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MG MGB GT V8 Factory Originals Technical - Old Rover update

I have an old 10.5-1 commpresion early type/rope oil seal engine which should run on 5 star petrol.
A friend suggested that I could use composite head gaskets, this will lower the commpresion, and a set of sd1 heads I have,I also have a spare 216 crane cam & lifters to go on,perhaps retard the ignition?
Any comments please
thanks Dave.
DK Lowe

I'd be tempted to use the tin gaskets, keeping the compression ratio high. Put on the sd1 heads (especially if they are Vitesse) and also an sd1 front cover and oil pump gearset. Then you can get rid of the points dizzy for better sparking. Pop in your new cam and use some aftermarket octane booster when you refuel. That would make a nice engine for an mgb... After all, we are all interested in increasing the performance of our cars otherwise we wouldn't be going to all the trouble of a conversion in the first place! Maybe I have a vested interest. I'm building a 10.5 :1 engine, 20 thou overbored, tin gaskets, sd1 front cover, vitesse heads, dual plane offy with a 390 holley and late 35dlm8 electronic ignition.
A low compression engine (due to composite gaskets)with the older oil system and points distributor seems like a bit of a shame after all the other work that will already have been carried out.
Just my view....
Nick Bentley

I read something like this in Rogers book. I'm not at home for another week. I'll look then if no one else replies. They are supposed to give a better seal and the ratio came down quite a lot.

Thanks for the replys,I just realised I spelt compression wrong,twice! (must be Friday night syndrome)
DK Lowe

You need to know how maney are on the old rover pistons. We will not reuse the early rover pistons with more than 50k on them. The pistons will come apart, with the piston breaking. The newer heads have a better port, for power, the heads both have the same CC in the comb. chamber. If you use the fel-pro or the newer rover 4.0 head gasket you will drop the comp. to a true 9.5 to 1 & with my early motor set up with a cam, 9.5 cr & a hot Buick dizzy with elect. ing. I could run 89 oct. (U.S. mid. grade). I would put in a oil pressure spring or shim the one you have to 40-45 lbs. We drilled the oil gally to 1/2" & put on a bigger die. oil pick up tube, to help the oil pump out. Ask around &
see if someone makes a rubber rear seal for the crank, we have made them for 15 years. If you retard the timming you will lose the M.P.G.!!! You should look at the F/I that was on the range rover with a 3.5 motor, 5 M.P.G. BETTER!!!!, but you can only go up one bump hotter cam. 74.5 G.T. with rover 5sp & 3.0 rear, 14.5 1/4 mile! set up this way with carb & 14.8 with F/I.
Glenn Towery


I run a Vitesse engine with compsite gaskets, If you are concerned about loss of CR you can afford to have them skimmed a little, mine were done...I use Optimax exclusively with no problems , and can get 30 (UK) MPG on a motorway easily on hot-wire EFI.

M Barnfather

My CR is 10.8:1 on the 4.6 and it runs fine on 97oct optimax or similar. ocasionally I have had to put in 95oct and have not noticed any difference.
I have done back to back tests on a 4.0L engine with composite and tin gaskets and the difference is very noticable.
High compression, warm cam, flowing heads is the way to go. IMO.


This thread was discussed between 21/04/2006 and 23/04/2006

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