coil inside? A dual spring is not necessary for that cam, an old low-lift generic grind. Dual's would be helping to increase the damage caused by the rollers.

Maybe someone else can weight in here who's done this, but I would suspect the cam is trashed - sorry!

GSRacing

i agree with above i actually just had my engine builder on the phone and he said the cam is for sure trashed and you should never be aloud to build an engine again ... i told he to put his inside voice on no worries there but i would pull everything back apart make sure you didnt send metal through the engine get a correct valve train setup and re assemble

InfernalVortex

iTrader: (4)

Everyone learns these things eventually if they play with this stuff enough.

Go get a roller cam, inspect your lifters to see if they're okay and try again. Roller cam will make a lot more power for you too.

TreeFiddy

If the lobes are gone, it explains all the symptoms. I'm curious, what is the chance it got 50 miles, I thought it probably would have shot itself during breakin.

BTW Lumarus - did you try to break it in?

Lumarus

I have removed my intake to take a look-see at my lifters. i pulled them out and EVERYONE of them are still DAMN near perfect. BARELY any signs of wear! i took a light and shined it down on my lobes of my cam, slowlying turning the balancer the cam shows NO signs of ANY ware at all. ...seriously every lobe was like perfect. No scratches scuff or breaks. the car has only been driven roughly 70-100 miles. maybe ive lucked out and its all good? idk. Ive placed new hydraulic flat lifters in, im waiting on my vortec 1/8thik gaskets to come in the mail and ill be firing it back up. ....and yes my valve springs have the damper coil inside. but i was told my cam isnt trashed becuz of several reasons. ONE being that i didnt drive it long (but i did drive the **** out of it, idk, did good doughnuts lol) 2nd because of the dog bones holding the lifters in place keeping them from spining, 3rd because the lifters were self adjusting that not too much pressure was applied. ...idk but sumin has to be rite cuz there are NONE n i mean NO signs of damage anywhere. drined my oil, no metal on my magnet plug, oil filter was clean....idk lucky maybe. or maybe it just could have worked out fine. maybe not ment to be ran that way but just works, with loss of power. but im sure eventually it whould of came apart.

Lumarus

...another thought...FLC? may have a few flat lobes? ....should i continue with my new lifters or should u replace the cam? cuz i mean it may have no signs of ware anywhere but the points where the cam was made to spin the lifters may be smoothed out? but, if that were so whouldnt there be a lil bit of metal in my oil? the rollers on my lifters have no signs of wear, no scratches nothing...but is it possible the lobes are smooth flat all the way around....lol basiicaly turned into a roller cam just with egg shape lobes haha

TreeFiddy

Why are you trying to run a FT cam anyway, when you've got a roller setup? Like Infernal said above, rollers make more power and are better in every way.

Sounds like you may have lucked out, so far. However, FT's are really sensitive to any kind of slight damage, which will over time excavate the lobes, even if they look ok at a cursory glance.

Now you've added the correct FT lifters, on a used probably damaged cam - even if broken in correctly, I wouldn't expect it to survive long.

Then you've got all the hassle of oil zddp and additives. Also don't forget - you'll need longer pushrods for the shorter FT lifters.

Lumarus

Just a quick update for the curious. After removing the roller lifters i put in FT Lifters and the longer push rods stock lenght. Everything is majorly lubed up with lucas. My vortec gaskets came in and ive reinstalled intake n carb. waiting now for cylicone to dry for front n back intake gasket. ill post tomorrow my "Luck" as u can say. Hopefully all goes well. OH!! and reason y i left flat tappet cam in insted of replaceing it with roller cam is cuz for three reasons, one money, two more work, three the sound. not really much into the HP at this point, just wana have a good sound out my exhaust n cruse the hwy with my 315 to 325hp lol...

TreeFiddy

Well, it's your engine's funeral! If you are hell bent on sticking with flat tappet, at least get a new cam and break it in properly, and use a zddp additive. I think you are ignoring a major reprieve - enjoy your motor for as long as it lasts.

89RsPower!

Did you at least use new ft lifters and proper break in lube? How did the lobes look? Due to the difference in tappet shape I would be shocked not to see some serious gouges and really beat up looking lobes. Also didnt check to see if this was covered but you didn't use a cam retainer, spider tray, timing set for a roller engine or any other mismachted components in the build did you? Are you running the proper dist gear? If the lobes look somewhat ok just check to make sure they are all present and accounted for. Might want to use a dial indicator to measure the lobes to make sure they didnt start to wipe.. at any rate if you are putting it togather and hoping for the best make sure you start with new oil and a filter and change it again after cam break in. Was this engine machined at all? If yes was it decked and were the heads cut at all? If so make sure you use a pushrod length checker to be sure you're using the proper length pushrod. I'm crossin my fingers and hoping it all works out well for you, and cheap. Figured I would throw the pushrod question in since, much like your self, when assembling my first 350 I figured I could reuse the factory roller push rods, put it togather and it ran good for quite a while, that was until it broke a rocker stud while driving home one day. Turns out the excessivly long pushrods improperly loaded the rocker studs because I over looked something fairly basic. I got lucky and replaced just one screw in stud and custom length pushrods, due to the amount of material removed from the deck and possible height difference due to the use of aftermarket heads the proper pr's were much shorter than stockers.

Lumarus

Well, it fired up, and she roars pefectly! (for how long idk) but broke in cam...again. bahaha. at this point i know i have a eff up so y not just see eh? car seems to run fine, Lil hesitation on throttle but i played with the idler screws on my carb a while back before i realized i needed diff lifters and vaccum advance isnt hooked up yet... im hopeing the hesitation is cause by one of the other. or maybe not enuff fuel, i have regulator set on 4 after the inline fuel pump that puts out 8lbs of pressure. but was told the carb needs atleast 5lbs of pressure. idk, gota look that up. but i broke in cam, bout to change my oil again. and drive it a few days see how it does. lol im crossing my fingers too.