[williamtaylor]

Any suggestions on how to improve the running of your 308?

 

[kk61]

Hi

No answers from me here yet as I have only had the car a couple of months.

I would like to know how complex a task it is to reset the float levels in the carbs. (fibreglass 308).

When cornering sharpish I get a stutter when getting back on the throttle and also when I pull up at the lights I have to make sure I don't let the revs fall or she'll stall.

Both are symptoms I'm told of low float levels, so I am wondering whether it is a home job, or off the the workshop.

Any thoughts appreciated.

Kon

 

['75 308 GT4 (Peter)]

Float heights are very critical!

Float level changes are not difficult, but requires patience and time. Use a good quality dial caliper and you'll need a pair of needle nose pliers to adjust the limit tongs on the floats.

Measure float heights (both high and low) between the carb top (without the gasket!) and the float body (not the soldered seam!). Hold the carb top vertically. (see photo below)

Check with your Owner's Manual as to what the height should be, but it appears that 50mm is the norm amongst carb'd 308's. Float drop should be 58.5mm.

Be sure to check the condition of the needle valve - it should not have a ridge, but be nice and smooth. When removing the float fulcrum pin, always push it out through the split arm side (not the solid arm side). Support the split arm securely (placed on the top side of an open bench vise, opened enough to let the pin pass through. Try not to drop the pin onto the garage floor!). Use a small drift punch slightly smaller than the diameter of the pin to push it out (I think a 1/16" punch will work...). You should be able to push it out with hand pressure only - no hammers please!

Check to see that the floats don't have leaks by submerging them into a glass of hot water (it will show up as air bubbles rising from the leak area), or just shake them and you'll hear the gasoline splashing around in them.

If they're okay and leak free, set the float heights by bending the tongs appropriately, return the float to the top cover, put the pin back in, check the heights, repeat as neccesary.

When finished setting the float heights, also check that the jets (idle, main, etc...) are correctly sized - as per specs in the manual. When I bought my car, the previous owner changed them and messed up the float heights and it ran very poorly... One of the reasons why it was offered for sale for next-to-nothing!

Check also you're getting proper fuel pressure and volume (5 PSI and 26.5 gal/hr approx.). Check that the little brass inlet filters (seen in my first photo, top left corner) are clean and not plugged up.

Start with this and see if the car improves.

 

[kk61]

Peter

Thanks for the great response.

Judging by the detail and the photo's it's really a job for when you can justify pulling the carbs off, rather than something to be done in situ?

Kon

 

['75 308 GT4 (Peter)]

Peter

Thanks for the great response.

Judging by the detail and the photo's it's really a job for when you can justify pulling the carbs off, rather than something to be done in situ?

Kon

The carb bodies can be left on the engine, it's just the tops that need to be removed (each held on by five screws) in order to set the float heights. Rest assured, you won't disturb any other setting (idle speed, mixture) by doing this operation.

 

[CKRacing]

There are two upgrades that most DIYs can do to the 308 GTBi & GTSi.
1. K&N air filter
2. replace the 3" ribbed rubber intake hose with a 3" mandrel bend ALUMINUM or CARBON FIBER one. Looks better.
Charles

 

[Dino246gt]

Looks better? That's personal, but does it do anything for improving performance? Personally, I prefer originality, unless it's a noticeable improvement, like the fuse blocks and the K&N.

 

[Pete04222]

Good to see this thread revived. Dino246gt, I agree with you. If I have to replace a part I will get the best replacement available but I won't swap out a component because the new one looks better.

For the older 308's I think the best upgrade is swapping out the point type ignition for an electronic ignition. Performance gain is nil. Reliability gain is huge. Do a search and you will find the post from when I did this to my '79 308.

 

[Boxer]

Good to see this thread revived. Dino246gt, I agree with you. If I have to replace a part I will get the best replacement available but I won't swap out a component because the new one looks better.

For the older 308's I think the best upgrade is swapping out the point type ignition for an electronic ignition. Performance gain is nil. Reliability gain is huge. Do a search and you will find the post from when I did this to my '79 308.

Should Archie get this done on his 308 when they do the windows?

 

[Pete04222]

Should Archie get this done on his 308 when they do the windows?

No, he should not. If they are working fine then leave them alone. They're fine. There are 4 sets of points in the early 308. 2 Low speed and 2 High speed. Last time I checked the points were $75 each. That's $300 just for parts. An electronic ignition is $300. I did the work myself but labor costs would be the same either way. The distributors must come out.
The low speed points seem to fail first and you can just disconnect them and the car is fine for normal driving (with a higher idle speed). I drove my car for 6 months on just the high speed points. Archie should become familiar with the procedure on how to disconnect the low speed points for when his car starts backfiring like a 12-gauge shotgun. When the high speed points fail you have to pull the distributors out to fix it and at that point in time it is cost effective to swap it out to electronic.

 

[archiegibbs]

The 308 starts fine first time, every time at the moment, even when it's been left for a week. I'll bare this in mind if it starts playing up though.

More of a concern is the ancient wiring and fuse box. I may well replace the fuse box some time soon.

 

[Pete04222]

The 308 starts fine first time, every time at the moment, even when it's been left for a week. I'll bare this in mind if it starts playing up though.

More of a concern is the ancient wiring and fuse box. I may well replace the fuse box some time soon.

Best thing you can do Archie. One of the easiest and most cost effective upgrades you can do to the 308. This is a job even you can do. You can even get your boy to help you through the hard parts. Good Father-Son project. Search for my thread on doing this. Took me about 4 hours.

 

[archiegibbs]

Took me about 4 hours.

4 Hours :yikes::wall::cry3: That's 4 hours for you, it will take me 4 weeks and the car will never work again after i've finished. When the job's done I'll have a pile of spare nuts, bolts and washers that I didn't know I had, the exhausts will be hanging off, there will be no wheels on the car and the hood and trunk lids will have swapped themselves over :cry3:

 

[Pete04222]

4 Hours :yikes::wall::cry3: That's 4 hours for you, it will take me 4 weeks and the car will never work again after i've finished. When the job's done I'll have a pile of spare nuts, bolts and washers that I didn't know I had, the exhausts will be hanging off, there will be no wheels on the car and the hood and trunk lids will have swapped themselves over :cry3:

Yeah, but the windows will go up and down reliably. Isn't that what you're looking for? Christ Almighty, you're starting to sound like one of our whining customers.

I remember when one woman came in the shop saying her driver's side window wouldn't open and she wanted it fixed as cheaply as possible. You went out and smashed it with a rock and charged her 5 dollars. Jesus, I didn't think that woman would ever shut up. Now when it comes to your own car you're being picky?