Main Jet size for Autolite 1100?

[Route--66--]

I'm just looking to open the carb so am going to order the main large gasket for the Autolite 1100.
As my car looks to run rich I'm taking the top off to check float level .. but while it's open I thought I'd replace the main jet in case it's too large.... which I assume could cause it to run rich ??.. (assume I'm correct saying that?)

If I order a main jet is there a specific size I need to buy for my '65 Mustang 200ci (standard cam and head (as far as I know))

Thanks loads!

 

[MPGmustang]

it depends, what rpm does the engine poop out at? 3500-4000? I know it's stock but a stock engine will safely rev to 5000 maybe 5500 with little changed, like more gas and better distributor.

I rebuilt my engine, from water pump to flywheel, everything was replace/rebuilt/refinished. put the old 1100 carb/ LOM dis back on and the engine still stopped power at 3500 rpm, man was I ticked off. so I bought the DUI, ha now the power went up to 4000 rpm and still rev'd out to 5000 (but no more power from 4k-5k). thinking what else. I got a dyno and showed my A/F ratio was dangerously high at the higher rpm's (never finished that dyno cause the guy said I am hurting the engine by being too lean), but great on idle to about 3500 rpm so I got a bigger jet, I actually went way pigger, started with a 59 jet and went right to 67, :mrgreen: I could feel the difference, by the time I was done I was able to rev the 1 bbl 1100 carb and DUI to 5800rpm, that's when I knew I needed more carb. dyno showed a perfect mixture with the 67, tried a 70 and got a better torque curve but kept it at 67 for economy.

I know you don't think your stock engine will rev like my rebuilt, but it can rev to the same rpm's, maybe just not as fast. give it some more gas, with a 65-67 and try it, the worst that can happen is it's too rich and wastes $4... the other option to try is the distributor, timing and mixture is EVERYTHING.

 

[Route--66--]

Thanks for that MPG
I do think I'm running rich already as my plugs always tend to be black and furry.. although most journeys aren't very long so it prob isn't off choke for long enough .. although they do black-up extremely quickly..

No idea what it revs too as I have no rev counter .. although really must get one ... seems to rev very quickly
It's interesting you say about an engine being damaged if it's too lean .. I didn't realise that would be the case .. is that because the cylinders aren't being 'cooled' by the petrol vapour at high revs if too lean ..?

I too am mildly thinking about rebuilding engine due to a small amount of what I believe is piston slap when cold..
Did you take the engine out yourself?? or just let the garage do it all ..?

Cheers!!

 

[MPGmustang]

I gave the garage the engine, but I had them build a 78 block and 78 head, getting rid of my 68block 67 head, 63 exhaust ect...

the dmg he described is being too lean heats up alot more than being rich, your engine survives being rich, but being lean hurts it due to excessive heat cause lean has more oxygen and oxygen burns hotter, too much heat can warp pistons cause ping and eventually engine failure. before I pulled the old engine my rings gave out and started puffing ALOT of smoke and loosing oil weekly, dry/wet compression tests showed 2 cyl's rings failed.

you save so much in labor if you pull the engine yourself, I did have them assemble the new engine as I'd rther them have it put it together, but they didn't degree the cam. , 2 years later I tear it down to find the camshaft 11.5* advanced, I moved it to 4* advance and replaced the lifters at the same time added the 2bbl direct.

I wouldn't rely on the plugs, I tried and found I was running lean, when I did run properly they fouled often (2-3 times between oil changes I cleaned them) but I knew the A/F was spot on, turned out my valve seals were shot, replaced most of them with the rope trick and the fouling slowed but for every oil change I still had to clean them until engine rebuild.

 

[Route--66--]

Really interesting thanks

This is one thing that bothers me - even if I gave the engine to an engine rebuild place could I be sure they actually put it back together correctly .. :/ .. tend to find these days there are a lot of people who don't provide what you've paid for :/

my dry compression is about 175-180 psi and wet is close to 200.. it uses no oil though..

That's very very interesting about your plugs fouling yet the mixture is correct .. maybe I'm ok .. I can get mid 20's to the gallon (UK gallon tho)

Are you saying bad valve seats caused fouling then - do you mean that oil ran down from bad valve guides or that it causes black dry deposits ..?

Cheers loads again !!

 

[MPGmustang]

the valve seals, they sit inside the spring, it seals oil running dropping down the valve into the chamber. seats/guides I suspect were good.

your compression is better than mine, I'm sitting around 165-175, my stock engine was 110 max, 130 wet.