Need advice 360 timing chain cam/crank slightly off

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340challconv

340challconv

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Parsippany, NJ
Purchased a 360 from Mabco to put into my A66 340 Challenger short term while I pull the 340 for a rebuild.
I bought a hp version with flat top pistons and installed hp cam sited as a 272 cam
Cam specs; 272-272 duration 454 lift 110 lobe separation 52 degrees overlap, 216 216 duration @ .50
Power range 1500-5200 Considered the largest "stock" cam for this engine
In going over the engine for parts install; the timing marks are slightly off.
I call the manufacturer and he stated to leave the chain as is.

Pistons are flat top 30 over, no valve notches, piston to deck measurement is not a stock (deep in the hole) 360 with the higher compression pistons it measures out at about .087 below deck with number 1 piston at TDC.

I am no expert, and I have installed cams years back always aligning timing marks; is there a reason for the manufacturer to alter the timing in this manner with this hp cam and flat top piston?
Pic of timing chain sprockets and Number 1 piston at TDC
Any thoughts appreciated.

IMG_8963.jpg


IMG_8964.jpg
 
The best way is to degree the cam then you know where the cam is set.
 
I was looking at their 360 LA short blocks as a possibility depending on what mine looked like when I pulled the top end off... pricing seemed reasonable.

Manufacturer says leave where it is... did he explain why? If no explanation can be given... it's your shorty now... I'd line them up & degree.

With the slugs that far down the hole you could likely use 1.6 ratio rockers w/o issues.
 
Cam has to go 1 tooth(maybe 2) in a counter counterclockwise direction to line up the dots is my guess
 
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If that is the level of care when putting the cam/sprockets together, even not degreeing it. YIKES

Get a degree wheel and verify installed centerline. Better safe then sorry.
 
the thing with degree wheels is knowing how to do it dot to dot is for the home guy who builds maybe 3 engines in his life. installs a cam maybe 3 times etc.

THEN you need the adjustable crank gear after you degree it etc. telling the guy to degree it when its a tooth or two off isn't what he's looking for here
 
Yep it's out of time.

Needs to be cam dot 12 O'clock
Crank dot 12 O'clock
With #1 TDC up on compression.

20220430_203537.jpg
 
Thank you all for the replies. Never used a degree wheel before and always relied on dot to dot, even when I installed 284 purple shaft cams years ago. Time to learn a new skill
 
George Jets said:
Yep it's out of time.

Needs to be cam dot 12 O'clock
Crank dot 12 O'clock
With #1 TDC up on compression.

View attachment 1716005574
Click to expand...

You don’t know that. You’re guessing. I have had to move the cam gear to degree a cam with no other way to do it.

Ever use a gear drive? Ain’t no dots on that. The dots are there so a dude on an assembly line can throw that **** on and send it.

Forget the dots are even on there and degree the cam.
 
Rat Bastid said:
You don’t know that. You’re guessing. I have had to move the cam gear to degree a cam with no other way to do it.

Ever use a gear drive? Ain’t no dots on that. The dots are there so a dude on an assembly line can throw that **** on and send it.

Forget the dots are even on there and degree the cam.
Click to expand...
I don't think you moved it a tooth or two though. lol
 
fishmens67 said:
I don't think you moved it a tooth or two though. lol
Click to expand...

You‘d be surprised. On a 460 Ford it was that far off. A cheap assed regrind.

And that ASSUMES the dot is in the correct location. You can’t assume that. I’d explain how to set the engine at overlap and look at the lifters to see if it’s even close, but I’ve typed that out before and I don’t want to do it again.

That will tell you if it’s close, but not where it’s at.
 
The FIRST thing to do is to find and VERIFY true TDC for #1. I would go ahead and do it with the degree wheel and everything else associated in case you need to make an adjustment.
 
I'll just throw out there these two things. First, that cam sounds like the exact summit cam I put in my 318. Second, I'd say that cam is a tooth off by mistake. Just my observation.
 
318willrun said:
I'll just throw out there these two things. First, that cam sounds like the exact summit cam I put in my 318. Second, I'd say that cam is a tooth off by mistake. Just my observation.
Click to expand...
If anything, it won't run very well where it's at. if at all
 
340challconv said:
Purchased a 360 from Mabco to put into my A66 340 Challenger short term while I pull the 340 for a rebuild.
I bought a hp version with flat top pistons and installed hp cam sited as a 272 cam
Cam specs; 272-272 duration 454 lift 110 lobe separation 52 degrees overlap, 216 216 duration @ .50
Power range 1500-5200 Considered the largest "stock" cam for this engine
In going over the engine for parts install; the timing marks are slightly off.
I call the manufacturer and he stated to leave the chain as is.

Pistons are flat top 30 over, no valve notches, piston to deck measurement is not a stock (deep in the hole) 360 with the higher compression pistons it measures out at about .087 below deck with number 1 piston at TDC.

I am no expert, and I have installed cams years back always aligning timing marks; is there a reason for the manufacturer to alter the timing in this manner with this hp cam and flat top piston?
Pic of timing chain sprockets and Number 1 piston at TDC
Any thoughts appreciated.

View attachment 1716005507

View attachment 1716005508
Click to expand...
WHOWA WHOA STOP NOGO WAH--HOOOOAAAAWWWW!!!!
BACK UP JUST A MINUTE WILL YA!!!!!
How --- that is "just exactly how" --- did you determine that cam is "in time" (if you did not degree it) with the marks as you pictured???????????????????
 
Rat Bastid said:
You don’t know that. You’re guessing. I have had to move the cam gear to degree a cam with no other way to do it.

Ever use a gear drive? Ain’t no dots on that. The dots are there so a dude on an assembly line can throw that **** on and send it.

Forget the dots are even on there and degree the cam.
Click to expand...
You are confusing the issue. From what the OP has said I think the matter is simply that he screwed up and one sprocket is a tooth off. In other words, "he isn't" that far along as to degreeing, etc.
 
67Dart273 said:
You are confusing the issue. From what the OP has said I think the matter is simply that he screwed up and one sprocket is a tooth off. In other words, "he isn't" that far along as to degreeing, etc.
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I read as, the op bought an assembled engine and upon inspection found timing where it's at.
after calling the builder, they stated to leave it where it's at.:realcrazy:
 
fishmens67 said:
I read as, the op bought an assembled engine and upon inspection found timing where it's at.
after calling the builder, they stated to leave it where it's at.:realcrazy:
Click to expand...

Looks like the engine builder tried to advance the cam 4° by jumping the cam gear a couple of teeth.

Little does the engine builder know that any advance has been ground into that performance cam already and it should be installed dots at 12 O'clock.
 
George Jets said:
Looks like the engine builder tried to advance the cam 4° by jumping the cam gear a couple of teeth.

Little does the engine builder know that any advance has been ground into that performance cam already and it should be installed dots at 12 O'clock.
Click to expand...
yea and if it's off, it's usually just a tick either way.
 
There's one more scenario, and I've pointed it out before. What is stamped on that top gear? does it have both "S402" and "S296" on it? 402=LA 296= Poly. They look the same and, in all regards, are the same ECEPT the timing. It's different by 1 tooth.
View here= Cam degreeing help me understand!
 
George Jets said:
Looks like the engine builder tried to advance the cam 4° by jumping the cam gear a couple of teeth.

Little does the engine builder know that any advance has been ground into that performance cam already and it should be installed dots at 12 O'clock.
Click to expand...
What if the tolerances in the cam and crank sprockets are off in opposite directions? What if they are also off as compared to the crank and camshaft keyways? This is the whole purpose of degreeing a camshaft. To make up for all those possible discrepancies. No way in the world will I just ever install dots at 12 o'clock. I've seen one off by 13 degrees dot to dot.
 
fishmens67 said:
I read as, the op bought an assembled engine and upon inspection found timing where it's at.
after calling the builder, they stated to leave it where it's at.:realcrazy:
Click to expand...
OK I did not catch that "direction"
 
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