Using a series 3 engine block to rebuild a series 1 engine?
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Hello everyone, is it possible ? Are 4.2 l engine blocks compatible between the 3 series? I need to rebuild a series 1 engine with a damaged block. Idea is to use a block from an other engine rather than restaure as the original block is pitted and damaged. Thank you in advance for your kind help!
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The spacings changed from the 3.4/3.8 to the 4.2, but all 4.2 have the same bore spacing. There were 2 extra cooling passages added to the back of the block in 1968, but that won't matter between Series 1 and Series 3 XJ.
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All of the XK engines from 1948-92 have steel sleeves in an iron block. If your existing block is oversize an option is to press out the sleeves and install new ones to bring it back to a standard bore size.
Some of the engines had problems with the block cracking between the bores, so examine that closely - ideally have a machine shop use a specialized magnetic particle detection system to see if there are cracks. Some of the later blocks were slotted between the bores to help prevent cracking.
Series 3 heads have larger valves than the other engines, so in theory should have slightly better breathing. I doubt you'd notice a difference in the real world.
I think from about 1982 (?) the crankshafts had a special hardening and cannot be reground. They generally don't need it though.
A good history of the engine and it's changes over the years is written by Roger Bywater, a former engineer at Jaguar, 6 parts starting here: http://www.jagweb.com/aj6eng/xk-engine/
Some of the engines had problems with the block cracking between the bores, so examine that closely - ideally have a machine shop use a specialized magnetic particle detection system to see if there are cracks. Some of the later blocks were slotted between the bores to help prevent cracking.
Series 3 heads have larger valves than the other engines, so in theory should have slightly better breathing. I doubt you'd notice a difference in the real world.
I think from about 1982 (?) the crankshafts had a special hardening and cannot be reground. They generally don't need it though.
A good history of the engine and it's changes over the years is written by Roger Bywater, a former engineer at Jaguar, 6 parts starting here: http://www.jagweb.com/aj6eng/xk-engine/
Last edited by Jagboi64; 08-07-2023 at 12:43 AM.
The following 2 users liked this post by Jagboi64:
Greg in France (08-07-2023),
Jag7651 (08-07-2023)
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I've put a S3 engine in a S1
One snag was the S1 have round openings at the back of the cams, and S3's do not.
On a S1, the openings are plugged with a round seal, and their mounting bolts also serve to hold the throttle linkage.
S3's have fuel injection, and the cam covers are flat, so they were not drilled and tapped for the round seal, which means you don't have a way to hold the throttle linkage.
Once installed, there's no room to drill and tap, but if you do it before installation, you will be okay.
Rob
One snag was the S1 have round openings at the back of the cams, and S3's do not.
On a S1, the openings are plugged with a round seal, and their mounting bolts also serve to hold the throttle linkage.
S3's have fuel injection, and the cam covers are flat, so they were not drilled and tapped for the round seal, which means you don't have a way to hold the throttle linkage.
Once installed, there's no room to drill and tap, but if you do it before installation, you will be okay.
Rob
The following users liked this post:
Greg in France (08-08-2023)
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All of the XK engines from 1948-92 have steel sleeves in an iron block
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I’m glad I started this topic! So each of the two versions has its issues. Cracking or head gasket failure. Im guessing todays high quality gaskets must be better than the ones made in the 80s. So the way to go would be a block from 83 onwards fitted with my original S1 head and reassembled with a top quality gasket set after a re machining of the surface to ensure a perfect mount.
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