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modded engine - please help

aknight_sa

aknight_sa

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guys,

i have two problems about a modded engine i just installed, the first thing is when the car is cold and start it, it wont start unless i keep my foot on the gasoline peddle for a while as if i dont do that.. it will just go off...the guy who wants to sell it to me says that that is normal with modded engines..


second thing, after installing it on my 81 jimmy the car wont stay on specially when its on D (automatic)... so now i cant keep the car on.. the said that he was told that that is normal with automatic transmission.. anyway, i am returning the car as i cant drive it this way... is there a solutions for such problems...

Thanks
 
sounds like carb troubles.

need to mess with the choke and the idle speed.
 
If you have any specs on this engine (lift, duration, heads, compression, etc.) you should let us know. It could very well be carb trouble as well. If you know any info about what carb is on it you should let us know that as well.
 
here are the specs of the engine

CHEVEROLET RACING ENGINE, SMALL BLOCK 350, V8, 1983.

1. NEW SPECIAL OVERHAUL ENGINE.
2. NEW CAMSHAFT, SOLID 292 (LUNATI) CO.
3. NEW VALVE LIFTER, SOLID (LUNATI) CO.
4. NEW VALVES SPRINGS.
5. NEW HEAD COVER STANLES STEEL, 1.7 (EDEL BROK) CO. *
6. NEW RACING SPARK PLAG, (NGK) CO.
7. NEW DOUBLE AIR FILTER MEDUOM SIZE (EDEL BROK) CO. *
8. NEW AIR FILTER COVER STANLES STEEL, (EDEL BROK) CO. *
9. NEW CARBORATOR, 750 (DEMON) CO. *
10. NEW FUEL PUMP (350) GM.
11. NEW KIT DOUBLE CRANK AND CAMSHAFT POLYS & SPROCET SHAIN.
12. NEW KIT MSD IGNITION 6A. *
13. MSD DISTRIBUTOR. *
14. MSD COIL. *
15. MSD SPAK PLAG WIRES.
16. INTAKE MANIFOLD, (WEIAND) CO. *
 
292 is a whole lot of cam for a 350 in a truck. That is most of your problem, the engine will not make much power at lower RPM's and therefore has more trouble getting the vehicle moving. Assuming the problem only happens when the vehicle is cold, make sure that the choke is working properly. Otherwise, just raise the idle until it runs ok (with that much cam it may even need to idle above 1000 RPM).
 
when the car is warmed up it will stay on when on Nutral or on park.. the problem of staying on while i shift to Drive or when i slow down to almost stopping remains..
 
Sounds to me like a possible vacuum leak.

Heavily modded engines act that way too, so I wouldn't discount that, but every carbed vehicle I've seen that has had a vacuum leak has problems staying running in drive unless the idle is cranked up far enough to "hide" the problem.
 
You'll need a looser torque converter as well. If you have the idle cranked up where it wants to be, the low stall of the torque converter is pulling on the motor. It is not making much torque at this low of an RPM, and can easily be overcome by the drag of the tranny.

Did I say that right? Make any sense?

With the parts descriptions you are given, I would seriously doubt the compatibility of the parts used in the build. I mean chrome things are not made of stainless steal.

Is the solid cam adjusted properly? Is the carb adjusted right? Timing? This motor will require more fine tuning than your typical SBC....
 
This might be a jewel in disguise, as the previous owner might not have been able to make it run right, and is just getting rid of his headache.

I'd like to know more about the heads and intake.

That is a fairly decent list of parts, and may just require a cam and lifter swap to make a great motor for your truck....
 
i did find a gasoline leakage.. we tried to fix it at the gasoline pump.. but there is still gas comming out from somewhere
 
Could it be a clogged fuel filter. Always check the basics first. I would check the Fuel pressure just before going into the carb.
 
38377k5 said:
292 is a whole lot of cam for a 350 in a truck. That is most of your problem, the engine will not make much power at lower RPM's and therefore has more trouble getting the vehicle moving. Assuming the problem only happens when the vehicle is cold, make sure that the choke is working properly. Otherwise, just raise the idle until it runs ok (with that much cam it may even need to idle above 1000 RPM).
Click to expand...


38377k5... you hit the point exactly where the problem is... i just took the car to a guy who is experienced in modding 350 engines.. and he just asked about the camshaft and when we said it was a 292 he said the same exact thing that you said...

my question now is how can i solve this problem.. i was told that i should do one of the following:

1. change to a standard camshaft
2. change the torque converter
3. change to manual transmission

what do you think? or should i just raise the idle?? please give me your opinon..


thanks
 
You just need a smaller cam. Once you swap out the cam, the converter you have will be fine. You need to find out what compression ratio your engine is, because if it is a high compression engine a short duration cam is going to really bump up your cylinder pressures. This could leave you with an engine with some hefty octane requirements, so make sure to get all of the details on your engine and call or email a few cam companies, you'll save yourself some big headaches later.
 
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