I have this fresh motor that I have been building for about two years now. Everything is either new or rebuilt. So I take it to a local buick shop with a great reputation. They did a great job, they did some last minute things and got the engine going. Now that the car is home, there are a few things that worry me... When the car starts, it idles rough ( which is what I expect from TA's 500 hp street cam .499 lift I think). It has a good strong idle to it, but when I give it some gas, it hesitates, almost like its being choked out, or not getting enough air or gas. I saw everything they did at the shop, and it seemed to me that they checked everything, and took every precaution. I dont think its anything they did, they were great. I am new to building cars ( incase you couldnt already tell) and am a little nervous. They said it was ok at the shop, but Id be afraid to get on the road with it. I was backing into the garage today and it crapped out while backing up. I have checked everything I can think of. I believe the carb is an electric choke. I dont know how they work, maybe thats the problem? There is almost no exhaust, so I dont think thats it... Any suggestions are greatly appreciated. Rob
one more thing... Also today I noticed that the short hose going from the water pump to the intake seems kinked, or crushed by pressure. I plan to replace it immediatly even if its not important, but could that be part of my problem? Does the electric choke need to be hooked up to a vaccum port or something to work? I have an electric fuel pump, thats brand new, so i dont think that could be the case... Thanks, Rob
Rob, First off, what carb are you running? A slight hesitation usually is accelerator pump related, but could also be a timing issue. We really would need some more information in order tohelp you out. Jim Burek
When you add a big cam, the carb and ignition timing need to be calibrated to it. The carb will need to be jetted properly for idle and WOT. The distributor will need to have the curve redone to match the cam. Suggest you find a shop that uses a wideband air/fuel meter. This will allow you to dial in the carb and ignition perfectly. When I ran my new engine on the dyno, the carb was way too lean. Running the engine lean will damage the pistons.....
reply... Ok..here is what I have in the engine.. barry grant speed demon 850..converted from annular to down leg by them Mallory unilite breakerless dist T/A SP1 intake T/A 500hp street cam T/A Adjustable pushrods & roller rockers Stock harmonic balancer ( engine was er-balanced ) Federal Mogul power forged 10:1 pistons ( butterfly cut ) 69 430 Iron heads port matched & upgraded to stage 1 specs 70 block decked .30 Im not sure what else I could say that would help. When they did the startup, they set the timing, but Im not sure if they compensated for it. I did see them make some adjustments to the electric choke, but im not sure how that stuff works. Any advice is appreciated, I am mainly a body guy, and am new to all this. I am getting killed renting a trailer and trailering the car to different places, but live in the middle of nowhere, and the local shops are pretty basic. Please keep the advice coming. Thanks, Rob
Question "T/A Adjustable pushrods & roller rockers " Why would you have adjustable pushrods with roller rockers? uzzled: o No:
adj. rods & rockers... If my memory serves me, because I decked the block, more adjustment was needed than the roller rockers could offer alone.....I did that part of the engine last year, so I think thats why.... o No:
Rob, Pull a few plugs and take a look at them. If the electric choke isn't right, it could have fouled the plugs. That would explain your symtoms. Also if you dont have a dial back timing light, get one. Sears sells a really nice one for around 70 dollars. There is alot of info on this board, all you have to do is run a search for it. Then start reading, and ask questions when you don't understand something. It's not difficult, and we're here to help.
reply OK guys, Ive pulled the plugs and they look like charcoal... Also Ive had a few guys ask if the oil smells like gas, and I didnt think it did the other day, but i just checked it now, and it does. What does all that mean? I have never timed an engine before, but I saw them doing it after the engine started. All I know is that Ive heard lots of engines, and you can hear ( a least to me being a musician ) hen its in tune, and mine is not. I am trying to find a way to record a sound byte and post it here, but so far no luck. I have a friend that helped me build the engine, I am going to ask him to give me a hand timing the engine, but please keep the input coming, Im learning a lot. Thanks again, Rob
Rob, Change all the plugs. Then start the motor, and make sure the choke opens up as the engine warms up. Your plugs are carbon fouled. This can result from a choke that doesn't open, plugs heat range to cold, or weak ignition. The timing is probably fine if it was set correctly, it probably was. If the choke opens, and the plugs still foul, the carb may need to be adjusted or jetted leaner.
reply I'll do that. I forgot to mention the ignition. I have a MSD 6AL and a mallory promaster coil. I use champion plugs. It almost seems as though the choke isnt working because the car doesnt want to start when its cold, but when its warm it fires right up. Its about 40 degrees this time of year here in jersey, and the other night I went to fire it up, and it was about 25 or so, and it blew a lot of black smoke and wouldnt stay started, and after that was when this crap started, I can only assume thats when the plugs fouled. Is there anything else I can check to give an idea as to what the problem could be?
It sounds like a timing issue. generally if the choke is closed it will run rich but then if the choke stays closed it should start easier in cold weather. so these two problems are almost contradicting eachother.
When you set the choke, the choke blade will close over the carb throat. When the engine starts, the choke should open about 1/4". On a stock carb, there is a vacuum operated choke pull off, that opens the choke soon after the engine starts. This leans the mixture so that the engine will run without loading up. Normally, I would tell you to check the pull off, but I'm not familiar with your carb. You may need to adjust the electric choke, it may be set too rich. If a carb is jetted right(a little on the rich side), you don't need a choke. You may have to feather it to keep it running when cold, but once it warms up, it should be fine after that. What Champion plugs are you running? I would change the plugs, disconnect the choke, and see if everything works out.
Hi ROB, What heat range were the Champion spark plugs? I've always been a big fan of Champion plugs. Work great in a small block Chevy. I found that they do not do well in a big block Buick. Try an AC plug.about a R44TS. You are running way too rich. JOE
Is that a vacuum secondary or double pumper carb? If the former and you changed cam the vacuum signal change may adversely affect the power valve operation. Never mind - I see the power valve.
Yes, I just did this myself, but my block has never been milled. My original rods were fine, and were within spec after adjustment, but after you set zero lash on the valve, you must pre-load the lifter 0.030" to 0.060" if I recall. 60 mils is considerebale distance, the pushrod can be too short, or in your case probably, too long. TA warns in the instructions provided that adjustable pushrods may be needed, so I'd say you did just right. Those roller rockers are soooo much nicer than the stock units. It's a shame to cover them up
reply Joe, I agree, AC is definatly my second choice...I will try those, thanks.... Brad, I believe its a double pumper... Chris, Yes, now that you mention that is it....it was last year and my memory is a little fuzzy.... Also guys, I looked at my car last night and the choke plate is almost closed, maybe 1/4in opening....and something that one of you said made me think. I think my aircleaner is hitiing the choke plate and not allowing it to open. That would explain why they timed it at the shop and all was well...the aircleaner was off.....does this make sense? Please let me know your thoughts..... Thnkss guys ( and gals, I know its a new millenium ) Rob :3gears: :beer
reply Some new news... I just called Barry Grant and asked them about my problem... The duration is 290 intake and 308 exhaust on my cam. I was told that my carb is set for 240 and below. I imagine that there is some adjustment that can be made, but I guess I should have bought a bigger carb.... Rob
