Monty

We finally finished setting the engine up on the dyno yesterday and got it running. Unfortunately I didn't get to push the engine very hard or take any recorded dyno runs due to oil pressure concerns.

When we started it up initially everything looked good, it was registering 80 psi of oil pressure cold (I'm running Valvoline 20w50 VR1 Racing oil for break-in). However it settled down to about 20-25 psi at idle at 800-850 rpm. We were concerned about that because it had previously made a healthy 40 psi at idle last year when it was NA. Also the oil pressure was fluctuating, as much as a 10 psi span. When we gave it throttle, the oil pressure increased accordingly but it was still less than what we to see. So we pulled the oil pan and oil pump off. Jeff thought that the bypass valve in the oil pump was sticking, of course I couldn't help but have bad thoughts like spun bearings, etc. I guess it's kinda natural, but I was thinking what if I mis-installed the bearings, uppers and lowers mixed up, etc. I know I paid careful attention to that and double checked it so that kinda relieved my concerns.

When we drained the oil it looked perfect, no speckles of metal, no copper, etc. There was nothing on the magnetic oilpan plug, and the pan itself was clean. No tell-tale bearing chunks, and the valvetrain looked good when we took the valve covers off to adjust the valves as well. So we at least ruled out some kind of mechanical failure of the bottom end, or assembly error on my part.

We took the Titan pump apart and it looked perfect. I would have been pissed if the oil pump was the problem, considering it's $700 cost, but also kinda releived to identify the problem. For good measure we added a turn to the pressure adjustment, giving us about 10 more psi. After we buttoned everything back up, I also added another quart of oil just in case. We restarted it, same thing 80psi at idle when cold, then it fell down to around 30 psi this time, but still fluctuated too much for our liking. Jeff is farely convinced it's the oil filter. I'm using a Fram HP6 racing filter, the same thing they use in Winston Cup. Jeff said he's had
several instances of problems directly attributed to Fram filters, that once he changed to another brand, cleared up... I'm sure some of you guys have seen the website comparing the various oil filters, and FRAM didn't perform very well.

I've got a K&N HP6 equivalent at home we're going to try, made by WIX. The way the oil pressure was fluctuating leads us to think it the bypass valve in the filter opening and closing. We'll find out tomorrow. Here's a couple of gratuitous shots on the dyno. If you had asked me yesterday how I would feel if the day had ended like it did, I would have been unhappy, but I know we'll figure it out. I'm just glad we've been able to rule out any kind of catastrophic failure or assembly error. Although, I must admit, I find it hard to believe an oil filter could be the problem, but appearantly it's happened before.






Here's a little video I took of it idling. Nothing impressive, but it idles smoothly and has a nice lope.
http://www.montygwilliams.com/ttsbc427_idle.MPG

PonyKiller87

That is by far one of the sweetest motors I have ever see. Hope everything works out with the dyno and you get some good numbers.

PS Im not a fan of Fram, I had similar problems with oil pressure when I had one on, and it went away when I put a delco on. A friend of mine had a gram on his truck and the inside of the filter colapsed on it, dropping oil pressure down to 0, and blowing the motor. Not sure if he ever got Fram to pay for the new motor though??

RMK

$700 oil pump? I just swallowed my gum.

Amazing piece of machinery you have there, can't wait for the numbers.

Robert

I FLY UH-1

Monty,

I just got done reading your web page. Very impressive. Wish the best of luck with that new monster.

Monty

Thanks for the compliments.

Unfortunately, the oil filter was not the culprit, we still don't know why the oil pressure falls from 80 to 30 psi, and doesn't seem to build pressure like it should. Thankfully, we know that we haven't hurt any parts and there is no damage. We tried several things, adding .060" restrictors to the turbo oil lines, adding more oi to see if the sump was going dry, taking more oil back out to see if the oil was getting aerated. we even took the timing cover off ot make sure I didn't forget to install the pipe plugs.

Today we're going to swap oit the oil pump foir a Melling high volume big block pump. There really isn't much else it could be, I guess I hope it's the pump so that we can identify the problem and get it dyno tested and tuned, but on the other hand I am would be disappointed if it turns out to be the pump because the Titan Pro Billet pump is supposed to be the best wet sump out there, and at $700 it wasn't cheap. However, I am somehat skeptical that it is the pump because as I mentioned, we took it apart and it's basically brand new. Last year the engine made very good oil pressure, 40 psi at idle and 80 psi at WOT. The pump only has about 30 dyno pulls and maybe 300 miles on it.

I'm tempted to just run a belt-driven external wet sump pump so that I have access to it to adjust the pressure, etc, but the simplicity and reliability of an in the pan wet sump pump is hard to beat.

It's frustrating, but that's part of hot rodding I suppose. It could be worse, I know that.

a73camaro

Did you try another oil pressure gauge. Is the supply to the gauge good (kinked or partially plugged sense line)?

If it was an electrical gauge, possible bad ground?

Just some thoughts.

Monty

Yeah, we tried another oil pressure gauge (mechanical), we even tried it and the dyno oil pressure sender at different locations - same result. Thanks for the suggestion though.

I just got back from a local speed shop and picked up a new Melling high volume big block pump, along with a couple of pickups. After work, I'm going to go over there and install the new pump, and restart it. If it doens't cure the problem, I'm going to take the motor off the dyno and replace the restrictors with something smaller. On my Dart block, the lifter galleys are fed oil from both the front and the rear. Right now, the restrictors are drilled out to .200", everyone thinks thats way too big. I'll probably replace them with .125" restrictors.

Other than that, I guess I'll have to pull the motor apart but I don't think that's necessary. The crank and roads are all practically brand new from Crower, and they are dimensionally perfect, the bearings are new and all the clearances are perfect. We know there's no damage as the oil and magnet are clean.

I feel like it's the restrictors...

mat89RS

Can I ask how much money is in that "modified" corvette ?

SUPER CHEVY66

iTrader: (1)

Hey Monty i hope you get your problem solved because i really want to see some dyno sheets on this monster it will help me with my next build up good luck.

RMK

The phrase, if you have to ask you can't afford it, comes to mind with regards to this car.