mix and match of rockers

Hello all.
I'm rebuilding a replacement head for my 2.5.
The replacement head is from a later (metric) 2.25D which has very worn rockers and valves, but is otherwise good.
The existing head is from an earlier (imperial) 2.25D, where the gap between the inlet and exhaust valves is a few mm less.
Can I use the imperial rocker gear (or just rockers) on the more modern head? The nub of the question is really, are the rockers the same?

If you are changing the entire rocker shaft assembly, the easiest way to see if it will work is to try it.

The rockers themselves only swing on the shaft, so that shouldn't present any problems as they are adjusted by the tappets.

You might need to change over the pedestals, but the most important thing is to ensure that the oilways match up.

Also make sure that there is no play between the shaft and the rockers.

James would be able to give you more precise advice, so it might be worth sending him a PM.

Oldseadog said:

If you are changing the entire rocker shaft assembly, the easiest way to see if it will work is to try it.

The rockers themselves only swing on the shaft, so that shouldn't present any problems as they are adjusted by the tappets.

You might need to change over the pedestals, but the most important thing is to ensure that the oilways match up.

Also make sure that there is no play between the shaft and the rockers.

James would be able to give you more precise advice, so it might be worth sending him a PM.

Click to expand...

Thanks. If the new spring cups arrive in time, I'll check it all out this weekend and report back.

zeaphod said:

Thanks. If the new spring cups arrive in time, I'll check it all out this weekend and report back.

Click to expand...

The answer is that metric and imperial rocker sets do appear to match.
Of course, it's very difficult to know what is original on an elderly vehicle, but the rocker cover studs will be a good clue.
It appears I had an imperial 2.25 head, with metric rockers, fitted to a 2.5 metric block. I now have a later metric 2.25 head. Hopefully it will be fitted to the block this week!

In that case I don't think that you will have any problems.

Please let me know how you get on.

Oldseadog said:

In that case I don't think that you will have any problems.

Please let me know how you get on.

Click to expand...

Head and rockers back on last night without problem, tappet and rocker positions match up perfectly.

Great news!

Well done you!

Rebuild completed today, in awful weather. Plenty of hot tea was essential!
Worth it to hear her fire up again - and I must say it sounds a lot better. There's actually a crispness in the engine note. Didn't need to turn over too much to refill the fuel system - about 10 secs.
A few piccys:
A bit out of focus - note towel to try to keep the head dry whilst rebuilding.
41mm socket and drive to turn engine during tappet setting - very handy

Setting the tappets - I find a stubby screwdriver and ring works best. The zip tie on the feeler guage makes it harder to lose/easier to handle.

Don't forget the washers for the oil feed. The Allmakes head gasket kit includes new washers for this, and the injectors. recommended.

New washers on the injector, ready to go. These had always been missing before. The washers were cleaned prior to fitting. A little dab of grease keeps them in place when fitting the injector.

I found a deep 13mm socket works well on the injector nuts.

A 8mm socket works well on the glowplug tops.

Ans finally - cleaned up the thermostat housing before refitting. Thermostat is old, but tested and working perfectly.

Hope this has been useful, feel free to ask if you've any questions.

zeaphod said:

Hello all.
I'm rebuilding a replacement head for my 2.5.
The replacement head is from a later (metric) 2.25D which has very worn rockers and valves, but is otherwise good.
The existing head is from an earlier (imperial) 2.25D, where the gap between the inlet and exhaust valves is a few mm less.
Can I use the imperial rocker gear (or just rockers) on the more modern head? The nub of the question is really, are the rockers the same?

Click to expand...

you can mix and match and rocker gaps are all the same till 200 tdi