building my engine with 280 cam timing

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mike37 cdn
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building my engine with 280 cam timing

Post by mike37 cdn » Sat Aug 13, 2022 4:14 pm

hi i am building my motor in my 26 i am putting in a 280 cam were would i set the timing at i have been setting it at 15 ptdc as stock at number one cylinder is there different timing when using a 280 cam i also put in high compression pistons thank s mike


Scott_Conger
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Re: building my engine with 280 cam timing

Post by Scott_Conger » Sat Aug 13, 2022 4:27 pm

timing is like any stock cam, both to the crank, as well as the timer

if you want to go faster with the 280, use a stock cam gear

if you want to pull harder on hills, contact Dan McEachern and discuss a 5 degree advanced timing gear (suppliers sell 7 1/2 advanced, which I have but you really don't need the full 7 1/2 degrees). Your car will still idle well and will pull harder but at a little expense of top end speed potential.

regardless of the timing gear you use, all timing marks and timer timing remain as stock.
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Re: building my engine with 280 cam timing

Post by speedytinc » Sat Aug 13, 2022 7:35 pm

Scott_Conger wrote:
Sat Aug 13, 2022 4:27 pm
timing is like any stock cam, both to the crank, as well as the timer

if you want to go faster with the 280, use a stock cam gear

if you want to pull harder on hills, contact Dan McEachern and discuss a 5 degree advanced timing gear (suppliers sell 7 1/2 advanced, which I have but you really don't need the full 7 1/2 degrees). Your car will still idle well and will pull harder but at a little expense of top end speed potential.

regardless of the timing gear you use, all timing marks and timer timing remain as stock.
Its my understanding that the new 280 super is ground with more advance. No changes needed. I did recently install one for a customer & very much liked the overall performance.

The standard 280 has a lot of low end torque, maybe too much, & benefitted(s) by a 7.5 degree advance timing gear.
As I recall, when I set this cam @ 7.5 degrees advance, it gave me a split overlap @ tdc.

This was the set up I had (std280). I broke the advanced cam gear & put a DM bronze std timing cam gear in. It feels like I gained low end torque & lost some top end speed.(not what I wanted) My harmonic dead spot moved down to about 50mph from 58. (3.07) gearing. & is much more pronounced in rux.
The next step , I thought I might try advancing this gear 1 full tooth to get my top end back plus, but retain enough low end. Too much??
Cam timing is magical mystery to me. Trial & error. What have your experiences taught you?


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Re: building my engine with 280 cam timing

Post by Scott_Conger » Sat Aug 13, 2022 8:16 pm

I have only worked on my own engines for the last 8 years, so not much terribly broad experience for quite some time. Stipe's 280 responded very well to standard 7 1/2 degree advance in my '23, but lots of research tells me that this combo would benefit from dialing back some, thus my recommendation to contact Dan for a different gear with less advance. The Stipe does not (or at least, did not) have the advance dialed in, while the Chaffin's 280 cam already has it built into the cam and would be a mistake to add any more via a cam gear change. I hear that Chaffin's cam performs very well...I have not tried one, though. For many years, I was a champion of a modern "stock" 250 cam and even rejected having a 280 cam put into my dad's heavy depot hack. That decision was a poor one in retrospect...it really needs one.

Other than my own "T" work, or the periodic "T" tourist limping out of Yellowstone NP seeking patching up to continue, I pretty much concentrate on carb parts these days.

There certainly are other folks who have lots more and more current experience than me, who will chime in.
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Re: building my engine with 280 cam timing

Post by Steve Hughes » Mon Aug 15, 2022 12:55 am

Not speaking from experience here, but from what I recall reading from some earlier discussions. I believe that the Stipe 280 cam does not have the advance built in, but rather is stock timing with just the increased lift. The Stipe 290 cam rather than just having advanced the timing has been designed with a different timing, duration, overlap, etc. to provide a good compromise of low end torque and high end. I hope this is accurate.

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Re: building my engine with 280 cam timing

Post by Mark Nunn » Mon Jun 26, 2023 1:52 pm

I am responding to this old thread after reading several about advancing cam timing. There are benefits to be had advancing a stock cam 5 or 7.5 degrees. Chaffin's regrinds with advance built in so no advanced timing gear. Stipe may do that also. The problem that I have is with a recently-obtained 280 cam. It is a regrind in which I and the previous owner don't know who ground it or to what timing specs. I just know it has .284" intake and .287" exhaust lift. I was not looking for a 280 cam but it fell neatly into my lap at a recent club meeting. My current cam has substantial wear and due for replacement.

I am looking for suggestions of ways that I can determine if this cam is advanced while it is out of the engine. Even installed, how would I tell if timing is stock or not? This image has been posted many times on the forum. Does this offer clues? I have a spare timing gear that I can install for comparison. But I doubt that I could learn anything about cam timing.
timing gear.jpg


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Re: building my engine with 280 cam timing

Post by Moxie26 » Mon Jun 26, 2023 2:47 pm

Mark, you have a lot of good questions. When I had my engine rebuilt I had a 280 cam put in from Stipe and a 7.5° advanced cam gear installed. Engine runs nice and smooth and it is peppy ! No starting problems, no overheating, a very pleasing ride. As mentioned, the Stipe 280 cam has an increased lift with no increased timing change. Hope you will have similar results. ..... Any questions you have about the cam I suggest getting in touch with Stipe, and if the cam has been reground after purchase, send it to them to get the answers you need.

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Re: building my engine with 280 cam timing

Post by Mark Nunn » Mon Jun 26, 2023 3:57 pm

My cam was reground. I believe Stipe grinds new blanks. I'm hoping that I can use the cam gear pins and dial indicators to find lobe lift angles. One of my local club members has an adjustable cam gear that he is not using. I may be able to test with that gear either out of or in the engine.


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Re: building my engine with 280 cam timing

Post by Scott_Conger » Mon Jun 26, 2023 5:34 pm

Mark, with v-blocks and a degree wheel attached, you can fixture a drop indicator or similar to measure total .270 lift (in reality I think setting the measurement to .265 is more realistic to gauge a .280 regrind, but that's just opinion). That now mimics your valve including valve lash of .010". Then back up until JUST beginning lift on intake and set your degree wheel to Stipe spec for lift angle. You can now determine total duration and valve open/close events. If sitting on a surface plate you can also now move to exhaust and measure all angles and duration of exhaust. If it all matches a Stipe, then it's a Stipe. Whoops! Problem is Stipe doesn't regrind that I am aware.

So now, you must ask any/all Chaffin customers or Mark himself as to what the Chaffin regrind is ground to and use the same methodology as above. You will eventually find out what you have.
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Re: building my engine with 280 cam timing

Post by Art M » Mon Jun 26, 2023 10:27 pm

Scott,
Thanks for the excellent description of how to measure cam lobe angles.

I have never tried to measure the camshaft timing advance. I think it could be accomplished by using the cam gear timing mark that matches the crankshaft gear. I believe the marks match when #1 cylinder is at TDC, but I could be wrong. This is what I remember from working on small block Chevy engines 60 years ago.

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Re: building my engine with 280 cam timing

Post by Scott_Conger » Mon Jun 26, 2023 10:40 pm

Art, when the crank and cam timing marks are aligned, there are no pistons at TDC
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Re: building my engine with 280 cam timing

Post by ModelTWoods » Mon Jun 26, 2023 11:05 pm

I don't know who, or what, to believe about advanced timing on NEW or REGROUND cams. At some time since both Chaffin's and Stipe started producing NEW cams, Chaffin's has ceased the production of NEW cams and gone back to just offering the regrinds.If I am not mistaken (and Mark, correct me if I am) both the new and the reground Chaffin's cams had the 7.5 degree advance, built in.
Likewise, a year ago, I purchased a NEW 290 cam, directly from Stipe. I asked Stipe the question about advanced timing. they said, DON'T DO IT. Its's built in to the cam grind, so Mark and Bill Stipe (or your son), if you are reading this, please post a reply and set everyone straight on this issue.


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Re: building my engine with 280 cam timing

Post by Scott_Conger » Tue Jun 27, 2023 8:32 am

According to Glen in recent years past, Chaffin's performance (non stock) cams matured and improved over the years, with SOME advance (not necessarily 7.5 degrees) built into them for the last umpteen years. Chaffin's produced a whole series of cams for different kinds of performance. I would not doubt that different cams had different advance dialed in or out - you ordered your cam (at one time I remember 3 or 4 grinds being available) and you got what you got.

Stipe cams, from my memory, came in various grinds/lifts, but had no advance built into them...you could use them for speed, or advance them for power (and lose back some speed). I have found Stipe's 280 cam with a Dan McEachern 7.5 degree gear to be a wonderful combination.

Dan McEachern makes excellent timing gears - both standard, and oversize, for worn engines, 7.5 degree advance (which may be a bit more than is needed; it is 1/2 tooth advance) or, I think, he will make as much advance or as little advance as you want/order.

Finally, from what I recall Glen saying, you do NOT want to advance their performance cams made for the last many years, as it's alreadedy baked in.
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Re: building my engine with 280 cam timing

Post by Mark Nunn » Tue Jun 27, 2023 8:54 am

Without knowing who reground my cam or to what timing spec, I plan to install it with a stock timing gear and see what improvements or losses I get. My goal is not to increase top speed, but rather, to run better in hilly terrain. Anything will be an improvement over my current valve lift, which ranges from .170 to .189.


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Re: building my engine with 280 cam timing

Post by Moxie26 » Tue Jun 27, 2023 9:03 am

Good morning Mark.... For some extra piece of mind, it would take some time away from your project completion, but it wouldn't hurt to have the cam sent to Stipe for a check after someone had altered... This way you would know the actual lift now compared to the original setting.


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Re: building my engine with 280 cam timing

Post by Scott_Conger » Tue Jun 27, 2023 9:14 am

Mark

as worn as your old cam is, I am certain that you will be anything but disappointed with your new-found treasure.

Remember, no one sells a cam and then tells you that you must buy an advanced gear to make it work

You should probably plan to purchase a camshaft thrust washer kit (3042TK) to keep your cam in place - all the dealers sell them for reground cams
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