Leaded / Unleaded Head

[Guest Graham]

Hi Folks,

 

I've just received a head with a FR32 cam fitted ( 2 litre pinto), however I now think it's an unleaded head.

It was my intention to carry out a bit of porting over the winter as per Dave Andrew's instruction data. I was wondering if its worth fitting hardend valve seats to it, I don't have any problems with machining or fitting as I have access to our machine shop and can easily fit the seats with liquid nitrogen. Problem is I don't know where to get hardened seats or what the interference fit should be.

 

Any advice welcome

 

Graham

[Guest Battery Bill]

Graham

If you look on the internet regarding Hardened valve seats you might find the article I found when we Got our Donor "Ltr EFI" the article seemed very well reaserched and clearly stated that the need for "Hardened valve seats" was not necessary. It basically said that the manufacturers, rather than risk a future lawsuit regarding their heads just say "Yes it needs hardened valve seats". Then they are rid of any future problem.

Now of course I am no expert but this seemed to be a pretty persuasive article.

I myself have always run my cars on unleaded since 1987 (Cos I'm a cheapskate OK) This includes a Marina, a lot of Japanese cars and a Cavalier SRI with nearly 200k on the clock.

This post might grow a bit I'm sure.

[Peter Bell]

Graham if you do a search on this section you will find a recent thread showing the id. letters to tell if yor head is for unleaded or not. The simplest solution is just to start with an injection head which will have the inserts anyway, it also has a better shape in the inlet port where it sweeps around to the valve so less work required in that area, and it is mostly the exhaust side that needs the work.

Regards Peter

[Guest Takumi]

the Injection heads have hardened seats already, notice the bad match between the edges of the pressed in seat and the rest of the port throat. Ive smoothed mine down , so you cant see the join.

 

note: worth having 3 angle vale seats cut, and muich higher compression. longer duration cams only work well at high cr & high rpm. so have 1.5mm taken off to up your compression to 10.2:1 ( most you can have on cheap fuel, still splash 250ml of acetone in the tank too, just to be sure.)

 

After taking my Inj head (which I had been gas flowed) to COLTEC RAcing Engines, the boss guy, said 3 angle seats will help the gas flowing alot, @ £6.00 a seat, I almost choked ( as im poor), but bit my tongue and siad 'do.it' along with a 1.5mm skim. which was £45.00

 

happy porting..

 

 

tak.