Re: 374 Lifter issue?
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Forum Ambassador
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Perhaps when someone swapped in a 374 they changed the lifters and put in the wrong ones??
Posted on: 2015/11/6 21:46
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Re: 374 Lifter issue?
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Home away from home
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You will find that there has been endless discussion on this issue if you begin to dig.
The basic scenario is this: The input shaft to the oil pump wears and begins to allow air to be drawn in. Foamy oil is bad for the engine bearings; they wear and oil pressure begins to drop. Foamy oil combined with low pressure is an impossible combination for hydraulic lifters and the ones farthest from the pump will begin to tap. So your lifters may still be quite OK, but you will have to do something with the pump and have a good look at all your bearings, especially the center mains. The old timer's trick my friends and I used when driving tired V-8 Packards as cheap beaters was to fill the oil in to a quart over full. That would keep the air from being drawn into the pump and if the engine still had decent oil pressure you could get tens of thousands of miles of quiet driving.
Posted on: 2015/11/7 7:01
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Re: 374 Lifter issue?
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Quite a regular
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Hi Randy - the car is actually a 56 (the rear window which you can just see in the piccy is the big giveaway) - it had no front chrome or side trim when I got it, and the front guards were off a 55 clipper I think (the park lights holes were non existent) and I had to grab what I could at the time and 55 trim was all I could locate, so for better or worse it's ended up as it is - :)
Posted on: 2015/11/7 12:18
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Re: 374 Lifter issue?
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Quite a regular
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I think too, that the oil pump is cavitating a bit at higher rpm, I've got a bit of a plan to remove the vacuum pump (it's got electric wipers now) and place a thick lump of milled steel as a pump cover, reliant, of course, that the pump is still in good shape.
I've read on here regarding these olds oil pump conversion kits etc, but I still have to get hold of the bits and the local shops there don't readily ship to NZ. Cheers
Posted on: 2015/11/7 12:26
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Re: 374 Lifter issue?
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Forum Ambassador
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Thanks for your explanation. The side trim is 55, so between that and the front clip I assumed 55.
Ross gives good advice about running a quart over full. Eliminating the vacuum pump isn't as important as keeping the top of the oil pump covered in oil. Are those '51 scuppers on the rear fender or the later stainless versions and what is the lettering?? - just curious.
Posted on: 2015/11/7 12:56
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Re: 374 Lifter issue?
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Home away from home
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Muir-
Here are some pics of the plate to remove the vac pump
Posted on: 2015/11/7 13:15
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[url=https://packardinfo.com/xoops/html/modules/
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Re: 374 Lifter issue?
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Forum Ambassador
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It is an interesting mix of trim. I would have thought 55 too with the front fenders and side treatment. In addition to the 52 "louvers". what is the script on the rear door?
Posted on: 2015/11/7 13:55
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Howard
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Re: 374 Lifter issue?
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Home away from home
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Before resorting to pulling the pan (which may be nec),you may want to keep the pan 1 qt high as suggested above and try some other things. I have been driving a recommissioned 55 with orig oil/vac pump for 8+yrs now so I speak from experience. Is yours an un rebuilt orig engine or has it gone thru the machine shop boiled out,heads done etc? If the prior is true, -try dropping the oil ,replace with NON detergent 30W oil and add 1/4 qt of marvel.M.O. and lead substitute to your fuel tank if full (or same to 10 gal of gas).Make sure your carb Has NO leak down or rich issues to dilute the oil. You may not need to go thru the time ,exp, hassle of any other repairs suggested above. Please post experience here if dealing with an orig, non reman engine. There may be another issue at play.
Posted on: 2015/11/7 17:14
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Re: 374 Lifter issue?
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Forum Ambassador
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If you don't know that it has been done recently, don't hesitate - drop the oil pan and clean it and the oil pump intake screen; not uncommon to find 50% or more of the area of the pump intake screen choked with sludge. If you familiar with the job, drop the center main bearing and check the clearance with Plastigage. And check the hot, idling oil pressure at the INLET to the oil filter; this will give you a measure of the loss of internal pressure. Ross or others may have a better number but to have a warm comfy feeling I'd want to see at least 15 psi at the filter inlet.
Posted on: 2015/11/7 19:12
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