The V8 Owners Forum -

Probably just done myself out of big bore Pistons, as I gave in to a load of brake components to upgrade my rear brakes. One of the other jobs on the cards is to swap the diff out for a 3.14 tran x diff and uprated rear springs. I also have had a brake upgrade on the back burner to match the 6 pot fronts. I ended up getting the parts below. Need to make custom mounts and bespoke cables. Which I'll mock up over xmas when reconditioning the hub carriers and lobro joints in readiness for the diff swap.

B33fy wrote:Need to make custom mounts and bespoke cables. Which I'll mock up over xmas when reconditioning the hub carriers and lobro joints in readiness for the diff swap.

I was going to ask how you plan to mount the two calipers? Will be interested to see how this works out?

Tom.

minorv8 wrote:I have a more modest option waiting for the current engine to expire:




SBC Crower 6 inch rods and Icon +20 pistons from Real Steel.

The crank is a weirdo TVR crank with around 90 mm stroke. The only issue with this crank is that it has narrow TVR sized con rod journals.



So, the rods had to be narrowed a lot, the big end width is around 19,40 mm.



The only thing missing is a good block

I had the same issue with the TVR 500 crank and also narrowed the con rods. Don't buy Clevite bearings as they are too wide, so get standard RV8 ones.

SuperV8 wrote:
I was going to ask how you plan to mount the two calipers? Will be interested to see how this works out?

Tom.

The hub carriers are sierra's so hoping to make one mount utilising the two lugs. If not then two mounts using the lugs for the 4 pot and the hub carrier mounting bolts for the handbrake caliper. They may end up adjacent, opposite or some where in between depending on how it pans out.

Devonman, thanks for reminding ! I did have some fresh Clevites before I narrowed the rods and noticed that they will not fit. I have a new TVR 500 crank, rods and pistons as well and had to check the fit in those rods as well. Not surprising, too wide for them as well. I have not bothered with the bearings yet since the old engine has been working well.

I was assembling a 4.6 engine for my friend and noticed that one s/h rod bolt started to let go when torquing to 20 Nm + 80 degrees. I had set my torque wrench at a tell-tale setting (it would click just before the 80 degrees of rotation). Well, one of the bolts simply rotated over 90 degrees without never reaching the wrench´s setting. I removed it and there was some visible deformation.

So, even if the factory manual does not require the replacement of the rod bolts it might indeed be a wise move. Having said that, my current engine has s/h bolts and did not raise any alarms when assembled years ago. The next version will most likely see new rod bolts...

B33fy, here are some photos of the (almost) finished package: http://www.v8forum.co.uk/forum/viewtopic.php?t=14223

Thanks Minor, a tidy build. My Merlins are around 35cc, not sure how that affects the piston choice. Coops do those roller rockers you sell fit under Merlin rocker covers?

B33fy wrote:Thanks Minor, a tidy build. My Merlins are around 35cc, not sure how that affects the piston choice. Coops do those roller rockers you sell fit under Merlin rocker covers?

They fit under standard Rover covers so unless the Merlin covers are shorter then there should be no issue.

Rossco wrote:

B33fy wrote:Thanks Minor, a tidy build. My Merlins are around 35cc, not sure how that affects the piston choice. Coops do those roller rockers you sell fit under Merlin rocker covers?

They fit under standard Rover covers so unless the Merlin covers are shorter then there should be no issue.

I've got the heads now so I'll take a close look. There is some suggestion that spacers are needed under the covers when using a high lift cam.

Anyone know what compression I'd get using 4.6 Pistons with the 32cc heads? Or even 4.0 Pistons?

Still undecided on a few things. Been advised to use 4.6 +20 pistons and skim the block to get the compression up. Not that keen on taking material off especially off new liners as there would be nowhere to go if further work or reborn was needed done the line.

Against advice my preference would be 4.0hc Pistons with a thicker head gasket to adjust the C/R if needed.

If not then stick to standard bottom end and hope the heads,cam, ported inlet and ACT induction can get the power close to 300bhp.

Any thoughts anyone?

Visited ACT this afternoon and ordered up an induction system, the centre carbon plenum with jenvey throttle body. Manifold and base are being ported to 45mm with alloy trumpets being fitted. Also picked up a lightened flywheel and a few other bits including an Omex 710 ecu. So I can bin the megasquirt.

Anyone any thoughts on a cam? Also looking for a cheap set of uprated injectors (Gems manifold)

Out of curiosity; what clutch and gearbox are you using?

Tom.

SuperV8 wrote:Out of curiosity; what clutch and gearbox are you using?

Tom.

Going to go with the SD1 AP heavy duty clutch. It should be able to cope because of the low weight and less torque loading, the rear wheels are more likely to spin up. Will upgrade if it doesn't cope.

Refreshed LT77 box out of a Vitesse, again should cope for same reasons.

Not much of an update, still awaiting my induction system, delays at Jenvey unfortunately. Top hatted block sorted, found one already done in mint condition and took a punt on it.

A couple of queries, any suggestions on injectors? I was going to fit a synecdoche regulator adjusted to 3 bar. I was thinking green top 440cc injectors but I think they will be too big.

Any thoughts on pocketing pistons? I intended ordering a new set and sending them straight to the machine shop. My concern is will that work for the valves in the Merlin heads or do I need to measure up, trial assemble etc..

Rover heads have valves in different location than Merlins so ideally you need to trial assemble.

This is how my pistons look like

Thanks Minor, did you cut them yourself?