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MG MGB GT V8 Factory Originals Technical - Gaskets
I find myself needing new head gaskets. Can I just order head gaskets for a 63 Buick Special.
I just went out to the very cold garage to check my leftover Fel-Pro gaskets. I used the 63 Buick set and had no problem. Fel-Pro may have a listing for the Rover 3.5.
It was -22* here this morning and -35* yesterday. I'm sure it's a lot warmer on the Sunshine Coast!
I sent an email to you last week.
|It seems that there are a few choices out there - Snapshot taken from D&D's website:|
Individual Head Gaskets – Priced each.
$14.00 GUG-702538 Head Gasket – .016 embossed for 3.5” bore Buick or Rover.
$20.00 ETC-7819 Head Gasket – .018 embossed for 3.7” bore Rover.
$46.50 ERR-7217 Head Gasket – .050 composition for 3.7” bore Rover.
$ 18.00 8172-PT Head Gasket – .040 composition for 300” Buick.
$15.00 1174-BS Head Gasket – .040 composition for 3.5 bore Buick or Rover.
$20.00 7984-PT Head Gasket – .040 composition for 3.5 bore Buick or Rover.
$ 27.00 7995-PT Head Gasket – .040 composition for 3.5 bore Olds.
|I would go for composite gaskets every time, for the valley/manifold as well. They have much better sealing properties, especially for the water and oil passages. But if you have hydraulic tappets you will need to check the pre-loads and maybe re-shim, especially if you have had the heads skimmed.|
|Factory V8 gaskets are steel shim, putting composite on these instead has a massive efefct on performance as a neighbour found out, he had to do the job again with the thinner ones. 16 to 50 thou as above is quite a difference.|
I can't see you having to play with the hydraulic tappets, the whole point of them is that they can cope with a very wide range of tolerance in all valve gear components including head gasket thickness. Worth measuring just to make sure they are within tolerance, but that is anything from 30 to 120 thou.
Over the years I have had problems sourcing gaskets for my 69 Rover 3.5 "A what" they say. But I have now found out that the following all use the same gaskets.
Buick Skylark 61-63
Buick Special deluxe 61-63
Buick Special 61-63
Rover 3500S 69-71
MG MGB V8 75-77
MG MGB MK1V 75-77
Triumph TR8 80-81
|A 50 thou composite gasket will reduce the compression ratio by approx .5/1 if you have an engine which was originally 10.5/1 this may be an advantage, but if low comp. say 8.25/1 as per original MGBV8 then compression will be very low appro. 7.7/1|
Optimum preload on the lifters is 20 thou with uip to a max od 60 thou. being acceptable but will effect the RPM at which pump up occurs.
If you fit composite gaskets this will reduce the preload by approx 50 thou which may reduce preload excessively ie under 20 thou. you have to multiply the difference in gasket thickness by the rocker ratio of 1.6/1
The tin gaskets sre 18 thou thick and the composites are 46- 50 thou. the later 4.0 and 4.6 heads had the faces milled to compensate for the thicker gasket and the combustion chamber size reduced to 28cc from the earlier size of 36cc.
This thread was discussed between 27/01/2009 and 29/01/2009
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