Cam Advice Please and any other you can give!!

[Warks_Dubber]

Hi all..

First post on here so hoping people that know can help..

I have just completed my first season in the VWDRC and having won the Sportsman Championship am looking for quicker times next year.

My current best is 15.54 @ 83.5mph....

I have been racing a '74 bug with a 2110 engine in. For next season I have a new '71 bug, I am lightening the bug with all the usual tricks such as polycarb etc. and am also looking at upgrading the engine.. The current spec of this is:

Domello 82mm crank
Standard weight 8 dowel flywheel
1700lb kep cover JC
5lb equaliser pully
5500'' scat forged H beam con rods
Engle FK7 camshaft with straight cut gear (288 x 450 degrees)
1.25 ratio rocker arms
Johnson Cam followers
360 degree cam bearing set
30mm oil pump
AA forged 90.5 long stroke piston kit with lightweight wrist pins and tru arc clips
manton pushrods
scat swivel feet adjusters
autocraft shaft kit
Magnum 44 sport heads 40 x 35.5
springs shimmed to 1.5 degrees = 235lbs at 0.450 degrees
wb inner valve springs
barrel spacers
rocker arm spacers
rocker pedestal spacers
balanced crank assembly
compression at 8.5

Running twin Dellorto DRLA 40's

Now I know that the cam is far too mild for this engine. I have bought an Engle 125 cam to put in, and with this will of course need to up the compression..
My fear is... is this cam too mild still... The new car will be purely a racecar so street use isn't an issue... I don't want to get it wrong this winter and then have to split the case again for another upgrade....

Funds are limited (unless anyone out there would like to sponsor me!!!) so I am looking to get as much power as possible without over stressing the engine too much. Ultimately I will look to turbo it, but for the next season or 2 it's normally aspirated!

I am a large chap so I know my time will always be a little down but I know this engine is not performing to its potential!

Any help, advice, experience, ideas, thoughts etc. would be gratefully received / accepted...

Thanks in advance

Jas.

[richie]

What work is done to the heads? they are often the limiting factor, also what exhaust header does it have and what size?if the heads have a good port job on them then using a FK8 with 1.4 rockers would be my choice, if you do want to turbo it later on don't go made with the compression now, I would also think about some bigger carbs, proberly 45 dellortos or 44 IDF webers, finally I would take some weight from the flywheel.

Also what does it have for a gearbox? what will the new car use?

cheers Richie

[Old Guy]

Well Jas, it's the same old story.  "Speed costs money.  How fast do you want to go?"  Since you are limited on funds, there are several things you can do with your existing set up at very little cost.  First of all I think you're right that your setup is not performing to it's potential.  Your FK-7 only has .446 lift with the 1.25 rockers.  Trade those for some 1.4's and you'll have .500 lift.  Compression is about the cheapest horsepower you can get.  I'd flycut the heads and shoot for a minimum of 11 to 1.  Then use race gas.

You don't mention your trans at all.  If it is a stock trans, that's probably what's holding you back.  You need a sturdy close ratio trans.  I think that's where I would spend my money first.  Do you use slicks or street tires?  What RPM to you shift at and what is the RPM when you go through the lights?

I would not use an Engle 125.  The FK4X (i.e. FK46) series is designed for use with hi lift rockers where as the W series like the 125 was designed for stock rockers.  If you are going to keep the carburetion the same as well as the head ports and valve sizes then I'd think the wildest cam you could get away with would probably be a FK46 with .571L and 301D using 1.4 rockers.  Even then you would want to run the largest vents you could.  If you went to a bigger set of heads and larger carburetors then you could move up to a FK48 with .587L and 312D.

Congratulations on your Sportsman Championship.  Good luck and have fun.

Ron

[deano_dinosaur]

Id say those valve sizes are a bit restrictive, the carbs also. Thats top end would suit a 1776 / 1914 really.

[Zach Gomulka]

If say the combo right now is well balanced, except for those 1.25 rockers, they have to go. Definitely use 1.4's with that cam. The carbs could also be upped to 44's or 45's. This would be a nice motor that makes great power and is very driveable, but it's no racecar engine. You could still get into the high 13's though with practice.
You could go a step further by rebuilding the top end, installing 94's that fit in your 90.5 case for 2276, upping the compression, and nicely ported 42x37.5 heads with a 1 5/8" merge. 44's, 45's or 48 IDA's. Still very driveable, TONS of torque. My buddy has a similar 2276 combo with 40x35.5 heads, IDA's and it's very fun to drive.

If you split the case your wallet is the only limit.

[steve_pugh]

If say the combo right now is well balanced, except for those 1.25 rockers, they have to go. Definitely use 1.4's with that cam. The carbs could also be upped to 44's or 45's. This would be a nice motor that makes great power and is very driveable, but it's no racecar engine. You could still get into the high 13's though with practice.
You could go a step further by rebuilding the top end, installing 94's that fit in your 90.5 case for 2276, upping the compression, and nicely ported 42x37.5 heads with a 1 5/8" merge. 44's, 45's or 48 IDA's. Still very driveable, TONS of torque. My buddy has a similar 2276 combo with 40x35.5 heads, IDA's and it's very fun to drive.

If you split the case your wallet is the only limit.

Interesting.    What is the spec on your Buddy's 2276? 
Would fitting 94mm piston kit which fits into his 90.5 case lead to very thin wall cylinders?

Sounds like we are singing the same tune here Jase.    Not running megabucks, but also not running mega gearboxes.  :-)
Could we see 2 2276 in 2014? 

[Zach Gomulka]

He has Steve Tims 40x35.5 heads, about 9:1, FK7 with 1.4's, 1 5/8" and IDA's. It's no racecar engine, but it still puts a big grin on your face.
94's in a 90.5 case is done all the time, the base of the cylinder is thin but at the head is where it matters (the heads get bored for 94's like normal). The compression ratio will rise with the larger cylinders, all else remaining the same. If you already have the heads off and they are getting bored, if needed they can get a valve job, and little port job or chamber work to take advantage of the larger bore.

[Jim Ratto]

Your 40mm valve (unless you go very radical on valve timing) is limiting your peak HP rpm to about 5200rpm for your displacement. With the valve sizes you're running and the 40mm carbs, much more cam isn't going to do much, except narrow the powerband down. The K7 might be a tick on the conservative side, but for a good street motor (does the car ever see street use?) it's just about right. The FK8 would extend rpm up without giving up much down below.
If you were to move up to 44mm intake valve size (with appropriate ports) your peak rpm would move up to about 6300, and you could get away with an FK10-ish type cam (about 265-268' duration @ .050") and around .540" lift @ valve. And about 25-30 more horsepower with 37mm chokes in 45-48mm carbs.
Cut the flywheel weight down, use light wheels and tires, get suspension dialed in 100%, make sure engine is tuned to give its all. That stuff makes a world of difference too.

have fun,

[Warks_Dubber]

Hi folks

Thanks for the advice so far...

The first piece of the puzzle has been bought..

I have picked up a pair of Weber 48IDF's

So just need to make a decision on the oily bits now and the route to go!!

Jas.

[Warks_Dubber]

Finally made a decision

Along with the 48's I've gone for an FK87 and 1.4 ratio rockers...

Probably increase CR to around 10.5:1

just need to see what head work the funds will allow..

The countdown to next season begins!

[dannyboy]

hi jas
my old race/street motor was a 2276 on 48mm t/bs with 044s ported to wedge design and a fk87 with 10.1 cr in my car it ran 11.8 na with belt and 10.7 with a good shot of gas that engine took a fricken hell of a beating last season with over 100 passes on the gas and when it was stripped  and checked only needed a new barrel as there was a tiny crack in one of the barrels at the top ,other than that it was all perfect  i did use race gas when i was using over 50hp of gas just to be safe but it ran great on 97pump fuel
if  the combo you are building is almost the same you are in for a cracker of a season 

[Udo]

Finally made a decision

Along with the 48's I've gone for an FK87 and 1.4 ratio rockers...

Probably increase CR to around 10.5:1

just need to see what head work the funds will allow..

The countdown to next season begins!

That is a good idea ..
and put some bigger valves in the heads
Udo