My 4.6 V8 Rebuild Thread

Only 10K, I could knock out at least 300 and change for that much incl liners. And as above, the CD's will suck like an electrolux before the engines starving. They don't run out on the last 4.6 I did and that's running fine in a RRC, with 5 speed and no need to drop gears up the F3 or across the mountains.

And running constant over 100 is a sure way to soften the alloys in the block and heads leading to the usual, BHG's and throw away engines. Also liners shifting to boot.

For 25K I can do you 500+ from 4.0toyo 1UZ and up to 11,000rpm if needed, or 30K will get you 800+ and up to 18,000.

I received my new ARP head studs and main bearing cap studs and bolts today. These are the new items (not yet in the ARP catalogue) made specifically for the Rover 4.0/4.6 rather than the usual items for the old Buick 215 engine.

I bought them from Fabre in Sydney and for those interested the cost was $269 for the 20 head studs/bolts and washers and $155 for the bearing cap studs etc and cross bolts.

When the block comes back from the engine builders the crank etc will go in then assembly can begin.

Good stuff.

They're nice to look at aren't they? :D

Yep ;)

And they would want to for the price.

Still waiting for my block to come back before I send in the crank etc for work. I had intended to keep the engine low compression mainly because it would be easier to find lower octane fuels outback but on reflection I think it might be better to go high compression. This is because the engine will be running mainly on lpg or in regions where I can get higher octane petrol but even if it is not available as long as I do not push the engine it should still run on 91 Ron (so I am told).

I assume the only changes I need is to put in high compression pistons. Are there any other issues I need to consider in doing this??

Thanks

Garry

Not really.
However you could drop the CR a bit from HC by taking a couple of CCs out of the Combustion chambers. You can safely remove material around the inlet valve to unshroud the valve, over to near the head gasket ring.

One of the many maths experts can tell you how much to remove to drop say .25 to get under 9:1. I would guesstimate about 2CC.
Regards Philip A

Quote:

---

Originally Posted by PhilipA

Not really.
However you could drop the CR a bit from HC by taking a couple of CCs out of the Combustion chambers. You can safely remove material around the inlet valve to unshroud the valve, over to near the head gasket ring.

One of the many maths experts can tell you how much to remove to drop say .25 to get under 9:1. I would guesstimate about 2CC.
Regards Philip A

---

Thanks Philip - please excuse my ignorance but why would I go to the cost of putting in HC pistons only to then reduce their CR?

Cheers

Garry

I suggest around 9:1 is an excellent compromise between lpg and petrol operation. If you travel away from civilisation you can save your LPG for climbing difficult hill etc, or carry a container of octane booster. LPG makes a good low range fuel whereas petrol is good for longer range. Water injection is also good for suppressing detonation.

Quote:

---

Thanks Philip - please excuse my ignorance but why would I go to the cost of putting in HC pistons only to then reduce their CR?

---

Because 9:1 is about max you will get away with using 91 octane and is quite a bit higher than 8.25:1.

Regards Philip A

Quote:

---

Originally Posted by PhilipA

Because 9:1 is about max you will get away with using 91 octane and is quite a bit higher than 8.25:1.

Regards Philip A

---

Ok thanks.

Garry