Harold,first off thanks in advance for your time :)

As you know,I have the 280/288 UD hydraulic flat tappet in my 454 and have been very happy with it.
Anyway,when I built the motor 3 years ago,I installed this cam straight up or the stock position on the keyway.
I intend on doing your "quick and dirty" method as a reality check.
What is the reccomended install for this cam?

Doesn't he say 4 degrees advanced for pretty much all of his UD cams? I have the 272/282 Solid and he said put it on the 4 degree keyway on my timing set.

Daniel

Hey Chris,
Since you recommended this cam to me let me answer. He recommends installing on a 106 icl. For me this ended up on the 4 degree advanced keyway.

He usually answers anything between 105 and 108 will run very well.

Finally got to drive my "motorhome" engine a couple weeks ago. All I can say is what a great cam and a BIG difference from my former SB. Could not be happier.

Stickman, If you installed it on the 4* adv keyway, that should push it to 8* adv if all was correct. UD & Lunati ( as well as most others typically grind their 110 cams on 106 ICL). The timing issues arise from trying to find ICL on assymetrical lobe cams. That is why I always check cam timing at both .050 lift (from the timing card) as well as published lifter rise (lobe lift) at TDC - which is by far the most accurate.

I'm guessing there might be a mild ET or MPH gain with it 4* advanced?

Garry,glad to hear you're happy :thumbsup:

Actually i think it is the 2* advance, i forget off the top of my head. I am using the Cloyes true roller timing set, so whatever the advance keyway is on that.

Daniel

Actually i think it is the 2* advance, i forget off the top of my head. I am using the Cloyes true roller timing set, so whatever the advance keyway is on that.

Daniel


that would be 4*

But, if you don't physically degree the cam...are u ever gonna really know where it is? :)

The easiest and most accurate way to check the cam - after the fact is to check the lobe lift at TDC - get this info from the cam manufacturer. Assuming you have a correctly indexed balancer and timing tab it is simple.

IE: Comp XR279HR ; lobe lift is listed as .079 @ 106ICL, .065 @ 110ICL. With #1 Rocker arm disconnected, establish base measurement from base circle of cam. Rotate the engine to to TDC and measure lift (measurements taken off top of unloaded pushrod in this case, unless intake manifold is off). For ICL of 108ICL I would need a lift of .072. If it is .079 or higher, I know the cam is in advanced to 106 (or more), if it came up as .065 or lower, I know it is in at 110ICL (or later). When I checked mine ( after doing the .050 timing), it came in right on the money. This method is foolproof and accurate.

The cam manufacturer will provide this data for the cam lift - they have it on file. It is also useful data in pre-planning valve clearance. Knowing that I needed .072 @ TDC lobe lift equates to .122 valve lift + .060 clearance = .182 clearance. Before you ever take the cam out of the package or final assemble the shortblock, you can mock up at least one cylinder, bolt on a head and check for clearance. Very simple engine assembly procedure. You can knock the cam timing and clearance all out in one install.

I prefer to check the cam at max lobe lift. All normal OHV cams are symmetrical around the nose, even unsymmetrical ones like I do.
1st---Find TDC, then find it 2 times more. Align your degree wheel with TDC.
2nd---Find max lift, then find it 2 more times. Zero your dial indicator at max lift.
3rd---Rotate the engine backwards .100", then turn it forward to .050" before max lobe lift. Mark your degree wheel, and write this number down.
4th---Continue to rotate over the nose until the indicator has dropped .050". Mark your degree wheel, and write this number down.
5th---Add the 2 numbers together, and divide by 2. Both numbers need to be in degrees ATDC.
This tells you where the max lobe lift is located. I run my designs 4 to 6 degrees advanced, so if your LSA is 112, the intake should be on 106 to 108 ATDC. Sometimes cams are ground with some advance in them. As long as the intake lobe is 4 to 6 degrees advanced from the LSA, the cam will run OK.

UDHarold

Harold, if the engine is completely assembled and in the car with all accesories bolted up, why not just measure the lobe lift at TDC? Otherwise, you are having to unbolt everything on the front of the motor to get a degree wheel on there.

GRN69CHV,

There are a lot of variables involved measuring lift at TDC. You almost have to allow +/-.004"(at least!) to allow for all these variables, and that is about +/- 1°. The 'quick-n-dirty' method is closer, I think.

UDHarold

Thanks Harold,and for all those that replied

ud harold, i just bought the lunati voodo 268 for my 396, 10.25 comp, std bore,oval port heads 290 casting,stock valves, rpm air gap intake,holley street adv carb 770,headers,i see that the cam already has the 4 degree built in to it already and lunati said to install the cam straight up, my question is it worth adding a extra 4 degree adv or staight up? the car is 69 chevelle 4 spd 3.31 gears[posi], just a cruisn car but also with performance in mine, thanks for any info bill:thumbsup: