Ordering and Installing Top Hat Liners for 4.6 Bosch Engines

StangGT5

Well-known member
Feb 4, 2019
295
130
Atlanta, GA
I have rebuilt Rover V8s, but always started with known good engines that did not overheat or make noise. However, I have good pull-outs from a P38 and a couple 04 D2s and would like to build a top hat lined engine. I would appreciate knowledgeable guidance on the following questions:
  1. Since top hat liners are supposed to be to Rover V8s what studding is to Powerstroke 6.0s, does it matter whether I start with a D2 or P38 block? I may opt to use the P38 block since they benefited from quality control methods, but if these liners are so great maybe it doesn't matter.
  2. Can the o-ringed (newer version) top hat liners be installed by any good machine shop? If not, is it worth shipping the shortblock to a machine shop familiar with Rovers (in the southeast, hopefully)? I would hate to ruin a known-good 4.6 that could just be rebuilt without new liners and run 200K if not overheated.
  3. Where is the best place to order the top hat liners and accompanying pistons (if needed)?
  4. Can you run 4.0 pistons on a 4.6 rotating assembly? I have seen some mention of this in the Australian Rover forums, and it appears to bump compression significantly. Will it still run on 93 octane without pinging in hot temps?
  5. I have always used stock camshafts, but have a 04 D2 with an aftermarket cam (bought that way, previous owner forgot brand) and it pulls noticeably better around 2250 and up. Are there any good aftermarket cams that do not sacrifice low end torque or require tuning?
 

Swedjen2

Well-known member
Sep 12, 2018
594
127
California
1. Do your blocks have any colored paint? Blue, yellow or red? The blue dot blocks are the best of the 3 as far as dimensional accuracy and eveness between bore diameters.
2. I wouldn't give the job to any machine shop. They would be learning on the job. I'd ship it. Someone around here must know of a good shop near you. If not you could ship it to D&D in Michigan. They've been doing work on aluminum V8's since the 70's, maybe earlier.
D&D Fabrications, Inc.
Attention: Dan Lagrou, President
Mark Lagrou, C.C.B.W.
8005 Tiffany Drive
Almont, MI 48003 USA
Phone: 810-798-2491 9:00 A.M. - 5:00 P.M. M/S EST
Fax: 810-798-2777 Anytime​

3. D&D has the liners and can machine and install.
4. Ask them.
5. I have a Wedge shop cam. I think it's more of a street cam and not an off-road, low torque cam. If I put it in Sport mode, it does get out of it's own way pretty well, but I would say its similar to yours - comes on around 2000-2500 rpm's.
I would try a Crower - quite a few here run them. I believe Turner Engineering out of the U.K. sells Kent Cams. They have an excellent reputation.

H180 Kent Sports Torque Rover V8 camshaft


Kent Cams H180 'Sports Torque' camshaft has been designed as a straight forward replacement performance cam for the Rover V8 engine.

With a duration of 262º and a valve lift of 11.2mm the H180 camshaft improves low end torque and is capable of increasing peak power by 22bhp, all whilst retaining the use of OE valve springs and maintains stable idle characteristics essential for: everyday use, on or off road, manual or automatic gearbox cars.

An improved version of the former Kent sports torque H180 v8 camshaft

The new camshaft is produced on an improved 'Chilled Iron' cam blank which gives significantly superior reliability over the original production cams.

We recommend replacing the hydraulic cam followers when changing a camshaft and using Competition Cam Shaft Lube
 
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Maximumwarp

Well-known member
Mar 22, 2015
836
26
Fairburn GA
There’s a machine shop out in Winder called Eagle Machine. They specialize in British stuff. I’ve had them do a cpl sets of D2 heads, and they came out beautifully, but of course liners are a bit more involved. Call them and see if they’ve done it before, good chance they have.
 
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Lake_Bueller

Well-known member
Aug 11, 2004
2,105
59
56
Beloit, WI
  1. Where is the best place to order the top hat liners and accompanying pistons (if needed)?

I actually have everything you need already in a box from Turner Engineering out of the UK. I bought it with the intention of having a block done with the flanged liners. At the end of the day, I found a totaled D2 with a freshly rebuilt engine. The parts are listed in the classified section. Search "Turner"
 
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StangGT5

Well-known member
Feb 4, 2019
295
130
Atlanta, GA
Guys, thank you so much for the all the response. This is very helpful. I have a bit of time before I move forward, but your responses have provided a great roadmap. I will contact the machine shops noted above.

Swedjen2, I have not checked the block colors yet but good idea. I think one of us has recieved the color designations backwards though. The rover engine guide I have says the red blocks are the best, and blues were the worst. Based on that, P38s should have red blocks and my 04 D2 engines could be red or yellow (hopefully not blue).
 
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wrldky

Well-known member
Apr 21, 2004
410
7
Raleigh, NC
Had my 4.0 resleeved right here in Raleigh, NC from a Machine Shop that does a lot of them for a local Rover Garage. Had the engine rebuilt and the sleeves installed for $1850. The sleeves I bought from Turner Engineering for 474 Pounds. Pistons were 220 pounds from Rimmer Brothers.
 

mark.kellgren

Well-known member
Aug 23, 2005
54
4
Charlotte
Had my 4.0 resleeved right here in Raleigh, NC from a Machine Shop that does a lot of them for a local Rover Garage. Had the engine rebuilt and the sleeves installed for $1850. The sleeves I bought from Turner Engineering for 474 Pounds. Pistons were 220 pounds from Rimmer Brothers.
what was the name of the Raleigh shop?
 

Knightspirit

Well-known member
Sep 22, 2019
251
84
Mount Shasta, CA
"1. Do your blocks have any colored paint? Blue, yellow or red? The blue dot blocks are the best of the 3 as far as dimensional accuracy and eveness between bore diameters."

The early P-38 blocks were RED as I understand it - and had the best tolerances. As they got into the D2 series, the tolerances got worse and worse. So the P-38 block will be the best one - regardless of color. Here's a thought though. I had a lengthy discussion with someone very familiar with these rover V8's and he concludes that the 4.6 was and is a design flaw from the get go. He said that the longer stroke of the 4.6 goes beyond the water jacket - thus creating an over-heat scenario. He recommended building a 4.0 "Hammil" build (look that up) and getting a better, more reliable motor from that build. He also recommended using a 4.0 block - since they were less prone to heating. If you use the P-38 block - check it for cracks and warping of the cylinder bores.

Apparently - the killer build for these motors is swapping out some different brand parts (since it's actually a Buick motor really) and addressing all of the weak links - replacing the cam, piston rods and pistons, and using a special valve spring set up as well in a 4.0 configuration. I can post the whole discussion if any one really wants to read it....

D&D seems to know all of this stuff?
 

Eliot

Well-known member
Feb 4, 2008
736
47
Bozeman, MT
"1. Do your blocks have any colored paint? Blue, yellow or red? The blue dot blocks are the best of the 3 as far as dimensional accuracy and eveness between bore diameters."

The early P-38 blocks were RED as I understand it - and had the best tolerances. As they got into the D2 series, the tolerances got worse and worse. So the P-38 block will be the best one - regardless of color. Here's a thought though. I had a lengthy discussion with someone very familiar with these rover V8's and he concludes that the 4.6 was and is a design flaw from the get go. He said that the longer stroke of the 4.6 goes beyond the water jacket - thus creating an over-heat scenario. He recommended building a 4.0 "Hammil" build (look that up) and getting a better, more reliable motor from that build. He also recommended using a 4.0 block - since they were less prone to heating. If you use the P-38 block - check it for cracks and warping of the cylinder bores.

Apparently - the killer build for these motors is swapping out some different brand parts (since it's actually a Buick motor really) and addressing all of the weak links - replacing the cam, piston rods and pistons, and using a special valve spring set up as well in a 4.0 configuration. I can post the whole discussion if any one really wants to read it....

D&D seems to know all of this stuff?

I was always interested in the heads from TA Performance V8. They breathe much better.
 

rovercanus

Well-known member
Apr 24, 2004
9,643
244
o-ring liners are a band-aid to stop a cracked block from leaking combustion gases into the cooling system.

pinning just stops the sleeve from hitting the the top of the head and making noise
So don't use a cracked block.
 

Knightspirit

Well-known member
Sep 22, 2019
251
84
Mount Shasta, CA
Ya post it please.

OK - you asked for it - here is the whole conversation - great info. Part 1:

The ( Hammil ) Builds Involved Using the crank, rods and heads from a D1 or 4.0 D2 and a custom grind cam, along with Bee hive or short coil valve springs to prevent coil binding,, Special machine work on all of the sleeves after first decking the block.. I personally like the pan and front cover set up on a D2 better than the steel pan on the D1,But it also depends on which truck you are putting the finished engine in.. You can change the bore slightly and have forged pistons custom made for less money that stock rover parts, There are 4 or 6 tricks of the trade that can be done this way and you end up with a very low residual friction engine, that makes 90% of available torque only 300 or so rpms off of idle ,climes to 100% and then holds that torque up to about 4,000 rpm after that they go a bit flat.. They end up being extremely durable ,and drive out like a coiled spring on the low end.. The builds is expensive to do, The D1s and D2s may be getting to old for this to be practical any more.. But would still be very viable for a 90 or 110.. It will work Gems or Bosch either way..

Well I think most guys think they should build for horsepower, When realistically what your really need with this sort of vehicle is useable torque.. I Have built a couple dozen highly modified engines, looking for only 2 things, (1) useable torque, and Durability.. This is a really great way to go except for the guy that wants to tow a Fairley heavy trailer at 70 MPH, You have to sacrifice the high end a bit in order to get the low end torque.. If you are ok with that and don't mind not having high side gains this will be good for you. .But if you want an increased high side you should do an LS swap.. With Gems and Bosh aside, the late 4.0 and 4.6 blocks are identical, The only difference is that by that stage Rover was owned by ford, and some thing were already slated to be discontinued, To bridge the gap ford Invested is sonogram testing equipment, and every block was tested by hand, the testing was somewhat subjective, and resulted in the block being identified by simply putting a dab of paint on the engine block Vallie above where the cam runs, The best of the blocks with the least amount of core shift were chosen to become 4.6 liter engines, ones that did not make the cut for that became 4.0s and ones that did not make the cut for that became new replacement short and long blocks both 4.0 and 4.6..Yep the sold the worst of the blocks as new replacement engines... Go figure why so many were prone to failure???

So in theory if you are building an engine a 4.6 that has never been replaced with a factory new short block should be the best block to choose, But at the same time that block has been tutored with the heat produced by the 4.6 builds.. Guys don't really understand the thermodynamics involved... A 4.0 and 4.6 have exactly the same bore and even run pistons and ring sets with the same part numbers; to get the extra .6 liter the 4.6 has a longer stroke and as such shorter rods, Which in turn messes up your rod to stroke ratio which is a whole other story about what not to do when designing an engine.... Just sticking to the thermodynamics for now, the crank and rod configuration in a 4.6 allows the piston to be powered father down the cylinder sleeve, and actually allows the (Fire deck ) of the piston to be shoved down into an area of the block that is no longer exposed to cooling water on the outside, as a result, ( ON PURPOSE, AND WITH FULL UNDERSTANDING OF THE ENGINEERING STAFF ) that small area of the sleeve routinely ran as a hot spot under load..

This caused thermo stresses in this area of the block that eventually end up causing swelling and or the start of a thermo crack. This is basically why most of the 4.6s ended life with slipped sleeves, Usually on the 2 or even 4 rearmost cylinders, as they were farthest from the water pump and could run quite a bit hotter.... In short, a 4.6 Block was the best of the blocks available when the left the factory, But after being exposed to thermo stresses for 100,000 miles maybe not so much.. If you already have a 4.6 block it is definitely worth cutting out the rearmost sleeves, then hitting those counterbores with a sunet hone, just ever so slightly, in an effort to just clean it up enough to measure the ID at several places while keeping careful notes, And also looking for cracked areas running vertically, up the back side of the aluminum.... Generally speaking although a 4.6 block was in theory a better block when in left the factory, a block from a well maintained 4.0 will be in better condition and is a better candidate for a new build.. I Have all of the information in my notes someplace, but I could not put my hands on them easily, I will try to look them up if you have more questions.. But anyway there were I think 4 generations of Buick / Rover alloy blocks.. Very early blocks had 14 head bolts per side which did not work out so well, early blocks were also 2 bolt main cap configuration and early blocks had NO reinforcement across the cam Vallie.. If you plan to keep the rig indefinitely, I would start with a block that was originally 4.0 or a very well checked out 4.6 You will want a block with 10 head bolts per side, 4 bolt main caps and the 3 cam Vallie braces.... If you hold it to 4.0 liter you can actually builds a really good and very durable engine for a D1 or D2..I can give you more details later if you want...