Ferrea/BrianCrower/Head Work Q's

[dumbo]

Ok here's the story.
I bought the Ferrea 1mm OS valve kit off of SIP, with a stage three BC cams.
I had my head port/polished and built by and engine builder so I'm more or less relaying the message, haven't got a chance to see it.

He phoned me the other day and said he was having trouble setting the valve clearance on the exhaust side. The intake side was no problem, close to stock.(Which apparently the BC 272's base circle is identical to the stock 7m cams, so that side is good.) None of the shims come close, about
.080"-.085" clearance. And if he swapps the intake for the exhaust cam the problem stays with the exhaust side, so it isn't the cams.

So either the valve itself is the wrong part number(wrong one) or the seat wasn't machined for the 1mm over valve,...right? The shitty deal is the head is allready bolted to the bock

I know there isn't much of a question there, but please any input from either personal or word of mouth. Lets hear it.

 

[TweeT91109]

Umm try looking into a different head...not to put on the car, but like a test head...see if the problem still occurs with stock valves, cause that 1mm of over size can be causing the problem. The only reason I say this is, maybe BC used a stock head to develop the 272's. If this is the problem, get stock valve sizes from Ferrea, if you can that is...

 

[IBoughtASupra]

If youare grinding the valves and adding bigger cams, you will either need to grind the shims to get the right clearances or buy new shims. If grinding them, remember to soak them in cold water since they expand when it heats up.

Your machinist should know this. This will always happen with bigger cams and grinding the valves.

 

[dumbo]

Ahhhh ok....Any good advice out there?

No I'm just having a fucking bad day guys sorry, then my damn engine. The base circle is the same as stock, and the overall valve length is the same as stock. So either the valve is to short or it isn't sitting in the head far enough right?

 

[TweeT91109]

Ahhhh ok....Any good advice out there?

No I'm just having a fucking bad day guys sorry, then my damn engine. The base circle is the same as stock, and the overall valve length is the same as stock. So either the valve is to short or it isn't sitting in the head far enough right?

Ok so do what the guy did above your reply said to do, regrind the shims to get them clear....

 

[adampecush]

i think you are misunderstanding...grinding the shims isn't going to close the clearances. If the valves are sitting too far off the seats, the clearance is going to be opened up considerably. I'd try to have the machine shop check out the seating of the valves with a boroscope if you don't want to remove the head. If the valves are indeed installed wrong, they should be footing the bill. If the valve length is correct, and the valve head dimensions are also correct, they likely didn't ensure the valves were correctly seated.

I suppose the shop could always make you a new set of shims as well, but you'd run an increased risk of spitting them out.

 

[dumbo]

The higher the shim the easier it is to spit them out I guess eh? I talked to him and he's getting a stock 7m cam for a comparison before the head comes off. I really hope the head doens't come off but do you guys think the hg will be ok to reuse? It's a HKS Stopper 2mm. ARP studs.

 

[87M-GTE]

Yes, you can reuse MHGs.
As long as you clean off the black coating on it first.

 

[dumbo]

Well he had the head off and the seats are correct. The valves are also the same everall length of the stock ones. And he also compared the stock base circle to the stage 3 BC cam. Everything checked out and he doesn't get it, but he ordered taller shims and she's gonna be done next week Good enough for me.