Packard Forum Index » V-8 (1955-56)

I finally got my 352 built up and installed in car last weekend,I've got a project blog on here,but wanted to direct this issue to the engine experts!!I Got it running earlier this week,and have been chasing down and correcting Fuel,Timing,and ignition issues,I've finally got most of that ironed out and have car running pretty well!!I have one major issue,I have extremely high oil pressure,I have destroyed 3 gauge's(Thankfully Oreiley's keep replacing them LOL)The pressure goes up past 100 PSI!I feel pretty sure I have a pressure relief valve stuck,I figured after i ran engine a little It may free up,(no such luck)!I tried blowing compressed air through the oil galleries where oil filt. plumb's in,still no luck!! I also have some top end lifter clack(not too bad),probablly just the norm. for these engines.I just wanted to see if anyone had any idea's on this oil pressure problem,and If it is relief valve,how to get it unstuck?Should I just go ahead and pull the pan?Is pump salvageable? Is the relief valve serviceable? This Is a fully rebuilt 352 for a 1955 clipper custom!It was rebuilt 27 years ago and never used,it had been stored in a garage and Hasn't ran until I started it this week! I pulled oil pan and inspected everything before I started building motor up,everything looked great! I also blew compressed air and solvent through oil pump,oil galleries and ETC,before install!Any help would be appreciated! Also does anyone know what line hooks up to the nipple fitting coming out of the back of the carb.,not the brake hose but the one that tee's into the side of the fitting on pass. side of car?? Does anyone have a vaccum schematic for this car?? Thanks to all!!

Will let the engine guys chime in on the oil, but not much vacuum tubing in a 55 so sounds like that might be one of the vacuum sources for WS wiper. The base of carb should have a steel tubing to dist, the power brake and one of WS wiper sources. The other wiper source should be from a fitting on passenger side of block just above oil pan.

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Thankyou for the schematic!!

Sounds like a stuck pressure relief valve to me.

BUT, i am curious, u mention o'rily gauge. Where is the feed line connected to the engine?????? I assume this is a MECHANICAL gauge and NOT electric gauge.

You mentioned the vacuum fitting tees into the one on pass side of car. If you meant the carb fitting and the one on block are actually connected, that shouldn't be. The balancing valve is supposed to be the only connection between the two sources and will cut off one or balance inputs so the wiper motor has the strongest vacuum all the time.

High oil pressure on a Packard V8 - will wonders never cease? The only possible cause is a stuck pressure release valve in the oil pump. Probably all those years of sitting caused the assembly lubricant to turn to stone. Since you've already pulled the pan, drop the oil pump, put it on the bench, disassemble it and clean the pressure release valve inside the pump body. Let us know what you find.

As an aside, if you have noisy lifters with over 100# of oil pressure, you've got another potentially serious problem in that area.

Good luck, jack vines.

Packard V8:,It is a mechanical gauge,connected where the oil pressure switch normally goes!! HH56: Do not have those 2 connected directly,I just have a empty spot for line going in to the side of the rear carb. fitting,based on the schematic on here,Im thinking one of the two side by side vacum hose's on the firewall go there!! Jack Vines: Ha ha,I knew somebody would say something about the HIGH OIL PRESSURE,wouldn't you know I have to be different...LOL!!!When I described It as a little lifter noise,It's not really lifter's It sounds more like just some rocker arm chatter,Im just not use to hearing quite that much with more modern V8's!Im hoping,once I get this Oil Pressure straightened out,and I can run it a little more,It will smooth out!! Keep in mind this engine has ran very little!I do not have oil pan off,engine is installed in the car,I was hoping It would unstick on it's on,but It appears I will be pulling the oil pan!! Thanks!!

Remove the oil pump. Get u're digital camera batteries charged up. We will need some pics. THere are oil pump variations that we need to keep in mind. There are 2wo different PR valve pistons and springs. Most likely the problem is as Jack stated, a varnished up pump. In this case using snake oils to free it up is probably not advisable.

As for the "lifter clatter" or "rocker clatter" lets address that problem after u get the pump streightened out.

NO!, ,Wait a minute!!!! Lets try something first.

Remove a valve cover, the easy one to remove is the left one. RUN the engine with the valve cover removed and pay close attention to how much oil exudes from the rocker shafts. Is it running completely dry?????

IS this a 55 engine or a 56 engine????? Note that EARLY 55 engines have rocker arms with pee holes. Mid to late 56 had no pee holes.

BTW, the Packard V8 engine in good condition should run just as quiet as any modern V8.