Martin6107

For those of you that have rebuilt, repaired or tinkered with a 4.6 Modular engine, what tips would you pass on to someone about to tackle their own 4.6 DOHC rebuild? I am looking for tips or hints specific to the modular motor that folks want to pass on to me to help make sure this project is a success.

Here is the background ….

I bought a 96 Cobra Convertible in May that was barely running. After a bit of tinkering, I found that the secondary timing chain on the right head had snapped. Bits of chain had been getting munched up in the engine over time and evenly redistributed through the oil. Yuck! Everything turned alright, but I was concerned about all those chunks of junk floating around in the oil passages. So, it was time for a Teksidectomy.

Fast forward, the engine block is fine. It will be bored 0.030 over and decked. The crankshaft is likely going to just need a polishing or a slight grind. I decided stay with stock Speed-Pro Hypereutectic Pistons but upgraded the connecting rods with a forged set from MMR. The engine will be ready to pickup next week. Tousley Ford has provided me with replacement timing set and all the factory replacement parts I need for this rebuild.

The heads are being reworked by a local specialty shop that does a lot of work for local racers. The right head needed a bearing installed in one cam bearing journal. All 4 cams can be brought back to spec with a polishing. Both heads will be surfaced, get a 3 angle valve job as well as a bowl blend to improve airflow efficiency. The heads will be done by Friday.

My objective is to get this beast back on the road with 10-15% improvement over factory form. There are no plans to boost it in the future which is why I didn’t bother with forged pistons. I am just looking for something to cruise in style when the weather is good and be able to keep up with new of the new V6’s.

I have successfully rebuilt several other (non-modular) engines over the years. What recommendations do you folks have to help me get this engine back together and running again? A Ford Service Manual and Haynes guide are already in hand. What other ‘stuff’ do I need to know about to be successful?

school boy

first off, why put forged rods and not forged pistons? i understand the staying n/a part but spend a little more and you could have had a tough short block. but anyway, if you are going to assemble it, get a degree kit to degree in your cams. if degreed in correctly, youll pick up a couple of ponys. ask around for what to degree them at.

Martin6107

If budget was not relevant, then anything would be possible. This is not the case. The objective for this build is 10-15% over factory horsepower. A good set of forged pistons easily runs 3X the cost of hypereutectic. The build objective did not warrant investing in forged pistons. I chose to replace the stock connecting rods with forged I-Beam rods to help with high RPM stability.