New engine, popping under boost??

Do you remember when you had mine on the dyno? It ran good until you got on it and started sputtering. Turned out to be a burn plug wire.

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Originally Posted by farmtruc

valve float at 4krpms and 3psi with good springs, probably not, but i'll check the springs, a bad spring could cause valve float.
could be poor sealing valve, i'll check that.
cam in straight up, runs too good under no boost conditions.
fuel pressure, rock solid! a1000, -10 line everywhere, aero fpr.
no maf
i hope it's not ckp or wheel, that would suck!
i don't think it's the wrong wheel, it would backfire and spit randomly and a lot more often.


changing those tomorrow.

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fuel pressure regulator? :lol:

At least we won't know what fixed it since have the engine was replaced all at once.....:LOL:

Shotgun approach worked hahah!

I can rule out plugs because I did in fact change those, that's a lot easier than heads I guess.

I installed the same wires and coils.

The only difference are the heads, now I'm upset!

Here's the story; I sent off some perfect condition heads to a shop, I changed my mind and requested my heads be sent back, when I got my heads back, they had been in the vat machine, cleaned and different valves were in there.
I was told they "cleaned them up".

I was always doubting that because the heads I sent off were in perfect condition, came off a running turbocharged truck (with only a few miles on it) and there wouldn't be any reason to clean them up.

I think I got some heads that were sitting in the corner.

So, if the problem are the heads, bent valve, bad seat, etc, what do you think?
Springs are brand new, I put them in there.

let me know,
allen

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Originally Posted by farmtruc

So, if they are the heads, bent valve, bad seat, etc, what do you think?

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One of those. Now put them back on and let's do a leak down to find out. :dancenana:

If you have a short block lying around and a beernight you could try them on that. You can also turn the head over with the chambers sitting up and the deck level and pour some solvent in the chambers and look for the valve that drains into the head. This will show a leaking seat. Take that valve out and then check it for straightness. If it's straight, the seat or valve job is the problem.

Sounds like scum to me.. its everywhere

get em allen!

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Originally Posted by GasGuzzler

One of those. Now put them back on and let's do a leak down to find out. :dancenana:

... This will show a leaking seat. Take that valve out and then check it for straightness. If it's straight, the seat or valve job is the problem.

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Ok, I just tore the engine down and I'm going to reinstall the heads to do a leak down, LOL yeah right!

I can turn them upside down and fill the chamber, that's about all the time I have.
I'll just sent them off to the machine shop, have them shaved, reworked, valve job and new valves put in them.
Oh well.

Quote:

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Originally Posted by farmtruc

Ok, I just tore the engine down and I'm going to reinstall the heads to do a leak down, LOL yeah right!

I can turn them upside down and fill the chamber, that's about all the time I have.
I'll just sent them off to the machine shop, have them shaved, reworked, valve job and new valves put in them.
Oh well.

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JR the guy who does the head work up here is freakin awesome. PM jon or kurt an they will get you his info.

i use a guy who build outlaw altred motors in waco, he does amazing work and is very fast