Most likely yes. You should at least measure one or two and preferably all. Jegs has a nice variety pack of shims and a vavle spring micrometer. Not costly either. Many find it takes up to a 0.060 shim to get back to stock. Do not forget there is a seal boot with a built in shim that you need to count when you use the valve micrometer. Its .045 IIRC. I just posted a bunch of specs from the valve spring install on my motor. PowerStrokeNation - View Single Post - Rebuild Update

 

I didn't shim mine and there doing fine..

 

Really??? Have you read about many others not shimming them.

What did you buy at BRAINS Truck Shop? LOL.

 

Depends on what you read I guess. No disrespect TARM, I have learned a lot from you and I am still trying to figure out what to do.

Wickky, with the 1.15 housing, how does no-wastegate affect things? I have read about the possible surge issues with the 1.0 at low rpms but I wonder about the wastegate.

 

What you want to do is MEASURE. You are already doing that. You also are having machining done to the seats valves etc. Tell you what shoot a PM or give Dave @ swamps a call.

But there is no reason at all with 910 that you would ever not want to have your spring height set to what the stock spec is. That means on almost any engine with some miles and or head work done on it you will be shimming. I think your builder was talking about height without the seals on as that is the only way to use a valve spring micrometer. With it in you are looking at 1.75-1.76 to be in spec. That will give you 134lb seat pressure.

Consider this. Take your max boost and subtract that from seat pressure. That is what you will have then.

Factory new is 110lb so its not like you are jumping up much. But what about when things begin to wear. All springs loose tension slowly with each and every compression cycle. Think stock 110lb springs @ 100K miles only have 70 lb seat pressure.

 

This is all new to me.... I have a Mustang with a 331 hydro roller engine and when I put springs in it I did not shim or measure.... just slapped them on and that thing hits 7k rpm no problem....

My question to you Tarm is what size shim do I need to run in order to get the best/ideal spring pressure?

Killa with stage 2's that are currently in the truck the 1.15 rocks... never ran it with the 1.0.... no surge or anything that I can report.

 

No I haven't but I am only running them for another year then I'm building the motor and go with hypermax springs.

 

Happy now?

 

Would it hurt to just put a .030 shim in when doing the 910 valve spring???

My engine has i little over 200,000 miles on it..

 

Won't hurt, we measured mine and with new valves, we used .030 shims to attain around 116lbs and 1.775" install height. Without new valves, you may be able to shim more but you may want to measure them with a micrometer.

 

OK thanks