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

3.8 Engine rebuild

Thread Tools
 
Search this Thread
 
  #81  
Old 03-25-2024, 05:20 AM
Peter3442's Avatar
Veteran Member
Join Date: Aug 2020
Location: Oxford, UK
Posts: 1,868
Received 1,318 Likes on 989 Posts
Default

As JB wrote, the oil pick up tubes go with the sump. The 4.2 sump and pick up tubes should transfer OK to the 3.4 engine.
 
  #82  
Old 03-25-2024, 08:55 AM
jayd2's Avatar
Senior Member
Thread Starter
Join Date: Mar 2021
Location: Oklahoma
Posts: 125
Received 24 Likes on 12 Posts
Default

Originally Posted by Peter3442
As JB wrote, the oil pick up tubes go with the sump. The 4.2 sump and pick up tubes should transfer OK to the 3.4 engine.
The 3.4 tube that goes from the block to the oil pump has a 2 bolt mount at the block. All of the tubes I've found are 3 bolt mounts.
 
  #83  
Old 03-25-2024, 10:15 AM
Peter3442's Avatar
Veteran Member
Join Date: Aug 2020
Location: Oxford, UK
Posts: 1,868
Received 1,318 Likes on 989 Posts
Default

Originally Posted by jayd2
The 3.4 tube that goes from the block to the oil pump has a 2 bolt mount at the block. All of the tubes I've found are 3 bolt mounts.
Sorry, I was thinking of the pickup tube from the sump to the pump. The pipe from the pump to the block has a different flange on the block end as you say. The pump to block might be available from one of the usual suppliers. Otherwise, it's a case of making one using the flange from the 3.4.
 
The following users liked this post:
Glyn M Ruck (03-25-2024)
  #84  
Old 03-25-2024, 08:03 PM
jayd2's Avatar
Senior Member
Thread Starter
Join Date: Mar 2021
Location: Oklahoma
Posts: 125
Received 24 Likes on 12 Posts
Default

I purchased both oil feed tubes today. The pump to the block feed line has a 2 bolt mount, most I found were a 3 bolt mount. Were there problems with the 2 bolt style mounts?
 
  #85  
Old 04-03-2024, 01:25 PM
jayd2's Avatar
Senior Member
Thread Starter
Join Date: Mar 2021
Location: Oklahoma
Posts: 125
Received 24 Likes on 12 Posts
Default Rear Main Seal

The engine is a 3.4 with a steel oil pan. The rear main seal assembly the "Cover", has an upper and lower where a rope seal would be installed. The two piece Cover on my engine does not have a channel for the rope seal (highlighted in red). The surface is totally smooth, what type of crank seal does the Cover use? The crank does have a scroll, is that the only seal for the rear main? Is the smooth style Cover like mine for the scroll type of crank?





 

Last edited by jayd2; 04-03-2024 at 01:52 PM.
  #86  
Old 04-03-2024, 02:36 PM
Jagboi64's Avatar
Veteran Member
Join Date: Jan 2013
Location: Calgary, Canada
Posts: 4,839
Received 3,148 Likes on 2,082 Posts
Default

I believe you have an early engine that didn't have a rear seal. I've never actually seen one in person before. You should be able to move over the 4,2 seal housing I think.
 
The following 2 users liked this post by Jagboi64:
Glyn M Ruck (04-04-2024), Peter3442 (04-03-2024)
  #87  
Old 04-03-2024, 04:08 PM
jayd2's Avatar
Senior Member
Thread Starter
Join Date: Mar 2021
Location: Oklahoma
Posts: 125
Received 24 Likes on 12 Posts
Default

Originally Posted by Jagboi64
I believe you have an early engine that didn't have a rear seal. I've never actually seen one in person before. You should be able to move over the 4,2 seal housing I think.
Does the older design tend to leak a lot?
When did they change to the rope style?
I found some post on switching over and it's supposed to require machining the crankshaft.
 
  #88  
Old 04-03-2024, 05:15 PM
Jagboi64's Avatar
Veteran Member
Join Date: Jan 2013
Location: Calgary, Canada
Posts: 4,839
Received 3,148 Likes on 2,082 Posts
Default

I think the older style would leak if you parked on a hill. To be honest, the rope seal also leaks, so I expect the early one really leaked. However, I have no experience with them. As best I can tell, the seal was introduced with the Mark 2, so approximately 1960.

The talk of machining the crank is when people convert to a later one piece seal. The end of the crankshaft is too large to get a one piece over the flywheel mounting flange. The 4.2 style seal is a 2 piece rope seal, as long as the housing halves are the same bolt pattern it should bolt to the block.
 
  #89  
Old 04-03-2024, 05:35 PM
jayd2's Avatar
Senior Member
Thread Starter
Join Date: Mar 2021
Location: Oklahoma
Posts: 125
Received 24 Likes on 12 Posts
Default

Originally Posted by Jagboi64
I think the older style would leak if you parked on a hill. To be honest, the rope seal also leaks, so I expect the early one really leaked. However, I have no experience with them. As best I can tell, the seal was introduced with the Mark 2, so approximately 1960.

The talk of machining the crank is when people convert to a later one piece seal. The end of the crankshaft is too large to get a one piece over the flywheel mounting flange. The 4.2 style seal is a 2 piece rope seal, as long as the housing halves are the same bolt pattern it should bolt to the block.
The scroll is part of the crankshaft, it must be machined off to fit the seal diameter.
 
  #90  
Old 04-04-2024, 05:12 PM
Jagboi64's Avatar
Veteran Member
Join Date: Jan 2013
Location: Calgary, Canada
Posts: 4,839
Received 3,148 Likes on 2,082 Posts
Default

Originally Posted by jayd2
The scroll is part of the crankshaft, it must be machined off to fit the seal diameter.
No, all the later cranks have a scroll as well as the rope seal. As far as I know, you can simply add the later seal.
 
The following users liked this post:
Glyn M Ruck (04-04-2024)
  #91  
Old 04-04-2024, 05:58 PM
Glyn M Ruck's Avatar
Veteran Member
Join Date: Jul 2012
Location: Llandudno, Cape Town, South Africa
Posts: 5,393
Received 1,452 Likes on 1,124 Posts
Default

The SKF flex seal. Scroll requires to be machined off crank.











 
  #92  
Old 04-04-2024, 06:16 PM
Glyn M Ruck's Avatar
Veteran Member
Join Date: Jul 2012
Location: Llandudno, Cape Town, South Africa
Posts: 5,393
Received 1,452 Likes on 1,124 Posts
  #93  
Old 04-04-2024, 06:18 PM
jayd2's Avatar
Senior Member
Thread Starter
Join Date: Mar 2021
Location: Oklahoma
Posts: 125
Received 24 Likes on 12 Posts
Default 3.4 Crankshaft

This is the crankshaft I have. There's a main bearing and the scroll, no surface area available for a rope seal without machining the scroll down to the diameter needed for a seal. The scroll is where the 2 piece cover is positioned.



 
  #94  
Old 04-06-2024, 08:19 AM
Peter3442's Avatar
Veteran Member
Join Date: Aug 2020
Location: Oxford, UK
Posts: 1,868
Received 1,318 Likes on 989 Posts
Default

It's not easy to judge from the photo, but I think yours is the early crank with the deep scroll that works without a seal. My opinion is that it's a satisfactory design. It will drip some oil especially if the car is parked with the nose high. What runs out is mainly oil that drains down the crankcase wall and is unlikely to have a major impact on oil consumption. If oil drips onto driveways worries you, add a catcher on the outside of the sump. Make the sides of the catcher low enough to empty the catcher in fast cornering.

Later crankshafts with the rope seal still have a scroll, but it looks more like a shallow groove. There are some upgrades to modern type seals. With these the crank is machined down to match a standard seal size. A load of hassle for a five bob seal.

As with many things, improvements and upgrades may claim some gains, but for most purposes the original is simple, efficient, and trouble free.
 
The following users liked this post:
Glyn M Ruck (04-06-2024)
  #95  
Old 04-06-2024, 10:09 AM
Glyn M Ruck's Avatar
Veteran Member
Join Date: Jul 2012
Location: Llandudno, Cape Town, South Africa
Posts: 5,393
Received 1,452 Likes on 1,124 Posts
Default

I generally agree with everything that Peter says. Much would be dependent on amount of use the vehicle gets.

My only concern is that our classics should not be polluting our roads & parking areas with oil. I fully accept that this engine is being fitted to a purpose made vehicle.

That is a very old scroll design. My Rope sealed rear crank has a very gentle scroll on it. It does not leak. It was fitted to the book with the correct Churchill tools & no trimming which is an absolute no-no.
 

Last edited by Glyn M Ruck; 04-06-2024 at 10:48 AM.
The following users liked this post:
Peter3442 (04-06-2024)
  #96  
Old 04-06-2024, 10:50 AM
Glyn M Ruck's Avatar
Veteran Member
Join Date: Jul 2012
Location: Llandudno, Cape Town, South Africa
Posts: 5,393
Received 1,452 Likes on 1,124 Posts
Default

Refresh page for edits.
 
  #97  
Old 04-06-2024, 02:18 PM
Peter3442's Avatar
Veteran Member
Join Date: Aug 2020
Location: Oxford, UK
Posts: 1,868
Received 1,318 Likes on 989 Posts
Default

Purely from what I've read, the 1950s 3.4 engines with the simple scroll had similar oil consumption to those from the 1960s with a rope seal. As the consumption isn't low in either case and 'normal' is extremely variable from a half to one and a half litres per 1,000 miles it's hard to be precise about how much passes the rear crank seals. Still, it's difficult to imagine that it's much more than 100 ml per 1,000 miles. Now we have to decide if that's a tolerable amount to spill on tarmac or if we want to collect it. If we use a catcher below the old scroll seal, the oil could be collected in a small tank and emptied at the usual service intervals. I've heard of arrangements that drain the catcher back into the sump, but there are various arguments against that. A third possibility is to try to suck/pump the liquid up into the inlet manifold and burn it.
 
The following users liked this post:
Glyn M Ruck (04-06-2024)
  #98  
Old 04-07-2024, 06:50 PM
Fraser Mitchell's Avatar
Veteran Member
Join Date: Dec 2009
Location: Crewe, England
Posts: 9,409
Received 2,451 Likes on 1,949 Posts
Default

Surely if the whole engine is in bits, now would be the time to install a lip-seal kit. The scroll is machined off as part of the procedure.
 
The following users liked this post:
Glyn M Ruck (04-08-2024)
  #99  
Old 04-08-2024, 09:26 AM
Peter3442's Avatar
Veteran Member
Join Date: Aug 2020
Location: Oxford, UK
Posts: 1,868
Received 1,318 Likes on 989 Posts
Default

I sort of agree with Fraser, but, if the scroll and housing aren't worn and the scroll groove is clean, then scroll seals can work very well for a very long time. With clean oil and the right clearance, they work forever and the leakage can be minimal.
 
The following users liked this post:
Glyn M Ruck (06-30-2024)
  #100  
Old 04-08-2024, 08:45 PM
jayd2's Avatar
Senior Member
Thread Starter
Join Date: Mar 2021
Location: Oklahoma
Posts: 125
Received 24 Likes on 12 Posts
Default HD6 Choke Operating Solenoid Assembly

My 3.4 has an HD6 set of carbs with a Choke Operating Solenoid. There is a tube called a "Starting Pipe" that I found in a parts diagram. Where is this Starting Tube located? What is it's purpose?
 


Quick Reply: 3.8 Engine rebuild



All times are GMT -5. The time now is 03:22 AM.