M20B25 Head mods

[MR 325]

Purchased a Seta bottom end with a rebuilt b25 head. + 272cam, hd rockers and 19lb injectors. Chika chika what!?

Very nice! You will love it.

[nando]

Purchased a Seta bottom end with a rebuilt b25 head. + 272cam, hd rockers and 19lb injectors. Chika chika what!?

score! now ditch the stock ECU and/or get a tune, it will really wake it up.

[SkiFree]

Please, elaborate...

;)

For posterity on the reground cams



The factory M20 eccentric allows for approx. 0.060 of adjustment. If the base circle of the reground camshaft is reduced more than .060 (The original factory cam base circle is approx. 1.1", so you'll measure the difference on the reground cam) then you will obviously no longer be able to adjust the valve lash with the factory eccentric.

Oversize eccentrics will offer an additional .060 of adjustment.

[dude8383]

Very nice! You will love it.

score! now ditch the stock ECU and/or get a tune, it will really wake it up.

Werd. Mike picked this up from me. Can't wait to see where the build goes :)

[Tree25]

For posterity on the reground cams



The factory M20 eccentric allows for approx. 0.060 of adjustment. If the base circle of the reground camshaft is reduced more than .060 (The original factory cam base circle is approx. 1.1", so you'll measure the difference on the reground cam) then you will obviously no longer be able to adjust the valve lash with the factory eccentric.

Oversize eccentrics will offer an additional .060 of adjustment.

I have the IE billet 272... Would it be stupid to use the stock eccentrics?

[Tree25]

Werd. Mike picked this up from me. Can't wait to see where the build goes :)

Denis really hooked me up with the setup! I was researching the same one forr a bit now and so it happens he was already finishing up the build. Really a great guy. Thanks again Denis

[MR 325]

I have the IE billet 272... Would it be stupid to use the stock eccentrics?

I've seen many M20 heads with aftermarket cams and have yet to come across one that needed oversized eccentrics.

[mRodiek]

Some good info on here! Minus the S50 talk lol

[SkiFree]

I have the IE billet 272... Would it be stupid to use the stock eccentrics?

On a billet 272 cam you would not be reducing the base circle and therefor not need the extra adjustment.

On a Mondo-big billet cam you might need to go with oversize eccentrics as once you reach a certain point you will need to reduce the base circle to achieve the higher lift.