After the below findings I need to make the decision to Rebuild or Replace this 4.6 engine and greatly appreciate any constructive input.


Keep in mind I’ve owned this 04’ Disco 80,000 miles since new and have maintained it beyond the OEM manual.

Due to a decreasing oil pressure verified by external oil pressure gauge I decided to investigate. I also was burning about 1 qt of oil every 500 miles and completing a compression test revealed about 20psi less on the #4 cyl.

I pulled the oil pan and did not have a clogged sump pick up. Pulled the front cover and inspected oil pump which does fall outside limits. Purchased a new front cover.

Since I had the pan off I decided to pull the #8 rod cap and the #3 main cap to inspect the bearings. The #8 rod was showing copper and the #3 main looked good. This finding at the minimum would drive me to rod bearing replacements which could have been done with the motor in the Disco. I still haven't addressed my oil consumption issue which I believe is coming from bad ring so I decided to pull the engine for a complete teardown and inspection.

After having the engine out of the truck I pulled the heads which visually looked O.K. Then pulled the pistons out which lead me to discover that all of the upper rod bearing were down to the copper but only the #8 bottom half was down to the copper, I believe this is due to the force of the power stroke wear directing force on the upper bearing half. Probably would have been too long before I had some rod knocking or a spun bearing. I was interested in the clearance on the rod bearing so I plasti-gauged a rod and it was between .004-.005 well out of tolerance. The Pistons looked good and the crank measured round and within limits. I didn’t have a ticking engine which makes sense because the cam and lifters are in really good shape.

Not having a bore gauge to measure my cylinder bores I decided to take the engine to a well know highly recommend race engine shop for full detailed inspection. I just got the call today that the cylinder bores are all .005” out of round which in terms of ring sealing is very bad. In talking with Mark at D&D the engine can be bored .20 over with new pistons of course. The engine shop said the sleeve walls are about .80 thick so a .10 hone=.20 overall final would not jeopardize structure integrity of the engine. All this said I’m worried.

The Cost Options-

#1. Cost to rebuild original engine with be looking at an estimated=$3,300.00

#2. Cost to replace with Turner Engineering Assembly remanufactured with cross bolted block casting (not 3.9) fitted with ductile iron flanged liner upgrade, remanufactured crankshaft & conrods and includes new original equipment pistons, bearings, camshaft, timing equipment+head work=$3,650.00

I’m leaning toward the Turner Replacement but do like knowing that my engine can be built to very high standards with top quality replacement parts.

 

A presumably fluxed and top hatted motor with all of the big end bearings and machine work already done for $350 more than possibly finding you need massively oversized bearings somewhere on yours, or finding that once the liners are pulled and the buckets over bored that there's a crack that needs repairing, etc? Sounds like you're leaning in the right direction.

 

I wonder what caused the engine to be in this shape at only 80k miles? I would definitely go the route with flanged liners.

 

Turner is the way to go.
Why not look into a set of built 4.2 heads and let that new engine breath?

 

Mike,

Tell me more about the 4.2 heads? I have SAI.

 

Are you getting these prices straight from Turner? That option number 2 looks pretty good. On their website the also show to have a NEW block for about £350 more.

 

Go turner....

they have a great rep. and the prices for what you get are right on... when the times comes for me to replace or do major overhaul I am going to go to replace with TURNER.

 

Have you decided to go with the Turner Replacement engine? I will be in the market soon and want to know your experience with them. How much was the shipping from the UK? Plus the return freight of your original motor?

 

I did go with a turner block only since they did not have any short blocks. I purchase the reman sleeved block and I believe it was aboutv 1800.00usd and freight was 120ish. They did not require a core return. The were excellent to work with and the block was in the US within two days. One thing to note is the will send you an engine with a bore set for installation with new pistons. If you will use your original pistons you will want to tell them the diameters to get the optimal skirt to wall clearance of .001. PM me with any questions.

 

So what caused your excessive engine wear to begin with?
What oil were you using before?
What was your total cost?