Top Hat liners

[ppyvabw]

is the slipped liner thing more commom with the 4.6 than the 4.0???

Don't think so Ian, the 4L and 4.6L blocks were graded according to how thick the parent metal was, Red had the thickest ally around the liner, then yellow, then blue. Red was only used in 4.6s and blue was only used in 4s, yellow was used in both applications depending on the stock of red or blue. That's according to Des Hammill. Apparently the 4s were awful.

The 3.9 which had the same bore I think was ok for some reason, there were failures but not nearly as many.

That's how I understand things anyway.

[chodjinn]

So, with the heads off, you can actually move the liner by hand?? Holy crap!!!

yeah, you dont need much to move them when they go!

[ChrisJC]

The liner that I removed from a block with a crack behind the liner was not hand tight. In fact I just about reached the limit of my 12ton press before it moved, and it went with a heck of a bang!!!

But then it hadn't slipped, it had just got a crack in the block.

Chris.

[Wotland]

Mmmmmm I follow this topic and I am always curious to know how T-liner affects the integrity of the block.
Genuine Liner has an OD of 98mm and T-liner has an OD of 99.06mm.
Many blue grade blocks have been repaired with T-liners with success. And some of this blocks have only 2.1mm wall thickness. One time T-liner fitted wall thickness is only 1.6mm.

But I ask me if the fact later blocks are X-bolted does'nt generate too much constraints around tunnel bore and at bottom of liners. That's why some block crack finally.

[katanaman]

Lots of theories on why they fail really. Weak mixture for emissions, stretch bolts causing too much stress to bad design which is different to the 3.9 blocks. Top hats do seem to work whatever is left of the alloy round the sleeves. Course the top hats are thicker so maybe they can take more stress on their own and to be honest I don't really think 2.1mm of cast alloy is very structural anyway.

[matchmetisse]

My 4.0 l was tapping like a gud un and I thought it must be a loose liner,after stripping it down it turned out to be the ebay bargain "new"cam and tappets that I had fitted worn after 3000 miles Anyway am now building a 4.6 with my old block which is in good condition but I am having top hat liners fitted for piece of mind.I have just returned from the machine shop who is doing the work and would reccomend them,a lot of v8developments blocks on the floor waiting to be done,when he showed me the Ferrari Daytona engine that was under a milling machine I was well impressed!Cost is £650 including pressure test,and new cam bearings! www.chesmanengineering.co.uk