New Cam Same Power
- Thread starter archerandethansdad
- Start date
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archerandethansdad
Well-Known Member
Yeah right now it's at TDC but the cam gear i got wasn't adjustable. I assume that's what you mean?
Correct. It's supposed to be 4* advanced from that 112, or at 108 ICL. If it was mine, I'd put it on down around 102. That would help it out a lot.
That said, on a 200K mile engine, you might just drive it as is, have some fun and wait till the next build.
Sounds like it's ready for a little boost, 4 to 6 pounds would work miracles! Well, for a little while, anyway...
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harrisonm
Well-Known Member
That is WAY low. You should be around at least 130-140. If all cylinders are at 100, you need a COMPLETE rebuild.
512Stroker
We are all here because we are not all there.
Did you degree in the cam when you installed the new cam?
Never trust the dots on the timing chain gears.
pishta
I know I'm right....
feed it some upper cylinder lube and see if the rings dont pick back up. Sounds tired on a 200K motor with a carb......probably a nice ridge in the cylinders and the rings just cant cope with the different diameter up there. Put the old cam back in and then save up for + pistons and a bore. Cheap would be to find the thinnest head gaskets you can find and try those, you could have some Fel-pro .050's in there when a Mr Gasket .022 would give you a little bump off the bat.
This Is a severely UN-balanced combination.
dartfreak75
Restore it, Dont part it!
First off welcome to the forum its nice to have you!
What you are experiencing is a classic case of too much cam! Your cylinder pressure of 100psi is right on mark with a low compression stock well used 318. Iv owned a bunch of them I know all to well lol. That cam is probably to much cam for a mild 9:1 360. Your probably at 7.5 to 8:1 but there is stuff that you can do. Without changing gears or converters. Timing is gonna be your friend. @318willrun is running 20 initial and like 40 total in his 318 with low compression you can get alot more than 12-14 . We can work on the tune and get some more out of it. But don't expect a whole lot
More than what you begain with. When I first started my 318 build alot of members told me start with getting a tight sealing engine before worrying about cam and bolt on stuff. They are right. A good hone and ring job (depending on the shape of your cylinders) and a valve job make sure they are sealing can go a long way on a budget 318. You can't afford to loose any more compression due to a leaky valve or ring! Recheck all your cylinders with the throttle Wide open. Then report back if they are above 100 and consistent then chances are you have don't have any broken rings or bad valves. We can raise your compression a little with some thin headgaskets, do you know what gaskets your using now? After we determine all that we can work on tuning your carb and timing.
What you are experiencing is a classic case of too much cam! Your cylinder pressure of 100psi is right on mark with a low compression stock well used 318. Iv owned a bunch of them I know all to well lol. That cam is probably to much cam for a mild 9:1 360. Your probably at 7.5 to 8:1 but there is stuff that you can do. Without changing gears or converters. Timing is gonna be your friend. @318willrun is running 20 initial and like 40 total in his 318 with low compression you can get alot more than 12-14 . We can work on the tune and get some more out of it. But don't expect a whole lot
More than what you begain with. When I first started my 318 build alot of members told me start with getting a tight sealing engine before worrying about cam and bolt on stuff. They are right. A good hone and ring job (depending on the shape of your cylinders) and a valve job make sure they are sealing can go a long way on a budget 318. You can't afford to loose any more compression due to a leaky valve or ring! Recheck all your cylinders with the throttle Wide open. Then report back if they are above 100 and consistent then chances are you have don't have any broken rings or bad valves. We can raise your compression a little with some thin headgaskets, do you know what gaskets your using now? After we determine all that we can work on tuning your carb and timing.
Maybe with all the help here, if heeded, the OP can maybe improve things, but that’s way too big a cam and without changing other parts (big ticket items and/or more involved labor) i think he’ll be underwhelmed regardless. RRR’s advice on degreeing it in at 102 or so might be the best advice that’ll make the most of the situation.
dartfreak75
Restore it, Dont part it!
If he digs deep enough to retard the cam he might as well pull it and replace it.
The Summit cam is a “In general bump up cam” that I don’t recommend myself. I firmly believe that another cam would be very well more suited to making some “Upgraded Power” to enjoy. This is where paying the piper is worth the expense.
Probably so. I say your cam is ro large and the cylinder pressure to low on a small displacement engine. Further hindered by a low stall and the 3.23’s. There is t much ceiling above to reach for your n this combo and a tiring engine.
You should be looking at a cam with a intake duration @.050 or 218 at a maximum.
Please be specific and descriptive and exacting! So far you have been not. The devil is in the details.
What cam and intake are you running and do you have headers? Dual exhaust? Power brakes?
If you state your running a Holley carb only or just a *** cfm carb, we can not really help very well. Your answers are topical and vague and such will be the answering responses.
dartfreak75
Restore it, Dont part it!
Carb and timing tuning is where i would start.
archerandethansdad
Well-Known Member
Thanks for the response. I did do a recheck on the cylinders and i was off they came back 2,4,8 at 120. Number 6 came in at 135. 1,3,5 also came in a little over 120 and 7 was at 130. The heads are only a few years old with less then 5k miles on them and the valves were increased over stock with 69cc chambers. Doesn't burn oil or blow smoke. I do plan on doing a ring job over the fall/winter. I'm sure it's a timing issue like i said i'm not expecting a strip car just a nice cruiser but i would like to be able to smoke the tires from time to time just for fun. Factory manual says 135-155 is the factory compression. Let me know what you think.
dartfreak75
Restore it, Dont part it!
Those are not bad numbers for a 318. Do you have basic tuning tools like a vacuum gauge and a timing light?
archerandethansdad
Well-Known Member
Yes i do. I've got a AVS2 650 on it now it came with a Holley 1850 electric choke 600. The previous owner got into some bad gas and it was just filthy and i couldn't get it to act right. Of course after i removed the fuel tank and found it was full of rust did i find out why. Either way at 14 degrees and fuel mixture set up i'm getting right at 15inHg of vacuum at 750 rpm. When i'm cruising at 50-60 I'm running at 2200-2300 and not sure if that's where it should be or not. I have 3.23 sure grip rear and 3 spd auto trans.
fratzog lover
Well-Known Member
Something like this would make you alot happier.
Voodoo Hydraulic Flat Tappet Cam - Chrysler 273-360 256/262 (lunatipower.com)
Voodoo Hydraulic Flat Tappet Cam - Chrysler 273-360 256/262 (lunatipower.com)
archerandethansdad
Well-Known Member
Thanks for the suggestion. I think I'll keep the cam i've got. like i said it's got good response. If i have to build up to the cam i'm ok with that. The heads are aftermarket and the valves were enlarged and the heads have been bowl ported with upgraded rockers and springs.
Is that cruising at 50-60 mph or degrees on the distributor? at 2200-2300 rpm?
With 3.23’s, automatic trans and stock sized tires (or close) Id think you have oversized tires. Larger in diameter. I’d say the rpm is low. But good for cruising.
If it is timing, then I’d say 50-52 total is fine with the vacuum advance hooked up. 60 degrees would or should be a bit much on cruise timing. Low compression engine and more so with open chambered heads like more timing at WOT & cruise.
dartfreak75
Restore it, Dont part it!
Without knowing your distributor setup we can't know if 14 degrees is good or not.
Are you running vacuum advance?
Have you checked your total timing ?
Do you know how much mechanical advance you have ?
Check these and then get back.
I would do this...
Disconnect and plug the vacuum advance if you have one, make sure there are no vacuum leaks anywhere.
Hook up your vacuum gauge to manifold vacuum with the engine warm the engine off take both mixture screws all the way in then both 2 full turns out. Start your engine see where your vacuum is. Go in 1/8, 1/4,1/2 turns in see where your vacuum goes then do the same out see where you get the highest vacuum at idle. Once you get the highest vacuum. Let's work on your timing. Set your idle where you want it check your initial timing with your timing light. Bump up your timing 2 degrees at a time and listen to the engine does it speed up ? Did your vacuum increase? Take your idle back down and do this step again until your no longer getting a rpm gain. Then check and see if your getting any starter kickback, if all is well there take 2-4 degrees out of it and let check your total. To check total i use the idle screw check the initial again. Then bump up the idle speed 2-3 hundred at a time and record your timing every time until you no longer get a different timing lets say its 40 degrees at 2800rpm then take your initial and subtract the total that's how much mechanical advance you have in the distributor. Work on that then let us know.
Are you running vacuum advance?
Have you checked your total timing ?
Do you know how much mechanical advance you have ?
Check these and then get back.
I would do this...
Disconnect and plug the vacuum advance if you have one, make sure there are no vacuum leaks anywhere.
Hook up your vacuum gauge to manifold vacuum with the engine warm the engine off take both mixture screws all the way in then both 2 full turns out. Start your engine see where your vacuum is. Go in 1/8, 1/4,1/2 turns in see where your vacuum goes then do the same out see where you get the highest vacuum at idle. Once you get the highest vacuum. Let's work on your timing. Set your idle where you want it check your initial timing with your timing light. Bump up your timing 2 degrees at a time and listen to the engine does it speed up ? Did your vacuum increase? Take your idle back down and do this step again until your no longer getting a rpm gain. Then check and see if your getting any starter kickback, if all is well there take 2-4 degrees out of it and let check your total. To check total i use the idle screw check the initial again. Then bump up the idle speed 2-3 hundred at a time and record your timing every time until you no longer get a different timing lets say its 40 degrees at 2800rpm then take your initial and subtract the total that's how much mechanical advance you have in the distributor. Work on that then let us know.
448Scamp
Running Free
You need to pull it back apart and degree the cam. I didn’t read where you did that, so you haven’t a clue where the cam is timed. Once you know where it’s timed, you can determine if you need to change it.
dartfreak75
Restore it, Dont part it!
If he is gonna go that far he might as well replace the cam that we all have agreed is too large for the combo. We need to try and get it running the best it can with what he has.
448Scamp
Running Free
It’s going to be hard to do that if the OP doesn’t know where the cam is. How do we know it’s not in at 114, or even 116? You can’t tune that out if that’s where it is.
Phreakish
Well-Known Member
Not to mention, if he plans to replace pistons later - why buy a cam now and a cam after the compression bump?
Going to a 102-104 ICL will gain some pressure and low-end while only losing what he's not using (since OP says he's not tracking the car).
I'd advance the crap out of it, then focus on timing/tuning. Once the new slugs are in, a more 'optimal' cam would make a ton of sense. Right now, it's much more of a gray area.
OP should probably start with some pictures of the spark plugs. That should help give some better guidance than blind recommendations at timing and tuning..
dartfreak75
Restore it, Dont part it!
Yea thats what I ment if he goes that far he might as well rebuild it.
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