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New 440 rebuild - looking for quench #2657330
05/20/19 08:30 PM
05/20/19 08:30 PM
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So Cal, USA
Fab64 Offline OP
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Hi all,

I recently had a 440 engine built for my '71 Satellite, and am not entirely satisfied with the way it turned out. Long story short, I think there is too much clearance above the pistons, and I'm not getting good quench. Here are the build details:

late-70's 440 motorhome block, bored .030 over (4.350)
Cast crank, stock stroke 3.75
Stock "LY" connecting rods
Edelbrock Performer RPM heads 60929, 84 cc chambers
SRP 213455 pistons, 6 cc valve reliefs
Mr. Six-Pack cam & lifters
tti headers, full-length, 2" primaries
six pack induction

The block was decked and trued, and pistons are .010 down in the hole
Head gaskets are Victor Reinz, which my builder says are .050 thick (presumably, this is compressed thickness).
This means I have .060 clearance from top of piston to head surface.
Combustion chambers have 84 cc, and piston valve reliefs are 6 cc. This calculates to a c/r of 9.73:1.

My understanding is that I should have about .040 clearance between piston and head for good quench/squish.
If I switch to a head gasket that's .030 compressed thickness, this would give me good quench, and raise my c/r to 10.17
I live in California and the highest octane gas available here is 91.
My question is: does anyone see a problem with changing to a thinner head gasket? That is, no danger of pistons hitting the head? Any other concerns?

I'd appreciate any opinions or suggestions, thanks.

Roger

Re: New 440 rebuild - looking for quench [Re: Fab64] #2657333
05/20/19 08:42 PM
05/20/19 08:42 PM
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Ontario, Canada
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Stanton Offline
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Trade ya ?!?!? I have .035 and I'd rather have .060 !! Sure .045 or.050 would be nice BUT I'd leave it alone at .060.

Re: New 440 rebuild - looking for quench [Re: Fab64] #2657347
05/20/19 09:40 PM
05/20/19 09:40 PM
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Lincoln Nebraska
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RapidRobert Offline
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.040" quench is ideal & reportedly it goes away fast above .045". I cant say if the ping reduction bennie of quench would negate the ping increase from the additional SCR (not my area) but I'd be doubtful of pump 91 but a person could always proportion in some race gas as needed. Any other potentials for why it ain't performing? (not enough advance/wrong cam/carb tuning needed). Sumpin ain't right tho.


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Re: New 440 rebuild - looking for quench [Re: RapidRobert] #2657389
05/20/19 11:36 PM
05/20/19 11:36 PM
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Michigan
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What’s the soecs on the cam - lift, duration at .050”, etc. ?

Last edited by Transman; 05/20/19 11:37 PM.
Re: New 440 rebuild - looking for quench [Re: RapidRobert] #2657404
05/21/19 01:14 AM
05/21/19 01:14 AM
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So Cal, USA
Fab64 Offline OP
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Originally Posted by RapidRobert
.040" quench is ideal & reportedly it goes away fast above .045". I cant say if the ping reduction bennie of quench would negate the ping increase from the additional SCR (not my area) but I'd be doubtful of pump 91 but a person could always proportion in some race gas as needed. Any other potentials for why it ain't performing? (not enough advance/wrong cam/carb tuning needed). Sumpin ain't right tho.


It's actually performing pretty well, but not as well as I think it should be. I did a lot of research and planning before this build started. I designed it to have .040 quench, and my builder was not comfortable putting the pistons that close to the head. Unfortunately, I didn't find out the thickness of the head gaskets until after everything was together.

Re: New 440 rebuild - looking for quench [Re: A727Tflite] #2657407
05/21/19 01:20 AM
05/21/19 01:20 AM
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Fab64 Offline OP
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Originally Posted by Transman
What’s the soecs on the cam - lift, duration at .050”, etc. ?


Unfortunately, I don't know. Mr. Six-Pack does not divulge his cam specs, but I told him this was a street car, and I didn't want anything too radical. All I know for sure is the LSA is 114, and the intake is much less than .236, sorry.

Re: New 440 rebuild - looking for quench [Re: Fab64] #2657410
05/21/19 02:16 AM
05/21/19 02:16 AM
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Bend,OR USA
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Some thing you need to know about piston to head clearances are that the piston to cylinder wall clearances can add to the deck height of the piston when it rocks over after firing and reaching TDC work shruggy My message is the center of the piston may be .010 down from the deck but what are the outer edge doing when it is running shruggy
I've seen from .003 to .012 height differences due to the piston to wall clearances on the outer edge of the pistons shock
.042 has worked well for me, .035 piston to head clearances was hitting on both sides of the pistons in my old pump gas six pack stroker motor shock .042 didn't upshruggy
that motor ended up with 10.78 to 1 compression and had no issues on Oregon 91 octane pump swill with 10% ethanol in it shruggy
My cam was much bigger than yours though, 260 degrees at .050 intake side with 266 @ .050 on the exhaust with 108 LSA installed at 106 intake lobe centers

Last edited by Cab_Burge; 05/21/19 02:19 AM.

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Re: New 440 rebuild - looking for quench [Re: Cab_Burge] #2657432
05/21/19 08:15 AM
05/21/19 08:15 AM
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lewtot184 Offline
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i think there's a lot of misunderstanding about quench distance. .040" is considered the minimum. anything beyond .060" is considered to begin to diminish the positive effects of quench. I don't consider your quench distance a major drawback; especially if you take in the effect of eventual carbon build-up. john erb of united engine & machine has a good write up about this. don't believe all the internet jockeys.

Re: New 440 rebuild - looking for quench [Re: lewtot184] #2657444
05/21/19 09:06 AM
05/21/19 09:06 AM
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Warren, MI
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your quench is fine. why do you think the engine is under performing.

couple of things to look at...
1. ignition timing, where is it set?
2. headers too large
3. air fuel ratio? have you had this checked?
4. what springs in the secondaries?
5. what advance springs in the distributor


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Re: New 440 rebuild - looking for quench [Re: Jerry] #2657448
05/21/19 09:20 AM
05/21/19 09:20 AM
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Minn
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Originally Posted by Jerry
your quench is fine. why do you think the engine is under performing.

couple of things to look at...
1. ignition timing, where is it set?
2. headers too large
3. air fuel ratio? have you had this checked?
4. what springs in the secondaries?
5. what advance springs in the distributor




I have never heard anybody at the dragstrip worry about quench. Jerry above here has some great points.

Re: New 440 rebuild - looking for quench [Re: Jerry] #2657456
05/21/19 09:42 AM
05/21/19 09:42 AM
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Originally Posted by Jerry
your quench is fine. why do you think the engine is under performing.

couple of things to look at...
1. ignition timing, where is it set?
2. headers too large
3. air fuel ratio? have you had this checked?
4. what springs in the secondaries?
5. what advance springs in the distributor



This!

provide the answers to these questions, and start doing some tuning. If you have the timing set at the factory specs, the motor won't run at it's potential.


1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
Re: New 440 rebuild - looking for quench [Re: SportF] #2657469
05/21/19 09:55 AM
05/21/19 09:55 AM
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Originally Posted by SportF
Originally Posted by Jerry
your quench is fine. why do you think the engine is under performing.

couple of things to look at...
1. ignition timing, where is it set?
2. headers too large
3. air fuel ratio? have you had this checked?
4. what springs in the secondaries?
5. what advance springs in the distributor




I have never heard anybody at the dragstrip worry about quench. Jerry above here has some great points.


Never heard the OP mention a dragstrip. In fact, when replying to the cam specs he said street car.

Re: New 440 rebuild - looking for quench [Re: Sniper] #2657523
05/21/19 11:53 AM
05/21/19 11:53 AM
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lewtot184 Offline
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fuel delivery has always been the biggest performance related issue on a street/pump gas 440 six-pak for me. springs in the secondaries were next in line. get that solved and then go after the timing. closing the intake valve too soon can create a headache.

Re: New 440 rebuild - looking for quench [Re: lewtot184] #2657573
05/21/19 01:27 PM
05/21/19 01:27 PM
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So Cal, USA
Fab64 Offline OP
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Thanks for the input so far, everyone, but I think this post is getting off track. There are several benefits to proper quench/squish other than simply making more horsepower. Obviously, not everyone agrees with these benefits, or on the amount of piston-to-head clearance that's required to attain them. I'm not trying to be a wise guy, but it wasn't my intent to debate this or to defend my position on quench. I do have some timing issues in my engine, and I am working on addressing those separately. My objective in this post was to get opinions on whether or not .040 clearance from piston to head is too close in my application. I respectfully ask that we try to stay on that subject.

Re: New 440 rebuild - looking for quench [Re: Fab64] #2657579
05/21/19 01:47 PM
05/21/19 01:47 PM
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.040 might be too close, we don't know how much your piston to bore clearance is and how much your piston rocks in the bore. also if your burning some oil eventually you will have carbon buildup on top of the piston and you'll have even less clearance. I wouldn't go less than .040 on the quench, in fact I would just keep what you have. are you having detonation problems now?


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Re: New 440 rebuild - looking for quench [Re: Jerry] #2657592
05/21/19 02:43 PM
05/21/19 02:43 PM
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Fab64 Offline OP
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Originally Posted by Jerry
.040 might be too close, we don't know how much your piston to bore clearance is and how much your piston rocks in the bore. also if your burning some oil eventually you will have carbon buildup on top of the piston and you'll have even less clearance. I wouldn't go less than .040 on the quench, in fact I would just keep what you have. are you having detonation problems now?


I was getting some detonation at higher rpm's, when the secondaries come in. I am using a distributor I got from Rick Ehrenberg on eBay. However, it's giving me more total mechanical advance than I want. We had to retard initial timing to 10 degrees, and fatten up the jetting, to stop the pinging. Unfortunately, now it doesn't run as well in the lower ranges. Tomorrow, I am taking the distributor to a local guy to put on his machine, and measure exactly how much mechanical advance it's giving, and at what rpm's (I want to see how closely it matches Ehrenberg's published specs). Depending on what I learn, I'm thinking maybe I can use an FBO distributor limiter plate to restrict the total, which would allow me to bump the initial timing back up.

As far as piston rocking, my bore size is .030 over (4.350) and my pistons are also .030 oversize (SRP 213455), on stock "LY" rods. I didn't ask my builder if he measured this, but I'll check with him.

Re: New 440 rebuild - looking for quench [Re: Fab64] #2657595
05/21/19 02:54 PM
05/21/19 02:54 PM
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Originally Posted by Fab64
Originally Posted by Jerry
.040 might be too close, we don't know how much your piston to bore clearance is and how much your piston rocks in the bore. also if your burning some oil eventually you will have carbon buildup on top of the piston and you'll have even less clearance. I wouldn't go less than .040 on the quench, in fact I would just keep what you have. are you having detonation problems now?


I was getting some detonation at higher rpm's, when the secondaries come in. I am using a distributor I got from Rick Ehrenberg on eBay. However, it's giving me more total mechanical advance than I want. We had to retard initial timing to 10 degrees, and fatten up the jetting, to stop the pinging. Unfortunately, now it doesn't run as well in the lower ranges. Tomorrow, I am taking the distributor to a local guy to put on his machine, and measure exactly how much mechanical advance it's giving, and at what rpm's (I want to see how closely it matches Ehrenberg's published specs). Depending on what I learn, I'm thinking maybe I can use an FBO distributor limiter plate to restrict the total, which would allow me to bump the initial timing back up.

As far as piston rocking, my bore size is .030 over (4.350) and my pistons are also .030 oversize (SRP 213455), on stock "LY" rods. I didn't ask my builder if he measured this, but I'll check with him.
I bought 2 of those limiter plates last week. they are waaaaayyy off! I'm betting your distributor has a 13 degree plate and that with 10 degrees initial is 36 total and no pinging. if you want more initial timing change the plate, or weld it up to get the degrees you want. pinging isn't always timing or cylinder pressure. any contaminates in the chamber will cause pinging. I went thru the .040" quench thing the first time I did this 20 something yrs ago. I was real anal about it! a few engines later with .050"-.055" quench and no difference. just try to avoid .060"+. change whatever you want but I doubt the head gasket thing is worth the time or money.

Re: New 440 rebuild - looking for quench [Re: lewtot184] #2657631
05/21/19 04:33 PM
05/21/19 04:33 PM
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Fab64 Offline OP
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Originally Posted by lewtot184
I bought 2 of those limiter plates last week. they are waaaaayyy off!


Well,that's disappointing. Actually, you're the first person I've read about who's had bad luck with it.

According to Ehrenberg, my distributor should give about 26 degrees total, all in by 2500 rpm. I'll talk to the distributor guy tomorrow about restricting it to something closer to 18 total - or maybe I'll try to get a 9 degree plate. That way, i could set initial to 14-18, and still stay under 34-36 total.

I don't know that I'm going to go to the trouble of switching out my head gaskets. It depends on what I can achieve by playing with the timing.


Last edited by Fab64; 05/21/19 06:16 PM.
Re: New 440 rebuild - looking for quench [Re: Fab64] #2657635
05/21/19 04:45 PM
05/21/19 04:45 PM
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I would suggest: (1) setting the initial with "the vac gauge method" (2) get 34-36 total (initial+slots) useing the right slot pair on the FBO plates (I was not aware there is a prob with em). (3) mix/match spring combo so you are just under the pinging point at WOT up thru the gears on your hottest/driest(most likely to ping) day then (4) plug in the can (if used) & adj it with a 3/32 allen so you are just under the ping point under varying RPM/load conditions in everyday driving on your hottest/driest day & there are differenct cans available that the curve starts at different in hg levels (do your homework there) & you can shorten the total as needed (strips of epoxied feeler gauge) & increase it slightly (file notch wider) as needed. Peoples' hearing varies & there is silent ping so give it a slight cushion & you want to be "reasonably" close to that "pinging" line but never over it. & check that it will crank over when hot & if balky use an ign cutout to get it cranking then switch on the ign or retard the initial (1) deg & retry. Those guys who mod dists can get em in the ballpark or even close but every eng is different & dead on needs alot of adjusting/tweaking.


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Re: New 440 rebuild - looking for quench [Re: Fab64] #2657647
05/21/19 05:14 PM
05/21/19 05:14 PM
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My opinion: 0.040" will work fine with your motor from a clearance stand point. I would definitely prefer that over 0.060". It may, or may not have detonation problem, but I believe that I could work through that based on the fact that you seem close now. Knowing the cam ICL could have a bearing on the detonation outcome along with several other items. All that said, now that its all together, I don't know if I would go chasing after this.

What seems odd to me is that you wanted a motor with 0.040" quench but you got one with 0.060". How did that happen? FWIW, whether its the motor build, or the distributor, the more ownership you take in it, the better the results will be.

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