I recently bought whitey of grimwolge to doner a few parts to my KE55 and a mates KE70. Well what I was wondering was what cam people have had the most success with a 5K. I'lll be running a 32/36 weber and extractors to begin with, using a 4K head, ported by my mate (thanks Mick). I'll be upgrading to a single 45mm DCOE carb at some point too. Whitey has a massive 88 - 42 cam, I don't think the 5K would be too happy about that as a streeter ... or should I wait and see now nice it rumbles.

 

I'll be running 202 Holden H/D valve springs, because these were inteded for a stage 3, 6 cyl cam, should I only use the outer spring? They are bloody hard eh.

 

How much should I get shaved off the head, will it up the compression much, is it worth it?

 

Has anyone put in oversized valves in a 5K, I can get the machining cheap, what valves fit? Will it be worthwhile? I'm not sure of the biggest bottleneck up top in a K motor.

 

Do I need to shim the oil pump to keep enough oil pressure up at top end?

 

Cheers

Edited April 20, 200521 yr by beerhead

25-65 for torque and peak power at 7500

20-60 for more torque, but less peak power at 6500

i think these are the most ideal cams for a 4K/5K motor, other people have their favorite cams too

 

get the springs tested. stock seat pressure is 70lb. you wouldn't even be able to move tired old stock springs very far with your hands

 

CC the head and work out your compression ratio. there are formulas online to do this. the best way to raise compression is to deck the block so the pistons poke a little into the head gasket. then deck the head but not too far. you may find you need to lower compression? though i doubt it

 

1600 ford laser valves are one of the options stewart looked into when he was thinking of a bigvalve head. i expect done properly, you'd end up using valves from two different applications. a valve catalog has a massive list of measurements, ask your machine shop to find something suitable

 

the biggest bottleneck in a 5k is the valves. then the shitty stock head ports (especially inlets), then the fact that the manifolds are on both sides of the engine

 

yes, shim the oil pump spring about 2-3mm

 

you're going to need extractors, don't put an exhaust on bigger than 2"

then the fact that the manifolds are on both sides of the engine

 

:P

Heres the cam that i'm running on my 5K. Mines been converted to solid lifters. I'm happy with the cam - but will be happier when i have the carbs sorted out.

 

The 32/36 weber might be a little big. Last week i had my car at the dyno shop for 3 days while they tried to get it jetted right. They leaned out my 32/36 to optimal, but found the throats of the carb to be a little big for the motor - they suggested maybe 28/32 weber. In the end i just had them re-jet an Aisan carb to keep me going until i can sort out something better.

I know Xany runs a 28/32 ADFA carb on his 5K and is very happy with it.

 

I'm running dual valve springs on my head - Not exactly sure what car they are from.

 

A Double row timing chain would also be high on your shopping list.

Edited April 22, 200521 yr by kangaroosa

or SUs :P

 

this topic is already active in another thread

http://www.rollaclub.com/board/index.php?showtopic=1119

Alrighty then I think I'll have to ditch the 32/36 at some point. I'll try runny whitey's cam for a while, see what happens :P. Grimwolge, do you think the carby has something to do with the dead spot at 60 k's. How hard is it to get a pair of 40mm side draught webers running well? Are they as bad as the rumours of constanty needing to be tuned? Are twin su's a good option on a 5K? Just wondering too, where's a good place to source a double row timing chain?

Edited April 23, 200521 yr by beerhead

easily :P