ahu conv in caddy van PROBLEMS

[s3_luke]

hi chaps, right got a problem with my mk2 caddy van, it started life as a 1.9 sdi code AEY, and has recently had a conversion to a TDI AHU.
So the engine went in fine and ran spot on, untill we discovered that the H/G had blown, not a problem untill it was replaced. The guy that done it for me was dropping it back to me untill it rattled itself to pieces, while waiting for recovery he whipped the head off ( roadside) and discovered that the cap on top of the lifter had been smashed to pieced, but no valve or piston damage. It was replaced and ran at his house for a good 20 mins untill things got loud (like hammers banging together) so he whipped the head back off and found nothing wrong, the bottom end turns over sweet, as does the head (while off), but while the engine was bolted up you couldnt turn it as it was jammed :/, like the valve was bouncing the piston but all the timing was literally perfect, could it be lifters failing and valves just and just tapping the pistons? any info would be amazing as its my work van and its causing major issues, cheers lads, luke

 

[rpturbo]

So how many miles are on this AHU? Was this just idling when it started making noise like hammers or driving under load? If you can not turn the engine over with the head on, something is certainly hitting, most likely the valves. From what I know of these it only takes a small hit to bend these valves. When he pulled the head off, he should be able to see the shinny spot where either the valves made contact, or the piston is hitting the bottom of the head. Was the head ever milled? How thick is the head gasket he is using? Sounds like there has been a lot of luck so far if no major damage, I think some clearances need to be checked before you have a junk engine.

 

[BigVWman]

i would be thoroughly checking those valves before any more damage is done! It sounds like an impact to me. Possibly sticky lifter in the lifter bore causing issues? even if you think they are all great now is the time to check often a bent valve will show itself in a few thousand miles as dropped valve and then you have really big issues, it fatigues and breaks off causing rod, piston, and head damage as well as occasionally a trashed block with a hole in the bore or serious sidewall damage!

 

[s3_luke]

thanks for the replys !! turns out the guy damaged the ahu head when changing the h/g and fitted the aey sdi head which i wasnt happy about at all, sourced another ahu head, but are there and differences between the two heads? the problems have only occured when fitting this new sdi head?? m