Hi all.

To cut a long story short, i have problems with the fact that my Ferrea 1mm oversized valves makes contact with my JE "Off the shelf" 85.5 pistons, this was discoverd during final rebuild.

So now im looking at new pistons, or having the valve cutouts on my JE pistons reworked for larger valves.

I just read some thread here at MLR that JE pistons have cutouts for standard size valves, not bigger ones. To bad i didn"t read that earlier :wallbang:

My question; Do you think it"s ok to rework the pistons i have, enlarge the cutouts so they can handle my larger valves ? Will this have an impact on the reability of the pistons ? I have an experienced workshop that can do the job for me.

If new pistons is needed, where do i find 85.5 pistons that have larger valve cutouts sufficient for my +1mm larger valves ?

Short spec:

Evo 8 engine.

Fully built head, Max ported - polished - Ferrea valve guides - Ferrea +1mm oversized valves - 37mm exhaust valve seats - Ferrea valves seals - 3 angle valve seats - GSC S2 cams - GSC Single spring with titanum retaiers.

Both the head and block have been decked (Minimum req)

JE 85.5 Pistons - Eagle rods - Evo 8 MR headgasket - e.t.c 2.0L

Need to know your thoughts asap, so i can order new pistons if needed.

Brgs Axel

 

I would just get the valve reliefs cut out on the pistons you have. You can actually do this in the car using a piston notching tool. I am not sure where to get one but i have seen it done.

 

Really ? Well the pistons have allready been removed from the engine, so i might pop by the engineshop i spoke to today and see what he can do.

 

the 1mm valves are .040 larger thats all. The pistons can be fly cut for valve reliefs , or have the reliefs opened up on what you have. Sounds simple enough.. good luck.

 

Yeap, one think that 1mm larger diameter valve wouldn"t make such a mess.

Well, i"ll have to see tomorow what happens.


More info is welcome !

 

bump

 

The pistons can be flycut while installed, so there was no reason to remove them. The procedure is as follows:

Apply some grease to the valves on one cylinder. Install the head and rotate the cams until the valves make contact. Remove the head and note the location of the grease on the piston. You will need to note and cut the areas with grease, and use this as a template for each piston.

Tape off all the water and oil holes on the block deck. One at a time, bring a piston to TDC, tape off the others (we don't want aluminum shavings in the engine), and carefully do your cutting.

When all is done, the best prospect is to apply a little WD40 to the surface of the piston and the valves, and putty each piston, attach the head, and turn the crank. You want to have at least 0.060" clearance on the intake side, and 0.080" on the exhaust.

Be prepared to install and remove the head quite a few times to do this correctly. Don't feel bad about it, I had to do the same thing, and all is well now.

 

A local domestic tuner actually has a bit that acts as a valve. You put each piston at TDC and used the "valve bit" to grind a relief in the piston. It is actually pretty neat. He only had to turn the bit by hand, any power tool would cut right through the piston. It was pretty neat, very labor intensive though.

 

Yes, I've seen them. I know Isky sells them, and probably others.

In any case, you will have to have a steady hand and be patient and calculating with it.