Good throttle stop recommendation.
Thread Starter
Racer
Joined: Sep 2012
Posts: 262
Likes: 0
From: Roanoke Va.
Good throttle stop recommendation.
I posted earlier about my newly rebuilt 427 running on or dieseling. I have checked and done all the recommended things. Timing is right on, carb has been rebuilt, idle set at no more than 750. All this done by a very reputable old time hot rodder, with dieseling being the complaint. I still have some dieseling. So the last resort suggestion by Lars and others was a throttle stop. Does anyone know of the "best" one to buy? "Best" being defined as getting the job done once and for all.
Race Director
Joined: May 2006
Posts: 18,782
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Found the earlier post http://forums.corvetteforum.com/c3-t...dieseling.html
Looks like you never answered some of the questions.
What is your initial timing with vacuum disconnected?
Are you running ported or manifold vacuum to the distributor?
Did you adjust the secondary throttle stop on the passenger side of the carburetor, 1/2 turn from fully closed.
This is the solenoid http://www.summitracing.com/parts/HLY-46-74
Looks like you never answered some of the questions.
What is your initial timing with vacuum disconnected?
Are you running ported or manifold vacuum to the distributor?
Did you adjust the secondary throttle stop on the passenger side of the carburetor, 1/2 turn from fully closed.
This is the solenoid http://www.summitracing.com/parts/HLY-46-74
Last edited by MelWff; May 6, 2014 at 01:04 PM.
Drifting
Joined: Oct 2005
Posts: 1,529
Likes: 148
From: East London/SW Essex UK
I posted earlier about my newly rebuilt 427 running on or dieseling. I have checked and done all the recommended things. Timing is right on, carb has been rebuilt, idle set at no more than 750. All this done by a very reputable old time hot rodder, with dieseling being the complaint. I still have some dieseling. So the last resort suggestion by Lars and others was a throttle stop. Does anyone know of the "best" one to buy? "Best" being defined as getting the job done once and for all.
Thread Starter
Racer
Joined: Sep 2012
Posts: 262
Likes: 0
From: Roanoke Va.
Melwff- #1- I believe the timing is set @16. I just had my engine builder set it on the dyno. Plus the guy that just rebuilt the carb. said he checked it. I just have an old time timing light and not one of those fancy ones, which I believe is needed for this job. That's mainly why I left it up to the pros. #2- the vacuum line is hooked up from the vac advance on HEI dizzy to front of carb. #3- I have not touched any adjustments. Again, I was leaving it up to the shop that rebuilt the carb. It was/is running good besides the dieseling, so I really didn't want to mess with it. Besides, as you can tell, carbs are not my strong point !!! (Holley 750 CFM DBVL pumper.) Car is at front end shop right now getting front end rebuilt and aligned. I will see about that secondary adjustment this weekend when I get the car back. The good thing about all of this is I am about "through" (yeah right!!) with this "resurrection".
Thread Starter
Racer
Joined: Sep 2012
Posts: 262
Likes: 0
From: Roanoke Va.
Thank you very much for helping me. I thought about just bringing it back to the shop that just did the carb. But I figure if he knew how to correct the dieseling, he would have. That was the initial complaint. Guess I'll give it a try now.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Back when you posted you never answered this question.
On a new engine I would say that your spark plugs are the wrong heat range and the tips are so hot that they are glowing causing the run on.
In the last couple of months I have rebuilt two 427/390's To give them some more get up and go. New big blocks have lots of friction and run hotter. I start out with two ranges colder.
Another thing many old time mechanics don't understand timing or ignitions even though they claim to. If the mechanic set your timing at 16 at or near idle. 99% he doesn't understand initial vs full advance and adjusting the mechanical advance curve to limit the total
On a new engine I would say that your spark plugs are the wrong heat range and the tips are so hot that they are glowing causing the run on.
In the last couple of months I have rebuilt two 427/390's To give them some more get up and go. New big blocks have lots of friction and run hotter. I start out with two ranges colder.
Another thing many old time mechanics don't understand timing or ignitions even though they claim to. If the mechanic set your timing at 16 at or near idle. 99% he doesn't understand initial vs full advance and adjusting the mechanical advance curve to limit the total
Thread Starter
Racer
Joined: Sep 2012
Posts: 262
Likes: 0
From: Roanoke Va.
Back when you posted you never answered this question.
On a new engine I would say that your spark plugs are the wrong heat range and the tips are so hot that they are glowing causing the run on.
In the last couple of months I have rebuilt two 427/390's To give them some more get up and go. New big blocks have lots of friction and run hotter. I start out with two ranges colder.
Another thing many old time mechanics don't understand timing or ignitions even though they claim to. If the mechanic set your timing at 16 at or near idle. 99% he doesn't understand initial vs full advance and adjusting the mechanical advance curve to limit the total
On a new engine I would say that your spark plugs are the wrong heat range and the tips are so hot that they are glowing causing the run on.
In the last couple of months I have rebuilt two 427/390's To give them some more get up and go. New big blocks have lots of friction and run hotter. I start out with two ranges colder.
Another thing many old time mechanics don't understand timing or ignitions even though they claim to. If the mechanic set your timing at 16 at or near idle. 99% he doesn't understand initial vs full advance and adjusting the mechanical advance curve to limit the total
As far as timing goes, I don't really know the degree that it is set. Like I said, I left that up to the engine builder AND it was double checked by the mechanic that rebuilt the carb. The engine builder, Terry Walters, from Roanoke, Va. is a superb machinist. He has a stellar reputation and has been at this for over 30 years. Believe me, he knows his stuff!!! Chevrolet even farms out "new" motors to different machine shops around the country to try different parts combinations on a dyno. His shop has a 58something (572 maybe) CI. chevy engine right now that he is testing for Chevrolet. They are allowed to use different heads, intakes, etc. to see what aftermarket parts work good. He told me he currently has more than 100 hrs. of testing on that engine. My point is simply that the timing is not the issue. Now maybe the vac. advance or some other aspect of the timing is off or not working, but to question Terry Walters timing is like asking if the pope Is Catholic!!!!!
I will try the plugs though. Thank you for the suggestion.
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Thread Starter
Racer
Joined: Sep 2012
Posts: 262
Likes: 0
From: Roanoke Va.
I am having a hard time finding plugs. Can't believe it. Are these "colder" plugs all that rare? Only # that Advance Auto had was Autolite 403. None available unless I order em, which I guess I'll have to do. Auto zone didn't even list a normal plug for a 427!!! I think I just got an incompetent counter person!!! Anyone know the brand and some #'s for 1 step colder 427 plugs? Thanks PS- Ordered the throttle stop. Tired of this problem!!! Can't put car on market for sale with a dieseling engine, even if it is brand new!!