Fuel/Oil additives...post 20 year engine sit

[Orange72ChevyC10]

I have my truck running after 20 years of sitting, I had to soak all cylinders in mystery oil to get compression back, etc...

My question now that it idles, is there a good conditioner for fuel or oil additive.

SeaFoam, Restore, etc!?!

I'm trying to diagnose a loss of power around 2,200 rpm...truck basically falls on its face. It could be tied to timing but I'd like to address the above regardless.

Stock sbc350, "new" quadrajet, HEI

Jason

[imjeff]

I'm assuming you put fresh fuel in. The ethanol (a solvent) will clean your tank out sloshing around. Unfortunately, it will clog fuel filters until all the old varnish works through. Kind of sounds like she's fuel starved under load.

[wreckedchevy]

all the troubles I ran into after letting it sit for 10 years were in the carb, once I got that all cleaned out it run's like a champ. I immediately put fresh oil in it and did it again after about 200 miles.

[imjeff]

Unless you put a new fuel tank in it you will stir up sediment and varnish that will clog your fuel filter, not your carb.

[Orange72ChevyC10]

Fuel tank was acid bathed and is pushing clean fuel. I get what sounds like small back fires out of the carb under load and then it falls on it's face.

Thanks for the replies so far, I will take any and all advice. I got a digital timing light to set total advance timing as the factory mark maxes out at 16'

[70cst]

Orange72ChevyC10 .... here is a bump for you.

Oh yes ...

to the forums and from Ohio.

Sit tight as others will chime in

[Ironangel]

You've described a lean condition, most probably clogged filters, fuel bowls and jets clogged. A cleaning while installing a carb kit along with a new inline filter will most likely take care of the backfiring and let her wind up and blow the cobbs out of intake and the mice out of the exhausts...Dont waste your money on SeaFoam, BerryMans Chemtool B-12 is as good or better for less than half the cost. I'm a firm believer in Marvels Mystery Oil as well. Drain the old oil and fill her up with your favorite zinc containing oil along with a good 16oz shot of Mystery Oil and run her for a one or two hundred miles. Check your rear end grease,(change it) flush the cooling system, bleed out the old brake fluid, and power steering fluid if it has it, new plugs, check that timing and drive her like ya stole her! Take a grease gun with ya when you crawl under her...Oh yeah, if shes got an automatic transmission, might as well get a screen & filter and fill her with fresh Dextron III. Fresh gear lube if shes a stick.

[Orange72ChevyC10]

Thanks 70cst...it's been a fun first project truck for sure.

[Orange72ChevyC10]

Thanks Ironangel, and yes the # of grease zirks has been surprising! changed steering gear, trains filter and gasket, brake pads, booster/mc, bled brakes...and ps it has a reman'd carb (2months old)...not saying it isn't clogged just strange.

If it helps, at idle I can floor it and get it to 3,500+ rpms with no issue, it's only while in gear going down the road.

[MagmaJct]

Originally Posted by Orange72ChevyC10

If it helps, at idle I can floor it and get it to 3,500+ rpms with no issue, it's only while in gear going down the road.

Power is essentially RPM * torque. With a lean mixture, you'll get great RPM, just no torque.

You had the tank acid washed, what work was done to the carb? Gasoline "rots" leaving a white gummy like substance that will clog any small passage in the carb.

I'm only familiar with VW Solex carburetors and the Edelbrock 1400 series carbs. How many barrels? Likely a partially clogged main jet, power jet, in the primaries or the secondaries.

Good Luck, and keep us posted! Nothing like searching old posts to solve a current problem, and not find a "hey here's how I resolved it!" (I know, I've been guilty of that!)

[Orange72ChevyC10]

MagmaJct, thanks for the response, the carb is a new reman from the parts house, tank and fuel lines were cleaned and a new fuel pump was added to the mix.

Ok so here's the latest, I set my idle timing at 10' btdc, and turned the adjustable vacuum screw counterclockwise until it stopped then test drove, driveability improved...

I'm now 5 turns to the right on Vaccum advance adj, with more fine tuning to go.

I went to set total advance timing and I'm all in (Vaccum adv plugged off) by 2100 rpms. Oh and I fried my digital timing light in the process (best $15 protection plan I've bought)...so I haven't set total advance timing.

Once I set total timing I'm going to work on the carb mixture screw and see if I can get it dialed.

Should I be all in at 2100 rpm? I've got the heaviest springs on the dizzy.

[69chevy lwb]

Take a look at the ignition system. I had an identical problem on my 292 and the cause was the breather was pulling oil into the intake and ruined the center 2 plugs. It would run great until you put any load on it then it would only rev to about 2k. I replaced the fuel pump and filters along with going through the carb and replacing the distributor before I figured out the issue. Which sounds real stupid I threw all that money at the problem without checking the plugs to see what the problem was

[Orange72ChevyC10]

69 chevy... by breather are you saying the pcv valve is pulling oil? Not question your logic just looking for clarity. Pic of motor bay added for your reference.

[69chevy lwb]

Yes I was getting blow by due to failing rings and on the 292 the pcv vents into the center two cylinders. Do a compression test and check plugs along with fuel pressure then you can narrow it down don't assume it's anything test it all you might just save yourself down the road

[Orange72ChevyC10]

Thanks will do

[69chevy lwb]

No problem. I hope your problem doesn't turn into a ls swap that's not the best way to solve your problems!

[Orange72ChevyC10]

It might be. Ha

[LockDoc]

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Have you checked the small filter in the carb inlet? It catches particles that the inline filter doesn't, so the inline filter can look clean and the carb filter will be clogged.... Just a thought.....

LockDoc

[truckdude239]

You said it was a parts house reman carb i went though 8 of those none no good. I bought my last one fron nationalcarburetor.com im betting you have a bad carb

[Orange72ChevyC10]

Thanks for the input all, I will post updates soon