Engine and Transmission Tech

Dropped both a 4.0 and a 4.6 off at the machine shop. He tells me both blocks have out of round cylinders and need to be bored or at least mega honed. He can't find oversized pistons and recommends I send the pistons out to have a coating sprayed on the pistons and then hone the cylinders until they are round. The coating on the pistons is good for a few thousands to make up the difference from the extra honing required. Cost for the coating is around $300. Short of dropping $2K to have top hat liners installed, what are my options? Seen lots of threads where people are talking about Ford 5.0 pistons and Chevy 305 pistons, etc. Whats my best cheapest option? Don't mind throwing extra cash at the problem as long as its worth it. I just wanted a rebuilt 4.6 for one of my TR8s and wanted it cheap. Not looking for big HP. My LS3 powered 8 takes care of that. Just want a cruiser that my wife and daughter can enjoy.

Real Steel in UK used to have +20 pistons for 4.6, actually still advertise them. Might be worth asking ?

DW4620 piston set £156,32
AZ4620 ring set £46,98

Prices include UK VAT.

[www.realsteel.co.uk]

Likely your best, cheapest option, if available. Cross your fingers on the liners.

Todd, 4.6 block supposedly better than 4.0 for liner issues. 4.0 pistons in the 4.6 block have a little higher compression.

Ended up ordering .020 over 4.6 pistons from Rimmer Bros. Supposedly they were having a 15% off sale, but I didn't get the discount. Guess I'll have to call in the morning and see whats up. To my door price was just under $400. There was no listing for 4.0 oversized pistons or I would have gotten those. The 4.6 was a late 2002 block. At that point in time they only made 4.6 blocks, so doubt its any better than the 97 4.0 block.

Quote:

I have now found the reference from Des Hamill's book "how to power tune rover V8 Engines". He states that in 1993 Land Rover were aware of the problems with the variation in wall thickness in 4.2 engines and later 4.0 and 4.6. The wall thickness of the bores varied between 2.1 and 3.0 mm. After 1997 blocks were given one of three grades blue minimum of 2.2, yellow 2.5mm and red 2.8mm a daub of the appropriate colour was put onto the valley of the block. Until 1997 4.0 engine were made from 2.2mm to 2.5mm blocks and 4.6 engines 2.5mm and above. after 1997 4.6 engines were only made from red blocks ie 2.8mm and above unless there was a shortage of thick walled blocks. Some pre 1994 blocks left the factory with as little as 1.2mm of wall thickness.
[forum.britishv8.org]

The exception to this is that I have read that Rover did not build all engines in-house & their suppliers used whatever engine blocks they had

The Brits certainly took the game of Russian Roulette and made it their own on this one.

Jim