1149 Mono Replica

[Ian Anderson]

Jim

Do you know if the jets etc you are using are actually the correct sizes - if they have ever been used before they may have beed drilled / reamered out and then the size stated on the jet is not correct.

It can then appear you have all the same jets in but 1 or more more may not be the correct jet size and give untold problems.

Yes they are expensive but starting with a known new set could save you hours / months of headaches

I'm also not sure how the quality control on new jets is now but I've also seen some new ones not being "as described" and needed replaced

Ian

 

[JimmyMac]

Jim,
Have you checked the pressures on your fuel tap and regulator units ?
Perhaps you could try bypassing the fuel tap and use one tank for your commissioning.

 

[Jim Rosenthal]

I appreciate the encouragement. Frankly, reading about someone elses problems would be a welcome relief at this point, although I don't want anyone else to have problems. I'm ready for some progress on this, I have to say.

Some things I forgot to mention; John Shriver and Ron have made up a steel cover for the shift linkage; I haven't seen it yet, but the photo I saw looked great, and it ought to be ready for paint and installation quite soon. Also, the emergency brake lever will be mounted on a steel plate that will absorb the force of applying the lever to set the brake, and mount under the dash, which hopefully will solve that problem. Still need a mount for the overflow bottle, but that's coming (this is John's busy season) Although there's no upholstery in the car, sitting on the webbing and the completed seat backs is actually comfortable, at least for short distances.

I do a lot of complaining, but there is a lot about the car that is really good, and Ron gets all the credit for turning a pile of bits into a functioning GT40. What we need is for the engine to act a little more grateful for all the attention Ron has given it; if she doesn't, I'm putting her on a twelve-step program with no premium fuel until she shapes up.

 

[Jim Rosenthal]

Ian, the jets are labeled and each 150 is the same size as the others, for example. You're right, a "150" may not meet specs for what Weber calls a "150", but there is no way for me to know, and if we can arrive at a set of jets etc that make the engine run well, the issue of how close they are to specs isn't so important to me. A good question, though, is this: how predictable is the difference between jet sizes? Are the differences in jets' sizes consistent, which would permit some consistency in tuning changes? I have no idea, but Jim Inglese has been at this for decades. I do wish he lived around here or the car was in CT, I have to say. He's at a distinct disadvantage since the car isn't where he is.

Fuel pressure has not been a problem. The regulators are able to give a consistent 3 pounds, and there is a good quality pressure gauge on the fuel log. And I have a spare one, too.

 

[Scott Calabro]

Hi Jim,

I feel your pain, but in the end looking at and listening to those 8 venturies make it all worth it!

You can check for common jet size with the shank end of a drill.

This is a great mod to keep dirt out of the idle circuit (jets), it works very well. Before I installed it I would occasionally lose 1 or sometimes 2 cylinders at idle. You can easily tell by the somewhat cold primary pipes on the affected cylinder.

Webers like clean fuel, and to be kept clean!

CB Performance - Online Catalog

Additionally after hours of tuning, by the book, I have found that Webers do not like pump gas no matter brand or octane. I think it is due to the fact that you now have 4 fuel bowls sitting on top of a hot motor on shutdown. The 10% alcohol quickly cooks off and the remaining gas becomes stale .

My 289 was very difficult to start after sitting for only 1 week!

Switching to 100LL or race gas or mix of pump / race gas, completely changed the way she runs. It now starts instantly. In fact in October of 2009 I pulled in the garage after my last run and shut it off. April 2010 it fired off instanly after letting the pumps run and 3 or four pumps of the gas pedal.

I know it will do the same in a week or two when I get it outside. AVGAS does not go stale.

Maybe my experience with pump gas is non typical but after you get it tuned, run one of your sponsons dry and throw 5 gallons of 100LL or some Sunoco race gas in and you will be floored.

It is amazing what 100% gasoline does for a carburetor!

I'll get my jet/emulsion/air-corrector sizes for you so you can compare.

Cheers,
Scott

 

[Jim Rosenthal]

I would very much like to know what size jets, what air correctors and what emulsion tubes you have in your engine. Do you have 44IDFs as well, like I do?

I see the point on the jet doctor. Ron has some racing fuel around, maybe we'll try that. We have been using 93 octane pump fuel. This engine doesn't have that high compression, and it has very good aluminum heads; I wouldn't think it would make a difference.

 

[Scott Calabro]

Hi Jim,

Yes, I have quad 44IDF's. Its not that you need the high octane number, its the fact that pump gas goes stale so fast. Fuel here in Mass. is blended at 10% ethanol. So all else being equal the engine is going to run better simply because you have increased the BTU/lb (energy) content of your fuel.


Too much to describe here as it will seriously drift your thread, so if you want, call me some time and I can run through how I got my IDF's running great. No rocket science just patience.

Better yet, go to Carlisle this May with Ron and I can show you.

Either way I'm sure you and Ron will get it tuned.

Cheers,
Scott

 

[Jim Rosenthal]

PM me numbers to reach you on, Scott, and I will call you. I am not going to wait until May to get the car running. Not unless I absolutely have to....

 

[Jim Rosenthal]

An update and a bit of good news; the oil leak coming through the bellhousing is neither the rear main seal nor the oil gallery plugs. The rear flange of the Scat forged crankshaft is drilled all the way through for the bolts which hold the flywheel on. (in my other Ford 302, the holes are not all the way through the crankshaft flange) Oil was seeping past the threads of the bolt holes and working its way down to the bottom of the bell housing.

So all we need is sealer for the bolts, and reassemble everything, and back to the Webers etc. And look at your SBF crankshaft, and keep this episode in mind when you assemble YOUR engine- if the holes go all the way through the crank flange, you'll need sealer on the bolts when you attach the flywheel.

 

[Randy V]

Every Ford 302 I've done has had the holes all the way through... I use liquid Teflon thread sealant on Super clean threads (use Lacquer thinner to clean the threads in the crank as well as the bolts)..

Good luck with the Webers!

 

[Chuck]

I can report with comlete confidence that none of the jets had been drilled or modified before the carbs were delivered to Jim. No need for Jim to worry about that issue.

Jim

Do you know if the jets etc you are using are actually the correct sizes - if they have ever been used before they may have beed drilled / reamered out and then the size stated on the jet is not correct.

It can then appear you have all the same jets in but 1 or more more may not be the correct jet size and give untold problems.

Yes they are expensive but starting with a known new set could save you hours / months of headaches

I'm also not sure how the quality control on new jets is now but I've also seen some new ones not being "as described" and needed replaced

Ian

 

[Chuck]

Scott's observations regarding pump gas got me thinking, and hopefully this is not too far off theme.

I have noticed that if my GT, which now has a Holley, sits for three or four weeks without being run ( like the dead of winter ) it requires a fair bit of cranking. But if driven weekly or more it starts right up.

Wonder if the alcohol content of pump gas causes it to absorb atmospheric moisture that then settles in the bottom of the bowl of the Holly four barrel so that the first shot of "gas" is actually water, making it hard to start?

By the way, when those Webers were on my GT it always started up easily. Indeed the ease with which it started was amazing to me, particularly with no chokes. They would idle well, even when cold.

 

[Jac Mac]

Every Ford 302 I've done has had the holes all the way through... I use liquid Teflon thread sealant on Super clean threads (use Lacquer thinner to clean the threads in the crank as well as the bolts)..

Good luck with the Webers!

Ditto & Likewise on the flywheel bolts-- Jim probably had his motor done by a chev guy....which could explain some of the issues he is having

 

[Dalton Veitch]

Oooh Jac Mac. That's cheeky.

 

[Jim Rosenthal]

Actually the motor was built by Burtonsville Performance Machining, here in Laurel, MD. You would be hard put to find an engine shop that does NOT build Chevys, there are so many of them around.
There is still an oil leak, it turns out, two of them. The pan will have to come off. I don't think the Weber jets were drilled or anything like that. I agree if gas sits around it will go stale and the ethanol WILL absorb water- we know that from boating experiences- but that isn't the case here. There is a local (well, Virginia) shop that does a lot of Ferrari restorations and has had an original GT40 in for service recently, including rebuilding the Webers. They have offered to help, and look at the car if need be. And it may come to that. But maybe we can get it sorted out. I know this rig ran well on Chuck's car; I think it didn't take kindly to the period where it wasn't doing anything.

In the realm of good news, I saw the shifter cover today for the first time. Another work of art by John Shriver. If it wasn't going in the car, I'd hang it on the wall, I would.

 

[Jac Mac]

IIRC you might have mentioned that you had them fit the main bearing caps from a 'Mexico' block to your engine, I assume that in order to do this they would have line bored the main bearing tunnels, I hope for your sake that in the course of doing this work they also checked the concentricity of the rear main seal groove in the cap / block, particularly if your using the later two piece rubber seal [ the early 'dogs turd' type is more forgiving in this instance].
PS, dont forget to remove 'that' pin & stagger the ends[one up, one down]for the rubber type.

 

[Jim Rosenthal]

Well, I hope they did. They said they did. All that work is on the original invoices for the engine build.

 

[Jim Rosenthal]

Everyone got a holiday from the Weber troubles over the weekend. We'll try again this week, chasing things like dirt in the carbs and vacuum leaks etc. And the oil leaks as well. I would say we've gotten to the point where virtually all of the cars systems work as they ought to, with the important exception of the carburetors and the oil pan leaks. Everything else is pretty much squared away- brakes, clutch, cooling, electricals... and if the car ran like it should, we'd be taking it to the upholstery shop right about now. We'll get there, but it's going to take longer than any of us thought it would.

 

[Scott Calabro]

Hi Jim,

Here you go.

293 CI, 11/1 CR, 5.4 rods, C30Z solid flat tappet (289 HP grind)
34 deg total advance @ 3000 rpm, 12 deg initial.
Ceramic heat insulator gaskets with rear heat shield and no dreaded turkey pan to make adjustment/service more difficult.
Float @ 11mm (reduces dangerous effects of percolation)
Fuel press 3.5 psi
38mm chokes
55 idle, 1 turn out
150 main
F11 e-tube
170 corrector
100 oct. avgas

YRMV

 

[Jim Rosenthal]

Thanks! I will ask Ron to look at these. It sounds fine. I think our problems have nothing to do with jetting and more with other fundamental problems which prevent us from getting the jets etc dialed in.