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MG MGB Technical - 1.625 intake vales in CAM 1006

Restoring a '72 bgt. The head shop called yesterday and said the head is cracked in two places. I have a later head, CAM 1106, that I plan to use. I know that the rear rocker pedestal needs to be replaced to match the oil feed holes. Can the larger, 1.625" intake valves be installed in the 1106 and is this a good idea? I'm looking for some modest performance gains with head improvments.

Thanks, Tom
Tom Custer

Tom,

just changing to the some what larger inlet valves will not boost the perfomance in any usable way. If you intend to change the timing gear for the 18G version, it will show a little improvement, but even then not very much. It is a good idea to have the ports clead out and 3 angle valve seats cut for the inlet valves on this occasion and you will gain an average plus in the region of 5% with this mods.
There will be further advantages if the head is ported and gas flowed but you should also considre an other cam then, a higher CR, reboring and other pistons, a modified dizzy, other carbs, exhaust manifold and system, lightening and ballancing the crank gear and flywheel...

Ralph




Ralph

I should have checked the spelling on the subject line! Ralph, basically the only mods I plan to do are to rework the head and use a mild road cam.

Tom
Tom Custer

Tom-
I think that you made a typo. Yow meant to say CAM 1106, right? The larger intake valves will do nothing for performance unless you increase the size of the intake ports to compliment them. Peter Burgess did these same modifications with the CAM 1106 head that I had on my previous engine and the results were excellent.
Steve S.

Tom,

This is exactly what I am doing. I am going to have Sean Brown do my head. With a supercharger on my MGB having a cylinder head with 1.625 intake valves, professional port and polish, 3 angle valves, bronze guides can only add to performance. Also the CAM 1106 has redesigned cooling passages that help with higher combustions chamber temperatures.

Ray
Ray 1977mgb

Thanks for the info gents. Yeah Steve I meant the CAM 1106. Is there anything especially tricky about enlarging the intake ports or is this something that should be fairly routine for a fellow whose primary business is building performance heads?

Gracias, Tom
Tom Custer

I had 1.625" valves installed in my 69 head when it was in for seats and guides plus porting and flowing bench work. Not a big deal, they just cut the seat to the new diameter. Don't forget multi-angle seat grind.
A Dodge

Ray- Great news...you just can't leave well enuf alone, eh? My SC head was ground by PB with attention to exhaust side tuning. That is why I recently went extrudi-hone on the stock LCB ci ex manifold: to complete the slippery slope all the way out with 2" pipe and a single Peco.
Don't forget to digi-pix that head upon return and post for us, please. I have a print of the PB head right now on my desk with my family photos. We're a very strange group I think. Cheers, Vic

vem myers

Vic-
Which outfit did the extrude honing on your exhaust manifold? How much do they charge for the service?
Steve S.

Vic,

Yes, We are a strange group. My car is so finished I got bored of nothing else to do so maybe that is why my old head said LEAK. I don't mind though as this type head will only help the Supercharged engine. Should pick up a couple HP. Already have the Peco setup and will stay with it. I like the way it sounds.

Supercharger forum is empty anymore!

Any more Dyno records? Keep us informed!

Ray
Ray 1977mgb

This thread was discussed between 02/12/2007 and 04/12/2007

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