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EFI Conversion on a 76 PCM 351W

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Post Options Post Options   Thanks (0) Thanks(0)   Quote GottaSki Quote  Post ReplyReply Direct Link To This Post Topic: EFI Conversion on a 76 PCM 351W
    Posted: July-26-2022 at 9:38am
218/224@50 is a little hotter than mine at 214/224 and more like one of tim's at 218 duration if i recall right

But what sort of piston you choose to get 11:1 on 62cc chambers?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote swaterca Quote  Post ReplyReply Direct Link To This Post Posted: July-25-2022 at 7:38pm
Also on the PCM exhaust the back water port is blocked and the front port is open.   However since the O2 sensor needs to be on the front (no room on back) this means that both the back and front port are blocked, since the riser block water port is blocked at the O2 sense.  So 33% loss in cooling but the only way it will work.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote swaterca Quote  Post ReplyReply Direct Link To This Post Posted: July-25-2022 at 7:27pm
Here are the cam specs

                                  Intake   Exhaust
Gross Valve Lift            0.494   0.500
Duration at 0.050          218     224
Lobe Lift                      0.309   0.3130
.006 Tappet Lift            261      275
Lobe Seperation           112

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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: June-03-2022 at 10:19pm
Most of the EFI systems do not like large camshafts, his note says he has 261/275 duration but does not list at what lift, that cam is either fairly mild or pretty wild depending.  I understand the newer systems are better than the older systems for large cams.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nubf14 Quote  Post ReplyReply Direct Link To This Post Posted: June-03-2022 at 12:55pm
I don't have 11:1 but the self-learning did work just painful since you don't have the manufacturer AFM (MAP or MAF) curves. Lots of options and if you can find a boat dyno that would work. The system does provide lots of possibilities for custom curves. I have had zero issues except for finding a fuel sending unit with return line built into the unit, Still trying to make that work correctly on my boat. I need to drill a new return line in the tank but have not had the opportunity (don't want to blow myself up LOL). Holley does sell a system with return at the EFI unit but that was not "Marine" approved when I started my search for EFI/TBI.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AlfaDon Quote  Post ReplyReply Direct Link To This Post Posted: June-03-2022 at 12:42pm
Too much compression for a boat engine that's under load all the time.  If you can't tune it with a carb, EFI will be even more difficult  All of that self learning stuff is marketing crap.  You're better off paying a Holley expert to tune it on a dyno before it's installed. Then self learning can fine tune it


Originally posted by swaterca swaterca wrote:

Sorry not trying to hide anything.

Rebuilt engine Al heads 175cc 62cc.  Intake valve 2.02 in Exhaust valve 1.60in

CAM           Intake    Exhaust
Gross Lift    0.494      0.500
Duration     261         275

11:1 Compression.

Just cannot tune the Holley 650, so looking at EFI.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: June-03-2022 at 11:46am
Even with aluminum heads at 11:1 compression you will have trouble trying to run on pump gas.   91 or 93 octane is the best you will come up with today.   In a light car with a 4 speed and maybe a 4.11 rear gear people get away with 11:1.   In a boat with high loads right off idle you are asking for detonation big time.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote swaterca Quote  Post ReplyReply Direct Link To This Post Posted: June-03-2022 at 9:54am
Sorry not trying to hide anything.

Rebuilt engine Al heads 175cc 62cc.  Intake valve 2.02 in Exhaust valve 1.60in

CAM           Intake    Exhaust
Gross Lift    0.494      0.500
Duration     261         275

11:1 Compression.

Just cannot tune the Holley 650, so looking at EFI.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote swaterca Quote  Post ReplyReply Direct Link To This Post Posted: June-03-2022 at 9:46am
It looks like the kit only comes with one O2 sensor, is that all you guys used.  If so did you put 2 riser plates on or just one.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: June-03-2022 at 7:36am
Originally posted by swaterca swaterca wrote:

Is the part below for a PCM 351W?

Thank you

Hard to say, since you don't show any part

But if it's the one linked earlier and down below again, then it's right. It has the right openings to fit the PCM gasket to maintain the water distribution as the manifold had before spacer installation.


And it would be installed with the O2 sensor at the rear squeezed in under the riser

The modified one that nubf14 used works for him, but looking at his installation pictures and the pictures of the Volvo plate and the way he has it installed, he's changed the water distribution path through the riser.

PCM has the back opening on the riser blocked off by their gasket forcing water through the side and the front openings. That's how Darrell's port side manifold would be set up from the factory, unless he changed it.

His plate and gasket setup looks to have that back opening wide open and the front opening blocked off except for a couple of tiny holes or maybe the front and rear openings are blocked

Maybe he did it this way for clearance for the O2 sensor. Lots more working room with the sensor at the front. Maybe it didn't fit at the back.

Does the change in the distribution have any big affect on the cooling of the riser and downstream exhaust hoses?...............probably not but it's something to think about.

His seems to be working OK Wink

A search here on CCF will give you some reading on riser gasket installation.

PS .........................You seem to be a little secretive about what you're planning on doing


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Post Options Post Options   Thanks (0) Thanks(0)   Quote swaterca Quote  Post ReplyReply Direct Link To This Post Posted: June-02-2022 at 8:27pm
Is the part below for a PCM 351W?

Thank you
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nubf14 Quote  Post ReplyReply Direct Link To This Post Posted: June-02-2022 at 7:43pm
I used the VP and just drilled the holes a little bigger. Still using the same O2 sensor. Have about 110 hours on it now. I also upgraded my distributor right after the EFI so cannot honestly say which made the biggest difference. Starts and runs like a new boat and I burn general gas (87) and have not tweaked it at all.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: June-02-2022 at 7:13pm
Originally posted by gun-driver gun-driver wrote:

Originally posted by swaterca swaterca wrote:

Sorry did you buy the riser blocks?

Link from earlier in his post
 https://www.ebay.com/itm/222482543306
 

swaterca, that link takes you to an adapter for Volvo Penta manifolds, but if you go to their website (Performance Fuel Injection Systems) you can find an adapter that's for PCM 351w manifolds,if you're doing something with a 351w PCM engine.

Here's a link to the right adapter plate


Not really knowing what you're planning to do, you might want to surf around their store on the website Wink

They have complete marine TBI kits too.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gun-driver Quote  Post ReplyReply Direct Link To This Post Posted: June-02-2022 at 5:58pm
Originally posted by swaterca swaterca wrote:

Sorry did you buy the riser blocks?

Link from earlier in his post
 https://www.ebay.com/itm/222482543306
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Post Options Post Options   Thanks (0) Thanks(0)   Quote swaterca Quote  Post ReplyReply Direct Link To This Post Posted: June-02-2022 at 5:49pm
Sorry did you buy the riser blocks?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote swaterca Quote  Post ReplyReply Direct Link To This Post Posted: June-02-2022 at 5:48pm
Would it be possible for you to send a drawing of the riser block?

Did you do anything special to try and protect the O2 sensor?

How have the O2 sensors held up?

Do you require an extra fuel pump, included in package?

Do you change any linkages?

Thank you for your help.

Brian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nubf14 Quote  Post ReplyReply Direct Link To This Post Posted: June-02-2022 at 12:59pm
Yes I did the riser blocks to fit.

https://photos.app.goo.gl/9CL63sBR3Y11SQTJ7

I had to custom make the rear bolts (treaded rod) as you don't have clearance for bolt.
Darrell Sanderlin
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Post Options Post Options   Thanks (0) Thanks(0)   Quote swaterca Quote  Post ReplyReply Direct Link To This Post Posted: June-02-2022 at 12:55pm
Good morning...can you describe your setup.

I am thinking of doing the same think on a 93 Nautique ,  I have modified the engine with a aggressive CAM and Al heads and cannot get it tuned with the holley.

Did you put riser blocks in for the O2 sensors?

Thank you,

Brian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rosconole Quote  Post ReplyReply Direct Link To This Post Posted: June-08-2020 at 3:06pm
You probably already saw this about the linkage https://www.youtube.com/watch?v=ap2tdGnrmxw&t=651s

Just make sure you have E85 compatible PTFE lined fuel hoses as well.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Peter6000 Quote  Post ReplyReply Direct Link To This Post Posted: June-08-2020 at 2:32pm
welcome to the world of fuel injection, I'm happy to hear that you did not get scared by all the comments fro our carburetor fans.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nubf14 Quote  Post ReplyReply Direct Link To This Post Posted: June-08-2020 at 1:52pm
The thermostat is 140 so ordered a new 160. Reset timing to 8 BTDC and boat is running better than ever (manual said 6 I was running 10 before). VERY pleased so far with my Sniper EFI upgrade. Also able to run ethanol gas now so saving about 45 cents per gallon in my area vs non-ethanol. I have heard some that run E85 but I am staying away. Excellent throttle response and idle/full/idle never misses a beat. New timing and lower idle setting have gotten rid of the in-gear stumble. I am still going to install the new linkage to reduce the rear butterfly open as I don't need all that for my engine under 300 hp.

O2 Profile Side

O2 Front

Had to use treated rods in the rear because I did not have enough room for the longer bolts in the rear holes once the 1-inch plate was installed.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rosconole Quote  Post ReplyReply Direct Link To This Post Posted: June-05-2020 at 6:23pm
I saw one of the rocker crawler guys used something similar to this linkage to not have such a hard out of the gate throttle with all 4 butterfly's open..https://www.efisystempro.com/sniper-efi-progressive-linkage-kit
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gun-driver Quote  Post ReplyReply Direct Link To This Post Posted: June-05-2020 at 5:38pm
Would have to be I would think if it’s even in there.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nubf14 Quote  Post ReplyReply Direct Link To This Post Posted: June-05-2020 at 2:55pm
I don't know either been trying to figure it out. I think my thermostat may be sticking (full open). I will know better after the weekend. Never worried that much about temp before as long as it was not hot.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gun-driver Quote  Post ReplyReply Direct Link To This Post Posted: June-05-2020 at 2:28pm
Originally posted by nubf14 nubf14 wrote:

Good day on the lake (6/4/2020) and 160 is hard in my boat. I have to run about 3400 for 10 mins to get 160 or greater

I don’t understand this. Why??
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nubf14 Quote  Post ReplyReply Direct Link To This Post Posted: June-05-2020 at 1:51pm
Good day on the lake (6/4/2020) and 160 is hard in my boat. I have to run about 3400 for 10 mins to get 160 or greater (no skiers today). It starts well (better than carb) but is still working on cold idle. IAC is working to hard but EFI table is not complete. Also, little stubble from neutral to forward/reverse. I have to advance that fuel curve so it does not stubble. Once in gear, best throttle response I have ever had (full to idle or idle to full). I do have to adjust the carb spring as a little too strong and rolls back the tach/speed I set. My feeling is 15-25 hours and should be running like a new boat.

So review so far:

cost
ease of installation
performance

I have read a lot about O2 sensors going bad so the jury is out on that piece of equipment.
Darrell Sanderlin
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rosconole Quote  Post ReplyReply Direct Link To This Post Posted: June-04-2020 at 3:51pm
Interested in how it runs under 160 degrees where the learn mode open /closed loop starts typically Have you had it under load on lake yet?   Pretty much any drop in efi walbro style pump will be USCG cert. the in line probably should be , Probably depends on where you mount it really. Glad to see it running!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GottaSki Quote  Post ReplyReply Direct Link To This Post Posted: June-04-2020 at 3:00pm
John!

My regrets missing your response,! it must have rolled under my view back in March!

a few of us have spent lots to time in 454 boats and hearing them sing for a long tome,

so a 15 pith prop is leaving a lot on the table. I know you have endurance in mind, but just be aware there is a point of diminishing returns and nothing is free,.

RPMs itself wont hurt it..

Consider this....pick any loading, speed etc.the same amount energy had to get expended over time to do the same amount of work whether you go high rpm or low rpms.

In the low rpm high pitch example, this means fewer power pulses per distance traveled, however each power pulse has to have more energy. therefore lower manifold vacuum, and higher side loads on the pistons.   

Also, there is a fixed power delivery available at each rpm.   a 390HP engine 5000 may only have 230 available to you at 3600 rpm, that just wont pull 4-5 footers well.

higher pitch and high rippems means less energy needed per power pulse, higher manifold vacuum, and more power available if you give it more throttle, read responsiveness.
it really doesn't same much fuel and isnt that hard on the engine.. One could argue easier.

I think efi wont fix any dullness, it a gearing issue.

EFI wont give you 400 hp at 3600 to pull 4-5 footers. Only forced induction can do that.

let her rip!

we can consult on the carb issues
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nubf14 Quote  Post ReplyReply Direct Link To This Post Posted: June-04-2020 at 1:53pm
I just finished my conversion (Holley Sniper EFI.) The first day on the lake was 6/3/2020 will keep everyone posted. The hardest part was the O2 sensor. I found this on eBay and was able to redrill all holes with 3/8 and make it fit perfectly.

https://www.ebay.com/i/222482543306

EFI installed
https://photos.app.goo.gl/bRgMZNWoRFMbyMre7

I have to remove the manual fuel pump this week (left as a backup plan just in case the EFI install failed). I purchased as a marine kit from Holley but never got an answer back about the fuel pump being USCG approved. That is the only outstanding item of the install. If I find out unapproved I will buy a USCG pump.

BTW runs way better than a carb but mine was in need of replacement ($735 vs $1235). Next up is DUI distributor but that is another season.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Footer 1952 Quote  Post ReplyReply Direct Link To This Post Posted: March-21-2020 at 8:12pm
So Tom,

You're sayin 3600 RPM Bogus??

Surely the Wolfpack is way ahead of me!

https://www.google.com/search?q=wolfpack+barefoot+boat&sxsrf=ALeKk02IifvIE1OWcGjz0eCMB4v9LHmg3g:1584828676751&tbm=isch&source=iu&ictx=1&fir=n_Rf8EM69el31M%253A%252C6wrMasVmayWIIM%252C_&vet=1&usg=AI4_-kSasx9ZwPVnJLQR6le6AZB62rHknQ&sa=X&ved=2ahUKEwi4z7ryyqzoAhW3lHIEHbUQBY8Q9QEwCXoECAcQBQ#imgrc=n_Rf8EM69el31M:

Enlighten Me!!

John
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