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-   -   Look at my cam degree results (http://www.hotrodders.com/forum/look-my-cam-degree-results-227981.html)

GMC boogie 01-05-2013 09:19 AM

Look at my cam degree results
 
SBC hydraulic roller. Valve events at .050 listed on cam card:

IO 8 BTDC
IC 40 ABDC
EO 48 BBDC
EC 0 ATDC

As found:
IO 7 BTDC
IC 46 ABDC
EO 47 BBDC
EC 6 ATDC

Another thing, This is suppose to be a 228/228 duration at .050 cam. It measures 233 on both the intake and exhaust. What is the deal with that?

Specs on cam is 228/228 at .050 280/280 at .006 110LSA 4 advance. install intake lobe to 106 centerline.

7+180+46=233 intake
47+180+6=233 exhaust

Also done the Intake centerline method and got 109 which tells me I need to advance the cam 3 to put it at 106

I am very confident I have found true TDC. I am using a fixture that fits in the lifter bore with indicator that reads directly off the lobe for the degreeing process.

GMC boogie 01-05-2013 10:16 AM

It is a custom grind. I am not going to say the company.

Someone told me the fixture I am using for degreeing off the lobe is not accurate as it has a different radius.

Going to redegree using an actual lifter.

cobalt327 01-05-2013 10:53 AM

Quote:

Originally Posted by GMC boogie (Post 1630884)
It is a custom grind. I am not going to say the company.

Someone told me the fixture I am using for degreeing off the lobe is not accurate as it has a different radius.

Going to redegree using an actual lifter.

If you were using a roller radius indicator on the flat tappet lobe (or vise versa), you'd see an error, but it would be larger than what you're seeing, and it wouldn't add duration to just the closing side. Even a slightly different radius from the lifter your cam uses would not indicate what you're seeing, so it's not the tooling, per se.

This sounds like a mistake by the manufacturer, or they have pulled a cam off the shelf that's close to what you wanted- but even w/that, it's more cam than you bargained for.

I'd be on the horn to these guys...

BTW, if you use a hydraulic lifter to recheck it you should make it solid to remove the lifter piston travel from skewing the measurements. Stack it full of small washers or fill w/grease.

GMC boogie 01-05-2013 11:04 AM

The motor is in short block form on the engine stand. It is a hydraulic roller cam and the fixture I have that fits in the lifter bore has a plunger for a roller camshaft.

I checked amount of degrees from .050 on the opening side to .050 on the closing side just to verify and it is 233 degrees. What a bummer, not that much bigger but bigger than I want.

GMC boogie 01-05-2013 11:54 AM

I degreed again(several times) using the actual lifter/mag base/ indicator and got:

IO 4 BTDC
IC 44 ABDC
EO 44 BBDC
EC 4 ATDC

4+180+44=228 What it is suppose to be.

228/2 = 114 -4 = 110 intake centerline.

Now if I advance the cam 4, my timing events at .050 should be as the card states,correct?

cobalt327 01-05-2013 12:18 PM

Your previous measuring set up must not have been parallel to the lifter/pushrod and/or the radius was way off. Still doesn't make much sense that it was off only on the closing sides...

In any event usually the advance will be correct when the cam is installed straight up. Can you show the cam card?

GMC boogie 01-05-2013 12:38 PM

I was using this fixture:

http://www.jegs.com/images/photos/2494925.jpg


When I degreed using the traditional method of off the lifter, my results were correct other than needing to advance the cam 4.

Someone told me using the fixture I used the first time would skew the numbers due to the different radius and so it did.

I listed the cam card specs in a previous post,they are posted correct.

110 LSA 106 ICL 228/228 280/280

cobalt327 01-05-2013 01:18 PM

Quote:

Originally Posted by GMC boogie (Post 1630922)
I listed the cam card specs in a previous post,they are posted correct.

110 LSA 106 ICL 228/228 280/280

The cam card will often say what position it's to be installed in to get the amount of advance correct. Example:

http://www.hotrodders.com/gallery/da...ti_camcard.jpg
Otherwise if it's ground on a 110 degree LSA, move it to 106 degrees if you want it 4 degrees advanced.

GMC boogie 01-05-2013 02:05 PM

Yeah, I need to move it to 106. Timing set is not adjustable. What about using a 4 offset key?

cobalt327 01-05-2013 02:49 PM

Quote:

Originally Posted by GMC boogie (Post 1630947)
Yeah, I need to move it to 106. Timing set is not adjustable. What about using a 4 offset key?

Well, it's that or a bushing in the cam gear. The offset woodruff would be the easier of the two, and could be said to be a better choice because the three bolt holes holding the cam gear on don't need to be elongated.

GMC boogie 01-05-2013 06:48 PM

I installed a 3 bushing and now my readings are:

IO 9 BTDC
IC 39 ABDC
EO 49 BBDC
EC 1 BTDC

I am within 1 of the cam card, I think I will leave it as is.

vinniekq2 01-05-2013 10:21 PM

some people machine the crank and use 2 keys.
BTW,custom grinds are similar in price to off the shelf grinds,or should be

cobalt327 01-06-2013 03:13 AM

Quote:

Originally Posted by GMC boogie (Post 1631064)
I installed a 3 bushing and now my readings are:

IO 9 BTDC
IC 39 ABDC
EO 49 BBDC
EC 1 BTDC

I am within 1 of the cam card, I think I will leave it as is.

It's fine like you now have it IMO.

Two keys? Maybe for a blower hub. He's talking about changing the phasing of the cam. Cutting a new keyway does not need to be done for a simple cam timing change.

vinniekq2 01-06-2013 11:42 AM

(I would run it at 3 and be done with it. Dont want to take any chances with the offset key failing.)

my response was to this post.I doubt a key would fail.Just offering solutions or alternates,trying to not judge. The 1 degree cam phase is a mute point when the timing chain stretches


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