Quench/closed chamber heads should help prevent detonation with the same sized chambers as the open heads.
440 problems/quenching?/advice needed
- Thread starter dkbug
- Start date
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Don't run it anymore until you figure out for sure on the camshaft and valve train.
dkbug
Well-Known Member
That is the plan. I'm definitely swapping out the cam though. I do not need that big of a cam. It has a 2800 stall converter so what I will end up doing is researching what cam will put me where I need to be. The main goal for me is to be able to keep the factory style rockers. I do not want to invest in adjustable rockers until I can get the ones I want, which aren't cheap. I am not opposed to building some new heads though. I figure I can score a set of 906's that I can work over for around $150-$300.
moper
Well-Known Member
What head gasket did you use to put the heads on the engine?
The cam is not "big" in the least. It's actually a very good and mild grind. Perhaps a great match properly set up with the correct parts.
IMO it is one of the best Purple Cams there is.
thesiren74
Well-Known Member
What dizzy are you using? Is it recurved? What your total timing?
..........I have used the 528 mechanical cam in a number of builds....it is well suited to ur engine......put in some hydraulic lifters and get the preload right and u will pretty surprised how it runs and performs, like RRR said its 1 of the best cams out there even for how old it is...........kim.......
dkbug
Well-Known Member
Hydraulic lifters on a solid cam? I don't think that would run very well. haha.
I am using a factory electrictronic distributor with factor style electronic ignition. As far as the timing goes it doesn't much matter at this point because I have the wrong combination of valve train parts. Big cam without adjustment with pushrods that are much too long = disaster waiting to happen. I have moved the distributor as far as it would go either way and it doesn't change a thing. Once I get a cam that will allow me to run valve train I have, I will take a timing light to it and set it the correct way.
I do have to agree with you rusty. That cam has really good specs and I am sure with the right valve train and heads it would be a power house. I would rather have a bit lower duration though. This cam isjust a bit choppy for my taste lol.
I am using a factory electrictronic distributor with factor style electronic ignition. As far as the timing goes it doesn't much matter at this point because I have the wrong combination of valve train parts. Big cam without adjustment with pushrods that are much too long = disaster waiting to happen. I have moved the distributor as far as it would go either way and it doesn't change a thing. Once I get a cam that will allow me to run valve train I have, I will take a timing light to it and set it the correct way.
I do have to agree with you rusty. That cam has really good specs and I am sure with the right valve train and heads it would be a power house. I would rather have a bit lower duration though. This cam isjust a bit choppy for my taste lol.
moper
Well-Known Member
You have some very basic issues. The cam is not too large, and in the last 440 I had with ported 516s, it idled like a kitten and still went low 12sd at 114 in my '70 Cuda. What you have. is a mechanical camshaft that you do not have adjustable rockers with. My impression is the reason it runs like crap is the rockers and pushrods. Depending on the head gasket, the compression should be a real 10.5, or up to 10.8. Depending on the installation of the cam andhead gasket, you may have enough valve to piston clearance, or you don't. The pushrods are wrong. The rockers are wrong. Replace those and set the lash, and run it again. that cam is not a large cam by any means, but it has to have the right parts and be set up properly - which you missed. At this point, any refernces to quench are not needed simply because you've got parts problems.
Marcohotrod
Well-Known Member
since U think the pushrods may be 8.9" and stock are 9.2" , just for laughs with a thickness gage check and see if there is any lash and what it is. the 284* / .528" is the smallest cam in the mopar catalog, and asks for .028"/.032" lash. think about measuring actual deck height, checking the cam and lifters for wear, running the heads U have with a blue fel pro gasket for a perfectly acceptable 10.6:1 and quench in a lightweight car. save the money for new heads and buy adjustable rockers now instead of later. if the cam / lifters U have are smoked I suggest a 292*/.510" hydraulic with stock rockers. what do U plan on for rear gear ratio / rear tire size?
dkbug
Well-Known Member
Well let me put this into perspective. With 906 heads, this motor checked out at ~10.75:1. (Verified by a great friend of mine who owns a machine shop) That is with open chamber heads. Now, throw a set of closed chambers on there and recalculate.
ops: there is no way this motor is at said compression with those heads.I am going to invest in adjustable rockers as soon as tax season comes in. Until then, ill have a smaller cam and open chamber heads. If I calculated it right, this said combination of parts should, in theory, run like it should.
So I repeat, adjustable rockers will come. Just with a different combo.
Now, the fun part. I called hughes engines and he laughed at the combination and said he couldn't believe this was happening. I told him I agree. He told me that with those heads with a zero deck and no relief flat tops, I should have gone to church since it didn't detonate itself to death on pump gas. He assumed 13:1+. I agree with him. He told me open chamber heads and a smaller cam to allow non adjustable rockers would be fine inefficient, but fine. Efficiency will come with different pistons.
moper
Well-Known Member
Again - your respectable buddy measured one set of 906s - and if that is what he came out to, that set of 906s were milled to reduce the chamber size. Hughes is full of **** - and that's not the first time. But at this point you're all set with whatever plan you have. Good luck to you and Merry Christmas!
dkbug
Well-Known Member
This is true. However I am not going for a crazy hot rod motor. Whether its 9:1 or 12:1, i will enjoy it the same. I made up my mind based on the cumulative input of others. Im going with what the majority are saying is a good idea.
What sort of pistons are in the motor? Flat tops? Domed? Can you describe them?
dkbug
Well-Known Member
"440 - 1978 block.
FROM WHAT I HAVE BEEN TOLD~~~
it is a stock stroke with a 20/20 crank
stock rods
aftermarket flat top pistons (.030) WITHOUT VALVE RELIEFS
ZERO DECKED....
I have 516 close chambered heads from a 1967 383
fresh valve job with very little porting done
springs to match the cam
STOCK VALVE ROCKER ASSEMBLY... I know..
Weiand dual plane intake
750 edle carb
Cam specs~~~
Mopar performance .528 purple mechanical camshaft/ I measured this lift to be correct.
Didn't calculate the duration.."
FROM WHAT I HAVE BEEN TOLD~~~
it is a stock stroke with a 20/20 crank
stock rods
aftermarket flat top pistons (.030) WITHOUT VALVE RELIEFS
ZERO DECKED....
I have 516 close chambered heads from a 1967 383
fresh valve job with very little porting done
springs to match the cam
STOCK VALVE ROCKER ASSEMBLY... I know..
Weiand dual plane intake
750 edle carb
Cam specs~~~
Mopar performance .528 purple mechanical camshaft/ I measured this lift to be correct.
Didn't calculate the duration.."
In other words, you're not sure because you have not seen them.
dkbug
Well-Known Member
I told you what was in it. Flat top pistons that are zero decked with no valve reliefs. I put the current heads on it. This is verified.
Marcohotrod
Well-Known Member
great machining and rods and crank, exactly .000" deck on all 4 corners. when I said 10.6:1 I did not assume , I referenced the federal mogul performance catalog. that is with 78 cc heads, what size chambers are your closed chamber heads. please measure your current valve lash, we are very curious and it only takes 2 minutes
Ok, I didn't realize you had assembled it. I missed that part.
Keep in mind that 906 heads unmilled are around 90CCs chamber volume so that may help your situation.
I am not aware of a piston with no valve reliefs that can achieve zero deck height without heavy block milling. I assume when you installed the heads you verified the zero deck height also?
dkbug
Well-Known Member
Correct me if I am wrong, but if the top of the piston meets the deck to form a flat surface all the way across the head, this is zero deck. If so, then yeah its definitely zero!!
I managed to score a really nice set of 906's for an absolute steal. Since I was able to find these at this price, I will start looking for a reasonably priced set of adjustable rockers.
Take a look at these babies!!! Pics on the next post..
Well, generally deck height is measured with a deck clearance gauge, because measuring in thousandths of an inch is impossible to do with the naked eye. So you will have better success if you measure it, but yes it does sound like maybe it has been zero decked.
With a 90cc chamber, I come up with 10.16:1 so you will have trouble on pump gas with a small cam.
dkbug
Well-Known Member
10.16:1 on 91 octane should be fine I thought. People in Oklahoma claim that they can safely run 91 with 10.75:1. Now, I take that with a grain of salt of course, considering that most of the "built cheby's" here are junk thrown together... Cause " theys all the same"....
Now, my plan is to actually measure everything. I am quite sick of going into this blind. If what you are calculating is correct, my assumption is that that compression is with the .43 head gasket? I will more than likely be running and thicker gasket to avoid problems with running pump gas. Even though I live less than a mile from my local drag strip, I am NOT down for $9 a gal for race gas.
dkbug
Well-Known Member
Pics
dkbug
Well-Known Member
Exhaust measures at 2.14" and intake measures at 1.81". Ill be checking the cc's soon. The valve job was recently done and the springs were for a .590" cam.
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