Forgot to mention. I used a degree wheel to verify as well.
Is this LA360 XE268 cam kit deal good for my combo?
- Thread starter JoePole1
- Start date
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1969reddart
or is it Copper...
Ok. I must be stunod or something. First off, I didn't purchase my current crane cam but I thought dot to dot ( what I called straight up) was how mfg recommends installing the cam and it should perform as advertised barring any other engine mods. In the H-260-2 that would be 204/216 260/272 427/454, 112 lsa. Now don't some cams have " built in" advance? Are you saying dot to dot is 4 degrees retarded??
Second....I just bought a 3 key adjustable timing set for my magnum.
Can use on this LA. It's a double roller comp 3103. That would mean each key notch is 2 deg. It looks like I can only get 4 degrees max advance per comp. I'm at 112 and you recommended 108 so NG?? Remember, the LA is coming out summer of next year so doesn't need to be "optimal". Plus the car is most likely parked until spring.
Thanks.
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Ok, lemmie see if I can help you out. "Dot to dot" is the manufacturer's way of assembly. Technically, yes, when it is assembled "dot to dot" it is "supposed" to be correct. Sometimes.......and very, very seldom they come out like that.
The reason it is "RARE" it's in the correct place just stabbed dot to dot is because of machining tolerances between parts. When you are speaking in DEGREES, it's very easy to see where a simple machining tolerance can throw off camshaft timing. Was the camshaft keyway machined EXACTLY? Was the camshaft gear keyway machined EXACTLY? Was the crank keyway and crank gear keyway machined EXACTLY? The chances of "ALL THAT" being DEAD ON 100% are VERY slim. This is why it is IMPERATIVE to use a degree wheel to get the camshaft timing right where it needs to be. ...and yes, from the desctiption of the way your engine runs and the low cylinder pressure, I suspect the camshaft timing is retarded. How much? Who knows? I've seen "dot to dot" installs retarded 10 degrees. The point is, without a degree wheel, you do not KNOW. That's why it's so important to good engine performance.
Yes, but ONE MORE TIME the three keyway gear is really crap. It does not give you enough of adjustment in cases where you are "way off" and it sounds like you may be. You NEED a good billet timing set, for a couple of reasons. First, they are quality. They are not the cheap POS that's going to stretch a country mile as soon as the engine is broken in. Secondly, they will have the nine keyway crank gear so as to be able to zoom in much more accurately on the camshaft timing. I don't know how else to say it.
Thanks R3. I did use a degree wheel so I feel confident it was installed as advertised.....so 112.
No. If it's at 112, it's FOUR DEGREES RETARDED. It should be at 108.
You've made a common mistake. You've confused the lobe separation angle with the intake center line. The lobe separation angle, or LSA, is the distance between the peaks of the intake and exhaust lobes in degrees. It is ground into the cam and cannot be changed.....unless it's reground.
The intake center line is the method used to determine "WHERE" the camshaft is installed. Your intake center line, or ICL is 108. That means it is advanced from the LSA FOUR DEGREES.
If it was ME, I would go on down to 106 ICL. This will advance the cam a total of 6 degrees. The reason I recommend that is because of the low cylinder pressure. Those extra two degrees will help a little more.
mopowers
Well-Known Member
Hey Rusty - I'm curious why you think he's got low cylinder pressure. It's a stock '78 360 bottom end with a mild cam and he's got 150psi cranking pressure. That's seems like more than I would expect from a stock low compression 360, even with the milled heads.
What would you expect from his engine in terms of cranking pressure?
I'd like to see 170-175 and he can get it there.
I thought the SB mopar XE268 was cut on a 110 LSA and installed at 106
It is. That's not the cam I've been talkin about.
James Clews
Well-Known Member
I just built my 318 for my chrysler and because this is not meant to be a hi performance engine like my 410 I purchased the cheaper Mel Gear timming set from rocket australia for $80 as it has three way crank gear that says 4 degrees plus and 4 degrees minus and zero. As I always degree my camshaft I proceeded to degree it but came up at 1.5 degrees retarded on dot to dot. This was unaceptable because I knew that with chain stretch it would be more retarded in a short time. I put the set together at the 4 degrees advanced keyway and degreed it again but then came up with 6.5 degrees advanced. WTF. The crank sprocket is 4 degrees which is 8 degrees at the camshaft even thou the box says 4 degrees retard or advance. Well I bit the bullet and purchased a rollmaster set( made in Australia) for $180 that has nine way adjustable and set it up dot to dot and it was excact to the cam grinders specs. So I advanced it 2 degrees to allow for chain stretch down the track. What I thought was incorrect camshaft specs turned out that the cheap melgear(made in the USA Jackson MI) was a total piece of ****. Still have it new in the box. So even if it is only a cruiser don't skimp on the timming chain set!
Hay, thanks for that! Much as you can preach it to people, sometimes they cannot "get it" without an example and yours is a perfect one. Did you get it running? How does it do? IMO timing is one of the most important things for an engine and it just doesn't pay to skimp on the timing set.......even with a stocker.
mopowers
Well-Known Member
Didn't engine masters test advancing, retarding, and running a cam straight up on their dyno test mule? I can't recall what the results were.
Thanks. Found the episode but you have to be a subscriber to MT.
https://www.motortrendondemand.com/detail/advances-in-cam-timing/137155/
https://www.motortrendondemand.com/detail/advances-in-cam-timing/137155/
PRH
Well-Known Member
Well...... almost.
But you have the right idea.
The crank turns twice as fast as the cam.
The three-way sets advance/retard the “cam” 4 degrees(camshaft degrees)...... which shows up as 8 degrees on the degree wheel.
Those 3 way sets are pretty useless for trying to dial in a cam IMO....... as you discovered.
Results would be more dependent on how close the camshaft is to the combo.
Degreeing the cam and checking the advance curve you have as well as running more initial timing as needed on your existing setup may serve you well.
PRH
Well-Known Member
The .050 timing specs for the Crane H-260-2 show it as a 112, installed at 107........ so “in theory”, it should have 5* advance ground into it.
5* advance is pretty standard fare for a lot of Crane grinds.
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James Clews
Well-Known Member
Rusty! No I do not have it running yet. I put the motor and box in a couple of days ago but still need to wire, plumb and build the exhaust yet. I am in no hurry as I am retired but as christmas is around the corner and my son gets me to come in to his smash repair business to run him around I may not have it running for a few weeks. Sometimes for an old fella like me I don't get a lot done in a day because it is so hot here at the moment 40c plus (about 108f)
Well keep us posted, James! I want to hear that bad boy!
James Clews
Well-Known Member
Rusty here is a few snaps!
PRH
Well-Known Member
It’s just the LSA minus the intake C/L on the cam card.
In this case, 112-107=5
Of course, some factory cams(and likely, other cams as well) are actually installed retarded.
The stock 318hft cam is on a 109, installed at 110(1* retarded).
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