340 oil pressure? Help

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72bluNblu said:
Right, except it’s a roller cam!
So everything you said was completely irrelevant. No cam break in needed for a roller cam.

And yeah, you totally jumped all over the guy. And you’re totally wrong to boot, because you popped off without even asking if it was a flat tappet cam. Open mouth, insert foot.



10-30w is pretty light, but it’s a brand new engine. With the plug out I’m not sure you’d even manage the pressures you’ve got, but it’s possible.

Check for the plug. If it’s installed and that wasn’t the problem, you can go 15-40w or 20-50w. Thing is, your oil pressure now is as high as it’s going to be. The tolerances should be as tight as they'll ever be with a brand new engine. So, if the plug wasn’t left out, there’s a chance you have fairly loose tolerances on that brand new engine.

I’d check for the plug, then try a heavier weight oil before I messed with the oil pump. Just see what you get first. Modern machining techniques usually give tighter clearances than what these engines had 50 years ago from the factory, so, it follows that you should see higher pressures than was normal in the 70’s. You may have clearances that are a bit on the loose side. Which isn’t necessarily bad, but it’s worth figuring out now. Talk to your engine builder, better to get it sorted while it’s still under warranty from the shop.
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Yeah I just checked and the plug is in I'll try changing the oil when I get the chance and go from there. It wouldn't surprise me if the shop built it a little sloppy unfortunately I heard the bad reviews on him after the fact and the good ones before lol thanks for the advice I'll keep you posted on the outcome
 
RustyRatRod said:
Yeah I saw it was a roller WELL AFTER the initial post that SHOULD HAVE included that info. I didn't jump all over anybody. Are you head of the snowflake club now?
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Right, except if you’re some expert that actually deserves a tech editor badge you should probably have asked the guy if he had a roller cam in it before you called him stupid in your very first comment.

But you didn’t. You started cap smashing and calling him stupid before you had enough technical information about his build to even have a clue. But you couldn’t possibly ask those questions, because he should know to post that for you.

And then you went right back at him, telling him he should read up on something first when you can’t even read all the information he has posted in this thread.

And now you’re calling me a snowflake because you’re having a tantrum about being wrong? Sure buddy, ok.

Ryan ekes said:
Yeah I just checked and the plug is in I'll try changing the oil when I get the chance and go from there. It wouldn't surprise me if the shop built it a little sloppy unfortunately I heard the bad reviews on him after the fact and the good ones before lol thanks for the advice I'll keep you posted on the outcome
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Well, try the heavier weight oil and see what happens. Get some more run time on it and see what the pressures do when the engine is fully up to temperature. Those aren’t the pressures I’d want to see on initial cold start up, but that doesn’t necessarily mean you’ve got problems yet.
 
Ryan ekes said:
Yeah I'm going to pull it and go with a high volume just for good measure. What weight do you run?
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Mopar Tim said:
i am not saying your engine has a problem, BUT there is a plug behind the dist drive that a non mopar builder forgets lots of time,I forgot it one time myself. Low oil pressure is the result of that. Kind of common, and can be installed with the engine in the car, a real pita but can be done. Not saying that is your issue but something to look at.
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Great recommendations. This was my problem when a fresh magnum built yielded 15 cold and 5 warm pressure. It’s definitely worth a look.

Jake
 
Ryan ekes said:
Ok guys I finally got the freshly rebuilt 340 in the cuda wired up and ready to go and when I started it my oil pressure was around 15-20 on a cold start idle and up to 45 around 2000 rpm. I'm running 10-30 and the majority of people are saying this is super low on a fresh motor and something isn't right. All thoughts, experiences, advice and pointers will be greatly appreciated thanks
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I had a similar issue on my first rebuild... It turned out that the machine shop did not put the oil galley plugs in the front of the lifter galleys... Pull the timing chain cover off and then remove the camshaft thrust plate and make sure that there are two plugs behind the plate...

Read this article to see which ones exactly:

https://www.forabodiesonly.com/mopar/ams/how-to-assemble-the-front-of-a-small-block.12/
 
So then, rings, valve guides, bearing surfaces,timing set and all the rest of the internal engine parts don't need a break in? Since when did I get specific about WHAT was breaking in? I was simply referring to ENGINE break in.

Whether it has a roller or not is really a moot point. It's still a good idea not to let it idle, as you WANT good oil splash on a fresh engine so everything gets lubricated. At least I do.

But I guess that's bad information, too.
 
Ryan ekes said:
my oil pressure was around 15-20 on a cold start idle and up to 45 around 2000 rpm
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From what I am reading the OP has started the engine once where he noted the pressures above. He has not even taken the engine any higher than 2000 it seems [cold], so nobody can predict what oil pressure it will have ABOVE 2000.

Using Brians method with 10psi/1000 he will end up with perfect oil pressure when he starts breaking the engine in at HIGHER revs than 2000 rpm! All plugs seem to be in place and he should just commence with the break in job at the recommended rpm's before he starts throwing parts at it (absolutely with RRR here!).
 
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Well now that you met RRR(who's not that bad by the way) , I agree .. your pressure is a bit low, but not going to kill your engine ... factory oil pressure spec is much lower than most folks are "comfortable" with ... to bad so sad on that one .... i personally think you should continue with your break in and see where the pressure settles when the engine is at operating temp .... plus you would not be seeing the pressures you currently have if those plugs were left out...
 
IF the engine only ran for 5-10 seconds and 40psi is all you saw then what you are seeing is perfectly normal. IF the engine ran for 2 minutes or more and 40psi is all you saw then that is low. Find out why. Should be 70-80 psi cold with a fresh build, don't care if it's a std volume or high volume. Use a std volume until you learn where and when a high volume is applicable. It took me a long time to figure out where and when to use a high volume pump--it probably is not the best knee-jerk solution. I use a high volume about 10% of the time. If you truly only have 40 psi cold @ 2000rpm then Houston we have a problem and you need to go deeper than an oil pump. ----Unless the shop is so shady they installed a VERY worn out oil pump-which is VERY unlikely. J.Rob
p.s. My bet is the roller lifter bodies are undersize or the "band" cutout is in the wrong position causing massive hemorrghing.
 
4spdragtop said:
Throwing **** at the screen here but wouldn't a high psi spring in oil pump help?
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If you broke you're leg and and had to walk with crutches until you died--OR had the option to instantly fix you're leg and walk for a long and happy life--which would you choose? J.Rob
 
What oil pressure gauge gave you this reading? The one in the dash OR a Chinese under dash unit or a plumbed in "master" gauge?
 
Stock oil pump typically run 50 - 60 psi...

A high pressure spring will give about 65 - 75 psi...

Mellings oil pumps only come with a 72 psi pump, so changing them to a high pressure spring will only give you about 3 psi more... Not worth changing the spring in a Mellings...
 
hydraulic or solid lifters ,cam lift? fully groove main bearings, and was the crank ground for racing clearances
 
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Ryan ekes said:
Yeah I just checked and the plug is in I'll try changing the oil when I get the chance and go from there. It wouldn't surprise me if the shop built it a little sloppy unfortunately I heard the bad reviews on him after the fact and the good ones before lol thanks for the advice I'll keep you posted on the outcome
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If you want to look/diagnose it yourself, I will give you the advice that my mentor Ken Neve told me back when I was having my oil problem and everyone insisted we were ok:

Get an oil pump priming shaft and spin the oil pump while you tear into the engine (intake, timing cover), look for where the oil is GUSHING out ---> that will be your leak/pressure loss....

Back then the priming shaft was not available, but I had welding class in high school, so I bought the proper size hex wrench (if I remember correctly it was 5/16" hex) and cut off the bend, then welded it to a 3/8" rod... I then took it to the garage that we rented and tried it and saw no oil gushing... Then my nosy brother came in and saw the drill and shaft on the engine and just had to give it a whirl... Suddenly a jet of oil came shooting out from behind the camshaft thrust plate and squirted 6 - 10 feet right at me while I was standing in front of the engine... I lit up and told him to do it again (he thought I was going to start a fight with him at first)... He did it again and another jet of oil came out... We removed the camshaft thrust plate and there were no galley plugs in the holes...

After putting the oil galley plugs in and reassembling the engine, it had 65 psi....

I've had some people criticize me :realcrazy: and say that the camshaft thrust plate will seal the galley holes, but I found differently and ALWAYS use the galley plugs... My experience proved to me that I needed them... It didn't squirt when I did it, but when my brother did, which tells me that it may not always seal properly without the galley plugs behind the thrust plate...

Since then I always run high volume with high pressure spring to get 75.... A little too much oil and pressure is better than not enough... It's better safe than sorry, especially with oil pumps...
 
the factory spec is 55 psi @ 2000 rpm. I run 10w-30. the low pressure is not caused here from the bypass in the pump-so a higher pressure relief valve spring will not increase pressure. I run a hi volume pump with a 7 quart pan cuz I go to 7000 rpm-I do not think a hi volume pump is the answer here. throw on a high flow oil filter. maybe leaking at the cam thrust plate-but check out this plate that was sold by moparperf. probably the issue is loose clearances - main or rod bearings, or the dreaded large chamfer at the tops of the lifter bores and roller lifters
cam plate.jpg
 
Mopar Tim said:
i am not saying your engine has a problem, BUT there is a plug behind the dist drive that a non mopar builder forgets lots of time,I forgot it one time myself. Low oil pressure is the result of that. Kind of common, and can be installed with the engine in the car, a real pita but can be done. Not saying that is your issue but something to look at.
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krazykuda said:
I had a similar issue on my first rebuild... It turned out that the machine shop did not put the oil galley plugs in the front of the lifter galleys... Pull the timing chain cover off and then remove the camshaft thrust plate and make sure that there are two plugs behind the plate...

Read this article to see which ones exactly:

How to Assemble the Front of a Small Block
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Double Ditto, on this! Happens a lot when Cheby and Ferd rebuilders do a Mopar! The camshaft thrust plate blocks the holes but not very well, so low oil pressure is often the result. This is definitely not easy to check, so give the heavier oil a shot first. I wouldn't be happy with that oil pressure on a new build either....
 
Marcohotrod said:
the factory spec is 55 psi @ 2000 rpm. I run 10w-30. the low pressure is not caused here from the bypass in the pump-so a higher pressure relief valve spring will not increase pressure. I run a hi volume pump with a 7 quart pan cuz I go to 7000 rpm-I do not think a hi volume pump is the answer here. throw on a high flow oil filter. maybe leaking at the cam thrust plate-but check out this plate that was sold by moparperf. probably the issue is loose clearances - main or rod bearings, or the dreaded large chamfer at the tops of the lifter bores and roller liftersView attachment 1715142985
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I have never used that plate I always use the SP plate not sure what year the changed them
camthrustplate003.jpg
 
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