Hi,

I've just registered with the forum but I've done a lot of reading here and I can say this is a great resource with lots of very useful information, so thanks to all the contributors.

I'm seeking advice regarding a 1998 X308 3.2 (AJ26), loss of compression suspected liner failure. Replacement engine was purchased but it's an AJ27, so it's not as simple as dropping it straight in.

Mechanic working on the car has 2 suggestions:

a. swap AJ26 heads onto AJ27
or
b. block driver's side (RHD) camshaft sensor, and replace camshaft in second cylinder bank with camshaft from AJ26, so that correct cam position signal is sent to ECU

Option A sounds like it has more chance of working to me, unless other changes with the AJ27 would conflict with the older heads and ECU.

Could someone please advise whether either of the above options are possible, or what else may be required to make this engine work?

Thanks for any input.

Mark

 

To turn the AJ27 into AJ26 you'll need to:
-swap the heads and cam covers (VVT solenoids and cam adjusters ARE different). Also it's a good time to do a valve job and to replace valve seals. Don't forget to adjust the valve lash. BTW, the lifters are not identical on AJ27 and AJ26.
-swap the oil pan and filter housing
-swap the front cover
-swap an oil pump
-swap the flexplate
-swap the intake and throttle body
-a whole bunch of gaskets and seals, it's better to replace them while an engine is out. There's a gasket kit available.
I've did the opposite process a year ago, so it's possible

 

Moscow- Are the lifter buckets on an AJ26 thicker (the tops) than the AJ27s? I used two from the AJ27 buckets on the AJ26 head and am going to have to use oversized shims to pick up the clearance slack. (minor annoying tick tick tick) The other option would be to swap the head but I am not interested in spending the time on that (yet?)

 

Well, the original poster has a 3.2, so no VVT problems. So that leaves the cam pulser cam that pulses the sensor, the throttle body (intake manifold?) and the flex plate (different number of teeth). Thje heads, oil pump and cover all relate to the proportional VVTS on the AJ 27.

 

Yes, they are

 

Thanks for the replies everyone, I appreciate the input.

I have gone through dsnyder586's thread that covers what is basically the reverse of this situation, putting an AJ26 block into an AJ27 car with associated differences. I'm just wondering whether the exact reverse is true in this situation?

I'm specifically wondering about the oil sump/filter/pump. I understand from reading other threads these things need to be upgraded for the VVT system in the AJ27 heads, but in this case the AJ27 engine is stepping backwards to the older AJ26 heads/cams, so can the oil system just remain the newer AJ27 components?

Also just in regards to Option B (camshaft swap); this post mentions differences in the VVT systems that makes me think it's not as simple as just swapping the camshaft or CPS trigger from part '2' to part '1' (pictured below).
However if anyone believes this option may be possible I'd be interesting in knowing, as it would be a lot less effort than swapping the heads!

 

Mark:
Am I confused? You said the car was a 3.2 - I thought the 3.2 did not have VVTs.

 

thanks for your reply sparkenzap and yes, it is a 3.2 but I was under the impression the only one without VVT was the supercharged 4L. If the cam on the 3.2 is indeed fixed it would be a good thing, as that's one less element of complexity in the whole situation.

I'll await feedback on the idea of just swapping out the end part of the camshaft so it's compatible with the AJ26 CPS/ECU. I'm sure there are things I'm not thinking of but I still need to chase the simplest option!

 

I would just use your AJ26 cams on the AJ27 heads.

Don't forget to plug the oil feed on the AJ27 head for the VVT unit!

 

We do not have 3.2 engine here and my documentation does not cover them, but unless something changed midstroke, I am pretty sure the 3.2 has no VVT.

 

There is no VVT on the 3.2. Look at the front of the valve covers, and you'll have wires and blind plugs that aren't connected to anything.

 

So, that makes this entire thread subject to re-thinking. I would say you have to deal with the camshaft pulse cam, both in tooth count and orientation, and you need to refit the original flex plate with its different tooth count, then re-use the AJ26 intake system. I am not sure which intake parts bolt up, but I do know, at least on the 4.0, that the injectors and induction are different.