StealthElephant

The motor came out the 2nd time because it leaked oil, and I had it completely remachined/cleaned since the bearings showed metal had run through the engine.

It's still leaking oil, so it's coming out for a 3rd time so I can redo the oil pan/timing cover to stop the leaks once and for all (1 full tube of RTV later, I've just accepted that the engine has to come out).

My friend recently built a SBC for himself, and his doesn't leak, so hes going to do it for me.

Now my second concern is should I replace the pistons and/or cam.

I have no idea what is wrong, if I have cosmically bad luck, or if I just need to never touch an engine again. Either way, I'm getting 8MPG with lockup. I bought a brand new MSD Probillet distributor. I took it to my machine shop told them my engine build, they put it on a distrib machine, and dialed in the advance curve. 20* mechanical @ 2600 RPM. I run 14* initial timing. My idle is rock steady @ 750RPM in neutral, 625 in gear. Once she warms up, it idles like an EFI car.

MSD says the vacuum advance gives 10* advance @ 15" of vacuum, unadjustable. Well I get 16" of vacuum on the highway at 65 MPH, however my fuel milage tells me that the vacuum advance isn't working. I used to get 12MPG without lockup with my old accel distrib before the 2nd rebuild, nothing changed between the rebuilds as far as parts that would effect how the engine runs. Either way, paying 2.28$ for Sunoco 94 is getting old, it's guzzling gas, and I'm always dancing on a fine line with the compression as high as it is. Should I just get flat top pistons?

Even if I manage to figure out why I'm getting 8MPG, will I save myself headaches if I just buy the new pistons and lower my compression?

I plan on putting in a higher stall converter when I pull the engine out so I didn't know if going with the 274XE cam would do any REAL WORLD help. People just carelessly throw words like "bleeding off cylinder pressure" and other crap like that. With the 268XE cam the car idles great, drives fine. Would the 274XE help at all? Would it do me any good as far as performance or streetability? Even if I lost a small amount of idle quality thats not as big a deal if it would help the engine run better in general.

Dave

rangelec

what is the rest of your setup? gears? etc. I have an 86 Z28 350 with vortecs, hot cam and a 750 cfm edelbrock 3.27 gears 26 mpg 3.70 gears 21 mpg at freeway speeds with Tremec 5 speed. And it runs high 12's! My compression is 9.4:1 stock 97 chev pickup block and pistons

5.8L Camaro

Mabey the problem dosent lie within installing the oil pan/cover, but the pan and timing cover themselves. Get new ones.

StealthElephant

The stock pan/cover leaked after the 1st rebuild, 2nd rebuild included brand new oil pan/timing cover and a one piece gasket.

I was told aftermarket pans don't seal well, but I really didnt' have much choice since the stock one was beat.

I have 3.23s, everything else is in sig.

kretos

get a stock replacement

SLEEPER 86

sounds like you are crankin things down too tight and deforming the lips of the cover and pan,take the ratchet off and just use a socket extention to tighten those bolts.you just need to tighten enough to compress the gasket a bit.
Eric

kevinc

Or...and this is just a thought...use a torque wrench and tighten them to spec?

ljnowell

Who uses a torque wrench on valve covers or an oil pan? Or even a timing cover? I never have, and they never leak either.

Streetiron85

I've never used a torque wrench on cover or pan. But it sounds like it might be a good idea in this case. Possibly he doesn't know his strength.
In addition to that I highly recommend a product called "Right Stuff" (Not Great Stuff). The only trouble with Right Stuff is, if youre unlucky and you have to redo your engine again, the pan will be deformed if you have to remove it once more after putting it together using right stuff.

As far as your mechanical and fuel consumption problems, there's clearly something that's being overlooked.
Maybe you're reading the wrong books. Repair manuals sometimes fall short of covering all the bases.

You're having a variety of problems that each need to be addressed individually.
I think you'd have better luck getting answers if you didn't try to get all your questions answered in one thread.

StealthElephant

The funny part is, I did torque EVERYTHING with a torque wrench. Oil pans are rated in inch pounds, I did it. The 1 piece oil gasket I have has plastic rings in the bolt holes which limit you from overtightening.

As for fuel economy. I don't know what else I can do. I am using a brand new MSD probillet HEI unit that was curved and reweighted by a speed shop on a distrib machine for my engine setup. My initial is set where everyone has told me it needs to be (14-16*). The MSD manual says 10* vacuum advance @ 15" of vacuum. I have 16" of vacuum at highway speeds, so I have no idea what the problem is. The engine idles nicely, has good response, which is whats annoying, it's not as if it's running poorly, everything is good except that it leaks and gets 9 MPG.

The sad part is, the old Accel distributor that was all screwed up (I reweighted it myself like 3 times, as opposed to the MSD unit which was redone on a machine so the exact curve and timing amount could be seen) but the Accel unit was giving me almost 12MPG with no lockup. Now with this MSD unit I'm getting 9 MPG with lockup. Pretty damn pathetic. The only thing that changed from the 1st rebuild was the distributor, oil pan, timing cover.

Streetiron85

You can buy a tool called a Mityvac, that's a hand held vaccum pump that makes it easy to check your timing curve.
Ever seen one of those? They're not that expensive.
You can use a Mityvac and a degreed balancer cover which is also pretty inexpensive, and a timing light to find out exactly what your timing curve is with the dissy mounted on the motor and the engine running.
I'd suggest a vaccum ga if you don't have one already.
With those tools, at least you ought to be able to eliminate your ignition system as a trouble source and move on to the next problem.

ede

got all the bolts in the front of the engine? i'll bet not.

StealthElephant

The smog pump bolt hole is plugged.

It's crazy, for a long time I could not figure out where the oil was coming from out front. I could run the engine and lay under there and not see where oil was coming. Well my buddy's dad came one day, he layed under and watched, after I shut the engine off, oil starts leaking past 1 of the timing cover bolt holes. Like, a good 10 drops just starts pouring out of one of the timing bolt holes. It was nuts, with the engine running, no leak from the timing cover, yet you shut the engine off, and one of the bolts starts dripping.

SSC

Dont mix RTV and gaskets use one or the other, except on the small spots in the corners. Your chevy dealer can get you a replacment OEM pan, yes they are still avalible for 2 peice RMS blocks as well. Some engines are prone to leaks to matter what you do but usually they are very small and not noticable for months. Use thread sealer on all bolts.

The higher stall converter will reduce fuel economy. The XE 274 wont help either, I'd suggest a smaller cam even if it doesent look good on paper. Ive personally switched my off the shelf choice to Crane cams. Crane seems to give more accuracy in what they advertise. A Crane 266 H, is a great NA performance cam thats works in the usable RPM range.

What kind of heads do you have? If they have fairly small chambers and your dead set on using them again go with "DISHED" pistons and keep the compression low. High compression setups are great if you can run preimium fuel and all the advance you need but if your droping timing to keep from detonation its not worth keeping the compression up.
Theres lots of people who hve gotten away with high compression setups but it doesent work for eveyone.

StealthElephant

I'm using 64cc Vortec heads and sealed power 10.7:1 .125 Domed pistons. I've been contemplating having the piston's dome milled off to bring me down to 10:1. That should give me more breathing room with timing, and as long as I keep running Sunoco 94 I should be good.

Any idea on the price of the OEM replacement pan? I've heard that sometimes they charge you ridiculous price (like 200$)

Streetiron85

I haven't searched to see if guys say they're any good, but summit has pans for $23.
Shipping is free til Christmas too.
A set of hyper flattops would cost less than having your old pistons milled, I'll bet.
RTV is some pretty good stuff, but it doesn't touch "RightStuff" for sealing.

my3rdgen

I will second that! "Right Stuff" is just what it says. We use it at work and it keeps the water out of all the j-boxes, pekker heads, and electrical panels. Works great.

65panhed

Haven't you ever heard of stealth elephants auto service/we pay the tax/thanx very much..........Knocks off 20-40 %

kevinc

Hold it...aren't you the guy who put on chrome stuff and didn't scuff off the chrome from the sealing surfaces?

I have some recollection and your username rings a bell...

If you torqued them correctly they shouldn't be warped, just check them w/ a straightedge, if they pass then scuff 'em down to bare metal where they seal and you're in business.

StealthElephant

Yep that is me.