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Discussion Starter · #21 ·
I looked into the fluidampr, (probably read about it on this page) but I decided against it because of cost, and I’m running one off a 24v. So far I’m happy with the vibrations. If it starts rattling things apart I will re-evaluate!
 

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The regular 24 valve dampener has little to no effect on vibration on a 4bt. It won't hurt but it lacks the weight of the fluid type. The 4bt does not have harmonics like the 6bt. The 4bt dampener adds mass to the crankshaft to help control the vibration. The factory Cummins unit with the adapter weighs around 26 lbs. Yes, cost is usually the determining factor as to whether you use a dampener on a 4bt. The stock 4bt unit which is basically a marine item was around $600 with the adapter and bolts. The same kit from Fluidampr is $700. Not a cheap option.
 

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Discussion Starter · #24 ·
Well I guess I spoke too soon. Took it out for a drive today, got it good and warm, had the same low pressure even with the higher idle. I changed the oil and filter with rotella 15-40 and had no change. I’m thinking I’ll go ahead and change the pump and work back from there.
 

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Discussion Starter · #25 ·
Any thoughts about going with a high volume pump? Diesel tuff has 5346430 for sale listed as a high flow for the 4bt. I am running a HX30W which may be taking some extra oil
 

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Any thoughts about going with a high volume pump? Diesel tuff has 5346430 for sale listed as a high flow for the 4bt. I am running a HX30W which may be taking some extra oil
I'd say it depends on useage.. I have a 6bt with 350,000 miles.. and it idles at about 15 fully warmed.. 65-70 cold... buyt notw powered up.. factory oil pump is fine unless you are doing high rpm /high power I don't see the point... but if you are going to replace the oil pump... Id suggest changing the cam bearing at the same time.. you'll be there anyways..
 

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Discussion Starter · #27 ·
So I finally got this thing put back together, I pulled the pan and pickup to clean and inspect, and also replaced the oil pump. I took it on a drive and got it warmed up, I was thrilled that after it was up to temp, my idle psi was around 40! Then as I kept driving, it wouldn’t come below 80 at idle, and acceleration would put it well above 120. Idled home and shut it off, restarted and it was perfect again, 30-40 at idle. Drive it around the block, pulled in the driveway and it was zero at idle unless I fed it some fuel. So I guess I’m looking at the oil regulator/and oil bypass seems like the regulator may be sticking. I do see some wear marks on the plunger, is it possible to polish these? Or just replace?
 

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I know you checked the oil gauge against another gauge but what type of gauge is it? Would be worth rechecking.
You can clean the plunger.
Cheers Steve
 

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Sure does sound like the regulator is malfunctioning. Also, the bypass should kick in around 65 PSI so this is really odd. Don't believe you've ever mentioned what type engine block, oil filter housing you have and which type gasket. You could have a miss match of parts there causing problems.
 

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So I finally got this thing put back together, I pulled the pan and pickup to clean and inspect, and also replaced the oil pump. I took it on a drive and got it warmed up, I was thrilled that after it was up to temp, my idle psi was around 40! Then as I kept driving, it wouldn’t come below 80 at idle, and acceleration would put it well above 120. Idled home and shut it off, restarted and it was perfect again, 30-40 at idle. Drive it around the block, pulled in the driveway and it was zero at idle unless I fed it some fuel. So I guess I’m looking at the oil regulator/and oil bypass seems like the regulator may be sticking. I do see some wear marks on the plunger, is it possible to polish these? Or just replace?
so if that doesn't work , check for a spun bearing.. like the cam bearing..
 

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Discussion Starter · #31 ·
Sure does sound like the regulator is malfunctioning. Also, the bypass should kick in around 65 PSI so this is really odd. Don't believe you've ever mentioned what type engine block, oil filter housing you have and which type gasket. You could have a miss match of parts there causing problems.
I’m using a glow shift multi gauge, but the factory gauge fluctuates as well.

Wouldn’t the cam bearing Cause low oil psi at all times?

i can attach a picture, but I don’t know what block it is. The tag is missing. I haven’t been into the oil cooler yet
Automotive tire Automotive design Motor vehicle Automotive exterior Engineering
 

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You have the standard 4bt engine block and it is likely a CPL 0767. The thing that identifies that CPL is that tilted exhaust manifold was only found on that one as far as I know. That tilted manifold was discontinued because they found it caused premature wear on the turbo bearings. The gasket for that filter head would be Cummins part 3929792 shown below. You can find those as cheap as around $7 to $22. If you need an engine serial number to look up parts you can try 44205343 or 44216332. They are both CPL 0767 but have different injection pump models. Neither of those ESN's show the exhaust manifold since it is no longer used.
 

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Discussion Starter · #33 ·
You have the standard 4bt engine block and it is likely a CPL 0767. The thing that identifies that CPL is that tilted exhaust manifold was only found on that one as far as I know. That tilted manifold was discontinued because they found it caused premature wear on the turbo bearings. The gasket for that filter head would be Cummins part 3929792 shown below. You can find those as cheap as around $7 to $22. If you need an engine serial number to look up parts you can try 44205343 or 44216332. They are both CPL 0767 but have different injection pump models. Neither of those ESN's show the exhaust manifold since it is no longer used.
Great info, I’ll probably pick one up and pull it apart and replace it, and the bypass if it keeps acting up. Do you know if the regulator plunger is specific? Or does the 3918428 cover all?
 

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On the parts, here are the current numbers. None of these are extremely expensive but you may find some wide price variations. Here's a complete regulator set for $18.05 coming out of China. Delivery time is about one month. 1 SET Plunger Spring Plug and O-Ring 3918427 3918428 3915787 3909397 for Cummins | eBay Buy it from a Cummins dealer and the plunger alone may be $30 or better. Just have to scan the net to see who has the best deal.

3936365 Bypass Valve
3918428 Regulator Plunger
3918427 Spring
3902425 Sealing Washer
3929792 Filter Head Gasket
4932124 Oil Cooler Gasket (Don't have to replace this one but might do it anyway)
 

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I’m using a glow shift multi gauge, but the factory gauge fluctuates as well.

Wouldn’t the cam bearing Cause low oil psi at all times?

i can attach a picture, but I don’t know what block it is. The tag is missing. I haven’t been into the oil cooler yet View attachment 131728
a spinning bearing will some times block the Oil hole to the bearing.. causing an increas in pressure.. and when it spins back to the original position.. so the oil flow hole is open... you'll lose most if not all oil pressure.. because the bearing is too loose..
 

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Discussion Starter · #37 ·
Well I’ve made some progress. I decided to put the manual gauge back on because the high psi just didn’t make sense, and the apparent sending unit issue seemed to be getting worse. I ended up mounting a good manual gauge temporarily and I’ve been driving it around and watching it. Seems to like to settle around 16 at idle when at temp and makes 45ish at speed. I didn’t get into the cooler, but i replaced the regulator plunger because of the wear marks on it. So I guess it’s just keeping a eye on it from here, thanks for the help everybody!
 

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I sort of suspect some of your issue has been a faulty gauge reading. In very cold weather these engines can have a high pressure spike on start up but it quickly goes away. Your pressure readings now sound more normal. A faulty regulator could also have been contributing to the problem so you've taken care of that.
 
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