Camshaft Choice

[TheCAB]

Just building up a Ph2 172 engine for sprint / hillclimb use only and my query is regarding cam choice. Whilst I appreciate that max bhp figures are nice, they are not in themselves the be all and end all, so looking for a cam which does not lose out on the low down torque side of things, plus they are expensive so trying to avoid fitting the wrong ones!!

The best spec Cat Cams, still retaining the hydraulic lifters, seem to be the 422 and 423 variants (overall engine specs would suit these). Anyone any experience of these in use, or any other suggestions most welcome, looking to max rpm in the region of 7800.


Cheers,

Colin

 

[MicKPM]

I've got 421's (some say identical to 423's) and I love them and what they've done to my mildly modified track toy. Power from 4k to the limiter has no let up but I also run an RS2 inlet but I've seen some great looking graphs on standard inlets to.

 

[Ph1 Tom]

422 and 423 need aftermarket management, stronger valve springs and bigger reliefs in the pistons. So I assumer you have these things when you say the specs would suit.

From data I've seen if you want peak around 7.8k rpm you want the 423s but thy lose out to the 421s below 6krpm. I guess the 422 will fall somewhere in between!

 

[Andyman]

My old Piper regrinds pulled like a train at the bottom end of the rev range where by my current 428's have made the car worse than stock under 4 thou rpm.

 

[sprintcup]

Just building up a Ph2 172 engine for sprint / hillclimb use only and my query is regarding cam choice. Whilst I appreciate that max bhp figures are nice, they are not in themselves the be all and end all, so looking for a cam which does not lose out on the low down torque side of things, plus they are expensive so trying to avoid fitting the wrong ones!!

The best spec Cat Cams, still retaining the hydraulic lifters, seem to be the 422 and 423 variants (overall engine specs would suit these). Anyone any experience of these in use, or any other suggestions most welcome, looking to max rpm in the region of 7800.


Cheers,

Colin

Depends what class your running in, I run in 1B and drive to events so would say 421's max, I run a Gripper dif and lower final drive on the standard engine with standalone ECU and stock inlet.

If your in 3B fully stripped and caged on a trailer then 422's or 423's with a HC build and forged but you'll need stand alone ecu and Jenveys or AT TB's.

Regards Russ.....

 

[TheCAB]

Car will run in 1B, fully road legal, but not looking to drive it to events at this stage- so not really concerned about road manners. The 422/423 cams appear on paper to fit the bill but didn't want to be too greedy at the expense of good low / mid range performance. The stock 172 is certainly lively enough as it is so just looking for a marked improvement on what we've got.

 

[sprintcup]

Car will run in 1B, fully road legal, but not looking to drive it to events at this stage- so not really concerned about road manners. The 422/423 cams appear on paper to fit the bill but didn't want to be too greedy at the expense of good low / mid range performance. The stock 172 is certainly lively enough as it is so just looking for a marked improvement on what we've got.

Sounds good, I gained 4+ seconds at Anglesey per lap with just the Gripper/FD change running on AD08's, hoping a well built engine will gain me the 2+ seconds I need to get near the quick cars,
I think the Clio's a little heavy on the hills tbh , I'm not sure if the above cams will loose you that low down response you want to retain but good luck with the build.
What championship are you running in?

Regards Russ............

 

[Pauleds]

When my engine goes bang I will change stuff.

Who did your gearbox Russ and what final drive is it now (and what is standard)?

I'm trying to get more traction this year as it spins enough with the little power it's got.

 

[TheCAB]

[
What championship are you running in?

Regards Russ............[/QUOTE]

Looking to run the car in the Longton & District and Liverpool MC championships. I am just the spannerman / watcher it's my lad who will be the most important bit - " the nut holding the wheel".

Do you rate the gripper as a better diff than the Quaife - if so is there much in it?.

Colin

 

[sprintcup]

Do you rate the gripper as a better diff than the Quaife - if so is there much in it?.

Colin[/QUOTE]

Gripper is your best bet as your on a trailer as well, possibly see you at the odd event as I run in this championship along with Paul above.

I'll send you a Pm about the box and final drive Paul so not to clutter this thread, your best speaking to Gripper direct, standard I think is 4:1 or even 4:4 can't remember there is a thread with the details.

Regards Russ

 

[Ph1 Tom]

If your trailering and competing I'd get the gripper with something like a 4.3 final and the shorter 5th gear.

Then get the 422 cams, they don't lose much bottom end but make more at the top than the 421.