Cam?

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Shunyun

Shunyun

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OK, I'm getting my hands on a 73 225 /6 w/o a cam shaft. To be specific, the brass (?) gear was shredded. As I understand it (haven't seen it yet,) oil pump is a steel gear and distrib is plastic. That make sense? So two questions:
1) when I replace the cam what should I look out for? Component mismatch?
2) what cam? I'd like to optimize for aggressive city driving.

BTW, I've got my original engine (65 dart) with a spun bearing at cyl#5. Current plan is to swap the stock cam.
 
Call Dave Crower at Crower Cams. He hooked me up with a nice custom grind for my ex's 64 Dart engine. It was a stock single bbl carb and stock exhaust, he ground me a 260° duration .495 lift cam for her 225. It performed better than stock and she was very happy with it.

www.crower.com
 
You need to be changing valve springs with a .495" lift cam. You will be getting too close to spring bind at .495". You should limit lift to about .445" with stock /6 valve springs. 340 springs are a common step up for springs if you need to. Also there are some Sealed Power springs that will work; I can look up the PN if interested.

You may also want to contact Doug Dutra for some good grinds for all stock springs; he is over on www.slantsix.org as 'Doctor Dodge'. He can also advise you on the gear issues better than anyone around; he has done considerable research and work on the pump gears and has an article on that site about the subject that is worth your time reading.

For a simple cam change, I would be looking at a .445/244 duration cam from Doug Dutra. I would not go with the stock '65 cam unless you need to keep the $$ spent minimized; the lift of the pre-'71 (or thereabouts) stock cams is lower than your '73 and the engine will have noticeably less 'poop'.
 
Nm9theham, thanks, really appreciate that guidance. I've got time to make these considerations so this is good stuff!
 
Oregon cam grinders is also a great resource for slant cams. Cheap and tons of cams/lobe profiles. Quite knowledgeable as well!
 
People here say the Competition Cams offering with the nitride coating (CS380?) tends to eat up the oil pump gear.

If your 1965 engine spun a main bearing, I understand that ruins the block. When I bought a rebuilt long-block slant in 1994, the guy quickly removed all main bearings from my old engine to insure no spun bearings. If so, the core was useless to them.
 
I assumed he meant #5 rod bearing....???

Spun mains can be fixed by re-line boring the crank caps and saddles. Done it before.
 
nm9stheham said:
I assumed he meant #5 rod bearing....??? Spun mains can be fixed by re-line boring the crank caps and saddles. Done it before.
Click to expand...
Hmmm, good point; I haven't opened it up yet but all I know is
- compression test is nil for #5
- pencil at top of cylinder hits the top of the piston and stays there when I turn the engine.
- there's no nasty scraping, nocking or clunking noises when running.
- Engine runs, just real rough
So I assume that, whatever the cause, I'm safer to go with a fresh engine and use the original for parts.

On that note, I've got a 78 /6 from a volare'. Hoping I can use the stock 65 cam, oil pump and distributor.
 
If you mean that the pencil is being put in to the spark plug hole and indicates that the #5 piston stays at the top of the cylinder, sounds like a broken connecting rod. Not sure I understand the pencil test, however....??

Use the '78 cam; it has more lift than the '65.

Have read the same about the Comp cams; do not have the facts in my hands however. But, the /6.org folks seem to favor Oregon.
 
If you broke a rod, you would get no compression in that cylinder. If you dont' have a gage, hold your finger in the hole.

I can't fault your plan of getting a 2nd engine for rebuild or spare parts. These slants are so cheap, no sense not having a spare if you have the space. One reason I love them is you can't make any expensive mistakes like you might with a later M-B or BMW engine.
 
Comp actually makes 4 cams for the /6 in their High Energy line, 2 solid, 2 hydraulic. [252S, 264S, 252H, 260H). Pricing is better through Summit than direct from Comp for both solid cams (~ $8.00) with free shipping from either source.

Generally when there is an oiling failure on the /6 it is the #5 cylinder that goes, usually the con rod. That comes from tales of woe on FABO and /6.org
 
BillGrissom said:
If you broke a rod, you would get no compression in that cylinder. If you dont' have a gage, hold your finger in the hole. I can't fault your plan of getting a 2nd engine for rebuild or spare parts. These slants are so cheap, no sense not having a spare if you have the space. One reason I love them is you can't make any expensive mistakes like you might with a later M-B or BMW engine.
Click to expand...
Yeah, I used a gauge. The pencil test is just to detect minute movement when hand turning. In my case, zippo compression and not the slightest quiver on the pencil. That piston is sitting right at the top and not moving.

Assuming a broken rod then, I suppose the bearing could be intact. Is replacement simple? I did it once long ago on a 351 Cleveland when I was young and stupid; now I'm just old and admittedly ignorant...
 
2 Darts said:
Comp actually makes 4 cams for the /6 in their High Energy line, 2 solid, 2 hydraulic. [252S, 264S, 252H, 260H). Pricing is better through Summit than direct from Comp for both solid cams (~ $8.00) with free shipping from either source. Generally when there is an oiling failure on the /6 it is the #5 cylinder that goes, usually the con rod. That comes from tales of woe on FABO and /6.org
Click to expand...
Thanks, good info! How do I decide which to choose? Any articles or threads you'd recommend? I mean articles specific to cam selection for the /6.
 
If it is not making any noise, then my guess is the top of the piston crown has broken off and is up in the top of the bore, with the rest of the piston still attached to the rod. That is the only explanation for the rod not flopping around in the cylinder and raising all heck when it is running.
 
RustyRatRod said:
If it is not making any noise, then my guess is the top of the piston crown has broken off and is up in the top of the bore, with the rest of the piston still attached to the rod. That is the only explanation for the rod not flopping around in the cylinder and raising all heck when it is running.
Click to expand...
Huh. Yeah, that makes perfect sense! Never imagined that could happen.
 
That is making a lot of sense; never seen such a thing but it certainly could happen. If that is the case then the bore will be OK.

I'd be pulling the head to see what is up and planning from there. Pulling one rod and piston (and its remains) is not all that hard if you can get the engine up and the pan off.

On the cams, I have not looked but the S means 'solid' and H means 'hydraulic' I presume; a solid lifter cam is what you want with your earlier engines. But personally, I would steer you to ask the question on www.slantsix.org.
 
Shunyun said:
Thanks, good info! How do I decide which to choose? Any articles or threads you'd recommend? I mean articles specific to cam selection for the /6.
Click to expand...

The CompCams site has a free cam selector piece of software that only requires a registration. The best single article I found over on slantsix.org, http://www.slantsix.org/forum/viewtopic.php?t=23314 , details what people have built. The darling of that crowd seems to be a 225 with 198 rods and bored out to use the pistons from the 2.2 4-banger.

On a personal note, I'm collecting parts for a fresh bullet for my 73 Dart Mordor. So far, I have a CompCams 264H, a double row roller 3 position timing chain, lifters, 390 cfm Holley converted to 4150, an oversize exhaust manifold (no EGR or carb heat), and a Hurricane manifold. My plans are to mill the head and the block .050 and bore out as needed. For all the chatter about 225s falling out of trees, the folks around here seem to want $300 for one, when I can find one. Personal situation has me holding off on the project for now.
 
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