The Stovebolt Site Forums The Shop Area Engine Shop 292 update

Just wanted to update you guys on the new engine/tranny. Had fun this weekend. Got stranded twice. Had to have it towed home from one of the local Chic-Fil-A restaurants after the throttle cable was burned stuck by the exhaust header. Bad routing on my part. The cable was resting against the rear header. As I pulled away from the drive through I noticed that I had no accelerator! So I managed to piddle along in first gear at idle to an open parking spot. Thank God for Triple A!

Went to the local AutoZone and picked up a new cable, installed it, routing it in a more intelligent manner and the accelerator works great. Throttle response is outstanding. The previous cable was a "Lokar" cable. One of their stainless braided cables. I never was able to get good response from it. The cable stretched and was not very flexible at all. And it cost 30 bucks! The new cable is a cheapie, 19.99 vinyl cable that works great. Very flexible and plenty of room inside the cable housing for the cable to slide freely.

Here's what's happening with the engine.

I turned down the idle mixture screws and increased the plug gap to .050. The plugs were sooty black after only about 150 miles. Fuel distribution is obviously not equal as the plugs got much more sooty from the rear forward. This is probably due to the design of the Offy intake, which slopes downward towards the front and upwards towards the rear.

But throttle response with the 500 cfm Edelbrock 1403 carb is outstanding. There are not flat spots and no noticeable bogging. Not even momentary. It's almost as if this combination of engine-intake-carb is factory preset. So at this point I think it's safe to say that a 292, bored .060 with a mild cam and headers is very comfortable with an Edelbrock 500 cfm 4 barrel carb. I haven't changed the float settings, nor the jets or metering rods. I have been contemplating leaning the primaries out one step (to eliminate the plug soot), but am a little concerned about being too lean. What are the symptoms of running too lean?

I put about 60 miles on the new engine yesterday afternoon. Acceleration is now impressive. I had no problems accelerating to interstate speeds, and actually had to back off the throttle a couple of times in third gear to avoid pushing the cars in front of me off the interstate. If anyone tells you that a mildly built 292 won't move a half ton pickup quickly they're lying to you. Trust me.

With the OD cruising at 70 is effortless. With the torque of the 292, getting to 70 is just as effortless. Anything over 70 though and I get an annoying vibration. It's almost certain to be the harmonic balancer. It's on "crooked" - but the odd thing is there is no vibration whatsoever in any gear (except overdrive) at any other speed.

I'm getting ready to change the oil for the second time. So far I've only run Penzoil 5w30 and would now like to go with the oil that I'll run from now on. I'm thinking of sticking with the Penzoil and bumping the weight up to 10w30. What do you guys think/recommend?

-ftyler

Fred, it's great you're enjoying the new engine.The 500 cfm carb is primarily designed for dual quad set-up and it's jetted rich for use a moderately tuned 6 cylinder.The Edelbrock tuning guide that came with the carb, shows the various combination of jets and rods to change the fuel mixture in steps.Look only at leaning the "cruise" mixture one or two steps, while keeping the power mixture the same.If you lean it out to far you will experience surging or flat spots when you depress the accelerator slightly at around 35-40 mph in 3 gear direct with a fully warmed up engine. Overleaning the part throttle mixture won't hurt anything for a short term while you are testing the new jetting combination.I wouldn't put much faith into plug readings, modern fuel additives may cause the plugs to run white even with a proper mixture and onece a plug is darkened,it won't lighten properly, so you can over lean by looking at the plugs in that case.
The vibration you describe seems to be independent of engine speed so look at the drive train, driveshaft balance or perhaps it's in the tranny itself, does it vibrate in 3rd direct at 70?.I notice on the A833 in my 51 truck, there is a sensation of increased vibration in OD around 45-55 mph, but it smooths out over 60 mph.Probably just the engine power pulses felt through the engine mounts.

I haven't tried 3rd gear at 70 yet, since the engine would have to turn over 3100 rpms to get to that speed. But I'll try it and see what happens. I guess if I get no vibration then it's almost certainly the tranny. Everything is silky smooth through the first three gears, even at higher rpms.

Tony there's no hesitation on goosing the throttle and no bog points. I did get a bit of a backfire when I went into the secondaries. Do you still think I might need to step down the primaries a bit?

-ftyler

Get the tuning guide and try it. If it drives better, great, and if not you change it back. If it is better, go farther and change it until it complains then back up a bit. Try rods first then jets. Changing rods is 5 minutes and jets is only a 20 minute job.

Nobody can tell you what it's going to like best from here.

As for the vibration, I've been reading that overdrives create some peculiar vibration issues. I'm ready to start playing with pinion angle to see if it helps. A recent HRM article was about a car modified by the GM Desert Proving Grounds. They were running 8 degrees POS pinion angle just to combat OD vibration. It sounds extreme, and may be a misprint, but I have read elsewhere that changing pinion angle may help. Wedge plates are an easy "try it."

Fred, you say the plugs are sooty black so it's running rich during normal driving, right? If you change only the rods like Chuck says,try to select ones that have similar smaller diameters to keep the high speed enrichment the same.The backfire from the carb when opening the secondaries is a temporary lean condition before the secondary jets can flow enough fuel.At the same time, the primary metering rods have raised into the richer power mode, so leaning the "cruise mixture" won't have any effect on this.

I plan on getting the calibration kit and going "1 stage" lean (about 4%). That only requires a metering rod change. Then I'll play it by ear from there.

Chuckthetruck sounds like you've had similar experiences with your A833 tranny huh?

-ftyler

Yes, slight vibration in OD that varies with speed. 75MPH and 85MPH are peaks in mine (2300 RPM and 2600RPM in OD). Other speeds are not a problem. Did wheels & balancing, u-joints & driveshaft phasing, new balanced driveshaft, so now I'm ready to give pinion angle a try.

Congrats on getting so much sorted out! Good to have a running ride.

IMHO, Pennzoil is possibly the worst major-brand oil on the market. Run anything else. There may have been a time when it was good oil, but that was long ago. It uses a very cheap, poor-quality package of additives, and generally breaks down quickly. Run Castrol, or Chevron, or darn near anything but Pennzoil.

Cheers!
George

George,

I've done a "Google" search and tried to pull up some information on Penzoil. So far all the information is about synthetic oil. And none of it is negative. :confused:

Do you have any sources of information regarding the quality of Penzoil? What do you run?

-ftyler

Having worked at a quaker state quick lube (which is also owned by penzoil) i can tell you the reps told me they dont even run penzoil in their delivery trucks, and they can get it for free. They chose to buy amsoil synthetic for their personal cars, and ran valvoline in their work trucks.

Castrol 10W30. Remember when the oil pump in my 235 failed? Oil provided enough cushion at 0 pressure to limp car off road, didn't ruin crank journals.

I use castol 20/50 and one bottle of STP oil treatment in my truck sure keeps it running smooth and quiet.

59Ptruck,

Thanks for the info, but I don't think I need to run anything thatthick in a new engine.

How much oil is that thing burning anyways?

Any other 'yay' votes for Castrol motor oil?

-ftyler

It doesn`t burn oil I drive 70 miles a day round trip to work. When I used a thinner oil 10/30 it would smoke a little and was noisy. When I built the 350 for my nova I thought that thinner oil for a newer motor would help it break in. But other drag racers I talked to where I live all run catrol 20/50 from day one. When the motor temperature gets hot any penzoil oil looks like water.

Sorry for the slow reply - been busy.

My source is Gordon Jennings. He's an engine design guy that has done car, motorcycle, miltary, aircraft, etc work. He used to write extensively for the car and bike magazines (Sadly, he passed away a couple of years ago.)

He once commented that, having reviewed the additive packages used by Pennzoil and a number of other major brands, that Pennzoil used the cheapest, lowest quality ingredients.

Gordon was an early adopter of the Internet; and has (had) a web page at: http://www.wheelbase.com/ I recommend it highly. Gordon was not a typical moto journalist; he was an engineer first, and if something was a piece of crap Gordon said so, and darn the advertisers.

Aside from that, given what a fleece-job Jiffy Lube, et, al, are, I would not use ANY product they sold. They are criminals, pure and simple.

Cheers!
George