Loooking for fuel injection opinion

[Hasbeen]

It is easy to check if an inlet valve is not seating properly.

When you check your carbs balance, with that hose in your ear, you should hear a smooth hissing sound.

If one valve is not seating properly, that hiss will become syncopated. Rather than a constant hiss, it will be hiss gap hiss gap.

It will also tend to backfire through the carb occasionally, more obvious when you have the air filter removed.

Good luck.

Hasbeen

[jeffremj]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Replacing the running carb system with the non-running fuel injection seems an expensive, non-productive retrograde step.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">Indeed, but why not replace the emission kit free, but hacked about, Stromberg system with an emission kit free, as standard, 2nd hand UK SU carb and inlet manifold swop [:)]

[sheetsofsound]

Yes, vacuum gage will be replaced today. Something I've been meaning to do...

Hasbeen: I didn't know that about the hiss sound and the valves. The hiss from both is even and of the same pitch and volume. The only occasional backfire I get is when the engine is under load. I think my mechanic fooled with the timing, so that is another job to re-do this morning. Ho-hum.

Jeffremj: Funny you should mention that. I happen to have a complete set of SU's with inlet manifold on a shelf in my garage, acquired by accident when I got one of my cars. The guy I got it from was a hoarder (in his case, Triumph parts among many other things) and he walked away and abandoned his house, leaving me with the contents. The SU's are just sitting there, as I wasn't able to sell them when I tried a few months ago.

[FI Spyder]

The Zenith's will work just as well as the SU's but the SU's are simpler and easier to work with (adjust)so many go for that option. Not my opinion but the opinion for our local club member that specialises in SU and Zentih carbs and does much of the work for the club). An interesting note, a friend has a Spitfire that he updated to UK spec. (SU's, 9 to 1 compression, dual valve springs) and when I asked about his Collector Plate and the fact he had put on SU's he said he had a sheet from a dealer that indicated that in Canada, Spitfire's could be specially ordered with SU carbs so if there was any dispute with ICBC he had the proof that the change was potentially correct (not that that option was available for the TR7).



- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[HDRider]

I'd check to see if the float valves are actually shutting of. If it is that rich you can probably see which carb is flowing more fuel by shining a light into the throat and looking at the jet with the motor running.

Alternatively I had a car once that had a gouge in the needle which messed up the mixture at idle. The needle was new but the person who installed it must have used pliers to press it into the piston body.

Edward Hamer
Petaluma CA

[Workshop Help]

As an aside, have you performed a compression test?

Mildred Hargis

[sheetsofsound]

At this point I have no interest in switching to the SU's, but it is food for thought.

Took your advice, HDRider, and shone a light into the throat. Looked equal.

Thinking about what Hasbeen said about sucking on the vacuum line to look for leaks, I tried it. Whadaya know - hissing sound. Couldn't figure out where the leak was exactly, so tried again - no leak. Weird. Took off the distributor cap - leak. Went around the car and tried at a different angle - no leak. This went on for awhile, due to me being a bit thick. Finally, I took the vacuum hose right off and there it was, a crack in the elbow at the distributor.

I think when the engine was rocking a lot because of the misfire at idle, the crack would open and close. When the engine would run at higher rpm's and smooth out, the crack would stay closed and seal pretty well because the engine was rocking less.

I still think its missing a little at idle based on the exhaust pulse. It hesitates at low rpm's, but I'm hoping that's because its set a bit lean, which I'm thinking will help me through our emissions test. As my mechanic friend is not working today, I can't put it on his sniffer before I take it through the test to check my theory. Plus, I have to shell out the $50 for a day's insurance and testing fees, instead of using his 'Repairer' tags to do it for nothing. Would an intermittent vacuum leak at idle cause high HC readings? I'm interested in anyone's thoughts on this before I put my money down and gamble on the test again.

Timing checked out ok, btw, as did the gap on the plugs. Cleaned the distributor cap again, although it was pretty good. Compression test - yes. The values were all pretty equal, although I don't remember off the top of my head what they were. The top of my head isn't what it was.

[sheetsofsound]

Update: Went through the test again. Failed. UG. But HC was way down from before - @600, down from 1359. The 'pass' is 413. Emboldened, I went home, leaned things out a little further and figured I'd recheck the timing and try and get through the test again before it closed today.

When I looked before, there was a painted mark from the PO that I used to check the timing. Mildred's words about other people's hands in mind, I figured I'd check the accuracy of the mark. With a wire brush, I cleaned it up a bit and found the mark had been painted at 10 degrees BTDC, not 0 as I had assumed. Stupid me. I scrubbed it clean, marked it at 0, started the engine, turned the distributor and... could not move the distributor far enough to get it past 10 degrees BTDC. It is rotated all the way, and 10 degrees BTDC is all she'll do. I should add at this point that the distributor is not original; not sure who it's made by. So it appears that timing is my problem.

I'm just not sure what to do next. I tried removing the adjustment bolt to see if I could get more range, but it won't move any farther even with the adjustment bolt removed.

[Hasbeen]

To get the timing to 0, you will have to pull the distributor out, & reinstall it back one tooth on the jackshaft. Do it with care, it is one of those things I could often get wrong, & have to try a couple of times to get it right.

That should get you to where you have enough adjustment to get anything between zero & 10.

Hasbeen

[sheetsofsound]

Haha - I wish I had read your post before I started. I pulled the jackshaft all the way out and then, in a horrified rush, realized my mistake, resulting in a long string of unprintable utterances. And then laughter. What an idiot. At least I'm learning. I will be moving it back in place one tooth clockwise at a time, probably for the next few days. Holy suitcase.

[Workshop Help]

Around these parts, we call those language tidbits 'technical terms', not 'unprintable utterances'.

Mildred Hargis

[sheetsofsound]

I stand corrected. It was very technical there for awhile.

[sheetsofsound]

As I am now in the process of putting the distributor back in the right way due to my earlier idiocy, can anyone tell me whether the first valve (starting from the timing chain) is an inlet valve or an exhaust valve? I don't want to remove the cover to help figure this out (and I'm not sure it would help anyway), and I haven't been able to find a diagram in a book or on the net that will answer this question.

[Hasbeen]

Pretty sure it's the exhaust, but my 7 is not here to check.

Just look down on the engine, & I think the front exhaust port is forward of the inlet.

Hasbeen

[Beans]

Exhaust it is [;)]

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