Idles great / misses when throttled up

[kinger952]

Replaced cam shaft idles perfectly slowly gave throttle engine starts missing it is a electrical issue I turned distributor a bit and smoothed out - shut off started again same thing new cap/rotor wires pulled plugs all look fine but going to replace in the morning - any other ideas I'm not thinking of. ?

 

[QBhoy]

What engine ?

 

[kinger952]

What engine ?

Sorry. 350. Labeled as 260 on rocker covers

 

[kinger952]

Replaced cam shaft idles perfectly slowly gave throttle engine starts missing it is a electrical issue I turned distributor a bit and smoothed out - shut off started again same thing new cap/rotor wires pulled plugs all look fine but going to replace in the morning - any other ideas I'm not thinking of. ? 350 mercruiser labeled as 260 on valve covers

 

[itsathepete]

You need to put a timing light on it. preferably an advance timing light so you can see not only the initial timing but the full advance as well. need details on engine setup. Vortec or not? Carb, I assume but which one? What kind of ignition? Points? Thunderbolt?

 

[kinger952]

You need to put a timing light on it. preferably an advance timing light so you can see not only the initial timing but the full advance as well. need details on engine setup. Vortec or not? Carb, I assume but which one? What kind of ignition? Points? Thunderbolt?

Thunderbolt ign .
I have already done the timing light adv .
I'm about ready to trash the thunderbolt ign is it possible to use same distributor for this ?

 

[itsathepete]

What are your initial timing and full advance numbers? TB modules can go bad, especially aftermarket ones.

 

[itsathepete]

Also what kind of cam? Roller or flat tappet? If flat tappet, did you use good oil with zinc to break it in? If not, could have rounded a lobe

 

[kinger952]

Also what kind of cam? Roller or flat tappet? If flat tappet, did you use good oil with zinc to break it in? If not, could have rounded a lobe

Flat tappet good oil used with plenty of assy lube soaked lifters as well lobe NOT rounded new camshaft this happened from the get go on new camshaft that's why I replaced camshaft two lobed on old cam were gone .

 

[kinger952]

Also what kind of cam? Roller or flat tappet? If flat tappet, did you use good oil with zinc to break it in? If not, could have rounded a lobe besides I could of seen rockers not moving if lobes were gone already

 

[itsathepete]

Have you done a compression test? A valve slightly out of adjustment can reduce compression enough to cause a miss

 

[Bondo]

Have you done a compression test? A valve slightly out of adjustment can reduce compression enough to cause a miss

Ayuh,...... Or a lean condition,....

 

[kinger952]

Ayuh,...... Or a lean condition,....

Yes I have between 105 and 112 all 8

 

[achris]

Yes I have between 105 and 112 all 8

That's low... Verify with another compression gauge...

 

[kinger952]

That's low... Verify with another compression gauge...

I will do that

 

[kinger952]

So now I go out and turn over engine and NO SPARK so I will check out distributor pickup and module

 

[achris]

Have you read through my document on the ignition system (link in your other thread)? If you have no spark, follow the fault-finder chart near the bottom of the document. One other thing I suggest to everybody (whether they are having ignition problems or not!) is to run a dedicated ground wire from the distributor body to the engine block. Also, if you still have the original 2 wire sensor, get the 3 wire!

Chris........

 

[kinger952]

Have you read through my document on the ignition system (link in your other thread)? If you have no spark, follow the fault-finder chart near the bottom of the document. One other thing I suggest to everybody (whether they are having ignition problems or not!) is to run a dedicated ground wire from the distributor body to the engine block. Also, if you still have the original 2 wire sensor, get the 3 wire!

Chris........

Thanks Chris I have had little if any extra time I had to sneak out just to work 5 minutes on the issue ( kids are in town from Portland) I 3will try to read tomorrow if I can thank you for all the info

 

[kinger952]

Have you read through my document on the ignition system (link in your other thread)? If you have no spark, follow the fault-finder chart near the bottom of the document. One other thing I suggest to everybody (whether they are having ignition problems or not!) is to run a dedicated ground wire from the distributor body to the engine block. Also, if you still have the original 2 wire sensor, get the 3 wire!

Chris........

Looked for it this morning - I must of lost it can you send it to me via email ? Dave95299@gmail.com

 

[Scott Danforth]

Yes I have between 105 and 112 all 8

if this is accurate, you need to pull the motor and do a complete rebuild on it. the motor may run and it may idle, however it will not have any power

did you over-tighten the rocker adjusting nuts?

the ignition troubleshooting guide is in the stickies (adults only) at the top of the link