2016 Pentastar engine... worth considering?

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Chris Matheny

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Yes, those plates you remember are often called block guards. I am personally not a fan. The D and B and even K series are brutally reliable. I like the K24 series with the timing chain setup just from preference. Sorry to hijack your pentastar thread.
 

pfarber

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pf:

Have you considered starting a build thread on your engine conversion?

It would be interesting to follow along.

BJC
I am still in the middle of some major car repairs, then a bathroom remodel, then a wedding. I plan to hit the airplane hard after spring. Right now its starting to get warm in PA, so that helps. But the plate is really full for the next 3 months.
 

pfarber

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On the wiring harness, no OEM wiring harness is really fit for aviation use. In aviation they are subject to a lot more vibration, and the connectors aren't great for it. My advice would be to go standalone EFI (Megasquirt would work well) to minimize sensors and use aviation grade connectors where able.

Chris, Honda engines are great car engines, but I would never use one for an aircraft. They use an open deck design that has the cylinder walls separated from the block to allow coolant to pass, and with the temperature variances we see in aviation would cause a number of issues (which is why you would never see me run a Viking).
There simply is no better starting point than the factory ECU. Megasquirt etc would need a LOT of work for optimum performance. Maybe on my next build it would be an option, but right now the main issue is to get airborne.

The Pentastar engines are beasts for what they weigh. And I've found a few places that have said they can configure the ECU to do what I need (stand alone). If not, I might have to carry a SKIM module somewhere, or possibly get a 'start box' to fool the emissions. Not huge hurdles.
 

pfarber

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Some tid bits:

Yes, I plan on a build web site. Posting updates here as milestones are made. But this forum doesn't give me the control I want to filter out tangential posts.

I have the complete engine and harness. I got a starter and alternator off ebay (total $60 delivered). The ECU for a 2016 is encrypted so I am going to buy a 2014/2015 ECU and mod that. Saves $200+ for the service to get the code. I could brute force the code, but I don't have time to rig up a breakout box.

Scale arrived for my gantry crane. I weighed the engine just because I wanted a starting weight.

The engine with no oil or coolant, no AC compressor or headers but WITH a starter and Alternator is 364lbs. There is some tare weight of about 10-20lbs because I lifted the engine still on its wood cradle.

My planning weight for the motor mount will be 400lbs. For reference the incredible expensive IO-390 (210hp) is 315lbs. So I will be about 75-100lbs more than an air cooled motor. But with a simple TPS adjustment I can run the Pentastar up to 270HP which is IO-540 country and those are 438lbs. The max HP for my E/AB is 260hp. So I could start at 250hp and be miles ahead of a certified engine.

So far I am less than $600 in for this little experiment. Got quotes from Airtrikes for a PSRU and 3 bladed prop. If all goes well the install will be signifiacntly less than $10k. Planning on $6k but $8k seems more realistic.
 

pfarber

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Reading some back issues of Contact magazine "Converting and Flying the FORD 3.8l v-6 engine" Issue 17 pg 2. The author puts the the weight of the engine:

"engine and redrive, complete with wiring, carb, oil filter, block heater, vacuum pump, starter, 60a alternator, motor mount and radiator weight 393 pounds".

WUT?

This would be a cast iron block and aluminum heads.

My bare Pentastar 3.2l with starter, alternator was 360ish but with some 2x4 cribbing.

So either the older v6 conversions guys were significantly off about weights or the aluminum vs iron block, at the v6 displacement level, is not as significant as I hoped.

Also I have 90% decided that the Megasquirt 3 EVO will be the ECU of choice. It just has to many advantages over the SDS unit IMHO. Both are good picks, but I think the SDS is more of a retrofit whereas the MSPro is more of a programmable drop in with significantly better tools to tune). Since the MS3 EVO is not a kit, but rather a hardened commercially produced unit with EMI and vibration protection I don't think reliability will be an issue. Although the SDS is also commercially produced, and not a DIY kit. Both are equal in this respect.

The major factors:
Supports CAN interface (this allows for custom engine monitoring via a full color app, not a tiny LCD)
Supports native automotive crank/cam sensors (don't need to add a tone ring and sensor)
Supports COP in sequential or wasted spark.
Supports idle air control.
Support sequential or batch injector timing (will probably run batch, but the option is there)
Programming software and logging just seem to be miles ahead of of anything SDS offers.
Way more inputs/outputs to monitor/trigger events.

If there is any feature that SDS has that I missed, or others think are just better, please let me know.
 

Heavy Iron

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So either the older v6 conversions guys were significantly off about weights or the aluminum vs iron block, at the v6 displacement level, is not as significant as I hoped.
I don't think it has anything to do with aluminum vs iron block, your block might be a few pounds lighter than the old Ford 3.8l V6 iron block.

The thing that people seem to forget on the modern engines is the weight of the DOHC cams, chains and 24 valves. 4 cams with those long chains and tensioning system and 24 valves and springs will weight significantly more than the single cam with short chain, no chain tensioner and 12 valves in the older style pushrod engines. DOHC 24 valve engines breath better at high RPM but are usually not any lighter than old-school pushrod engines.

Ron
 

wsimpso1

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Reading some back issues of Contact magazine "Converting and Flying the FORD 3.8l v-6 engine" Issue 17 pg 2. The author puts the the weight of the engine:

"engine and redrive, complete with wiring, carb, oil filter, block heater, vacuum pump, starter, 60a alternator, motor mount and radiator weight 393 pounds".

WUT?

This would be a cast iron block and aluminum heads.

My bare Pentastar 3.2l with starter, alternator was 360ish but with some 2x4 cribbing.

So either the older v6 conversions guys were significantly off about weights or the aluminum vs iron block, at the v6 displacement level, is not as significant as I hoped.
Cast iron does not mean it has to be heavy. The new aluminum case and head engines have double overhead cams, run to higher peak rpm, and are designed to be nice and quiet. Each one of those adds a bunch more volume - DOHC are bulky things, higher rpm limits requires higher stiffness in cylinders, around the crank, and in the cam drive system, and quietness takes some more stiffness. The 3.8L Ford had DNA going back to the 260 and 289 V8's, was pretty light for what it was, would get wheezy above 5000 rpm, and was noisey. If 5000 rpm was all you wanted, you were fine with it.

Billski
 

pfarber

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Cast iron does not mean it has to be heavy. The new aluminum case and head engines have double overhead cams, run to higher peak rpm, and are designed to be nice and quiet. Each one of those adds a bunch more volume - DOHC are bulky things, higher rpm limits requires higher stiffness in cylinders, around the crank, and in the cam drive system, and quietness takes some more stiffness. The 3.8L Ford had DNA going back to the 260 and 289 V8's, was pretty light for what it was, would get wheezy above 5000 rpm, and was noisey. If 5000 rpm was all you wanted, you were fine with it.

Billski
It seems that about 2005-2010 the vast majority of the V6s went DOHC and saw massive HP increases. V6s went from 150-180 to close to 300hp. So back in 2000, if you wanted 200hp, you looked for a v8, now a days a v6 does it, although the v6-v6 weight is still comparable.

I'm planning on 400 for the install weight, and its looking close. I'll be giving up 100lbs (about 15 gallons of gas) so I go from a 900 mile cruise to maybe 700 miles is an acceptable trade for me.
 

Chris Matheny

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DOHC did seem to increase the HP level but it did so with broad RPM range more than actual TQ increase in the range of RPM that we can (should) be operating these engines. If you are limited to a certain C.I. like we are with modern V6 engines then you will only make "X" TQ per C.I.. Since we do not operate these engines over a broad RPM range like they are in a car (4000 rpm range) the DOHC setup doesn't add as much use as it does weight and complexity IMHO.
 

pfarber

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DOHC did seem to increase the HP level but it did so with broad RPM range more than actual TQ increase in the range of RPM that we can (should) be operating these engines. If you are limited to a certain C.I. like we are with modern V6 engines then you will only make "X" TQ per C.I.. Since we do not operate these engines over a broad RPM range like they are in a car (4000 rpm range) the DOHC setup doesn't add as much use as it does weight and complexity IMHO.
double cams double the valves, which double the air flow. No rods means way less valve float. DOHC loves high RPM.

I do think that the lightest auto conversion would be like what Aeromomentum et al are doing... turbo 4 cylinder. But those engines are not found cheaply. So the trade off to get to my 'magical' 200hp mark is the DOHC v6.

Even if I give up 100lbs, the cost of a v6 puts me $1000's ahead. So in abuot 5-8 years I might start to see operating expenses 'eat up' my savings. I'm willing to make that trade.
 

Chris Matheny

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double cams double the valves, which double the air flow. No rods means way less valve float. DOHC loves high RPM.

I do think that the lightest auto conversion would be like what Aeromomentum et al are doing... turbo 4 cylinder. But those engines are not found cheaply. So the trade off to get to my 'magical' 200hp mark is the DOHC v6.

Even if I give up 100lbs, the cost of a v6 puts me $1000's ahead. So in abuot 5-8 years I might start to see operating expenses 'eat up' my savings. I'm willing to make that trade.
Double the cams does not double the valves, the single overhead cam honda J series V6 is a 24 valve engine the same as the pentastar, just with not variable camshaft timing independent of each other. This can be seen as a disadvantage for torque over a wide rpm range or an advantage of less weight and lower failure modes. Either way, to each his own, that's why were here and building our own airplanes right? A caveat, I have a flow bench in my shop and doubling the valves does not in fact double the airflow, it helps more with doubling the curtain area available but that's a whole other rabbit hole.
 
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wsimpso1

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double cams double the valves, which double the air flow. No rods means way less valve float. DOHC loves high RPM.
Not true. There are a number of four valve per cylinder engines running SOHC. EJ20/22/25 series from Subaru, Ford's modular V8 family, Honda has families of engines, where they build them both ways. Ford's Scorpion Diesel V8 is a four valve per cylinder OHV pushrod engine - The block/head combo looks like one of the fancy pushrod race engines from the 1970's until you get closer and realize how big it is.

DOHC has two main advantages - it raises the rpm before valve float occurs, and it allows independent adjustment of intake and exhaust cam timing. The first matters little in modern cars, but the latter can matter a bunch for emissions/fuel economy performance on the very low power cert cycles while allowing good power when you put your foot in it. The drawback is more camshafts and cam drive hardware and weight and volume and complexity to design/ build/ develop/ maintain.

Using the EJ engine with SOHC heads from Subaru as a mildly turbocharged airplane engine, they make excellent power to 6000rpm, weigh significantly less than the DOHC versions, take up less undercowl volume, and so make a better airplane engine than the DOHC version. As airplane engines, we do not benefit from variable cam timing, so losing that option is no loss either.

If your base engine can be had SOHC or DOHC and you are building a boat or airplane, go SOHC and have a lighter smaller package. On the other hand, if it is DOHC only and a great engine, go for it and be happy.

Billski
 

pfarber

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I WAS COMPARING THE PENTASTAR ENGINE COMPARED TO THE FORD V6 FROM THE ARTICLE.


TOPIC - STAY ON IT.
 

wsimpso1

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I WAS COMPARING THE PENTASTAR ENGINE COMPARED TO THE FORD V6 FROM THE ARTICLE.


TOPIC - STAY ON IT.
If you see specific posts that need moderator attention over drift or anything else, feel free to hit the report key, then inform us with a brief explanation of what is specifically bad in the reported post, and the moderators WILL look into it. Right now I can only guess which post got you.

I have been following this thread with interest. I did not notice any other contributors going places that you did not open up. To wit, an explanation of why a pushrod CI block engine can be close on weight and power to a DOHC aluminum engine seems to be more on-topic than discussing the benefits of MicroSquirt over SDS or the assertion that DOHC moves more air.

If your intent is to post progress without feedback, feel free to open a build log - You are the only one allowed to post in those.

Billski
 
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