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Need advice 360 timing chain cam/crank slightly off

Steve340

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That Summit cam sounds pretty good to me. It should work good.
If you can degree the cam it checks all the machining, keyway, slot etc locations. I agree with Moparleo it is advisable to do given the quality of parts these days.
The intake centreline method is the easiest. You just have to assume the cam itself is ground correctly.
 

340challconvert

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Thanks Steve
If you can degree the cam it checks all the machining, keyway, slot etc locations. I agree with Moparleo it is advisable to do given the quality of parts these days.
The intake centreline method is the easiest. You just have to assume the cam itself is ground correctly.
 

fasjac

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If you have your 340 crank and cam gear laying around, maybe compare where the keyway is machined??
Or at TDC look at/verify #1 lifters and see if they are same height. Just thinking out loud. Looks like everyone has mentioned the best way to be precise. Good luck Phil.
 

340challconvert

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Thanks for your thoughts
I adjusted the timing chain and sprocket dots to the 12 and 6 positions after they were initially off by about 2 teeth. I then checked cylinder #1 & 6, both moved to TDC (separately of course) and checked the lifter height. Lifter height measured exactly the same which should indicate = split overlap with no advance built into the cam.
 

Steve340

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Most cams have advance ground in to them. The amount of advance ground in is the difference between the lobe separation angle and the intake centreline. Usually 4 degrees.
The lifter could be anywhere on the base circle so your test would not really work and I would be hesitant to trust it.
You can advance or retard a camshaft more but at the expense of valve to piston clearance. A very experienced guy recommended to me that taking in to account the 4 degrees ground in to never go more than 2 degrees more advanced.
Being 2 teeth out wound be a monumental F**K up by the engine assembler - he would have had a really bad day.
I am suspicious you may be missing something.
I am sticking to my earlier recommendation of learning how to degree the cam.
 

340challconvert

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Steve, thanks again for your thoughts
Trying to get a specs sheet for the Summit cam.

I also plan on checking piston to valve clearance.
I want to use the 340 open chamber edelbrock aluminum heads I have new in storage for this 360.
So I am also in the process of measuring piston depth. Engine was rebuilt with flat top high compression pistons so this is also area for further review
 

Steve340

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Very good idea to check valve to piston. Even though your piston is way down the bore with no valve relief pockets it could get pretty close at TDC.
Calculating true compression ratio is also very easy at this point.
Edelbrock are good quality heads but don't believe the run out of the box crap.
Strip and check them I find the valve stem clearance is too tight and some of the seat work is not the best.
I get the seats cut to get them concentric and the guides honed and put them back together.
 

Chryco Psycho

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I would disagree Eddy are crappy heads ,with massive core shift issues & low quality Alum , I would return them if you can , I looked at 10 sets in a speed shop at one point , the best 2 heads were still not great .
 

BriceRoad

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My friend has had Eddy aluminum heads on his 340 Dart for over 10 years. No issues.
 

340challconvert

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Brice
Appreciate your thought!
I have heard a lot of feedback on Eddy heads from great to problematic
A relative to my brother in law owns a long term ownership machine shop
At this point, I am going to have him just check out the new heads
The area of concern seems to be the valve guides, especially the exhaust guides being too tight out of the box.
Others have reported finding no problems of this nature or any other issues
I have the 60179 Eddy heads with open chambers designed for use with the high compression 340 with the above deck piston.
I will follow up with the check out for peace of mind
Thanks for responding
Phil
 

Bret Schneider

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Just got a set of Edelbrock's Performer RPM heads. Had the machine shop check them as they've run across tight guides on these heads before as well. The heads were fine right out of the box. Good castings and didn't even need to touch the intake ports as they matched the gaskets perfectly. Still, money well spent to verify with a machine shop. Same as any head.
 

Challenger RTA

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As they said "to leave the chain as is." I would like to know their rime or reason Why! They would have to restore my confidence in their products.
 

BriceRoad

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340Challconvert (Phil): just to add on, my friend with the Dart did have a machine shop go over the heads and make sure everything was right when he had the the engine built. He doesn't race it or beat on it. The heads have stood the test of time at least with him and wow do they really dissipate the heat. His car never runs hot. He runs a 160 degree stat in it and the hottest it got was like 167. I told him he should run a 180 stat but it is his engine.

I agree with everyone that the timing marks should line up. That doesn't make sense to me to leave them not lined up.
 

Steve340

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You will be OK with those Edelbrock heads they are no worse than other named brands. I have come across faults on two other reputable brands - nothing that could not be fixed but a big NO to run out of the box.
The best part about all those heads is they use good quality components - valves , springs etc.
The only thing is you will need with those heads is you need the pistons to be above the deck otherwise your compression ratio will be quite low. Keith Black make an affordable plus 18 version.
The older design V8 motors need a bit of compression - I find 10 to 1 static compression ratio works well and is not to high to cause detonation problems if you run good fuel.
 

blubyou340

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Agree. Degree the cam. Advancing the cam would help bottom end and retarding the cam would help top end.
Doing either one also affect valve to piston clearance.
Did you contact the camshaft manufacturer or the engine builder ?
Advancing / Retarding a Camshaft
The dots do look off i would pull distributer. Make sure your set at tdc on intake then look at the dots then check cam card if they gave it. It will run on exh to o but we dont want that. Look in at oil pump drive in distributer hole make sure the slot is in a line literally with no 1 piston if the the dots arent in line top or bottom pull it and line them up ive had this happen to me from the machine shop build good luck
 

Racer Dave

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As usual I'm late to the party.... but this looks to me to be simply a case of not having the piston at true TDC and being a couple degrees past it. I don't *think* it is a full tooth off. Do you know if the engine shop installed an offset key to advance or retard the cam? That would make the marks misaligned as well. The quick and dirty check is to lay a straightedge along the red line I've drawn, rotate the crank so one of the dots is on that centerline. The other should line up.

When turning the crank with a wrench only a few degrees past TDC will misalign the marks, but the piston will look like it's still at TDC. I can't stress this enough - you must know the piston is at TRUE TDC. Because the piston dwells at TDC for a few degrees you cannot be 100% sure by eye only.

Get a degree wheel, make a pointer, make a piston stop - neither needs to be as fancy as the universal ones I made (I've built quite a few engines, not just Mopar). The pointer can be a bent piece of heavy wire (coat hanger) and the stop needs to stop the piston a little bit before the top of the cylinder. Drill holes matching the head bolt locations in a piece of angle iron or square tube and weld a nut to the underside. Basic stuff. Once you determine exact TDC this mystery will be solved...

After years of working together on my race cars, my son moved out of state and and is building a Mopar of his own. I'm trying to impart my knowledge via short tutorials I call "One Page Tech" articles and did one on finding TDC. If you are interested PM me, or if others are interested I'll post it.

IMG_8963 edit.jpg


pointer.jpg

stop.jpg
 
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