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great shot of your 2 LT-1's, did you win 1 trophy...or 2 ?
Regards
Roy
Hi Roy.
No awards on offer as this was arranged to support two local (to the event) charities, one being for disadvantaged kids - Hope House & Tŷ Gobaith and The Gwrych Castle Preservation Trust.
On a related note, the biggest American car gathering event in the north of the UK is the Stars & Stripes show usually around 4th July. This was my aim to get the yellow one ready for this event for its debut. I made it just having got the car running ok and looking presentable so enlisted a mate Simon to drive red and I took yellow. Up to this journey I hadn't covered but a mile in the car as I had it transported from the barn to my garage as the brakes were seized and as it tuned out none of the wheel nuts were tightened! Well Stars & Stripes is judged and held in high esteem so driving onto the show ground one of the judges saw me and explained that as red won best Corvette 2018 it wouldn't be judged! Ok fair enough, share them around I guess. Well it couldn't have worked out better as yellow won best Corvette on the Saturday which was a nice recognition of the work I had put in..
There were a couple of pro photographers at the show and their work is now up on the CCCUK book page and worth a look
An update on the original problem of stuttering at a stop while the engine is at temp. .The clutch fan is operating properly. The engine temp never gets over 160 degrees. I did notice that the fuel line on the output side of the fuel pump is touching the lower radiator hose. Not a good thing but this should not cause enough heat to cause fuel to vaporize. I replaced replace the hose and wrapped the fuel line with some thermal protective shield. The Carb rebuilt twice, new fuel pump, new coil, heat riser wired open and blew air back into the tank to clean any possible crap.
The car runs perfect under normal conditions but the min you take off like you were in a drag race with the secondaries kicked in, in first and second the problem starts when you come to an idle. If it was fuel starvation it would be happening during acceleration or under a load. At idle the rpms will start to fluctuate by 500 rpms and it will die if you don't give it gas. Giving it gas will keep it running, all that is needed is to give enough gas to kick it up to 1,000 rpm, anything below and it will die. The problem is still not solved....
I have done some research on fuel pumps for the LT-1 and found that they supposedly use the same pressure as any small block. Does anyone know if this is true or false?
The engine vacuum operates the wiper door and headlamps not just the ignition advance. If something is plugged or a check valve isn’t functioning properly it could effect the engine operation. Again, someone smarter than me may be able to be more specific.
Yes, that was the first thing I checked. I did find a cracked hose attached to the intake manifold but it didn't affect the problem.
I like to start with a solid baseline; have you adjusted the valves recently? If so, good. What's the engine vacuum reading at hot idle? And does the vacuum gage needle fluctuate, or stay steady?
The valves have been checked and adjusted within 300 miles. Vacuum at warm idle is 10-11 psi. and it does not fluctuate. It is like it is starving for fuel, pump the accelerator so the rpm's are about 1,000 rpm and there is no problem. If I let it idle like I am stopped at a light it will run fine and then it will start stuttering the rpm will swing 200-300 rpm. It will try to recover but will die. It will start with very little effort after it dies. This all starts after about 30 min of driving. I thought it was a thermal problem so I wrapped the fuel line. As I had mentioned before I have put on a new pump.
That vacuum reading is much lower than mine. Mine pulls 18 inches Hg at warm idle. Checked with multiple gauges to make sure.
At that low a vacuum and with the 780 cfm carb, I’m wondering if the induced airflow passed the venturies is enough to draw proper fuel into the intake manifold.
Just spitballing; are we sure that you don’t have a large vacuum leak, say at the intake manifold sucking into the lifter valley?
The gauge that I used was a $12 gauge from Harbor Freight and am not sure of the calibration. What has me baffled is, the car runs perfect for about 30 - 45 min and then starts to act up. It was in the shop yesterday on the Dyno and could not find anything out of the ordinary other than a little rich. I drove the car home (about 20
+ miles) in stop and go traffic along with freeway traffic and it ran perfect. In my driveway I let it idle like you were stopped at a light and it started acting up and stalled. It started up with no problem.
An update. I found a fuel filter back from the engine on the frame. I replaced it and found that they used a filter with 1/4 inch nipples where the actual fuel line is 3/8 of an inch. I replaced it with a 3/8 inch filter and drove the car and it seems to have improved the stumbling but not totally. The restriction seems to have been some of the problem.
book page and worth a look
