[Trizo-97]

Hey guys just joined the page. My old man has a few old sierra's in our junk yard and has donated me a 82 sj40. The car isn't running at the moment so I've pulled the motor out and I'm planning to rebuild it. On my compliance plate on the car it says it has an f10a engine. However on the block of the motor it says f8a. I was wondering if the block of the f8a and f10a are the same or not or if somewhere down the line someone has replaced the original motor with a f8a.
Cheers Tristan

[Technotron101]

The block is the same (I think) but I'm fairly certain the engine should be f10a if it's in that car. Unless someones changed it, though why I don't know.

Other peeps out there, is there any other way to tell, apart from the block, whether the capacity is 800cc or 1000cc?

Just going on a hunch though, because I read some time back that the blocks are the same just the top end changed. Don't take my word for it though, I'm no expert haha

[sideways]

The blocks are different, the F10a has a bigger bore. It is reportedly possible to bore an F8a out to fit F10a pistons but I doubt anyone has done that since the early '80s. F8as are practically worthless, where as F10as have always been sought after for LJ conversions so a number of tightarse Sierra owners put F8as in them when they needed a new motor. I've seen a few like that now.

Aside from the bore and part where F8a/F10a are stamped they're practically identical. Though you'l find LJ80 blocks aren't drilled and tapped to mount aircon or similar under the exhaust manifold. F10as are.

The heads are very close to the same too. Same valves, chamber, ports, cam profile ect but the F8as have a seal housing on the front of the head. This means the cams are different as the seal surface is in a different spot.

You could try and measure the stroke through the spark plug hole for that 1 in a million chance it's got a F10a crank and pistons in it but I think that's extremely unlikely.

[MrRocky]

Maruti 1ltr motors have the head stamped 800cc same head i thought.
On the block just above the sump near the startermotor should have the engine number stamped if its a 1ltr should start with f10a

[sideways]

Yeah, all F10as we got in Australia have 800 (no cc) on the head. F8as don't have that. Head is 100% different but interchangeable and no difference performance wise.

[Trizo-97]

Thanks for that guys. I'm just debating now whether to rebuild it or just try to get it going. I don't see any reason as to why it won't run. Motor feels fine turning it over by hand but didn't have a starter motor or carby. The sump has been reseated by a previous owner with a bit of all clear silicon haha. Would love to rebuild it but apprentice wages don't agree at the moment

[rustyzook]

My old F10as had 975cc stamped onto the block passagner side somewhere from memory, (could be remembering a different car but I'm sure it was the old sierras)