The Stovebolt Site Forums The Shop Area Engine Shop Fix 350 or O'haul worn 292?

I've got a 70 350 that has a problem. It has a rough idle and backfires through the carb, an edlebrock 4bbl, when its accelerated. I've put in new plugs, wires, rotor, cap, its an HEI dist.
I've checked the timing over and over. Rebuilt the carb, no change, can't find any vacuum leaks. I pulled the lifters, then the cam(stock hyd. cam) and can't find any damage there, pushrods roll straight, rockers seem to rock ok, compression runs 127 to 151, not great on that, but still??? I'm stumped. Checked all the vacuum hoses, new fuel filter, pump, holy cow!

Got a well worn(200K+) 292, in a 64 1/2t, been in family since new. Compression 72 to 119, burns gobs of oil, but starts and runs reliably, long as its got oil.

Fix the 350, overhaul the 292, for a 52 1/2t ?
About what would these cost? each?

The thing is too that on the 350 when I wanted to change plugs, had to loosen the left mount and jack up the engine so it would rotate a bit to get the plugs on drivers side, not fun. A straight 6 you can just get at 'em nosweat, also I wodn't have the exhaust manifold all over the steering box. Would have to mod the drive shaft, already an open type, though probably, i guess.

If it sounds like iI'm flustered, I am.
harry

Harry, Thanks for the support. Sound like you've got some issues. Hope someone is able to get it worked out for you. Hey you got any pics of your 52? JED

Jed

Wife and I are thinkin about getting one of those digital camers where you can like download the picture to the harddrive. Then were giong to hafta learn howta post the things to the web thing for this place, but so far no usable pics that we know how to git on to this thing. Later I hopeta. DO you have em of yours? My ol 52 needs one pile of body work, the rear of the cab both sides rust and my left front fender is squorshed from a lady who slid on the ice last winter into it. Darn! She kinda went down the left side and put a whack on the left rear to. So it goes.
harry

It sounds like you need a valve job. Sticking valves can cause the problems you're having, and the somewhat low compression is another symptom. How much mileage does the engine have? If it's a high-miler that hasn't been built lately, you'll be better off doing a complete engine job, no matter which engine you choose to use. The 292 is going to need a complete makeover, too, pistons, cam, reground crank, etc., so the cost of building either one will be similar. Parts for the 292 will probably cost more than the 350. Good luck!
Jerry

H R L

I had the 350 overhawled back in 91 and then sold the truck to a buddy who wanted to fix it all up. Well, he had family problms an it sat for long times witout even being fired up. Then he sold it back to me becaus it was doing the poppity backfire thing and money reasons, about a year ago. It seems it has not ben driven more than about 2500 miles or so. I would think you are right about it havig valve problems, maybe their stuck? Before I pull the heads is there any way to unstick em?

Probly I'm going to hafta do a valve job thouh? I was fraid of that. Thank you for helping and if you know how they might git unstuck I'll sure liste n and try it.

harry

Here's a fix worth trying, before you yank the heads. Get a can of Kroil, made by Kano Laboratories in Nashville, TN, and soak the valve stems from the top by removing the valve covers and squirting the valve stems liberally with the Kroil. Let it sit overnight or longer before starting the engine. Then add about 1/2 pint to the crankcase oil. It can't hurt it, and I've freed up some totally stuck engines by putting Kroil in the cylinders and letting it soak for a few days. It will smell a little funny while it's running, but 500 miles or so of operation, then change the oil and filter, can work wonders with one that's been sitting for a while! Good stuff!

www.kanolabs.com

Hmmmm- - - - -
Just looked at their website again, and they've got a specific additive for your problem, "Kreen". It can be used as a gasoline or oil additive to address carbon or rust problems on valve stems, etc. I've never used it, but I have used their products for over 25 years, and haven't found a bad one yet!

Jerry

H R L
,
Thank you again. Im going to git some Kroil tomarrow at the NAPA here and try soaking it like yuo said for a coupla days, see what happens.
Again, thanks.
harry

The question of rebuilding a 6cyl as opposed to switching to a 350 seems to come up a lot. Or in this case rebuilding a 292 as opposed to rebuilding a 350. You've got that 350 far enough apart and possible valve job anyway.
I used two price sources. Speed-o-motive has machine prices on their web site and Kragen (Parts America) has parts prices on theirs.

Cylinder boring & hone - $50/cyl...........6=$300 8=$400
Surface block $40 each side................6=$40 8=$80
Cut head for Hard valve seats $75/hd....6=$75 8=$150
Valve seats....................................need 6 need 8
Cut for oversize valves......$75/hd........6=$75 8=$150
New valves...same for 6 or 8..............need 12..need 16
Grind crank.......................................6=$95 8=$95
Magniflux crank.................................6=$45 8=$45
Resize rods....$9.50/ea.......................6=$56 8=$76
Hang rods on pistons...$7/ea...............6=$42 8=$56
Balance engine..................................6=$125 8=$150

As you can see, most machine work cost is in the setup. More pieces, more setups, more surfaces and more costs.

Speed-o-motive has several engine kits. Here are two, only to show difference between 292 and 350.
A "Deluxe Master Engine Kit" includes; cast piston, rings, rod & main bearings, oil pump, timing gears, cam & lifters and gasket set.
292 is $475 350 is $330
"Crank Kit" includes; piston, rings, rods, R & M bearings and crankshaft.
292 is $510 350 is $470
The 292 prices are higher in engine kits for all the outfits that I've checked, if they even have 292 kits at all. Most of the difference seems to be in the pistons. Six, 292 piston prices are well above eight, 350 pistons. Timing gears for a 292 are twice stock 350 and still above average 350 double rollers.

Kragen 292 and 350 prices

Pistons, cast Clevite........................6/$28=$169 8=$98
......... stock LPG 9:1pistons..............6/$45=$270 8=$0 already at 9:1
Rings, cast iron...............................6=$52 8=$20
Cam bearings..................................6=$26 8=$24
Main bearings.................................6=$35 8=$30
Rod bearings-same part# $3.19/ea......6=$19.14 8=$25.52
Oil pump........................................6=$18 8=$18
Brass freeze plugs.............................6=$8 8=$9
gasket set......................................6=$48 8=$46

As you can see, they will clean your clock on the pistons. The other parts are not that much different if you stay stock. I forgot to check cam prices. Stock 6cyl cams are usually higher than stock 8cyl. Hyd lifters are the same. You just need 12 or 16.

Higher parts prices balance lower machine prices. Of course your local machine shop may have other ideas.

If you don't let high performance chrome plated muffler bearings and delusions of racing a Viper cloud your judgement, you can probably get by cheaper with a stock 292 rebuild.
One other thing to remember. If you have to bore and get new pistons for either, you're getting up close to 350 crate motor prices. My one year old Classic Industries catalog has reman prices of $1380 for a 292 and $1200 for a 350. That option changes if you have to add core($250) and shipping, because you don't live near a similar outfit.

Depending on when the motors were built these expenses might not be required. I have several 350's built in the no-lead era that wouldn't need this. I don't know when the last 292 was built, but could it already have hardened seats?

And these two operations account for must of the difference in cost.

The 292 was still available in 1986....

Wow, thankyuo guys,

I've printrd outyour alls advice and comments. Its encoraging.

The 292 is what came in the '64, so guess its got no hardened seats in it.

Going to try freing up the valves on the 350 first, since its already mounted in the '52.

Oh, the wife is going to help me with the spelling and grammar(darn, she made me use a dictionary to spell grammer right, she says use "correctly" for "right") starting now. She says my english is lacking, I woulda( I mean, well, she means I would have) just said bad. This my third one, after the lawyers on the second one I guess I'm learnin' my place, she's sitting here watching me, you know what I mean? What's a dangling participle? My god it's(just got trounced again, I wanted to say its) got 4(this way I don't have spell 4) syllables in it, the "participle" thing I mean. ( Now she's making me go back and put quotes on "correctly" and "right", be back in a minute). Whew!

Well she's a good ol' gal. Women are o.k., I know a guy that owns one. He says some of them can be trained.(She's not smiling) Lordy I hope so, I'm scared. She says I'm a male showvenist(spelling?), I say oink to that. All I know is is that if I hadn't spent all that time in the principal's office I probably would have never made it through school. Boy, is this what they did in class? And I thought the principal was rough, I would have died in class. (Now she's on my case about using two is'es in a row, seems to me it reads nicer with two is'ses in a row). She does like these old trucks though so I will try to learn spelling, punctuation and all this other stuff, like grammar.

Well I'm going to go before I get hurt. :p

harry