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Head confusion - pocketed piston

Posted: Tue Oct 03, 2017 10:26 pm
by southernd
I've read the forums extensively but I'm just trying to get my head around what I need to do.

I have a standard Rover 4.6 V8 in a 920kg car. I want to upgrade the following over the winter:

Camshaft
Heads

I have a spare couple of heads for the 4.6 which I wish to upgrade to the Stage 3 RPI head kit as well as some port work. I've also looked at the cams however I see there is an issue with flat pistons(unlike pocketed in TVR).

So here is the confusion. If I put larger valves in the head are they any more or less likely to come into contact with the piston if I used a mild cam such as the MC1 or do the clearances remain the same? I'd obviously like to avoid putting in pocketed pistons if I can Very Happy

Many thanks for your help!

Posted: Wed Oct 04, 2017 8:14 am
by gd302
The MC1 gets rave reviews from what ive read about it, im not sure on the specs but the Tvr guys really rate it. Im currently doing a cam refresh on my 4.0 engine and its top of my list at the moment. (no cut outs)
Their stealth cam is also reported to be very good but requires cut outs.
Ive also read good reports about crower cams but ive had no success in getting any info on them.
Im no expert but if you don't go mad with the heads its the cam lift specs that cause problems with piston contact.
V8 Developments seem to be the most highly regarded suppliers and are one of the only ones that bothered to reply to my questions, they are worth a call and a chat.

Posted: Wed Oct 04, 2017 8:50 am
by southernd
Thank you, I'll give them a call :D I had read on the Crower 50232, they're much better priced than most of the others I've seen($200 against £535).

http://thebritishcar.com/archive/index.php/t-451.html

From what I read most need pocketed pistons though :(

Posted: Wed Oct 04, 2017 10:39 am
by gd302
Yes the full cam kit is about £500 including everything to do the job.
No point going too wild on a light car.