starter relay, next gen modification Options

[Tom]

Well, been meaning to get this done for a while. Didn't want the hot start kit from Bosche or the Ford relay, so I found one on line that I liked.
Installed the relay on a small bracket on one of the mounting screws for the relay board. Ran a new small yellow wire to pin 6 of the 12 pin connector and a brown ground wire to the bracket . Ran two 12 ga. wires fron the relay to the solenoid with the hot wire having an inline water resistant ATC fuse holder with a 30 amp fuse. Put some heat shrink around the normally used large yellow wire to protect it. On the solenoid side used tape to protect the connector that used to be hooked to the solenoid.
This relay uses 140 mili-amp so not a very large inductive spike to worry about, but I installed a supression diode across the relay coil anyway. Also put a larger one across the solenoid coil at the relay ( 87 to ground). This supresses the solenoid coil inductive spike to protect the relay contacts.
here are a few pics, and a link to more info: http://www.google.com/url?sa=t&rct=j&a...eg_6KDxZdKYQYGw This is the aeroelectric link
Oh, I tested it several times and it works just fine.
Tom
Edit: changed back EMF to inductive spike, sorry if this confused anyone. Inductive or transient spike is the correct term for what is happening here

[Tom]

Pics are large, so several posts will be needed.

[Tom]

another one

[76-914]

Very nice Tom, but I'm not taking my Ford relay off. (IMG:style_emoticons/default/laugh.gif)

[Tom]

76-914,
No reason to, the Ford relay is just great. I just wanted something hidden and different. Plus I had wire left over from the kits. My idle hands needed to do something!! LOL!
Thanks for the compliment too.
Tom

[Drums66]

.....Copy of the hot start kit in another location (IMG:style_emoticons/default/poke.gif)
& I'll also give you a compliment...is fine,looks good!
(hope it turns out to be as reliable as mine was....about 10 yrs old)
(IMG:style_emoticons/default/bye1.gif)

[Tom]

Drums,
Thanks for the compliment. (IMG:style_emoticons/default/smile.gif) Yea, by now they are all copies. (IMG:style_emoticons/default/smile.gif)
I expect it will last OK, but the next time I order any parts, I will order myself a spare relay just in case. Diodes are cheap at Radio shack, about a buck and the relay was $3.08, already had the wire from the kits for the fuses left over, the inline fuse was $3.29. So all together I have about $10.00 in this mod. I never had the "hot start" problem with this car, just wanted to nip it in the bud so to speak.
I can't get the link to transfer but here is the info that really got me interested in doing this modification.
aeroelectric.com.
Very informative write up. Even mentions that lots of small foreign cars come with no starter relay and end up having key switch problems.
Tom

[Tom]

I have been thinking of the next generation of this and want to add a push to start switch so when I need to "bump" the engine over it will be easy to do so from the engine compartment. A rubber cover over the push switch would keep accidental bumps to a minimum.
Tom

[Prospectfarms]

I have been thinking of the next generation of this and want to add a push to start switch so when I need to "bump" the engine over it will be easy to do so from the engine compartment. A rubber cover over the push switch would keep accidental bumps to a minimum.
Tom

The "bump" feature could also be useful as a "get me home" solution when the plastic electric ignition switch fails -- as they are so prone.

One ? I thought the starter juice was already relayed to the bendix. Incorrect? (AC VW's are not, and the kind of relay you've described is a good modification, but I thought that with all those five prong relay's, at least one would be switching starter current.)

Nice photos for your project. Thanks.

[TheCabinetmaker]

So you spent a little time and money to fix a problem that didn't exist? You have way too much free time.

[Prospectfarms]

(IMG:style_emoticons/default/blink.gif)

discuss starter switch problems

Hot start relay

[pcar916]

... add a push to start switch so when I need to "bump" the engine over ...

I have my button on the relay board under the dash and fed directly from the battery. I've never had to use it to get around a bad ignition switch, but had to after a spin at Texas Motor Speedway at Parade in 2004 the switch wouldn't work... the button however, worked like a champ.

I don't really want people to be able to see it. Then they might push it and if the car is in gear, which it will be if the car is parked, it's gonna lead to an embarrassing moment, possible an expensive one,

[Cap'n Krusty]

Look out Maude, here comes the rain on the parade!

In your search for a "hidden and different" location for your hot start relay, you've put it outside the protective cover for the relay board, exposed the connections to moisture by mounting the relay on its side, mounted it where it takes a long run of heavy wire to be effective, and used cheap Chinese crap for a relay.

In theory, you want a relay that will trigger at the low voltage often supplied buy the aging wiring on a 914, and you want it as close to the starter as possible, while keeping the connections out of the elements as much as possible. That's why I use a 6-volt Ford type relay, mounted close to the starter, and cover all splices and connections, other than those directly on the relay posts, with heat-shrink tubing. A fuse is unnecessary, and just another potential failure point. BTW, I have customer cars that have seen daily use for more than 25 years with the 6V relays, without a single relay failure. Ugly? Sure, but they're under the car where no one sees them, and they're convenient for service or bypass should they ever fail, which they don't.

The Cap'n

[76-914]

I have been thinking of the next generation of this and want to add a push to start switch so when I need to "bump" the engine over it will be easy to do so from the engine compartment. A rubber cover over the push switch would keep accidental bumps to a minimum.
Tom

Tom, if you kit this up, I'll take one. 2 reasons. You know my Chinese Ford style relay fused after < 3 days; 2nd, the push button start function. (IMG:style_emoticons/default/beerchug.gif)

[Tom]

pcar916,
I haven't finalized what I will do yet and was kicking around the idea of putting a solid cover that would have to be unscrewed to get to the push button. Your point is well taken and I think a solid cover would be best for safety's sake.

vsg914,
Obviously your cars have never had this problem. I am sure many others have had good luck with their cars also. This is my third 914 and my first one had the hot start problem often. Back then I just put a push to start switch back in the rear engine tin. I understand some don't like this idea and that's OK. However, it's hard to ignore the fact that this is a weakness on these cars. I have seen at least 8-10 threads on switch replacement in the last year. And you are right, I have way too much free time on my hands since I retired. (IMG:style_emoticons/default/biggrin.gif)
Tom

[Tom]

Cap'n Krusty,
Rain away, we PNWers are used to it! (IMG:style_emoticons/default/smile.gif)
Tom

[andys]

My '47 Ford had a button right on the relay that would move the contact and allow you to run the starter. I don't think the later ones have that feature.....It looked exactly the same as the one we today call the old Ford starter relay. Either way, that relay (solenoid) was bullet proof.

Andy

[ClayPerrine]

We had hot start problems with both 914s, but putting on a gear drive starter cured that once and for all.

(IMG:style_emoticons/default/biggrin.gif)

[pcar916]

... putting on a gear drive starter cured that once and for all

(IMG:style_emoticons/default/agree.gif) Never had another problem. I have four or five used 911 Porsche starters boxed up and just sittin' on a shelf. I can't think of any reason to take the time to fix 'em.

[Tom]

Prospectfarms,
No starter relay in the 914. There is where the problem starts. The inductive spike from the collapsing field causes premature wear and damage to the key switch and eventually causes failure of starting when the engine is hot. I suspect this can be all boiled down to the carbon deposits building up in the key switch causing more and more voltage drop across that contact until eventually the voltage drop is enough that the solenoid will not operate via the key switch. During bench testing myself, I have found that 9 volts or more is needed to operate the solenoid, any less due to bad contacts/wiring and the solenoid does not operate. Replacing the key switch/cleaning contacts should fix that. I haven't had to replace my key switch yet, but reading threads where others have, it seems like a semi-hard job. To me, a small relay to replace that would take 10 minutes and cost 5 bucks seems like a better solution.
Much of what I am repeating is in the article in the link in the first post if anyone cares to read it. Or you could go to the IEEE webswite and research relay contacts and why they use special alloys to reduce the arc damage on the contacts. key switch contacts are just copper I believe, or copper coated.
I am just putting info out here for those who want to use it and I would hope that those who do will confirm this by researching the links for theirselves.
I have no plans at this time to make kits for this as there are already vendors that supply this type of modification, minus the "bump" feature.
Tom