MKI / MKII S type 240 340 & Daimler 1955 - 1967

3.8 Engine rebuild

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  #261  
Old 08-18-2024, 03:45 AM
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Yes, quite a lot of oil mist escapes via breathers in all engines, which is one of the reasons that designs with catch cans have an attraction but may be difficult to make work. The plenum in the series 3 fuel injection intake is a low point in the intake and easily collects half a pint of oil. Fortunately, it doesn't upset the engine running too much.
 
  #262  
Old 08-18-2024, 08:08 AM
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This was the original filter location. The air flow at was definitely pressurizing the crank case. All of the engines I've owned had a vacuum line attached to the intake with an inline check valve.



 
  #263  
Old 08-18-2024, 08:19 AM
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Originally Posted by David84XJ6
A flexible breather line will let you vent engine to atmosphere, closer to the ground below your motor. You will get a messy oil film all over the side of the engine with your current configuration.

https://mossmotors.com/jes-8234-cylinder-head-breather

Rgds
David
I had a piece of scrap copper tubing and it allowed for a quick fix to see if crank case pressure was causing the rear main to leak. There is a long list of issues I still need to address to refine the installation of the Jaguar engine.
 
  #264  
Old 08-18-2024, 08:39 AM
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Originally Posted by jayd2
This was the original filter location. The air flow at was definitely pressurizing the crank case. All of the engines I've owned had a vacuum line attached to the intake with an inline check valve.

Apart from any effect of the air flow, you definitely don't want the filter. Flow from the breather is out from the crankcase. The filter serves only to block increase pressure in the crankcase as it oils up.

If you're not going to a more sophisticated system with a PCV (one way valves, catch can, etc), the ideal is to have the breather exit at or a little below atmospheric. Then, there's no pressure pushing oil out through crankshaft seals and the like, and not too much flow through the breather carrying out oil mist.
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Old 08-18-2024, 09:07 AM
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A vacuum based PCV might not a good idea, the rear main has no seal. Creating a vacuum could cause air flow to enter the rear main scroll, possibly allowing contaminates to enter the engine.
 
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  #266  
Old 08-18-2024, 11:43 AM
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to do it right, it looks like i'll need to route it back to one of the two new air cleaners i've installed. i think a plastic tube and fixing hardware for the tube was provided with each air cleaner. a hose of proper ID and two hose clamps should do it. if stout enough the hose may not need support...could i be so lucky?
 
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  #267  
Old 08-18-2024, 03:39 PM
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Cut bottom of breather pipe at 45 deg. with long side forward, to create slight low pressure area at breather exit (I would not add the filter). With the exit below the engine you will have sufficient airflow. The length of the breather pipe is sufficiently long that you will have to trim it to fit.

Later "smog" cars vented breather to the back of the air cleaner(s) to burn blow-by fumes, unfortunately this introduced blow by oil into the intake system and made a mess in the carbs. I added a $25 eBay universal oil catch can before filters on my XKE. This is pure environmental, no benefit to engine or performance. I assume since you now understand it's a jaguar engine, you have the obligatory "oil drip pan" on you garage floor.
 

Last edited by David84XJ6; 08-19-2024 at 02:16 PM.
  #268  
Old 08-18-2024, 03:45 PM
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With a proper Plenum Chamber the oil drips out of the plenum chamber drains.
 
  #269  
Old 08-18-2024, 03:52 PM
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With your vehicle you can do as you like.
 
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  #270  
Old 08-21-2024, 02:45 PM
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Default First Oil Change

I just completed the first oil change. The oil filter paper pleats inspection was good, it was very clean with minimal contaminates on the paper pleats. This engine has the downward facing oil filter, you must allow the oil to flow back into the pan to get an accurate level check. With 6 1/2 quarts the oil level is in the middle of the Full area.
 
  #271  
Old 08-21-2024, 02:52 PM
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Default First Engine Rebuild - Completed

This was my first engine rebuild, it was worth the effort. The engine is running great and I got to experience the rebuild process.
The Moss 4 speed with overdrive was also an interesting project. It had to be disassembled, cleaned and inspected, then reassembled. There were some issues but they were easily resolved.
 
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  #272  
Old 08-26-2024, 07:51 PM
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Default Oil pressure after oil change

Oil pressure higher after engine break-in and first oil change. The break-in oil was 30w with no detergent, it now has Valvoline VR-1 10w-30 racing oil. During the break-in period, the oil pressure was 25 psi at idle and 40 psi at 2000 rpm. With the Valvoline VR-1 the oil pressure is now 30 psi at idle and 50 psi at 2000 rpm. Should the oil pressure be different with 10w-30 VR-1?
 
  #273  
Old 08-27-2024, 03:09 AM
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It all depends where they blend within the viscosity range.



 
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  #274  
Old 08-27-2024, 03:29 AM
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Does the oil pressure stop rising at engine speeds above 2000 rpm? If it remains about constant, the relief valve is working and everything is probably OK. The usual guide is to have anything over zero at idle and 40 psi at 3000 rpm. (And of course there are all the usual previously listed provisos about electrical and mechanical gauges).
 
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  #275  
Old 08-27-2024, 06:21 AM
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Yes , as Peter intimates the electrical oil pressure gauges are notoriously inaccurate.
 
  #276  
Old 09-01-2024, 04:47 PM
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Default Laycock Overdrive - Engage/Disenage

The transmission, a Moss 4 Speed, has a Laycock overdrive. There is a mechanical lever and a solenoid on the overdrive that can engage or disengage the unit. How did the driver engage or disengage the overdrive? I haven't tested the solenoid. It looks like I could use the mechanical lever to operate the overdrive, is that possible?
 
  #277  
Old 09-01-2024, 05:22 PM
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Default Moss 4 Speeds

I just purchased 2 Moss 4 speeds with Laycock overdrives and 1 bell housing. One Laycock has a cracked housing and both transmissions are locked up. It will be interesting to see if any of the internals are good.
 
  #278  
Old 09-02-2024, 02:49 AM
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You cannot reverse these cars with the Overdrive engaged. That's why they have an inhibitor switch on top of the gearbox. If you do you will smash the rotary one way clutch & break the OD housing.
 
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  #279  
Old 09-02-2024, 05:07 AM
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Originally Posted by Glyn M Ruck
You cannot reverse these cars with the Overdrive engaged. That's why they have an inhibitor switch on top of the gearbox. If you do you will smash the rotary one way clutch & break the OD housing.
.... which is an extremely good reason for operating the overdrive electrically with the solenoid. Apart from that, it's really neat switching a gear in an old car by flicking a stalk on the column.
 
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  #280  
Old 09-02-2024, 03:59 PM
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Originally Posted by Glyn M Ruck
You cannot reverse these cars with the Overdrive engaged. That's why they have an inhibitor switch on top of the gearbox. If you do you will smash the rotary one way clutch & break the OD housing.
I just purchased 2 Moss 4 speeds with overdrives and one has a cracked overdrive case. I wonder if the damage was caused by a reverse/overdrive incident?

There are 2 switches on the transmission, one is for reverse, what is the other one for?
 


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