Curious compression rating on engine

Chorlton · Post by **Chorlton** » Sat Jan 05, 2008 2:06 pm

Ive just picked up a 3.5 RV8 (dont know why? Impulse purchase)
However the engine number is in the range 10A3XXXX yet it is marked 8.35.1 but I cant find any listing for that compression only 9.35.1
???? WTF ?

Post by **katanaman** » Sat Jan 05, 2008 2:46 pm

That doesn't make a lot of sense really. What is the last letter in the serial? It should be A but if it is something else then that could maybe point to something. I have never been able to find information on what the suffix letter stood for although I can tie some of them to specific uses like military and so on. Course its a 20+ year old engine and unless you know for sure it came out the original car and was the original untouched engine to that car then all it could mean is someone has messed around with the number.

Chorlton · Post by **Chorlton** » Sat Jan 05, 2008 3:31 pm

There is no letter at the end.
I took a closer look and the 8 figure at the front is actually a 9 that has had a little loop tapped in to make it look like an 8 there are also 2 old BL stamps on the number plate (BL =British Leyland)

Post by **katanaman** » Sat Jan 05, 2008 3:59 pm

Looks like the messed around with number theory is right then. It could well have been changed to 8.35:1 compression and someone has tried to do the right thing by changing the number. Only a strip down will tell I guess.

Chorlton · Post by **Chorlton** » Sat Jan 05, 2008 4:15 pm

is 8.35.1 better or worse than 9.35.1??

Post by **katanaman** » Sat Jan 05, 2008 4:30 pm

Better if you want to use forced induction, worse if you don't.

Chorlton · Post by **Chorlton** » Sat Jan 05, 2008 4:53 pm

katanaman wrote:Better if you want to use forced induction, worse if you don't.

I just thought it might be nice to poke into an old Kitcar I had hanging around. Bang an Offy manifold and an Edelbrock carb on it.
I mean Im not looking for mega horsepower

softdash3.9 · Post by **softdash3.9** » Sat Jan 05, 2008 7:53 pm

10A is a SD1 carb engine, and should be 9.35:1 CR, to my knowledge (might not be much

) SD1's never had a low compression option (like P6 Rovers & LR @8.13:1 CR) but the Vitesse was 9.75:1 CR

mgbv8 · Post by **mgbv8** » Sat Jan 05, 2008 8:26 pm

8.35:1 is the standard for the Factory built MGB V8.

mgbv8 · Post by **mgbv8** » Sat Jan 05, 2008 8:27 pm

Well, I'm sure my old engine is the same. I used this low comp engine for two years on comp head gaskets with a Weber 500 and a 150 shot of nos with no probs at all.

kiwicar · Post by **kiwicar** » Sat Jan 05, 2008 8:31 pm

SD1 with low compression, might have been for a market with lower petrol quality, Egypt maybe?

Third world racing again per chance?
Mike

RoverP6B · Post by **RoverP6B** » Sun Jan 06, 2008 8:39 pm

The V8 engines in the SD1 for the Australian market were low compression issues, with 8.13 : 1 CR, although the engine numbers were in the range of 15A....

Ron.

Chorlton · Post by **Chorlton** » Thu Jan 10, 2008 12:55 pm

mgbv8 wrote:8.35:1 is the standard for the Factory built MGB V8.

Now that could be it as it has 2 of the old fashioned BL logos stamped on the engine number panels, but the engine number doesnt have an 'A' like most others do.