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MG MGB Technical - Cylinder Head query

Can an earlier edition cylinder head, from a higher compression engine, be used with the lower compression engines?
ie: 1968 cylinder head & 1975 18V engine with exhaust valve cut-out in block.

Thanks.

JR
JR Ross

JR,

Someone who knows for sure will come along in a while, but in the meantime, here is a vague memory I have.

I think the head will fit, but that you will end up with even lower compression than you have now. I think the later heads had smaller combustion chambers than the older heads. If you are doing it to get the car running because your head is bad, I think you can do it to get it running.

I believe the lower compression engines got the lower compression from larger dishes in the pistons.

Don't grab any wrenches until someone else weighs in on the subject.

Charley
C R Huff

See www.mgbmga.com

FRM
FR Millmore

Hi JR

In original unmilled form the early pre 18v heads are approx 1 cc more than 18v heads, not a lot of difference, approx 10 thou or one skim/mill to get the head flat! Most heads have been milled at least once or more so not many are 'standard'

Peter
peter burgess

Hi there guys
Yep the heads swap over no worries.
JR- If you are going to use the rocker gear off your later head on the early head just double check that the oil feed hole in the head lines up with the hole in the rocker post. I've struck a problem somewhere there in the past but can't for the life of me remember exactly what it was but I think it was misalignment of them oil holes Cheers Willy
WilliamRevit

"I take 50-70 k off in skim and torgue em on..." so sayeth Hap Walthrop and I,ve found he's right. Eyebrows may need fuzzing depending on pistop to deck clear of in sitio pistons. Cheeers, Vic
vem myers

This thread was discussed between 04/11/2009 and 21/11/2009

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