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 Post subject: 1883 cc engine
PostPosted: Thu Jan 03, 2019 4:34 pm 
356 Fan
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Joined: Tue Apr 15, 2008 4:37 pm
Posts: 4059
Location: SW Los Angeles
I know there is a previous thread on the 1883 cc engine but, as an update, I'd like to add my recent experience with my engine.

Previously, I was running 40mm Dellortos with, what I thought were, 32mm venturis. I had been experiencing pinging under load. In conference with John Willhoit (who did not build the engine), we thought it was running too lean. Since the engine ran great in normal conditions, I opted to increase the air correction jets rather than increase the mains. There was a slight improvement but some pinging still occurred.

I dropped the car off at John's so the engine could be put on his state-of-the-art dyno. Hopefully he will have it available for demo at his upcoming open house.

The dyno showed a lean A/F ratio under load. Checking the carbs, it turns out the venturis were 28mm. The timing was also way off with a max of 39*. No idea how that occurred since the rebuilt 022 distributor hadn't been touched.

I opted to have John's 44mm Webers with 32mm venturis installed along with another 022 distributor with his proprietary curve and Pertronix ignition. Max advance 36*.

The results were easily discernable not only on the dyno but in the seat of the pants. Max torque of 126.6 at 4500 rpm and max h.p. of 124.2 at 6000 rpm.

A big "Thanks!" to John and his staff for solving the engine issues.

Mike

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Lomita, CA
'63 B coupe


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 Post subject: Re: 1883 cc engine
PostPosted: Thu Jan 03, 2019 5:29 pm 
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Joined: Thu Aug 22, 2013 4:29 pm
Posts: 338
Location: Lafayette, NJ
Wow, 28mm venturis with a 1883cc engine, that is small. I run 30mm with a 1720cc and feel it's a great combination.
Glad John got it sorted.


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 Post subject: Re: 1883 cc engine
PostPosted: Thu Jan 03, 2019 6:18 pm 
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Yes, the engine was under-carburated and the timing was way off. I also noticed an improvement when I had one of John's cams installed.

I ran 36mm Dells on my 1720 engine and it ran great.

Mike

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Lomita, CA
'63 B coupe


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 Post subject: Re: 1883 cc engine
PostPosted: Thu Jan 03, 2019 6:19 pm 
356 Fan
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Joined: Fri Jan 10, 2014 2:02 pm
Posts: 188
Location: Carson City, NV
Hi Mike, glad to hear that it is nicely resolved. Would you be willing to post more details of your engine and the whole dyno run data? I'm in the process of building my own 1883, and would love the help from your data.


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 Post subject: Re: 1883 cc engine
PostPosted: Thu Jan 03, 2019 7:06 pm 
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Location: SW Los Angeles
Hi, Paul:

I have the hard copies of the dyno data but being computer-challenged, I don't know how to post them. I can copy them and send them to you if you PM me your address.

Engine particulars:

NOS 912 case checked by Walt at Competition Engineering
912 heads cc'd and intake manifolds ported to match
Willhoit 1.9 carb kit w. tall filters (4" internal velocity stacks)
JE pistons, Nicasil cylinders
Stock C crank magnafluxed and balanced with flywheel, etc.
200 mm flywheel; SCAT gland nut
912 conecting rods, balanced
Willhoit cam
912 cam followers
Chrome moly push rods
Aluminum oil cooler
Precision Matters free flow oil filter on C third piece with Pure Power cleanable oil filter
Mainly Custom by Design sump cover
Stock Leistritz muffler
28 blade cooling fan tack welded and balanced

6 volt system with 022 distributor with Willhoit's proprietary curve & Pertronix ignition
Stock A/B fuel pump with electric fuel pump primer

Mike

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Mike Wilson
Lomita, CA
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 Post subject: Re: 1883 cc engine
PostPosted: Thu Jan 03, 2019 7:12 pm 
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Joined: Fri Jan 10, 2014 2:02 pm
Posts: 188
Location: Carson City, NV
Thanks Mike! Will PM you my address.


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 Post subject: Re: 1883 cc engine
PostPosted: Thu Jan 03, 2019 8:32 pm 
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Got it. In the mail to you tomorrow.

Mikr

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 Post subject: Re: 1883 cc engine
PostPosted: Thu Jan 03, 2019 8:59 pm 
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Joined: Sat Jun 21, 2008 11:16 am
Posts: 1763
Location: Santa Monica, CA
Mike, that sounds like a sweet motor! I know where you got the NOS 912 case. :)

An extra 40 horsepower is nice. What compression ratio did you use?

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 Post subject: Re: 1883 cc engine
PostPosted: Thu Jan 03, 2019 9:23 pm 
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Yep...the NIB/NOS case came from our mutual friend. Compression ratio was, per the builder, 9.8-1.

All the best, Edwin.

Mike

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 Post subject: Re: 1883 cc engine
PostPosted: Fri Jan 04, 2019 11:29 am 
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Joined: Wed Aug 27, 2008 6:38 am
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Location: England
Hi Mike
As the Dellorto 40 DRLA carbs flow one size higher than the Weber IDF, You only needed to swap out the smaller Vents for 32mm Vents and a re jet. If you still have them, swap them back and see what you think.
Regards Jay

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 Post subject: Re: 1883 cc engine
PostPosted: Fri Jan 04, 2019 11:58 am 
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Joined: Thu Dec 15, 2011 9:01 pm
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Location: Laguna Beach/Traunkirchen
Jay, I've never heard that Dellorto 40's "flow one size higher" than Weber 40's. Why so?

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 Post subject: Re: 1883 cc engine
PostPosted: Fri Jan 04, 2019 1:28 pm 
356 Fan
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Joined: Tue Jun 17, 2008 1:54 am
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Hi Mike-

Curious, what cam you had before and whether you did the swap without changing anything else? My 1883 is almost identical to yours with the exception of the cam, which is a Elgin 7819(?), close to Harry’s stump puller if I remember the specs correctly.

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 Post subject: Re: 1883 cc engine
PostPosted: Fri Jan 04, 2019 2:27 pm 
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Joined: Tue Apr 15, 2008 4:37 pm
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Location: SW Los Angeles
The previous cam was a good cam quality-wise but the specs weren't suitable for the engine. It wasn't stock nor an Elgin. Hindsight being 20/20, I should have been more thorough checking the carbs and timing curve. It is possible that it would have run better with larger venturis in the 40mm Dellortos.

I went with John's 44mm Weber kit as through his research and development, works extremely well with engines 1883 cc's and larger. Same with his cam and distributor curve.

We went on a spirited test drive yesterday and the car runs quick and strong through all gears. I haven't taken it out on the freeway yet but I can't wait to see how it will do in the tall 4th gear.

Mike

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Lomita, CA
'63 B coupe


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 Post subject: Re: 1883 cc engine
PostPosted: Fri Jan 04, 2019 2:43 pm 
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Joined: Sun Nov 21, 2010 11:36 am
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Location: Alberta
Craig Richter wrote:
Jay, I've never heard that Dellorto 40's "flow one size higher" than Weber 40's. Why so?


I was under the impression that the Weber 40IDF? was comparable to the Dellorto 36DRLA which has a 30 mm venturi. The Dellorto 40DRLA and 36 are the same except the venturi (30 vs 34) and different main, ac and pump jetting which can all be changed.

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 Post subject: Re: 1883 cc engine
PostPosted: Fri Jan 04, 2019 2:57 pm 
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Joined: Thu Aug 22, 2013 4:29 pm
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Location: Lafayette, NJ
Matthew,
I think you're mistaken. The DRLA40 had a 40mm throttle plate where a DRLA36 has a 36mm throttle plate.


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