4.0 Head gap tolerance?

[RussAdams]

I put a straight edge on my heads today. They are off due to an intake manifold leak. I'd already loosened the driver head so in for a penny in for a pound.

The passenger side is great.

The driver's side head has a small gap on either side of the middle cylinder.

I can get a feeler gauge .005 under the straight edge, but not a .006.

Does anyone know the allowable tolerance?

Do I have it resurfaced or is it ok as-is?

Thanks everyone!

 

[RussAdams]

They are EngineQuest heads by the way.

 

[pentode]

Old Alldata says .003 over a 6 inch span, .006 overall

 

[RussAdams]

Old Alldata says .003 over a 6 inch span, .006 overall

Thanks Pentode! Sounds like I'm good to go. Russ

 

[pentode]

Assuming you used a full length straight edge, I’d say you should be good. I don’t have another manual at hand to double check but those numbers sound sane to me. Good luck!

 

[RussAdams]

full length straight edge

those numbers sound sane to me

Good Luck!

Yes, it's a USA made 2 foot straight edge.

Thanks for the wishes!!! I'm in need of them on this project.

 

[pentode]

Hopefully one of the mechanics/engine builder guys will jump in to confirm.
Putting it back together is the fun part

 

[gaz]

@RussAdams
In reference to your "in for a penny, in for a pound",

Having them resurfaced, if needed is not a great expense... additionally it would be a great opportunity to let a reputable machinist do a performance valve job. While I do not know the history or use of this engine, if it has anywhere near 200k it will benefit from a solid valve job. No dought the guide are worn and the seat would benefit.

I have not checked the prices lately but I expect the head mill to be $200 and the valve job $250 not including replacement components (though valve guides and seals are very inexpensive).

 

[RussAdams]

if it has anywhere near 200k it will benefit from a solid valve job. No dought the guide are worn and the seat would benefit.

I'm just starting to take the valves out.

I had to torch some of the exhaust manifold bolts and want to replace the seals in case I torched em.

The first valve is out and looks in decent shape. But the guide is pretty sloppy. No sucking sound when I pop it out.

 

[19Walt93]

You already have it apart, have the heads done now so you don't have to do the job over again.