401 100+ psi much oil pressure
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Category: The Garage
Forum Name: AMC V8 Engine Repair and Modifications
Forum Description: AMC-made V8 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: https://theamcforum.com/forum/forum_posts.asp?TID=90367
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Topic: 401 100+ psi much oil pressure
Posted By: Rocketman
Subject: 401 100+ psi much oil pressure
Date Posted: Oct/18/2017 at 7:45pm
| My 401 is installed and as i primed the pump we noticed it was pegging the oil pressure gauge, and even managed to blow out the o ring on the oil filter. Searching says its either the bypass valve sticking, too small a hole in the steel plate from bulltear, or a plug in the bypass line. All the front accessories are from bulltear. Is there anything else it could be? Also if its the bypass spring assembly can I get them at auto'reillys napa parts? I figure they have the gaskets if I gotta drop the pump cover. Thanks. |
Replies:
Posted By: Rebel Machine
Date Posted: Oct/18/2017 at 8:26pm
I experienced the exact same thing. The bypass hole in the Bulltear midplate is too small. When the oil is cold it's thick and even with the bypass valve all the way open (I tested that by removing the overpressure valve spring) the midplate hole still doesn't allow enough flow. Either remove the midplate or enlarge the bypass passage to the same size as that on the oil filter mount side of the pump. -Steve- |
Rocketman wrote:Posted By: SKeown
Date Posted: Oct/18/2017 at 8:53pm
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Midplate, throw that gimmick in the trash! SKeown
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Posted By: mmaher94087
Date Posted: Oct/18/2017 at 9:57pm
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Just as an FYI, if the bypass plunger is installed backward; the filter canister will split like a cherry bomb went off in it. ------------- Mike |
Posted By: Rocketman
Date Posted: Oct/19/2017 at 1:29pm
| Okay, just so i can rule it out while i'm there, the plunger goes pointy side away from the spring? Thats what it looks like on diagrams i've seen. Rather ask and sound dumb than have to go at it twice. |
Posted By: Moffman
Date Posted: Oct/19/2017 at 1:42pm
Yes 
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Posted By: Rocketman
Date Posted: Oct/19/2017 at 1:55pm
| 10/4, 99.9 percent sure I put it that way but for all the time itll take to check no reason to not to. |
Posted By: SKeown
Date Posted: Oct/19/2017 at 2:16pm
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There's been a lot of talk about the inadequate AMC oil pump, but it's capable of blowing up the filter. A useful aftermarket component would be an adjustable bypass unit.  |
Posted By: Red20
Date Posted: Oct/19/2017 at 3:10pm
Hey! I've used Bulltear's midplate. Seemed fine to me. But yeah, a properly clearanced and true oil pump cavity and adapter with good gears and relief valve should work just fine. ------------- 1969 Javelin SST "Screamin' Banana" - Totaled Feb 2018 1973 Hornet Sportabout X "yellajack" - 360/727/TracLoc DAILY DRIVER |
Posted By: SKeown
Date Posted: Oct/19/2017 at 7:16pm
What real benefit does it provide? If you're concerned about wear on the pump cover get yourself a sheet of sand paper and eliminate it. I did mine on a formica countertop in about 10 minutes. Besides I don't like the need for a second gasket in conjunction with the unnecessary part. SKeown
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Posted By: Rocketman
Date Posted: Oct/19/2017 at 7:37pm
| Well, I pulled it off and sure enough i done goofed on the plunger, switched it around and broke in cam, all is well 30 psi hot afterwards, thanks for the help. Glad I didn't trust my confidence. Left all the bulltear stuff on cause they're adapter hole is the same as the gasket and steel plate, for what its worth. |
Posted By: 74Bubblefender
Date Posted: Oct/19/2017 at 8:31pm
That's what you were told on the phone when you talked to me. Now you just ruined Steve's day by saying you installed the valve backwards. He surly doesn't like the gimmick of a wear plate but he loves the idea of a 8pc adjustable pressure relief valve.  ------------- We are just about to forge new AMC V8 crankshafts.. please check here http://www.bulltear.com/forums/showthread.php?19564 |
Posted By: SKeown
Date Posted: Oct/19/2017 at 11:13pm
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It actually consist of 9 individual parts. That is something worthwhile, unlike a plate sandwiched between the pump housing and it's cover. If someone would create and market an adjustable oil pump bypass valve, that would be something useful I could recommend. I'm sure you could design one with 8 or less components that wouldn't leak. I understand they are available for Buick engines at a reasonable price. SKeown
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Posted By: Red Devil
Date Posted: Oct/20/2017 at 8:07am
That one was made using modified hardware-store parts for the seal, so a few extra pieces required to ensure it sealed reliably. The one I made to replace it used a hydraulic sealing nut, so only 3 more pieces than the stock assembly - adjusting screw, sealing nut, spring seat:  TA Performance sells an adjustable pressure relief for Buicks. It retails for $19.95 http://www.taperformance.com/proddetail.asp?prod=TA%5F1502" rel="nofollow - TA Performance Adjustable Pressure Regulator Bulltear's midplate retails for $29.00 **Sale** http://www.bulltear.com/catalog/product_info.php?products_id=217&osCsid=c3c22d36715eabf3566650615bac408a" rel="nofollow - Bulltear Midplate There are a couple issues with an adjustable relief valve: 1) People might adjust it incorrectly. Could limit range by limiting screw length and thread length. I guess Buick owners are more competent than AMC owners? 2) An economical bolt-in part might fix perceived oil pressure issues ... reducing the need for special nickel-plated timing covers, custom-machined oil pump gears, custom-order lifters with special OD, numerous trips to the machine shop to ensure the "right" bearing clearances, timing covers with race-style pumps, etc. Lots of options out there. Choose what works for your application. Hope this helps,RD |
Posted By: SKeown
Date Posted: Oct/20/2017 at 2:00pm
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The end of the adjusting bolt could be reduced to fit within the spring, thus eliminating the need for the spring seat to keep the spring centered in the bore. A milodon pan, adjustable pump relief and Johnson roller lifters (if running roller cam) is all that's needed to deal with AMC oil pressure issues for high revving performance use in properly fitted engine. SKeown
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Posted By: Hurst390
Date Posted: Oct/20/2017 at 4:44pm
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I've never had an oil pressure problem and have always had between 60-65# hot pressure in everything I have. Steve if your not getting over 45# then I would say you have a clearance issue or a leak somewhere,because your result is not typical IMO. My 401 J-20 I drive every day has 63# hot going down the road and all it has is a deep pan and a ford filter. Instant oil pressure on startup with the ford unit. ------------- SC/Hurst Rambler 11.62 120 100% Street Legal |
Posted By: Red Devil
Date Posted: Oct/21/2017 at 10:27am
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He wasn't getting over 45psi until he installed an adjustable relief valve. Now he can set it where he wants. So, yes he had a "leak" - the relief valve was opening at a lower pressure than desired. Same as OPs relief valve wasn't opening so had over 100psi. The stock pump is capable of generating lots of flow. The relief bleeds off excess flow, so controls the system pressure depending on spring setting and relief flow characteristics. No one currently sells an adjustable relief for AMC so either make your own, like I did, shim the spring or if operating pressures are ok, leave as is. Hope this helps,RD
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Posted By: Boris Badanov
Date Posted: Oct/21/2017 at 10:40am
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The Bulltear midplate is an excellent product if you need a midplate. That simple, I have a couple of them and there is no defect. The usual cautions need to be followed, like long enough screws and sanding or milling any severely damaged surfaces. Not trying to start a war here, it's just the facts. One note, if you are using a after market cover made of "billet" 6061T-651 the mid plate is good protection as the 6061 is less wear resistant than cast aluminum. ------------- Gremlin Dreams |
Posted By: Boris Badanov
Date Posted: Oct/21/2017 at 10:59am
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I made a few for external HD cam support plates. So far there is no easy way to make them leak proof. In my brief experience with the idea it is best to make a set of caps with varying depth of pre-load. This allows some adjustments and it impervious to road dirt. ------------- Gremlin Dreams |
Posted By: Red Devil
Date Posted: Oct/21/2017 at 11:24am
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I don't have a problem with the midplate as long as the relief hole is properly sized to not restrict and affect relief flow. It serves its purpose for those that think they need it ... but like an adjustable relief, it's also an extra leak point. Neither of the valves I made have leaked, but road dirt will get into the threads so clean before adjusting. The hydraulic sealing nut used on the second one we currently use on a circuit operating at 1200psi without leaks -but constant adjusting will wear out the seal and then it will weep, so need to fit a new one. Hope this helps, RD
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Posted By: Boris Badanov
Date Posted: Oct/21/2017 at 12:06pm
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That's why I went to a couple of custom caps to swap around to play with pressure on the Harley. All this is custom, the external cam support plate and the adjuster(S). A drop or two of oil may not bother a guy with an old Rambler. But Harley owners tent to be anal to an extreme about the polish and look of the bikes. ------------- Gremlin Dreams |
Posted By: Hurst390
Date Posted: Oct/21/2017 at 1:37pm
Your telling me 45psi is the norm on an AMC v-8? ------------- SC/Hurst Rambler 11.62 120 100% Street Legal |
Posted By: Red Devil
Date Posted: Oct/21/2017 at 1:59pm
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"Normal" is a pretty broad definition. IIRC, TSM spec is 13 psi @ 600rpm, 37psi above 1600rpm. 75psi max. My experience with 2000 rpm +/- cruise is 40-45 psi. Higher rpms = higher pressure. Thicker than 10W30 oil or cold temperatures = higher pressure. At some time the Melling replacement springs seemed to get about 45psi hot and didn't go much higher at higher rpms. Even when shimmed a bit. So I made an adjustable relief with a different spring that got > 65 psi at higher rpms. That's what I sent Steve to see if it would help him. And it did. I recently tried a newer Melling spring and it got 60psi at higher rpms. So there seems to be some variance in springs over the years, so maybe new ones are fine? Main point is that the relief is what is primarily controlling high rpm pressure, so make sure it is on your list of things to check. Hope this helps,RD |
Posted By: SKeown
Date Posted: Oct/21/2017 at 5:04pm
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If the relief spring limits the pressure to 45# then nothing you do will change that. You can tighten up the pump's end play, resort to reduced feed pushrods and even have the lifter bores bushed. You'll still have 45# pressure, that I can guarantee. The OP has shown us a way to determine how much pressure you're engine is capable of. You just need to reverse the bypass plunger and you'll know. So those that stick out there chest and brag about how much oil pressure THERE AMC engine has, it's because the bypass allows that. Take out the spring and shorten it, that will deflate there chest and oil pressure too. A friend had a 304 in a Jeep, the engine was completely worn out including the oil pump cavity and cover, but it still had well over 60#'s of oil pressure. Yes, you can simply shim the spring to increase the pressure, but it's better to have a means to adjust to the desired pressure. SKeown
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Posted By: Hurst390
Date Posted: Oct/22/2017 at 7:18am
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So there we have it..maybe the difference is the springs supplied by mellings... I just tried to convey that I've never had a problem with pressure..maybe steve just has a weak spring... ------------- SC/Hurst Rambler 11.62 120 100% Street Legal |
Posted By: Boris Badanov
Date Posted: Oct/22/2017 at 2:10pm
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if I thought there was any profit in it I would set up the lathe and make a few hundred sets of -stock to so many tenths(.1) deeper- caps so people (preferably experienced ones) could play around. It would be fairly cheap in large numbers. Make em from hex stock. We have a two spindle multi axis mill turn that is quite fast. ------------- Gremlin Dreams |
Posted By: SKeown
Date Posted: Oct/22/2017 at 4:10pm
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A person could supply everything needed except the pump fitting along with instructions on how to drill and tap the consumers fitting. The complete assembly is well worth $60.00 when you consider how much can be spent chasing ones tail in an attempt to increase oil pressure. SKeown
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Posted By: Red Devil
Date Posted: Oct/23/2017 at 9:08am
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The TA Performance adjuster retails for $19.95. I don't see why an AMC version should cost more than that? If you can tap a hole, buy the TA part and modify the AMC spring retainer to suit. If the Buick thread is the same, it might be a simple bolt-in. The first adjuster was just a fine thread bolt with the head cut-off and flats ground on it for wrenching and to allow the lock nut to slip over. The seal was a Teflon faucet seal threaded to match the bolt with a steel washer around the seal to prevent extrusion (washer drilled for a snug fit to the od) another steel washer and the locknut. Tapped the stock spring retainer and polished the surface for a good seal. The second adjuster used a standard set screw and a sealing nut. The retail cost is less than $5.00 for both pieces. Just tapped the stock retainer for the set screw, drilled a shallow coutersink to suit the seal nut and polished the surface so it wouldn't leak. The spring and seat I scavenged from a scrap logic relief valve. Just happened to have a spring seat and spring that worked ... but the adjuster would work for those who just shim the Melling spring with good results. The seal nut is manufactured by Bollhoff: http://www.bollhoff-usa.com/ae/us/fasteners/fastening-riveting/sealing-nuts-seal-lock.php" rel="nofollow - Bollhoff seal nut Hope this helps,RD |
Posted By: Boris Badanov
Date Posted: Oct/23/2017 at 11:11am
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Small production runs magnify costs exponentially. Not enough potential volume to make it worth making any more than one for yourself. The ones I made for HD's would cost a few hundred each but they were give-away prototypes, I never made another. ------------- Gremlin Dreams |
Posted By: Red Devil
Date Posted: Oct/23/2017 at 11:21am
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Bulltear sells the pump relief spring retaining bolt for $13.88. How much extra do you think it would cost to tap a hole when they are already stetup to machine? Add a screw and seal nut and pretty close to the TA price. http://www.bulltear.com/catalog/product_info.php?products_id=262&osCsid=ecfa3c27805623b51c4602f33ca74a9b" rel="nofollow - Pump relief spring retainer |
Posted By: SKeown
Date Posted: Oct/23/2017 at 2:31pm
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If you reduced the diameter of the adjusting bolt to fit within the spring by 1/4" depth it would center the spring and allow the use of the original spring. That way in addition to the drilled and tapped retainer fitting you would just need a socket headed bolt and the leak proof nut. If a person supplied the modified adjusting bolt and special sealing nut the customer could have the spring retainer fitting drilled and threaded and be in business. SKeown
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Posted By: 74Bubblefender
Date Posted: Oct/24/2017 at 10:43am
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Do you wonder what it does to the oil filter bypass operation?
------------- We are just about to forge new AMC V8 crankshafts.. please check here http://www.bulltear.com/forums/showthread.php?19564 |
Posted By: Red Devil
Date Posted: Oct/24/2017 at 11:34am
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The filter bypass works on pressure drop across the filter. If you're dumping less flow over the relief, there is more flow going through the filter and into the engine so the filter bypass may open sooner if pressure drop through the filter is higher than the filter bypass opening pressure, e.g. cold oil or high flows. A wise person may fit a filter that has a higher flow capacity, built-in bypass with higher opening pressure and plug the stock one. Those who understand that filtration systems are designed to keep the oil in the pan clean through multiple passes through the filter likely aren't alarmed by the bypass opening. Those who are concerned about maybe catching debris in the filter when the engine is failing and if lucky, reducing downstream damage might be ... but if the filter is plugged and bypass doesn't open, you get no oil to the engine. Do you wonder what a midplate with a hole too small for full relief flow does to the filter bypass operation? |
Posted By: 74Bubblefender
Date Posted: Oct/24/2017 at 2:01pm
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Can you find one?
------------- We are just about to forge new AMC V8 crankshafts.. please check here http://www.bulltear.com/forums/showthread.php?19564 |
Posted By: Red Devil
Date Posted: Oct/24/2017 at 2:38pm
Ask Rebel Machine, or refer to his Take 6 thread. 85psi with the midplate and no relief valve and 0psi with no midplate and no relief valve certainly seems to indicate the hole size is a bit restrictive ... at least on the one he installed?
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Posted By: 74Bubblefender
Date Posted: Oct/24/2017 at 4:18pm
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From a few years back? CSI = TMI ------------- We are just about to forge new AMC V8 crankshafts.. please check here http://www.bulltear.com/forums/showthread.php?19564 |
Posted By: SKeown
Date Posted: Oct/24/2017 at 5:32pm
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There's nothing more exhilarating than paying mega $$ for unneeded gegos!! How's that for a motto Matt?? Or maybe "We're the AMC enthusiast best friend!!". SKeown |
Posted By: jcisworthy
Date Posted: Oct/24/2017 at 5:51pm
 I drilled and tapped the factory spring retainer for 7/16 and installed a bolt, washer and nut to lock the bolt after adjusting. I used liquid teflon on the bolt threads.and it stayed dry. This was with a factory length spring. The first attempt was with a 3/8 bolt but it wanted to thread into the spring so I went up 7/16 and it pushed on the spring without binding.  ------------- Specializing in dyno services, engine building, and cylinder head porting rbjracing.com Phone Number 518-915-3203 |
Posted By: Red20
Date Posted: Oct/24/2017 at 6:47pm
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Well now, that's simple. What was your experience with adjustments? Pressure before and after? Etc? ------------- 1969 Javelin SST "Screamin' Banana" - Totaled Feb 2018 1973 Hornet Sportabout X "yellajack" - 360/727/TracLoc DAILY DRIVER |
Posted By: jcisworthy
Date Posted: Oct/24/2017 at 6:53pm
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When turning the bolt it gets to a point where the pressue takes a jump quick. That is the zone where you tune in the pressue. You can pretty much make any pressure you want with it and blow out an oil filter if you want to do that as well. ------------- Specializing in dyno services, engine building, and cylinder head porting rbjracing.com Phone Number 518-915-3203 |
Posted By: 73hornut
Date Posted: Oct/24/2017 at 7:10pm
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I was considering buying a new spring bolt from bulltear ebay, but not for $27, $12 of which is shipping!
------------- 71 Javelin 74 Gremlin 79 Spirit AMX Rogue Valley Rumblers Like Us on FB https://www.facebook.com/groups/1602825606650796" rel="nofollow - https://www.facebook.com/groups/1602825606650796 |
Posted By: Red20
Date Posted: Oct/24/2017 at 9:28pm
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Thanks for the info. And this pretty much determines your hot pressure while driving, right? Does it have much effect at idle? I'm looking into doing this one when I switch the thread adapter for a Ford FL1A filter. Do you think a nyloc nut would work? I'm at a steady 43 lbs hot going down the highway and 12 lbs hot idle in gear at 650 RPM. Cold startup is 58 lbs. The filter adapter was all rebuilt with new parts and the bottom end is all new. I may have some leaking valve seals though. ------------- 1969 Javelin SST "Screamin' Banana" - Totaled Feb 2018 1973 Hornet Sportabout X "yellajack" - 360/727/TracLoc DAILY DRIVER |
Posted By: amcenthusiast
Date Posted: Oct/25/2017 at 12:34am
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Where the general rule of thumb is 10 psi. more for every thousand rpm, the stock relief valve spring is rated at 60 psi. to make 10 psi. above the stock 5000 rpm redline. In my estimation, your oil system appears to be running as it should. Remember it doesn't hurt to smell the oil for gasohol contamination when you take a dipstick reading. Also look for tiny bubbles which indicate aeration needing a remedy. No, you'll want to use a stock type metal washer for the relief valve spring keeper bolt; 'plastic' washer will distort and create a leak. The stock AMV8 oil filter spec calls for a non-internal bypass filter, not to run unfiltered oil through the engine. ------------- 443 XRV8 Gremlin YouTube video: https://www.youtube.com/watch?reload=9&v=2DmFOKRuzUc XRV8 Race Parts website: http://amcramblermarlin.1colony.com/ |
Posted By: jcisworthy
Date Posted: Oct/25/2017 at 3:54am
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Idle pressure goes up also. Oil pressure 45 or above at full throttle is fine in my opinion. If you have that I would not change anything. I know stock eliminator guys running 30PSI for years turnng as much as 8K RPM's. ------------- Specializing in dyno services, engine building, and cylinder head porting rbjracing.com Phone Number 518-915-3203 |
Posted By: Red20
Date Posted: Oct/25/2017 at 6:01am
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Thanks for the info, guys. Always nice to have a second opinion. ------------- 1969 Javelin SST "Screamin' Banana" - Totaled Feb 2018 1973 Hornet Sportabout X "yellajack" - 360/727/TracLoc DAILY DRIVER |
Posted By: 74Bubblefender
Date Posted: Oct/25/2017 at 5:33pm
Your in oregon. UPS ground is $15.50 to central oregon on any package 1lb or less. ------------- We are just about to forge new AMC V8 crankshafts.. please check here http://www.bulltear.com/forums/showthread.php?19564 |
Posted By: 74Bubblefender
Date Posted: Oct/25/2017 at 5:34pm
 And folks wonder why every year there are less and less parts available. ------------- We are just about to forge new AMC V8 crankshafts.. please check here http://www.bulltear.com/forums/showthread.php?19564 |
Posted By: jcisworthy
Date Posted: Oct/25/2017 at 5:48pm
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I appreciate you and others supplying parts for the industry ------------- Specializing in dyno services, engine building, and cylinder head porting rbjracing.com Phone Number 518-915-3203 |
Posted By: SKeown
Date Posted: Oct/25/2017 at 7:37pm
I'll repeat, I consider this forum a source for information, not a place to hawk unneeded parts to unsuspecting members. I'm sorry, but that's my heartfelt opinion. SKeown |
Posted By: ARIZONAAMX
Date Posted: Oct/25/2017 at 8:22pm
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Bulltear is awesome.If you don't need their products don't buy them .simple solution. ------------- 68 AMX 401,727. |
Posted By: Buzzman72
Date Posted: Oct/26/2017 at 5:54am
X2. ------------- Buzzman72...void where prohibited, your mileage may vary, objects in mirror may be closer than they appear, and alcohol may intensify any side effects. |
Posted By: 73hornut
Date Posted: Oct/26/2017 at 6:59am
------------- 71 Javelin 74 Gremlin 79 Spirit AMX Rogue Valley Rumblers Like Us on FB https://www.facebook.com/groups/1602825606650796" rel="nofollow - https://www.facebook.com/groups/1602825606650796 |