454xli Repower

[waybomb]

Sound to me like a plugged oil cooler on the water side. Some impeller pieces maybe?

[SanJuanDreamer]

After speaking with a local shop, they found it odd that 454's would be running that low.
I have an appointment with their mechanic to hook up a mechanical oil pressure gauge.
It was mentioned that 454 bottom ends can last up to 2000 - 2500hrs (Depending on care) so were going to check.

[bud37]

Source of the post After speaking with a local shop, they found it odd that 454's would be running that low.
I have an appointment with their mechanic to hook up a mechanical oil pressure gauge.
It was mentioned that 454 bottom ends can last up to 2000 - 2500hrs (Depending on care) so were going to check.

When he does,if you can have him check the oil temp in the pan with an ir gun as you go thru the rpm range, should give you and him a better idea of the coolers and what is up with the pressure.....it actually is somewhat normal to have oil temp swings after hard runs that recover, but the only way to tell for sure is with the temp gun.
You say your good engine is the same?? Compare the two.

[Viper]

You can also have them send in an oil sample to a lab. That will tell you if there's abnormal main bearing wear.

[390Express]

I can post a pic of a 1996 454 Crusader XL, TBI if it’s helpful. Mine has a std, cast iron intake, and adaptor plate for the TBI.

[SanJuanDreamer]

Update - Mechanic came down and ran a compression check on the Port engine, as the previous shop couldn't provide the numbers when I had asked three times. They only said #4 was in bad shape.....
The only low spot we found was #3 at 130lbs, still within spec, but -2lbs less and it would be problem.
We ran it at 13rpm for about 20-25 minutes and the oil pressure stayed steady at 55lbs. Brought down to idle and again the oil pressure was steady.
The dash gauges showed the same as the mechanical gauge.
After he left, I took her out and ran her at 3600rpm for about 15 minutes and reduced to idle.
The gauges dropped to ~5lbs. After some time as the engines cooled, they slowly came back up.
Engine temp held steady at 170-075.

The oil was changed 10hrs ago, it smells gassey, which indicates gas is getting by cylinders or the TBI is providing too much fuel.
Going to use it gently over the summer and schedule for a repower.

[390Express]

Source of the post Update - Mechanic came down and ran a compression check on the Port engine, as the previous shop couldn't provide the numbers when I had asked three times. They only said #4 was in bad shape.....
The only low spot we found was #3 at 130lbs, still within spec, but -2lbs less and it would be problem.
We ran it at 13rpm for about 20-25 minutes and the oil pressure stayed steady at 55lbs. Brought down to idle and again the oil pressure was steady.
The dash gauges showed the same as the mechanical gauge.
After he left, I took her out and ran her at 3600rpm for about 15 minutes and reduced to idle.
The gauges dropped to ~5lbs. After some time as the engines cooled, they slowly came back up.
Engine temp held steady at 170-075.

The oil was changed 10hrs ago, it smells gassey, which indicates gas is getting by cylinders or the TBI is providing too much fuel.
Going to use it gently over the summer and schedule for a repower.

If you have even relatively good compression, and you're still getting fuel in your oil, you should be running extremely rich. Are you getting a lot of black smoke from your exhaust? Have you done anything to your motors that would have effected your tune? Is your plug hot enough? Do your plugs look saturated?

I'm not saying that your motors aren't tired, but I would do what you can to stop washing out your oil. If at all possible, I would try to run a hotter plug, more gap, better wires/cap, etc. If you get the fuel out of your oil, you may get your oil pressure up.

[km1125]

How is your oil level after you do these run? I can't imagine enough gas diluting the oil to cause your oil pressure to drop to ~5psi and then disappear after the engine cools for a bit. Maybe if it sat for a week. I would think if that gas was evaporating and that was the reason your oil was 'thickening' after sitting, then you'd have a STRONG gas odor after the engines ran.

Did you ever check the OIL temperature after -or while- you have it up to temperature?

Hot oil is also going to degrade a lot faster over the season and cause your engine to wear more. I wouldn't be overly concerned about 130 psi as much as I would the 5psi. You could run that 130psi cylinder for YEARS but I wouldn't bet so much on the 5psi.

[km1125]

Another thought.... Do you have separate trans and engine oil coolers or do you have the integrated "U" style unit? I'd also wonder what your trans oil temperature was after a cruising run.

Also, going back to the OP, the original issue was:
She has 1510hrs on both motors and port motor has a serious miss.
Shop says #4 cylinder is not holding compression.
Blue smoke and gas smell is strong.

Do you still have the serious miss, or was that resolved somehow?

Have you looked at fuel pressure ? You could have a faulty pressure regulator or a vacuum leak that is causing the pressure to be way too high and run it rich while at less the WOT.... that would cause dilution of the oil too. That could cause a miss too, on random cylinders.

[bud37]

SJD ....here is my advice....keep the rpm down, don't run the engines hard.....this discussion will just circle until your guy gets some oil temp readings before during and after a hard run.....if it is determined you have some noise ( clatter, knocking) when you see the 5psi pressure then put some heavy oil in there for the balance of the season.....quite honestly 5 after a hard run is still pretty close to minimum spec for hot oil at idle.Hopefully it is a fuel dilution problem or I believe as someone mentioned an engine oil cooler plugged if you have an engine oil cooler.