efi A Cam Position Sensor design - please critique

[uai]

you can just file/grind one lobe off the distributor and block your advance and run on contact...
I did this 

see here 

 

 

[tzei]

A friend milled upper cover and bracket for cherry hall. One cam gear bolt is about 19 mm long (and opposite bolt has larger washer to balance). 

[TobyB]

if you wanted to go super- stealth, there's a Volvo 142 distributor that uses a second set

of contacts in the base of the distributor to trigger the D-Jet setup they tried for a few years.

VW used the same thing in the later T3's.

 

t

 

[Healey3000]

16 hours ago, veronatii said:

@Healey3000 did you ever build this sensor housing?

Sadly, no. I may just end up going batch-fired, although Toby's suggestion of a Volvo dizzy is intriguing.

 

Damn you, Toby, just when I thought the decision was "final" :-).

[jimk]

1 hour ago, TobyB said:

if you wanted to go super- stealth

Super-stealth, ok

[Dudeland]

6 hours ago, Healey3000 said:

Sadly, no. I may just end up going batch-fired, although Toby's suggestion of a Volvo dizzy is intriguing.

 

Damn you, Toby, just when I thought the decision was "final" :-).

I did a little digging a while ago, and the reason I found for sequential injection was largely due to emissions,  at least initially.  Sequential on this displacement engine that is NA may not yield you much. 

 

The real benefit of having sequential injection is if you also run individual exhaust temperature sensors (EGT's) or O2 sensors.  The MS3 (not sure about other models) will allow you to tweak the injector cycle to balance out the fuel burn. 

 

This is especially important if you are running boost or high compression and you have an injector begin to fail.  It will help you not burn that cyl out... in theory. 

 

I am still on the fence about doing it, seems like a bit of B.S.  It is something that can easily be added later if you feel you need it. 

 

Let us know how it goes. 

 

 

 

 

 

[AustrianVespaGuy]

On 2/20/2024 at 6:19 AM, tzei said:

A friend milled upper cover and bracket for cherry hall. One cam gear bolt is about 19 mm long (and opposite bolt has larger washer to balance).

IMO opinion either this or a similar hole in the rocker cover with the sensor mounted to trigger off the fuel pump lobe is the better way to go than trying to use the distributor position.  I *almost* bored out a head once to try mounting a sensor in place of the fuel pump, but figured a good head was not quite the right part to experiment with. . .

[veronatii]

6 hours ago, AustrianVespaGuy said:

IMO opinion either this or a similar hole in the rocker cover with the sensor mounted to trigger off the fuel pump lobe is the better way to go than trying to use the distributor position.  I *almost* bored out a head once to try mounting a sensor in place of the fuel pump, but figured a good head was not quite the right part to experiment with. . .

I had a similar thought with using the fuel pump lobe.. has anyone done this? 

 

If I remember correctly, the fuel pump shaft is about the size of an M8 stud right? A quick google search shows there are several hall sensors available in that size..

[jimk]

23 hours ago, Dudeland said:

I did a little digging a while ago, and the reason I found for sequential injection was largely due to emissions,  at least initially.  Sequential on this displacement engine that is NA may not yield you much. 

 

The real benefit of having sequential injection is if you also run individual exhaust temperature sensors (EGT's) or O2 sensors.  The MS3 (not sure about other models) will allow you to tweak the injector cycle to balance out the fuel burn. 

 

This is especially important if you are running boost or high compression and you have an injector begin to fail.  It will help you not burn that cyl out... in theory. 

 

I am still on the fence about doing it, seems like a bit of B.S.  It is something that can easily be added later if you feel you need it. 

 

Let us know how it goes. 

 

 

 

 

 

Inaccurate injector dead time values (if you ECU is using them) is doubled for semi-sequential injection because injector is cycled twice per engine cycle.

 

Short injection pulse width times can be troublesome with semi-sequential because the commanded open time is halved.  Turbo'd engines with larger injectors experience this problem at low loads and at idle speed.

[Dudeland]

39 minutes ago, jimk said:

Inaccurate injector dead time values (if you ECU is using them) is doubled for semi-sequential injection because injector is cycled twice per engine cycle.

 

Short injection pulse width times can be troublesome with semi-sequential because the commanded open time is halved.  Turbo'd engines with larger injectors experience this problem at low loads and at idle speed.

The symptoms of the short injection pulse is a rough idle?, stumble?, hunting?  or all three?.   This is really interesting. 

[jimk]

Google "short Pulse Width" and quite a bit of info comes up.  Basically it adds time to the calculated pulse time to account for the instability of flow.

 

[Tommy]

10 hours ago, veronatii said:

I had a similar thought with using the fuel pump lobe.. has anyone done this? 

 

If I remember correctly, the fuel pump shaft is about the size of an M8 stud right? A quick google search shows there are several hall sensors available in that size..

That would be neat! And feasible I think. All sensors may not like oil that much, as I think the sensor would be completely under the valve cover. Cable could be sealed with just a cable gland on the side of the head.

[NickVyse]

This billet front cover came up on instagram from Steve's machine shop last week. Now that's a nice piece - I wonder how many keys it costs?

 

 

[tzei]

F/p lobe is easy to test - put the cam on lathe and sensor on tool post and set air gap and run at speeds.

 

Sensor needs to spec’ed for full oil immersion and temps above 120c. In a case of rocker failure it could get messy.

 

Sms version looks nice. Iirc this sensor wants wider trigger as appears in photo but if it works rpm’s used then all good.

[uai]

4 hours ago, NickVyse said:

This billet front cover came up on instagram from Steve's machine shop last week. Now that's a nice piece - I wonder how many keys it costs?

 

 

 

is this really billet?
Looks printed to me. 
So much effort (and money) for such an easy to tackle task.
If you have static ignition you might as well take one tooth off from your gear at the end of the cam and use the butchered cam gear as trigger wheel.
 

Edited February 22 by uai