HELP! All Mechanical Eliminated- Wont rev past 4K

[sblake01]

The Cam is a performance grind on old stock.not just stock re-ground to stock - Not sure if thats even possible.

Does that description of the cam come from Al's ad? If that's the case, like they say, 'tain't necessarily so'.

[john mcgarvie]

sounds to me like the valves are floating im sorry if i miset if you changed the springs or not

[Seanw987]

Yes, thats from al's ebay ad. The cam looked to be in great shape(machined) and the springs are double coil springs.

Of course "looked fine" means with the eyes not a feeler gauge....

I dont that its the issue although with completely disassembling the motor, there is not way to be certain that everything is within spec.

dont forget the old motor did this too and only after tweaking the carbs a lot to give more fuel did it rev up to mid 5K's but still was not right 100%.

[Seanw987]

so your suggesting a cam swap?

[pit crew guy]

If I didn't know any better I'd say it is a linkage problem. I had that happen to me years ago with a 65 Mustang!

[ChrisZ]

so your suggesting a cam swap?

Don't swap cam, at least not yet, find out what you have in that build, all you components have, list it here and you might get some more help.

Chris

[sblake01]

If I didn't know any better I'd say it is a linkage problem. I had that happen to me years ago with a 65 Mustang!

You know, that's kind of what I was thinking or at least something to do with the carbs. Old engine did it, new engine does it. Are they the same carbs, i.e, the ones from the old engine swapped to the new engine?

[ChrisZ]

You know, that's kind of what I was thinking or at least something to do with the carbs. Old engine did it, new engine does it. Are they the same carbs, i.e, the ones from the old engine swapped to the new engine?

Post #1 states "carbs swapped"

I still think we need some more information.

Chris

[sblake01]

Okay. Then I've got nothing. I could probably tell him what was wrong if it was EFI:)

[280~Master]

Just because one part was taken off and replaced with another part there is no garantee that the replacement part was in good condition. Even when new....

I seen this before on cars but its usally a different problem on each one.

I don't think the engine is what is bad. Even though it was from Datsun parts LLC.

Could be cracked distro cap, bad plug wires being grounded on the head, bad replacement fuel pump, bad carb floats. For this type of problem its hard to tell you what it is when you can't see, hear, feel the car running.

[john mcgarvie]

Hay bud this is just a guess but i think your valves are floating. Are the valve springs new. Or maybe the springs need adjusted.

[sblake01]

I think there all guesses at this point. He's been chasing this one for a while. It could just be a coincidence that the old motor did the same thing. If he swapped carbs what else would both motors have in common? Perhaps something in the drive train? Like I said, just guessing.