Just for giggles, have You put a vacuum gauge on the build & taken readings??
Say, at Idle, and under load ?
Well, it's my turn to ask for suggestions..
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Just for giggles, have You put a vacuum gauge on the build & taken readings??
Say, at Idle, and under load ?
Ok, i'll try to answer some of the newest questions. 1st, yes, the throttle goes wide open. Just so you understand, even if it was only coming open 1/4 of the way, it should have a lot more than what's here. 2nd, car has the same power in all three gears and in reverse. 3rd, I have not put a vacuum gauge on it because I don't have one. 4th, I got rid of the single exhaust and put a temporarily dual exhaust with glass packs that end before the rear axle when I installed the motor. It has manifolds, no headers. I have discovered that if you floor it, as the rpm's build it starts to cut out. I don't know if this would be a new clue, but i'm truly believing it's the cam.
moper asked if it has valve rotators on the exhaust springs. There was no answer. You want help, you need to provide answers. Valve rotators on ANY type of performance cam will result in poor performance, as those springs designed for rotators are weak as light beer.
Also, you said you've had a max of 16* initial timing so far. Still WAY low for the engine you have which is guaranteed to be less than 9:1. Probably somewhere real close to or maybe even "under" 8.
With that kind of compression, or the lack thereof, a high initial timing setting is the way to go. .........regardless of cylinder pressure.......which seems to be pretty dang good.
It's all in the timing. Whether it's not enough initial, whether you're reading it wrong (happens to the best of us) or whether something's amiss with the camshaft timing.
Probably do you well to get the degree wheel out if more initial timing does not help.
Also, you said you've had a max of 16* initial timing so far. Still WAY low for the engine you have which is guaranteed to be less than 9:1. Probably somewhere real close to or maybe even "under" 8.
With that kind of compression, or the lack thereof, a high initial timing setting is the way to go. .........regardless of cylinder pressure.......which seems to be pretty dang good.
It's all in the timing. Whether it's not enough initial, whether you're reading it wrong (happens to the best of us) or whether something's amiss with the camshaft timing.
Probably do you well to get the degree wheel out if more initial timing does not help.
^^^^^ Let me clear this up for once and for all^^^
^^^^^ Let me clear this up for once and for all^^^ I advanced the timing until it turned over very hard. I backed it off slowly, not even using the timing light. I also timed it using the timing light. I will assure you all that I know how to time a car, and I've dealt numerous times with cars with performance cams. Ignition timing is not the car's problem. 2nd, No, it does not have the rotators. Thanks for the replies, this problem is deeper than turning a distributer..... how i wish that was the problem. I will dig more into it next week. Right now, I believe it to be a bad cam, or very badi cam timing. Maybe I a tooth off on the chain, never made that mistake before but nobody is perfect. I will check it out next week
No need to get snippy. We're just trying to help and unless you answer completely, we cannot read your mind.
Also....once again, no one is questioning your experience. You asked for help. You're gettin ideas thrown at you. Forgive us if we don't know the whole situation and have to ask a few clarifying questions. Again, we don't know the situation, unless you say it all. Which you did not until that post right there ^^^^^^^^^
How is the idle quality? Is it any choppy at all? Smooth like stock? What's the vacuum reading in drive at idle? I don't think I saw that.......but I may have missed it. If the vacuum is low and you feel like you have enough initial timing, you may have too much cam......or as I said earlier, it may need to be degreed.
Also....once again, no one is questioning your experience. You asked for help. You're gettin ideas thrown at you. Forgive us if we don't know the whole situation and have to ask a few clarifying questions. Again, we don't know the situation, unless you say it all. Which you did not until that post right there ^^^^^^^^^
How is the idle quality? Is it any choppy at all? Smooth like stock? What's the vacuum reading in drive at idle? I don't think I saw that.......but I may have missed it. If the vacuum is low and you feel like you have enough initial timing, you may have too much cam......or as I said earlier, it may need to be degreed.
67Dart273
Well-Known Member
I said this earlier. You know what cam is in the engine? You can check cam timing fairly accurately if you are careful, right in the engine. You DO however, need to know what cam is there and obtain the card.
There HAS been cases here and other forums recently on cam timing screwups.
One example is my distant neighbor "out of town." He had a purple shaft which, it turns out, needs to be advanced "a ways" to run in a street engine, plus it was in a pickup. In that case, the cam drive / cam was off "dot to dot" which put the cam at least 2* FURTHER retarded from factory. As I recall we wound that thing ahead about 6*. According to him it made the difference between night and day.
Another is a guy over?? at MyMopar or somewhere. He had an advance/ retard cam drive --with multiple keyways. he had screwed that setup all up. Finally after he posted photos at the teardown, we all knew what was wrong.
Do not take ANYthing for granted.
You have not said a single word about checking the timing marks. (piston stop) That is one of the FIRST things you should have done --- if for no other reason than getting it off the table.
There HAS been cases here and other forums recently on cam timing screwups.
One example is my distant neighbor "out of town." He had a purple shaft which, it turns out, needs to be advanced "a ways" to run in a street engine, plus it was in a pickup. In that case, the cam drive / cam was off "dot to dot" which put the cam at least 2* FURTHER retarded from factory. As I recall we wound that thing ahead about 6*. According to him it made the difference between night and day.
Another is a guy over?? at MyMopar or somewhere. He had an advance/ retard cam drive --with multiple keyways. he had screwed that setup all up. Finally after he posted photos at the teardown, we all knew what was wrong.
Do not take ANYthing for granted.
You have not said a single word about checking the timing marks. (piston stop) That is one of the FIRST things you should have done --- if for no other reason than getting it off the table.
318willrun said:
So spend like??? $28.00 for a top of the line OTC, or equivalent...
Not That fuel is not the issue,
Or Some critter plugged Your exhaust,
Or the cam is poo-poo, however,
I am a simple 'Observer & Reporter' Not a 'theorist'...
Good Holy Racing Gods...
rip the cam & lifters out...
What of the Lifters?, pushrod length?, just on the 'by-n-by' You do know a flat lobe with sealed rings---
will still give an excellent comp reading???? think running compression---
Sorry, I'm out
Harbor Freight sells really cheap timing lights and vacuum gauges. You really need those in order to know "where things are", regardless of what else may be wrong inside. Once you get that ironed out, you will need proper tuning tools. Getting them now "might" show you something you've slipped up and missed.
I think some of the replies are a little on the rough side. It's the way it reads. 318Willrun is trying to explain it all and doing pretty good.
thanks for the input. I do have a timing light. I cannot tell you the cam, because it was in the motor when I bought it (i stated that earlier). It is marked H260. It idles fairly mild. Not as radical as, per say, a .474/280 MP cam. I'm leaning towards 67Dart273 in the idea that I have a cam problem. Could be I lost a couple of lobes, could be valve timing, or just a bum-grind. This is where I will start. I will follow up my findings. I will start by checking rocker movement. If that's good, I'll look deeper at the cam/timing. I may just put a XE268 in it so I know what is in there.
Well, "I" certainly have "no problem" backin out. It's not like this is a payin gig.
Fair enough, Rob. lol.... not upset with anyone.... and keep in mind this is not a motor I built, but a craigslist special....
. She'll be purring like a kitten as soon as I get some time to throw at her..... Just hoping for a "break through" idea to avoid more time, but I think I was hoping against what I pretty much already knew.
1967 'cuda
Dropped on Head as a Baby
The H-260 sounds like a Crane camshaft. I don't know if I'd suspect a flat lobe already if the components are as fresh as you described. This could be something as simple as a bad fuel pump that's barely supplying enough gas.
I'm thinking old school 260-H Comp "High Energy" grind.( roughly 212@ .050,110-112 l/c, .440 wish lift. Seen one in a rebuilt 360 Cordoba,with smog equipment. Laid rubber ,everywhere..
Back to basics: Check the balancer for slippage/wrong one, fuel delivery & pressure/ possible tired valve springs( dump the damn rotators...)
Back to basics: Check the balancer for slippage/wrong one, fuel delivery & pressure/ possible tired valve springs( dump the damn rotators...)
Pull the valve cover off and crank the engine over, watch to make sure all of the rocker arms/valves look like they are opening all the way...
^^This is my next move.^^ I've never lost a lobe before. If that is the case, I suppose the shavings have destroyed the bearings and cylinder walls?????????????? As for the fuel pump, it is new (mechanical) and the one that ran the 318 great.
tarvin890
tarvin890
sounds like something "plugged up"... weather it be in the intake system or exhaust to me
nm9stheham
Well-Known Member
The cam might be the Crane H-260-2, hydraulic flat tappet. Kinda mild: 204/216 duration at .050", .427/.454 lift, 112 LSA, and about 5 degrees ground in advance. This is a semi-torque/stump puller cam. It ought to jump out. Explains the mild idle and good compression readings.
Either plugged somewhere or really retarded cam as suggested.
If you lost a lobe, the shavings will generally go down into the crankcase and oil pan, then up into the pump and then into the filter. You might be OK, if the filters bypass never opened, but I certainly would replace the pump and pull it all apart to inspect everything. Hard to say exactly were the tiniest particles could go.
Either plugged somewhere or really retarded cam as suggested.
If you lost a lobe, the shavings will generally go down into the crankcase and oil pan, then up into the pump and then into the filter. You might be OK, if the filters bypass never opened, but I certainly would replace the pump and pull it all apart to inspect everything. Hard to say exactly were the tiniest particles could go.
I believe this is where my investigation on the cam led me, to the very cam you have described. I also believe you have nailed it all with valve timing. Nothing plugged on intake manifold or exhaust piping. I'll start into it 1st chance I get.
*Good News* - All the rockers moved exactly the same and looked totally normal. I removed the plugs and turned the engine over watching each rocker - all 16. So, I think I can rule out a wiped out lobe. I didn't use a measuring device, but every rocker well compressed the valve spring and by eye equally.
ALSO, here is a picture of what all the spark plugs looked like. Next is the timing chain. What are the suspicions of a faulty chain????? I put a Mellings double roller in it that offers the advance/retard timing of 4* or straight up. I used the straight up.
I didn't use a measuring device, but every rocker well compressed the valve spring and by eye equally.ALSO, here is a picture of what all the spark plugs looked like. Next is the timing chain. What are the suspicions of a faulty chain????? I put a Mellings double roller in it that offers the advance/retard timing of 4* or straight up. I used the straight up.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I think your glasspacks are on backwards, and/or restricted.There is a quickcheck for the split-overlap position, which very nearly always falls within a few degrees of TDC exhaust stroke.
You can measure the exhaust pressure with a pressure gauge. I should run less than 4psi.... 2 to 3 is better.Of course less than 1 would be excellent.This should be measured at full-load-WOT, and at or near to the engines torque peak. You can get an idea of the pressure by what's coming out of the tailpipe, but you kinda need to know what should be coming out, so that you have a basis of comparison. I just braze Nipples in the downpipes and measure it. Nice numbers to print on the work-orders. Customers like that.
You can measure the exhaust pressure with a pressure gauge. I should run less than 4psi.... 2 to 3 is better.Of course less than 1 would be excellent.This should be measured at full-load-WOT, and at or near to the engines torque peak. You can get an idea of the pressure by what's coming out of the tailpipe, but you kinda need to know what should be coming out, so that you have a basis of comparison. I just braze Nipples in the downpipes and measure it. Nice numbers to print on the work-orders. Customers like that.
1967 'cuda
Dropped on Head as a Baby
I realize that things such as worn cam lobes and mismatched timing between cam & crank are possible. The cam lobes rarely go flat immediately on a fresh motor with almost zero miles. Because you did do the cam installation yourself and say that you've never screwed up mating the two gears before, I'd say that it's not really likely you screwed it up this time. I would probably want to rule out carburetion because you're using a carb that worked well on your Belvedere.
Those plugs are SO clean that it's obvious you're not running rich. I still question the fuel delivery system. Is it possible that you've got a line kinked? If you disconnect the line from the carb and crank the motor over do you see good flow?
You mentioned that the intake seemed unusually warm compared to the rest of the motor. Maybe the guys that had suggested a restriction in the exhaust system are on the right track. I'd think if you make it hard for the burnt gasses to exit you'd likely to see some of the hot spent mix remain in the combustion chamber and possibly transfer more heat to the intake.
- just running the possibilities through my head...
Those plugs are SO clean that it's obvious you're not running rich. I still question the fuel delivery system. Is it possible that you've got a line kinked? If you disconnect the line from the carb and crank the motor over do you see good flow?
You mentioned that the intake seemed unusually warm compared to the rest of the motor. Maybe the guys that had suggested a restriction in the exhaust system are on the right track. I'd think if you make it hard for the burnt gasses to exit you'd likely to see some of the hot spent mix remain in the combustion chamber and possibly transfer more heat to the intake.
- just running the possibilities through my head...
Check the converter! If it's weak off the line or takes a lot of pedal to even move the car, but the motor runs and idles well otherwise, the converter could be bad!!
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