What have I done?? Good, OK, or Bad??

racprops

Well-Known Member
I have built a way out there engine....So far mainly on my own.

As it IS my last and only real serious engine build and done as no one I could find has ever done one this way and there was/is none I could find like it I felt I had to try it myself.

ALL the things I could read and all the advice from all of the people I thought knew their stuff led to this.

But as I near the finish line I received even finer details on the TPI set up and in going over all the details of this nearly finished engine with Adam a member of Speedtalk as NewbVetteGuy and he expressed major concerns of it being a knock monster…

He brought up the DCR (the first I heard of this) and feels I may have a big problem. But:

https://www.gofastmath.com/compress...atic-and-dynamic-compression-ratio-calculator

It comes up with: STATIC Compression Ratio: 9.31:1 and DYNAMIC Compression Ratio: 8.33:1

So at this point I am scared to move until I can feel it will not blow up.

Both he and I have posted on SpeedTalk and I have done the same on thirdgen Camaro.org.

So far no one has been any real help.

In this case this build started as a 350 in 2004, and is at last being finished. But I did a number of upgrades.

So here are the current details:


Vehicle: 1993 G20 van -heavy box. Some towing.

Goals: Loads of low-end towing torque and the best possible MPG. There's a LOT of focus on fuel economy, as you'll see.

Engine:

1990 SBC OE Roller Block - 30 over bore

Not decked (checked and ruled straight, heads too) but supposed to be .010" piston-to-deck clearance (I believe)

Machined 400 crank with 5.565" 400 rods

Older KB hyper D-dish pistons (M9890-30) -I couldn't find this piston but they look identical to the KB102-030, so I'm guessing -18cc dish. Set Bought 2/12/2004

As far as I know stock type rings…SEA 251K -.030 Ring Set (Premium) bought 2/12/2004

Total Seal second ring.

Top ring wide gap as per advice of KB piston tech support.

The piston top, combustion chamber, and intake and exhaust valve have all been Ceramic thermal barrier coated.

Piston skirts Teflon coated.

64cc (I think actually 65.3cc) Swirl port heads #14102193 1.94" / 1.5" valves; with good valve guide seals to keep oil out of the chamber.

1.5 ratio roller-tipped rockers (I know worthless rollers)

Head Gasket: A felpro gasket that came in a rebuild kit with a 0.045" compressed thickness

Lifters: Rhodes Roller VMax lifters

Cam is from Oregon Camshaft #806 roller cam:
Adv duration: 265/270 @.006 206/213 @ 0.050": lift: 413"/428", LSA: 114, ICL: 110
9.25:1 static CR

Running Rhoads V-Max roller lifters at 10% reduction so at low rpms she will be:
185.4/191.7 Lift 371.7/385.2 lobe sep. 114 = torque peak should be right around 1800.

Intake: Will be running an 87 Corvette TPI intake and have a few different TPI MAF PCMs; the plan is to enable Lean Burn mode at highway cruise. (16.5 AF target at cruise)

Injectors: Toyota Tundra trucks from 2000-2004 came with 12 hole Denso injectors @ 250cc;

Real Cold Air Intake air box getting air from behind head lights.

Stock cast iron exhaust manifolds. Considering 1.5 Tube headers.

I plan to run lots of EGR by electronically controlled system. Both to handle the lean burn and add in MPG, and even see it engine can be run with more throttle lessing pumping losses.

And perhaps water injection...Veri-ject system or NOS injection system with under the main injectors…injectors.


Rear Gears & Transmission:

343 rear gears

Rebuilt 4L80e out of a motorhome and a US Gear Dual Range overdrive (was Doug Nash) As a second overdrive - I have calculated a 1,600-1,800 RPM highway cruise @ 75 mph with the 4L80 in OD and the US Gear in OD with the 343 rear gears and18”Wheel and tires match factory tire wheel diameter.

Many tests have shown me factory V6 and V8s can get very good MPG at 1500 to 1800 RPMs, like 27 to 32 just by driving at those RPMs, speeds are 50 to 60MPH in their top gear.

I plan on adding second overdrive to get a great 5 gear so on paper my Van will be able to run at 1600RPMs and be doing 70/80MPH.


Questions / Concerns:


What's the safe "guideline" for the DCR of this motor and what should I do to minimize detonation risk?

But I am told that it reads like a very high knock risk situation; and we haven't done all the calculations, have run Dyno 2013 got great numbers…planning using PipeMax that would look at the extra cylinder pressure from the TPI intake...also call out best headers.

I have got all sorts of options for how to reduce the dynamic compression or knock risk, but which are the right ones?

Just pull timing from the tune where it tends to knock? I plan on running stock PCMs with Knock sensors. Will they pull enough?

I hope this is a good to go or that I will not need to make major changes to fix this potential knock monster engine + vehicle combination?


Commits and advice??

Rich
 
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ok, first your most likely OK! a dynamic compression of 8.33 is not all that bad.
yeah you need to test, and ID fill the tank the first time I drive with HIGH TEST 92-93 on the first drive just to be cautious.
your car might need the ignition timing backed off a couple degrees, but until you drive and test you won't know!
you can reduce the dynamic compression quite a bit by retarding the cam timing,, you could retard it lets say 6 degrees and that would effect the dynamic compression and only raise the average power curve sweet spot and torque curve maybe 250 rpm



 
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Well as per the cam grinder, it is installed straight up which we figured out it came with 4 degrees advance and the timing set are the common three slotted set so resetting it by using the 4 degrees retarding can easily be done.

Plus I would not mind moving the power curve up a little because:
 

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Wish we could find a program that reads 1000RPMs up...it looks like I did hit my wanted torque peak at 2000. Under 2k I just guess the curve.

Rich
 
This was kind of a fun build, every machine shop had the same reaction...it will not run right, OMG it will not run over 5000!! The heads, the TPI intake will limit it to 5K. This is insane.

My answer was look I am 73 (Well 60 in 2004 when I began this as a 350) and all my life every car I have owned has had a 5K red line...so I am used to that.

Rich
 
Here is our run in Dyno 2013: I was surprised that there seems to be little change between the stock cam and the 10% reduced timing and that it drops HP like a rock at 4K, I thought it would run stronger to 4.5/5K. And very little even going to a 1.6 Rocker.

Rich
 

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I must have something wrong, but if not then your DCR is much lower than you think. Look
over my numbers and see what you think. I don't use IVC at .050, that's an approximation for
calculating DCR, my Excel calculator uses IVC at advertised duration. You can download the
Excel file at the link below.


Below are the camshaft timing figures as calculated by Dynomation 6, which give me a IVC of
62.5°. Then you will find the DCR calc below that.

CamManager_Tab_CS_Oregon#806.jpg
CamManager_Tab_VET_Oregon#806.jpg

Don't worry about the numbers on rows 9 and 10, they are very small and can be ignored if you don't know
them. Technically thou they are part of the combustion chamber.

DCR_Oregon#806.jpg
.
 
As I am having help setting up Dyno and other than two tries my self, I cannot say if I got it all correct.

As for the static compression I worked with a Keith Black tech over the phone and he came up with 9.3 to 9.5 based on all the data he asked for.

What numbers do you need?

Cam timing at .050 Intake open .7BTDC close 33ABDC 45 BBDC Exhaust open 45 BBDC and Closes at -12 ATDC this is by the spec sheet.Below these is a hand written note: -18 1/2 Degree overlap @.050. Cam lobe lift is listed as .275 intake and .285 Exhaust. Lobe center line: Intake 110 and exhaust 118.

Then there is another set of numbers lobe Diameter intake 1.542 over 1.267 and Exhaust1.529/1.244.

Advertised duration at .006 265/270

That seems to be all the numbers, other that lift by 1.5 and 1.6 rockers. .413/.428 and 1.6 .424/.452

Rich
 
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As I am having help setting up Dyno and other than two tries my self, I cannot say if I got it all correct.
Some programs want a negative number for a dish piston and some want a positive number, so you need to know for sure what your Dyno program needs.

What numbers do you need?
There all right there in the last pic I posted above. Like I mentioned above, the numbers on rows 9 & 10 you can leave like they are. But everything else is needed. Below is the descriptions for each row I didn't post the first time, but might be helpful. Do you have Microsoft Excel?

You can download and install Open Office, it will use MS Excel files and it's FREE. There is more info in my post above if you follow the link to the calculator.

It sounds like your not sure about some of the numbers like the combustion chamber size, you really need to measure and KNOW FOR SURE or you are just guessing. Many times the hardest number to come up with is the Intake Valve Closing (IVC) angle, but with the numbers given to you by Oregon nails this down to 62.5°

DCR_Oregon#806.jpg


Cam timing at .050 Intake open .7BTDC close 33ABDC
Typically DCR calculators on the internet that use .050 numbers add about 15° to get the actual timing for the valve closing. So if you take your 33° + 15° = 48°. That's a long ways from the reality of 62.5°. But even that does not explain all the differences we are seeing.

You need to measure and not guess at any of these numbers in your engine build !
.
 
Thanks again for your input.

As for: " Some programs want a negative number for a dish piston and some want a positive number, so you need to know for sure what your Dyno program needs." I will see if the instructions say which.

We know the chambers are still stock so they are advertised as 64CC, Adam said he sees bigger chambers with the 193 heads he has worked with, so he said to use 65.3cc for the Swirl port heads #14102193 1.94" / 1.5" valves.

The KB Pistons are 18CC dished.

Thanks for: "Many times the hardest number to come up with is the Intake Valve Closing (IVC) angle, but with the numbers given to you by Oregon nails this down to 62.5°"

I will try running them again.

Rich

Latest run on Dyno:
 

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That seems to be all the numbers, other that lift by 1.5 and 1.6 rockers. .413/.428 and 1.6 .424/.452
There are so many numbers that it's easy to mix up a couple of them. Like the ones above don't agree with previous numbers. It's very easy to get one wrong.

In your graphic directly above, the stroke is shown at 3.75", but every other detail I've read points to a 350 cuin Chevy which has a stroke of 3.48" or did I miss something ?

SCR is exactly as I calculated at 8.63

IVC is the same at 62.5°

Don't worry, if you have the time to verify the numbers we will get this figured out !

1651447366558.png
 
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It is a 383 with a 400 Crank and rods. When i input the engine the program fills in the stroke.

"General Motors achieved the 400 SBC engine's displacement by increasing the bore to 4.125 inches and the crankshaft stroke to 3.75 inches –"

From https://itstillruns.com/small-block-chevy-400-specs-7350617.html

And yes a 350 has 3.48 Stroke, putting a 400 Crank into a 350 makes it a stroker...

And yes it is just .27 inches

Rich

PS one problem is I cannot see how to enter a 193 head with 65CC and piston with a 18CC dish, this program is not fine tuned enough to get the numbers right.
 
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Sorry I missed that here are the correct numbers, note the Correct heads and the combustion chamber size 95.59 which it makes a 9.20 Compression ratio.

Rich
 

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The SCR is reasonably close now when I change the stroke to 3.75". But the DCR is still much lower at 7.57, but it is certainly headed in the right direction. At 7.57 you will not have detonation problems on 87 octane gasoline, if this is the final and correct number.

1651452222102.png

You need to make sure the pistons you have are correct for a 5.565" rod length. The KB102-030 are for a 5.75" rod. This is a big problem if the pistons you have are the same.

Have you assembled the rotating assembly ? It should be obvious that something is wrong if the pistons or rod length is incorrect.
 
IF I had gone with a aftermarket 383 KIT you would be right.

But using a real 400 crank and real 400 Rods allowed my to use the pistons that were fitted to my 350 Block. See picture.

Most 383 Kits use a longer rod which does require high piston pin.

Some say using the 400 rods will product greater side loads on the pistons which why I have them Teflon coated.

So it looks like all the numbers came together....Compression is 9.22 DCR 7.57 great.

Thanks

Indycars


Can you tell me the program your using??

Rich
 

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I think the question of rather it will knock has almost been answered.

On that subject is the only remaining question is my having the pistons, , chamber and valves Ceramic thermal barrier coated.

I have had a couple people whom think this will increases the changes of knocking.

And one whom thinks Ceramic thermal barrier coating is a BAD idea.

Everything I have read said it is a great idea.

Thoughts?? Facts, personal uses??

Rich
 
The next question is ECM:

And the debate over the early Camaro and even my 93 Vans ECM’s batch firing feeding VS sequential port fuel injection

I would THINK sequential port fuel injection would/could be better for my slow engine...on the other hand having fuel waiting on top of a hot intake valve could be even better....and considering that port injection is at the head's intake and as has been pointed out does not squirt into an open chamber but at a closed valve the advantage of the 12 hole's finer spray may be lessened by hitting that valve a sitting there even for micro second. On the other hand a finer spray could vaporize better...

Also I lean towards MAF over MAP. Or better both.

As in:

From Jim: http://www.jimsperformance.com/portinj.html

The 94 and up LT1 is a sequential port fuel injection system. The injectors are fired in coordination with the opening of the intake valve. The distributor and electrical spark timing system, now referred to as "Opti-Spark Control", has an optical sensor which counts light pulses through a perforated disc in the distributor. There is NO timing adjustment for the LT1. The Mass Air flow sensor is back in 94 and is one of the primary sensors for fuel control. The MAP sensor is a backup for the mass air flow sensor. All other sensors are the same except that the TPS is no longer adjustable. (I will still have the TPI with its adjustable TPS)

This one I can go for: "Opti-Spark Control", has an optical sensor which counts light pulses through a perforated disc in the distributor.

I have had to replace the 4 wire module under the cap in my 93 so often I carry two spares. I was hoping to get rid of that weak point and add the 94 and up LT1 is a sequential port fuel injection system.

I have read and heard there was a lot of problems with the Opti-Spark Control, but I believe that was with the one on either the crankshaft or cam shaft, not the one in the distributor.

Also I already have a MSD performance distributor and performance coil, and might consider a MSD mulitspark coil system.

Thoughts?? Facts, personal uses?? Advice?

Rich
 
Also with the newer ECMs they may/should handle a 4L80e transmission allowing me to skip running two ECMs one for engine control and one for transmission control.

Which brings me to another question: Switching from a 4L60e to a 4L80e: Does this need a tune for the change?

Rich
 
The ceramic coating is a interesting subject, i have no experience of it, but have read that you "should" only coat one "side" of the combustion chamber, most likely the piston top, i guess?
Whats your thought about it, what are you hoping to achieve?
I thought it was for making the piston survive a little longer under extrem conditions, like detonation?
Can it also make the engine more efficient, maybe?
 
From what I have read ceramic coatings keep the heat in the chamber, resulting in more power and a cooler engine.

And in my case it was suggested by my current engine machine shop that as I was planning on running lean burn cruse it would be a VERY GOOD idea to protect the engine with ceramic coatings.

Rich
 
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