GENTLEMEN, START YOUR ENGINES!

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Mike Grant
356 Fan
Posts: 203
Joined: Mon Feb 18, 2013 2:25 pm
Location: Aptos, CA

Re: GENTLEMEN, START YOUR ENGINES!

#16 Post by Mike Grant »

I just installed one on my SC last weekend. Working in that space between the front of the fan housing and the firewall is a little tedious, but overall the install is very simple. I had to shorten the factory hard fuel line on the passenger side by 1.5" to get the right fit, and this is called out as a possible requirement in the instructions. It's pretty easy to gauge how much, if any, the fuel line(s) need to be shortened. The instructions are clearly written and include some helpful, high-quality photos. Also, Ron provides prompt and concise responses if any help is needed.

I can't provide a functional review until the car sits for a week or two. When the car sits for a few weeks, I have to pump the accelator many times and the engine will start and die 2 or 3 times before stable running. I'll be able to quickly tell if this improves the cold start, and I expect that it will.

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Eric McKinley
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Joined: Sat Dec 21, 2013 12:09 pm
Location: Belfast, Northern Ireland

Re: GENTLEMEN, START YOUR ENGINES!

#17 Post by Eric McKinley »

Mike,

Purchased one from Ron last week, its going to be a few weeks though before I get it on the engine.

I look forward to hearing your thoughts on it.

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Tim Brillon
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Joined: Mon Aug 06, 2018 10:47 pm

Re: GENTLEMEN, START YOUR ENGINES!

#18 Post by Tim Brillon »

Any other registry members with real world experience with this product? I am curious about two things: 1. how long the car can sit and still start quickly and also 2. an overall description of how the starting process is with the auto prime vs. without. My starting is similar to the above posted by Mike: pump many times, engine starts and dies 3-4 times before finally catching, need to keep revs at 2k or so for 5-10 seconds then it will idle smoothly.
1963 356B Super 90
2000 Boxster S
2008 997.1 Turbo

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Ron LaDow
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Location: San Francisco

Re: GENTLEMEN, START YOUR ENGINES!

#19 Post by Ron LaDow »

Tim Brillon wrote: Wed Apr 22, 2020 9:31 pm Any other registry members with real world experience with this product? I am curious about two things: 1. how long the car can sit and still start quickly
Me too,Tim; Pre Mat designs get revised as a result of customer comments, please, pro and con.
The image at the head of this thread shows the Rev 1 part (as still fitted to my C - 'cobbler's kids' and all that); it delivers a total of ~35cc to both carbs, and that C will start easily after 30 days 'rest', with CA-regulated 15% ethanol fuel. The production kits (Rev 5) deliver ~45cc.
It's worth looking at the evaporation path, and the reason the fuel stays in that cannister: From the 'at rest' cannister, the fuel (vapor) must migrate back through the fuel lines to the float valves, through those 1.35mm passages to get to the float bowl and then escape to the atmosphere. It does, given the vapor pressure pushing it, slowly, but that VP drops off as the volume decreases.
OK, 45cc? Well, each Zenith float bowl, with the float fitted, holds about 25cc of fuel, so the charge from the Pre Mat primer is not going to give you WOT performance on start-up; you'll have to look elsewhere for that. What the Pre Mat part does is ease starting. Assuming the float valves do their job, you'll have a full bowl on the left and a bit shy on the right. Statistically, that is.
One other comment: THE PRE MAT PRIMER WILL NOT MAKE YOUR ENGINE START IF IT WAS LAST TUNED UP IN 2002. TUNE UP YOUR ENGINE!
Tim Brillon wrote: Wed Apr 22, 2020 9:31 pm[...] and also 2. an overall description of how the starting process is with the auto prime vs. without. My starting is similar to the above posted by Mike: pump many times, engine starts and dies 3-4 times before finally catching, need to keep revs at 2k or so for 5-10 seconds then it will idle smoothly.
Pumping the pedal does absolutely nothing to help start the engine until there is fuel in the bowl. In fact, with empty float bowls, it delays the start, since the engine rotates more slowly, slowing the delivery from the fuel pump, every time the throttles are closed.
Absent any device to fill the bowl, hold the throttle wide open and crank twice at 10 seconds each (that was Kettering's epiphany; a high-horsepower starter motor will work since it's used momentarily! Or, say, 10 seconds). Then try pumping. If it doesn't start popping instantly, give it another 10 seconds at WOT, and then try pumping.
With the Pre Mat Autoprime fitted, I suggest this: Open the deck lid, push down on the carb lever and listen to the 'gurgle, gurgle' as the fuel falls into the float bowls from the cannnister; pretty good fun.
You can then close the lid, get into the car and act like there's fuel back there; maybe a pump or so, or hold the throttle part 'way open to increase the vacuum and start it at lower speeds. I do the later, letting the oil get to all the parts.
Do that once or twice and you'll probably just get in the car, hold the throttle to the floor 5 seconds or so, and start the car.
You asked, responses gladly received.
Ron LaDow
www.precisionmatters.biz

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