First real test drive today, after V8 swap.

[DeCaff2007]

For those that don't already know: 89 RCSB K1500, 5-speed, 5.7L V8 swap, aluminum heads, and Hedman headers.

I got the front end and suspension all back together yesterday. I actually renewed the registration and added this Heap to my insurance .

Cranked it this morning and it fired RIGHT up. I let it sit and idle and warm up for a bit, then took it out around the block a few times for a test drive. I'll be bringing it to the inspection station later today, maybe.

Here's the good and the bad:

Good: Starts right up. Goes in gear fine and seems to drive normal. It seems that the lights/horn/turn signals/wipers/yada yada... all work fine. I don't see any major leaks and it doesn't overheat.

The Bad: The wheel alignment is WAY off! The steering wheel is upside down and I can feel the front tires fighting each other, so much that it's difficult to keep it in a straight line down the road. I was going to get a 4 wheel alignment anyway, so the inspection station can fix that.

This thing is WAY under powered! I didn't expect NASCAR performance, but downshifting and flooring it produces almost no power. Almost like the timing is still retarded??? I would expect lack of power like this from a miss or a vacuum leak. None of which I appear to have.

Potentially very Bad: Upon startup, the oil pressure is near pegged. I expected this. As the engine comes up to operating temperature, the oil pressure gradually drops, and tickles the under 10 psi range. It then intermittently flashes the "Check Gauges" light. If I rev the engine up a little bit, the oil pressure jumps right back up to the 40 - 50 psi range. Wouldn't a bad sender be either ZERO or PEGGED? So that's the only real problem. Oil level is normal, according to the dipstick.

Oh, and even though the fuel pump/sending unit is BRAND NEW, the fuel gauge STILL does not provide an accurate reading. The gauge easily fluctuates between 1/4 and E, depending on how spirited my driving is.

I'm most concerned, however, about that oil pressure. Any suggestions?

 

[95burban]

Install a mechanical oil gauge

 

[RichLo]

Was it junkyard bottom end? Did you measure the bore when you swapped the aluminum heads? Sounds like a 305 with oversized tires, lol.

Can you post a link to your build thread?

 

[Drunkcanuk]

For those that don't already know: 89 RCSB K1500, 5-speed, 5.7L V8 swap, aluminum heads, and Hedman headers.

I got the front end and suspension all back together yesterday. I actually renewed the registration and added this Heap to my insurance .

Cranked it this morning and it fired RIGHT up. I let it sit and idle and warm up for a bit, then took it out around the block a few times for a test drive. I'll be bringing it to the inspection station later today, maybe.

Here's the good and the bad:

Good: Starts right up. Goes in gear fine and seems to drive normal. It seems that the lights/horn/turn signals/wipers/yada yada... all work fine. I don't see any major leaks and it doesn't overheat.

The Bad: The wheel alignment is WAY off! The steering wheel is upside down and I can feel the front tires fighting each other, so much that it's difficult to keep it in a straight line down the road. I was going to get a 4 wheel alignment anyway, so the inspection station can fix that.

This thing is WAY under powered! I didn't expect NASCAR performance, but downshifting and flooring it produces almost no power. Almost like the timing is still retarded??? I would expect lack of power like this from a miss or a vacuum leak. None of which I appear to have.

Potentially very Bad: Upon startup, the oil pressure is near pegged. I expected this. As the engine comes up to operating temperature, the oil pressure gradually drops, and tickles the under 10 psi range. It then intermittently flashes the "Check Gauges" light. If I rev the engine up a little bit, the oil pressure jumps right back up to the 40 - 50 psi range. Wouldn't a bad sender be either ZERO or PEGGED? So that's the only real problem. Oil level is normal, according to the dipstick.

Oh, and even though the fuel pump/sending unit is BRAND NEW, the fuel gauge STILL does not provide an accurate reading. The gauge easily fluctuates between 1/4 and E, depending on how spirited my driving is.

I'm most concerned, however, about that oil pressure. Any suggestions?

Many years ago, 98-99ish, in my 91, I came to a stop light and saw a light como on, it was the check gauge light. I saw I had zero oil pressure. Oh crap!!! I revved it and the pressure came back up. Figured I have to get it into town and off the highway so I just kept going, the pressure stayed normal while driving, but zeroed at idle or stopped in gear. Went to work, about 5min away, didn't overheat or sound weird. So after work went to the parts store, got a sender, changed it and all was/still is good.

 

[DeCaff2007]

Was it junkyard bottom end? Did you measure the bore when you swapped the aluminum heads? Sounds like a 305 with oversized tires, lol.

Can you post a link to your build thread?

No, I got whole engine from the corrupt Marketplace. Had a machine shop do all the normal stuff they do.

Trust me, it's not a 305. Even so, my 83 Grand Prix is equipped with a 305 from the factory and still has more balls than the RCSB.

My build thread? Uhm, it's somewhere in here: https://www.gmt400.com/threads/4-3l-to-swap.59181/page-12

 

[DeCaff2007]

Install a mechanical oil gauge

I wouldn't mind doing that. Any suggestions or maybe even a link?

 

[Erik the Awful]

The Bad: The wheel alignment is WAY off! The steering wheel is upside down and I can feel the front tires fighting each other, so much that it's difficult to keep it in a straight line down the road. I was going to get a 4 wheel alignment anyway, so the inspection station can fix that.

This thing is WAY under powered! I didn't expect NASCAR performance, but downshifting and flooring it produces almost no power. Almost like the timing is still retarded??? I would expect lack of power like this from a miss or a vacuum leak. None of which I appear to have.

Get a tape measure toe-alignment ASAP. That will at least allow you to test drive without the tires fighting each other and robbing all your power.

 

[DeCaff2007]

I appreciate the reply. It's already at the alignment shop. No more guess work and I NEED my garage open.

Are you serious about that robbing power?

 

[Erik the Awful]

If your alignment is seriously off, yes. But don't expect miracles when you get it back, more likely you have an issue to track down.

 

[Schurkey]

Erik the Awesome saved me a bunch of typing. If the alignment was that far off...yes, it can really kill perceived power. All that horsepower is going into scrubbing the tread off your tires. As he said, there's probably more diagnostics to do, but alignment is the first step.

And...CONGRATULATIONS on getting to the "first test drive" point. At some point SOON, (i.e., as soon as the truck is safe to drive) you'll want to hammer the throttle on the highway to "seat the rings". You'll want to whack the throttle open as far as you can WITHOUT DOWNSHIFTING from OD or at least 3rd gear. The perfect application would be overdrive + torque converter clutch engaged; but I don't think that's realistic without playing games with the transmission. Point is, you want to be in the highest gear practical--not first gear, not second gear. Accelerate to as fast as you feel safe--which might be the speed limit. Pull your foot off the gas, coast to your starting speed, and do it again...and again...until it stops being fun. The first 2--3--4 times you do this will probably be "enough" to get the rings in proper contact with the cylinder walls...which is why I do it about a dozen times.

In a perfect world, this is done on the engine-dyno immediately after flat-tappet cam break-in (potentially DURING flat-tappet cam break-in) but for those of us without dynos, it goes out to the highway as soon as practical.

Yes, the oil pressure is troubling. A "temporary" mechanical gauge, or a trusted aftermarket electric gauge to double-check the factory gauge, wiring, and sending unit is strongly recommended.

I put a GM "service replacement" crate engine in my '88 back around Y2K. A week or two later, I had frightfully low oil pressure on the factory gauge. That was my first of many experiences with the horrible, high-failure '88 style oil pressure sending units. I'm probably on #4 currently.