23/11/2017
Cheapest is not always best.
6 months ago we fitted a customer supplied brand new cylinder head to a T5 2.5pd the cost of our cylinder head which was a European casting exceeded the cost of the customer supplied ebay unit by £400.
While head was off we had injectors tested for good measure by our friends at United Diesel, test came back fine with all injectors in perfect working order, reason for replacement head was poor starting due to the usual worn injector boss’s in cylinder head.
As per standard with any garage we will not warrant customer supplied parts.
This week the van came back pluming white smoke out of exhaust we sent injectors away for testing only to find the nozzles were so badly eroded they were squirting diesel from the side of nozzles..... why was this ?
On investigation we found the injector holes machined into cylinder head for nozzles were between 0.5mm up to 1.2 mm larger than the holes of a genuine cyl head meaning corrosive exhaust gases were passing up the side of nozzles causing damage to injectors, with only cure being replacement of cylinder head and rebuild of all injectors, not good and not cheap to remedy.
We have been told by Koblenschmidt who normally supply our heads that they are aware of this issue with China sourced cylinder heads and the corrosion is also related to poor quality of alloy used in cylinder head creating a strong chemical reaction between injector nozzle and alloy of cylinder head along with poor tolerance of cylinder head machine work, they informed us this is the 5th time they have came across this problem and have already sampled one of these Chinese import cylinder heads.
Video below shows how inconsistent injector hole size was, factory hole size should be 7.2mm some of the hole sizes on this Chinese cyl head were 8.5mm in size.
Any companies fitting these heads please be aware of this.
Please note I am not looking for liability debates, the aim of this post is to inform.