LIFTERS WENT BAD????--NEED ADVICE

Cam specs sorry I'm posting for phone.

dirt_worker wrote:does this engine have flat top pistons or dished?

It has 22cc dish pistons.

It is my understanding that a lot of quench is not good for detonation either, just like high compression. And the goal for quench is about .035.

Question...would I be better off to have higher compression and lower quench or lower compression and higher quench? The reason I ask is because with the pistons & heads I have im going to have to choose the best of two evils. I've been researching head gaskets to get my compression down but im finding that in doing so im going to have an awful lot of quench.

For example, I found a gasket that would give me 9.37 compression and .077 quench. Another gasket I found will give me 9.22 compression and .085 quench. Also I found one with 9.76 compression & .055 quench.

Or could I keep the setup I have and just retard the timing when I tow and control detonation that way? Which would be the best way to go?

.035 is too tight on a typical big block bore, need to watch piston rock and hitting the heads.

.040-.045 is better

dfree383 wrote:.035 is too tight on a typical big block bore, need to watch piston rock and hitting the heads.

.040-.045 is better

The problem is that I won't be able to have .040-.045 quench AND lower my compression. Someone mentioned earlier that for towing I need somewhere in the neighborhood of 9.10 with aluminum heads. I can't get the compression that low without a huge number for quench. That's why im wondering if it's better to have a large quench number and lower compression, or lower quench and higher compression.

My pistons are dished (22cc) & is .005 below the deck. Heads are 72cc.

Was the cam degreed. If so was it installed straight up?

dirt_worker wrote:Was the cam degreed. If so was it installed straight up?

No it wasn't degreed. Yes it was installed straight up..

Instead of lowering compression you may want to think about a cam change. Changing the overlap will lower cranking pressure.

Changing the compression only a few 0.10s of a point will not make enough difference. If it does your too close to the edge.

If Pistons are where the problem is and one or more are damaged now would be a good time to order a larger dished piston even if it is a custom order.

78 F150 wrote:

dfree383 wrote:.035 is too tight on a typical big block bore, need to watch piston rock and hitting the heads.

.040-.045 is better

The problem is that I won't be able to have .040-.045 quench AND lower my compression. Someone mentioned earlier that for towing I need somewhere in the neighborhood of 9.10 with aluminum heads. I can't get the compression that low without a huge number for quench. That's why im wondering if it's better to have a large quench number and lower compression, or lower quench and higher compression.

My pistons are dished (22cc) & is .005 below the deck. Heads are 72cc.

Going back and reading previous posts.... How heavy are you towing? 10:1 is getting to high for and kind of heavy towing on pump gas.

You may want to reconsider your combos camshaft and pistons.

SandHillsHillbilly wrote:Instead of lowering compression you may want to think about a cam change. Changing the overlap will lower cranking pressure.

So ur saying I could use my current setup (heads, compression, pistons, head gaskets, etc...) But just use a different cam and it will solve my detonation problem? If so, exactly what cam would you recommend? Im wanting the most torque possible....

Going back and reading previous posts.... How heavy are you towing? 10:1 is getting to high for and kind of heavy towing on pump gas.

You may want to reconsider your combos camshaft and pistons.[/quote]

It's a 29' travel trailer. Uummm, 8700 lbs comes to mind but that's just a guess. I don't know off the top of my head.

What cam would you recommend that would give me the max torque possible but will also match the power/torque range of my SCJ-A heads? What overlap number should I be looking for.

How many inches is the engine? Manual or auto? How much gear? Tire size?

Whats the complete cam specs now? Part number?

dfree383 wrote:How many inches is the engine? Manual or auto? How much gear? Tire size?

Whats the complete cam specs now? Part number?

466 ci (460 bored .030), 4 speed manual, 3.50 gears (going to 4.56 next year when money allows), 33" tires.

It's a Crane hydraulic roller cam. Here's the cam I have... http://www.summitracing.com/parts/crn-359341

RPM range = 2000-5500
Intake Duration at 050 inch Lift:216
Exhaust Duration at 050 inch Lift:224
Duration at 050 inch Lift:216 int./224 exh.
Advertised Intake Duration:278
Advertised Exhaust Duration:286
Advertised Duration:278 int./286 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.556 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.580 in.
Valve Lift with Factory Rocker Arm Ratio:0.556 int./0.580 exh.
Lobe Separation (degrees):112

78 F150 wrote:

lghting94 wrote:

78 F150 wrote:I am using the highest octane available; 92 octane. The timing is set at 14*. I didn't hear any knocking when I was driving nor was it overheating. I hope is wasn't detonation that caused this.

this is only part of setting your timing your initial timing is set at 14 but what is your total timing after mechanical advance and vacuum advance?  If you didn't check this it could be as much as 60 degree or higher when driving, which can cause detonation.

Honestly, I don't know.. I didn't check it after setting the initial timing. However, the distributor was recurved and all advance was done by 2800 rpm & I think the total was supposed to be at 32° or 34°. I'm going off of memory so I could be a little off, but those numbers come to mind.

Question...if I have 10.13 compression and my psi is 15 psi too high, does anyone know how to calculate what the compression would be with 15 less psi? Would 9.5 compression be ok for towing?

Ok, I just looked up the information on my distributor. Here's the specs...

1000 = 0
1500 = 2
2000 = 6
2500 = 14
3000 = 16

10* vac advance at 18"
14* initial (btdc)
SCJ heads only need 28* - 30* total timing.

Isn't total timing determined by how a distributor is recurved and all I need to do is set the initial timing????? Not sure how that works? And total timing should arrive at what RPM?

First things first...... You have about 1.5 points of mechanical compression too much for a driver and tow vehicle with the cam you have listed. IMO

You need to get some pistons with bigger dishes and keep the quench tight .043 is a good place to shoot for. quench is very important on a street vehicle with pump gas (read shitty fuel) and what your trying to pull around.

The advance cure may need to be a little slower but that depends on where the dynamic compression ends up and what fuel you tune for.

I may be wrong here but if your initial is 14 and you have an additional 16 in mechanical at 3000 RPM that is 30 degrees timing at 3000 without the vacuum advance hooked up now add that in and your at 40 degrees total timing when pulling under load. Maybe I am misunderstanding how all this works and someone much smarter than I can come in and correct me but to me looks like you have way to much compression for a towing vehicle and to much advance in you distributor. I don't know enough about cams to say on it but would trust dfree

lghting94 wrote:I may be wrong here but if your initial is 14 and you have an additional 16 in mechanical at 3000 RPM that is 30 degrees timing at 3000 without the vacuum advance hooked up now add that in and your at 40 degrees total timing when pulling under load. Maybe I am misunderstanding how all this works and someone much smarter than I can come in and correct me but to me looks like you have way to much compression for a towing vehicle and to much advance in you distributor.  I don't know enough about cams to say on it but would trust dfree

That is 10 degrees at 18 inches of vacuum. Under load he is probably not pulling that much vacuum. Usually that is only at idea.

Since the OP was told before that engine was running that he had the wrong combination for what he wanted to do, but instead keep on until he found someone to say it would work, I'd say he should go back to him and let him advise him what to do now...

466cj wrote:Since the OP was told before that engine was running that he had the wrong combination for what he wanted to do, but instead keep on until he found someone to say it would work, I'd say he should go back to him and let him advise him what to do now...

X2  

466cj wrote:Since the OP was told before that engine was running that he had the wrong combination for what he wanted to do, but instead keep on until he found someone to say it would work, I'd say he should go back to him and let him advise him what to do now...

It is.... what it is........   

466cj wrote:Since the OP was told before that engine was running that he had the wrong combination for what he wanted to do, but instead keep on until he found someone to say it would work, I'd say he should go back to him and let him advise him what to do now...

First of all regarding being told I had the wrong combination of parts for what I wanted to do.... I also had a lot of guys telling me the parts I had could work if certain things were set up right. So I had people telling me it won't work and I also had people telling me it would work. You make it sound like every single person was of the same opinion that it wouldn't work and I purposefully ignored those opinions and did my own thing. That is definitely not what happened whatsoever!!!! Also, you seem to think that I kept searching for the answer I wanted and when I heard what I wanted to hear, I was justified in moving forward with my plans. That is so far from the truth and most definitely NOT what I was doing, contrary to your ridiculous belief.

Second of all, did you ever stop to think that there were many other pieces of the puzzle to consider other than just someone's opinion telling me it wouldn't work? One of the issues I had to consider when making the decision to move forward with this project or not was the fact that I already spent thousands of dollars on the parts and had all the parts in my possession BEFORE I discovered there was a possible issue with this combination. And there is also the fact that I didn't have the money to just turn around and buy the correct parts. It took me many many months (over a year) of saving money to buy the parts for this engine and they were not cheap, trust me. The heads alone cost $1900. Not everyone has endless amounts of cash to spend as they wish. Maybe you do, but I don't. And if you do have that luxury, it must be rough being you.....

So given the situation and circumstances at hand, I had to make a decision....do my best (with the help of others) to set the motor up and hopefully make it work with the parts I had by making some adjustments to a few parts I chose, or not build the engine at all and be out the thousands of dollars I spent on the parts. I chose to take a chance and build the engine and hope for the best instead of not building at all. Besides the fact I needed to use the truck instead of just letting is set for who knows how long until I could come up with the money to buy the correct parts. So that's one of the many reasons why I decided to take the risk and move forward and build the engine. It had nothing to do with your ridiculous beliefs about ignoring your advice and searching for the answer I wanted to hear.

FYI....it's looking like (and still to be determined) that a combination of too high compression, possibly timing (also still to be determined), and A/F ratio all contributed to this catastrophic result. It's a lesson learned, yet an expensive lesson. My game plan is to start over and get the compression down to where it needs to be by ordering some larger dished pistons and also make sure other things are set up in the right range.

So your smug, "I told you so" sarcasm is most definitely not necessary nor is it appreciated. Yeah I made a wrong decision; so be it; lesson learned. Making mistakes is how we learn and as long as we learn from our mistakes, then it's fine. But trashing me for my decision and rubbing salt in the wounds is not going to do anything other than make you feel better about yourself, make me (and possibly others) have negative thoughts about you as a person and make yourself look like an ass. Well guess what....Mission accomplished! Damn, it must be nice to be perfect like you and make all the right decisions in life and never make mistakes. It must also be nice to know everything about everything.

I myself don't claim to know everything about mechanics and there are still things I am learning, such as the "too high compression for towing" issue. However, I'm far from stupid and inexperienced. I've been doing my own mechanic work all my life and this is the first time I've had a problem like this. It happens; so be it. But when I run into something I don't know the answer to, I'm humble enough to set aside the stupid male ego and ask for help. Besides, that's one of the many ways we learn is by asking questions. And at the same time I'm very appreciative of anyone who is willing to take the time to offer advice and help me and at the same time I'm willing to return the favor somehow if I can. That is the reason most of us are on these sites is because we're needing help. So it would be nice if you (and others) would be a little more understanding of the fact that you don't know all the details of the specific situation or circumstance and the reason for making the decision I make and keep your negative comments to yourself. It's not helping anyone. If you can't provide helpful, positive advice, do us all a favor and keep your negative opinion and comments to yourself!!!

Wow epic post. Should I post up some of the old threads? I am one of the guys who gave you good advice and a lot of help on diagnosing your current issues. I am on the other board too.

You are where you are of your own doing and need to learn to own that. I've been around this stuff a very long time and seen guys make the same mistakes you have. In the end you listen to those that say yeah go for it, it will work.

As for cost of parts I know this too and know what your build is. I had forgotten, but recently looked at the old threads which is why I posted what I did. Honestly it is a lot of BS on your part. Bought the wrong parts, sell them off and get the right parts.

A lot of guys have been trying to help you. This thread and the one on the other board are epic and most of it did not have to happen if you listened. Told you to do a compression test very early on, but you did not listen until a few days ago. Could have save everyone a lot of time and yourself a lot of time and money too.

One thing is for sure no more free advice on my part. Is a saying "experience is what you get just after you needed it" A lot of what I know came at a price so I'm done. Good luck.