Valve spring shim ID too small

[turbovan]

I’m attempting to setup a pair of ported j heads and found that my valve spring height was roughly .018” too high. Although I believe that equates to only 6lbs on the seat I decided to order some shims. They are .015, 1.437 OD and .645 ID.
Just received them and realized the ID of the shims are too small because there is a .98” x .125 step just above the seat. Similar step on the retainer. My other set of J’s has this same step.
Should I buy a 63/64th drill bit and ream these things out? Or should I just skip them?

Cam is a summit 228 @ 050 480 lift single pattern
Comp 942 springs @ 1.718 installed height
Rockers are 1.6 intake, 1.5 exhaust
Torker2, and 650dp
‘80 360 stock bottom end and pistons

 

[billsdartgt]

it seems popular opinion is having shims, can you get different ones that would work?

 

[turbovan]

it seems popular opinion is having shims, can you get different ones that would work?

This is pretty new to me so it’s more than possible I don’t know how to look, but at this time I can’t find any shims with an inside diameter that would suit my heads; all too small. I searched for a few hours....
I feel like drilling them out would be pretty straight forward with the correct bit.

 

[billsdartgt]

wouldn't hurt to open them up to fit, since you already have them

 

[Marcohotrod]

what are the measured installed heights? what are the measured spring loads at these heights? what loads does the cam want? how high do u plan to rev to? usually spring seats are machined to fit non stock springs and shims. if u want the extra 6 pounds drill away

 

[nm9stheham]

Drilling out those thin shims is probably not going to work well. A reamer ought to be a lot better.

Just curious: Are you using some +.050 retainers? That installed height is higher than normal.

 

[PRH]

Using the std “VSI” numbers...... the “103” series shims fit those heads(1.500 x 1.031).

A- .060
B- .030
C- .015

Add HP for heat treated.
So- C103HP for heat treated .015” thick.

I think you could buy them in 16 packs from Competition Products.

That being said, you’ll want to measure the installed height of all the valves.
If the worst offenders are only .018” too tall...... I wouldn’t say the extra 5lbs is mandatory in that application.

 

[turbovan]

I measured the installed height at 1.718.
Haven’t measured spring seat load; just calculated.
Ferrea valves and retainers came with heads; don’t know if they are +.05

At time of purchase summit did not list a recommended spring, simply that it would not work with stock springs. Looking today they have some spring recommendations in the comments section below the cam listing 901s but then also stating they need 120 on the seat?
I don’t have a RPM goal, but want to be sure valve is controlled to wherever the engine makes power; summit states 2,500-6k rpm so I probably won’t take it past 6200 but heads are the wildcard. Before porting the engine was about done at 55-5600

 

[turbovan]

Using the std “VSI” numbers...... the “103” series shims fit those heads(1.500 x 1.031).

A- .060
B- .030
C- .015

Add HP for heat treated.
So- C103HP for heat treated .015” thick.

I think you could buy them in 16 packs from Competition Products.

That being said, you’ll want to measure the installed height of all the valves.
If the worst offenders are only .018” too tall...... I wouldn’t say the extra 5lbs is mandatory in that application.

thank you very much. This helps a ton

 

[mderoy340]

I would run the 942 springs with .015 shim. You could use a dremel with a stone to open the shim diameter and save some money.

 

[IQ52]

About the shims..................You are going to hate life if you try to enlarge the hole in those hardened shims. Order the ones Dwayne has suggested.

 

[Marcohotrod]

many have posted that going by published spring loads is often off. a shop may test a few springs for cheap $. might be worth a measure before spending time and money with shims guessing what may be needed