As some of you know, I ordered a DEV5 head for my Xh ute a week or so ago, this was supposed to be for the Wakefield Park track day but it didn't arrive in time because the 'overnight' courier took 3 days.
Anyway, those who have been reading any of my posts will be aware that I already have a complete DEV3HL kit, so all I needed was the DEV5 head/cam to turn it into the whole upgraded kit. (No I'm not selling the DEV3HL cam and valve springs).
The main reason why I was upgrading was because head gasket was leaking water and I had to pull the timing cover off because one of the guides had broken (I noticed this the last time I adjusted the cam timing).
I could have just re-coed my head, however a decent service is typically $400 or so, plus I wanted the bigger exhaust valves and a little porting done, by that time I'd be over $1000, so I though bugger it, for $2500 I grabbed the whole serviced, ported, and bigger exhaust valved DEV5 head.
This also included the DEV5 cam, new valve springs, setting up the cam, head gasket, timing chain - guides - tensioner.
Plus the advantage of a 20 or extra kw is also handy, not that I was complaining with how it went before.
Anyway, the head finally arrived yesterday, so we got stuck into removing the head and timing cover, everything was going smoothly until I pulled the timing chain off. It was then I felt the play in the auxiliary shaft.
Basically the shaft is stuffed, and so is the block. I've rang around and the best advise is to replace the block as not to many machine shops are willing to bore out the block and fit a bush.
And those that do, charge quite a bit.
Anyway, I've already sourced a replacement block, and surprise surprise it's from an AU.
$250 for a AU short block with 57k sounds pretty good to me, including the sump.
Apparently it is good enough to go in as it is, but I'm going to fit new rings and bearings anyway, plus balance it so it will be smooth free revving.
For those who don't know the advantage of the AU engine, it's the conrod length.
AU conrods are a little longer than the older engines and this places less side loading on the pistons enabling it to rev higher with less chance of splitting bores and cracking pistons. They also last longer for the same reason.
Typically when this kind of thing is done to an engine, they are also happier at higher revs with fewer harmonics, that's why AU's feel more refined and smoother when revved hard.
The AU engine is also more rigid because the sump forms an integral part of the block as it's bolted to the main caps.
I believe the crank also has a different number of counterweights for better balance.
I'm picking up the short block in an hour or so and will have the parts at my engine shop later today for him to source rings, bearings and balance the reciprocating parts.
Hopefully I should be in a position to reassemble it all tomorrow with it sliding back in the engine bay on Thursday/Friday.
I suspect the DEV5 package in combination with the AU bottom end will create a powerful and smooth engine.
Location: gold coast and off playing with 32psi of boost pumping into 4.1lt of pure ohc feralness and developing a 350hp n/a kit for ea-au i6, also making 5.0lt gear soon enuf
Posts: 1,043
Re: XH DEV5 project.
good to see mate,
good and keep us posted.
cheers.joe.
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live in S.E. queensland? bit of a revhead? click here!!--> speedphreaks
1000hp is underway. rods,pistons here!! t88 on its way!!
Anyway, the head finally arrived yesterday, so we got stuck into removing the head and timing cover, everything was going smoothly until I pulled the timing chain off. It was then I felt the play in the auxiliary shaft.
Basically the shaft is stuffed, and so is the block. I've rang around and the best advise is to replace the block as not to many machine shops are willing to bore out the block and fit a bush.
And those that do, charge quite a bit.
I thought the aux shaft runs on bearings, same as the cam ones on earlier 250's ?
I cant remember, its been years since my i6 was apart..
really look forward to hearing your results... already have the AU engine, just want to hear about the dev 5 bit.
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AU2 S-pack Owner: Silhouette Black, XR6 Wheels, Tickford Sunroof, C2R rear bar, Checker Plate Floor Mats, Chrome Door Sills, Blue Backlite Dash, Blue Painted Brake Callipers, Advanced Extractors, Magnaflow High Flow Cat, 2.5" Stainless Steel Mandrel Bent Custom Exhaust, Genie Muffler. Sony Explode 50w x 4 deck, Kenwood 140w speakers (front and rear), Boss 1200 watt Amplifier, 12" Orion Sub in custom box. More To Come!!
Just a quick update.
Picked up the AU short block, it was avery low k gas unit (35k), bores in excellent condition, crank excellent, just having the block chemically cleaned, balanced, new rings and bearings.
Machine shop has promised for Thursday pickup, so Friday assembly and weekend put it back in.
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1000hp is underway. rods,pistons here!! t88 on its way!! 
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