72 carb and spacer question: completed w/ hard starting suggestion...

[njoconnor]

Blue 72 will be going back upon the jack stands for some late Fall/pre winter's nap maintenance and tweaking. The list includes new H4 lamps and relays, new fuel pump and filter, plugs, etc. If I get real ambitious, I'll try and tackle the twisted off bolts the PO left where the flywheel cover plate attaches. (and, no, he did not leave enough bolt protruding for the "welded nut" trick..... )

But Job 1 will be installing a 14mm spacer under the current stock carb. This is intended to thermally decouple the carb from the intake manifold hopefully resolving a persistent (and somewhat erratic) hot start problem. I have spacer, gaskets, and a couple of different lengths of new 8x1.25 pitch studs (thanks for the info Csaba!!). Question: is there a recommended gasket sealer/goop/product I should use between the manifold, gaskets, spacer, and carb? I want to avoid air leaks at the carb/spacer/manifold connection. Also: I have the 2.5 inch square air cleaner in place of the stock round item; any chance the spacer may cause hood clearance issues (flat hood)? I'll be double checking the clearance before I start, but figured I'd ask.

Thanks

Neil

[bradartigue]

You should not need sealants - I oil the paper gaskets, some folks don't. Sealants compensate for flaws in mating surfaces and if you need them you're just masking another issue.

I've run idfs under flat hoods so unless you have a real tall carb like an adf you should be okay. I'm curious to know if the solution works (hot start problems I typically attribute to old weak mechanical fuel pumps)

[njoconnor]

Thanks, Brad! Based on some of the discussion on thi slat summer, I figure a spacer may well improve thngs. Might even give me a 1/2ft lb torque boost.... I'll report back, but it won't be warm enough for a real test for another 9 months......

Ordering your book this week. How do Iget an autographed copy???

Neil

[VAspider]

Neil,
I have had the spacer on my 69 for about 3 years, no issue with the height. Its close as I have a small indent of about 2" inches long in the hood pad. Looks to be the left front corner of the filter assembly.

Frank

[bradartigue]

Thanks, Brad! Based on some of the discussion on thi slat summer, I figure a spacer may well improve thngs. Might even give me a 1/2ft lb torque boost.... I'll report back, but it won't be warm enough for a real test for another 9 months......

Ordering your book this week. How do Iget an autographed copy???

Neil

It is telling that carburetors evolved into a two-piece (throttle body / mixture body) design towards the end of their popularity, and no doubt that the later carbs added a bit more torque - a 34ADF is a tall carb compared to a 34DMSA and the ADF is a torquey thing while the DMSA is less so. All that said, good luck!

Seriously, an autographed copy? I'm flattered - send me an email and I'll send you my address.

[njoconnor]

Frank, thanks for the info! I don't have a hood pad, so I probably have the room to clear. Pad's one of those future "maybe" considerations.

Brad, I like having autographed copies of books by authors I've met/corresponded with. PM on the way this afternoon or tomorrow!

Thanks

Neil

[njoconnor]

It was pouring yesterday, so I fell to work on installing the 14 mm spacer/gaskets (and while hood was up, reconnected the crankcase vent tubes). Just finished this morning, and I'm about to take the car on a test run to the library.

Anywho, most of you will recall one of my first posts was about hard starting issues. This issue plagued us off and on, usually when the weather was hot, the drive kinda short, and the waiting period between starts even shorter (think hot parking lot and a 10 minute dash into the store). One of the replies last summer suggested a spacer, to thermally decouple the carb (and float bowl) from the heat of the engine. As I was removing the air cleaner yesterday, I noticed the carb....moved. Once the cleaner was off, I discovered that all 4 carb nuts were so loose I could turn them with the edge of my index finger! And, considering the location of the nuts, I could sorta understand why: only one of them is easily reachable, and the rest are major PITA's to access with even 1/4 inch drive sockets and short wrenches. Lots of patient tweaking and small movements eventually got the nuts off, new carb studs and spacer installed, and carb tightened back down. Fired up immediately, with none of the stumble I'd become accustomed to. So, recommendation: for anyone who just acquired a carbed 124 from a PO, and there's starting/ running issues, check to make sure the carb is bolted down tight! Yeah, no duh, but who'd a thunk?? All you experienced Fiatistas already have correctly tightened carbs....

In case anyone else is considering the 14 mm spacer, you will need metric studs in the size of 8mm-1.25 pitch x 50mm. These "just fit", but the longer 60mm's come to close to the carb body to allow one to tighten the nuts.

Next project: fuel pump, followed by H-4's and relays. Followed (maybe) by 95amp alternator if the budget allows.....

Neil

[njoconnor]

Quick update. Yesterday's library run went very well, with the engine idling a bit high while cold, then dropping to it's usual 1100 once at operating temp. The engine definitely felt more responsive, with some noticeable low end pull, and everything felt smoother; not sure how else to put it.

With 50 degree highs and sun today, decided to take the Fiat to work. Started right up using the "Starting Device" (aka, choke, for the rest of us), no stumbles, no misses. Same noticeable smoothness and pull through the gears, and again, as it warmed, the idle revs came down as the choke handle was pushed back in (this behavior with the choke is what I experienced with my 71 Coupe, and until now, not with the Spider). While I'd like to think the spacer is helping, I suspect the real change was properly tightening the carb hold down nuts and eliminating a significant air leak/overly lean fuel/air mixture.

Otherwise...top down in a Spider on 2 NOV in Wisconsin....I'm a happy guy......

Neil