XU10 head removal + rebuild...Progress Started!

cam85

cam85

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OK Boys,

I cant seem to find my old thread so I will start a new one.

Long story short, is that I bought a car ( s16 ) with a suspected timing issue resulting in bent valves etc as usual. It was apparently diagnosed with no compression on cylinder 4. The motor also is an 88x87mm 2.1L job! So im very excited by the following news...

On my close inspection once I removed the cam cover weeks ago you may remember that I noticed that some of the head bolts were burred and I did not want to attempt removal for fear of further damage.

Today, a skilled professional was able to safely remove the head and we were able to see the damage.

Eagerly we lifted the head from the block, turned it over to find perfect valves.....Nothing bent.
Checked the pistons, like new, no marks. Still shiny..

I showed the skilled professional the inlet manifold that has been blown apart and he said. "Thats why it aint running! " Bascially was unable to run due to all the air getting past everything that measures stuff.....:confused: and so no goer

So we are now going to pull the head down. Test it. Reseat the valves for peace of mind. Strip the bottom end and do the same. Put back together and whack it in the 205...


Its going to be slow progress with me being overseas in a couple of weeks but I thought I would keep everyone updated.

Cam
 
Having a blown inlet manifold is irrespective of cylinder compression. Unless the compression test was done incorrectly, I think you will find something is amiss. Unless the pistons have been out recently and cleaned (perhaps for the 2.1L conversion), the pistons surface could be clean due to coolant from a blown head gasket or something.

A blowing manifold backfire could be as a result of something major.

Turn the head over with the valves shut and fill the headspace with petrol will assist in determining bent valves.
 
Yea,

As I said in the above, I think the diagnosis from the Mechanic was probably just to put the owner ( before me ) off form doing anything because he was unable to find the problem himself. So possible good compression but unable to find further faults due to the engine not running...


( The owner before me said there was a bang one day and then it never went again... )

We are definitely doing a leakdown test and also rebuilding the head anyway. We turned over the cams in the head and to the eye all seemed to be fine. But that never tells the rear story.

Ill keep you up to date as soon as i know more.

Cam
 
A little update.

The head has been skimmed beyond safe repair and is also showing signs of corrosion. My builder has advised me basically that its beyond repair as the seats will become exposed if skimmed any further. Lucky I have a spare head lying about! It also has fairly bad corrosion that you can see in the photos.

Next was the leak test with the old petrol in the chambers. Below are the results

The exhaust valves in cyl 3 are leaking like a sieve. Low compression, yes but not zero.
Cyl. 1 exhaust valves are also bad.
Valves in cyl's 4 and 2 are mediocre and very good respectively.
There's something funny about the inlet valves in cyl. 3. They're clean as opposed to the rest but I can't put my finger on it at the moment.
In the photo cyl. 1 is furthest away from the lens. There's no fluid in 1 & 3 because of the leaks.

Below are some of the photos taken.
 

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Why can't you take the head out to RAMS and get it welded up? Nothing is beyond repair out there. They currently have a Sierra Cosworth head (very rare), that dropped a valve during a race and the driver drove it back to the pits. There is literally nothing left of the chamber. Your head is walk in the park.
 
My work would have no trouble welding that up. We do stuff way worse than that all the time. You'd find someone to repair that no probs.
 
Don't need to spend the money on repairing at the moment when I have a spare that looks to be in very good health. The main concern was the gap of the valve seat area and the skimming required to clean it being too close to call...

Will be building up the new head once in back later this week and then the rebuild will commence...

Cam
 
Not much going on here at the moment. Back from the EU and starting to get a few things under way.

Stuck a fresher DFZ in the daily the other day as the original motor had an awesome knock and the clutch also packed up. New motor in, plenty of smoke form the dry valve stems as the motor had been sitting for a while. Connected everything up and everything worked! And see runs great!. Then the clutch release mechanism decided to break so its off the road again until I can get a hold of one!

Taking the other head and the block to the builder this week. On first inspection the other head has not been apart\skimmed etc, so should be a great base to make the best of the two. The block is also going over to be stripped down, new bearings and rings and then the lot back together. Any opinions on what colour I should paint it? I was thinking to stick with the standard black?

With the aid of a one PeterT, we have discovered that I will need a programable ECU to properly fuel it. The original plan was to run the motor on ITBs and try and reach the 250hp mark. The plan now is get it running sweet for the road on a GTi6 inlet and then plan for the ITBs.


Will update once again once the other head and block have had the once over.

Cam
 
I don't normally see the point of painting the block especially if it is aluminium. Paint doesn't stick very well to it and then it looks like crap, paint flaking off everywhere. But one reason I found useful to paint blocks is to trace oil leaks. My first attempt was an 807 renault block which I made red so it would contrast with the g'box which I made white (there's a few hidden places where leaks can happen on this combo) and after that I kept to this "tradition". Then again, I don't take my cars to show and tell.

One thing I learned, if you use the engine enamel (can't remember name right now) widely available of american origin, you need to get the block really clean and bake it hot for as long as you can. That way you will get good results. I did mine at about 110 degC for as long as I had the oven at work (overnight). Some light colours might turn darker though (I don't care).
 
The block is Cast Iron if that makes any difference. I would love to paint it white actually and have everything else black. Not a show and tell guy wither just think it would look cool

Cam
 
Haha!!

I think it will end up black. As will the gearbox. Might paint that the silver alloy colour though.

Did you happen to have one of those brackets?

Cam
 
Black is very good for heat dissipation, but no good for finding where oil leaks spring out from. Get it sandblasted. Properly. Nothing more annoying than taking it home to discover the odd bit of grease or rust hiding in some tiny little pore or crevice or whatnot.
 
OK. Little update.

Have taken the block and resh head over to the builder. The bottle end is getting balanced and lightened. As is the flywheel and clutch. The block is getting blasted and painted, fresh bearings and rings etc.

The head is going off to rams for an inspection, fretted up etc. The head is proven to make great power as is so will remain standard. Cams are getting sorted by PeterT. Probably stage 2 inlet and 1 exhaust.

It will be running on a haltech Sprint 500 with the intention of running on ITBs once funds can afford!!

My other 205 body will be coming up sometime next week to be prepared for the motor. Ill also keep progress of that.


Will have photos etc up over the next week or so.

Cam
 
Great news that the damage was not as bad as expected, or as bad as I was told lol. I wouldn't have had the time or skills to put in the work you are so glad it's in your good hands now. Hope you have it running like a dream soon enough!
 
Yea there was lots of things wrong with the whole assembly actually. Its getting the full treatment as to make sure there are no surprises elsewhere.

Looking forward to getting the engine going correctly. It would never really have run that well on the standard computer ( not enough fuel according to a few calculations ) so should be a hoot once I get the ITBs on it with a Haltech. Will be going for more aggressive cams while its apart.

Hows your shoulder after coming off the bike?

Cam
 
Little update.

The bottom end has been pulled apart and the news is as follows.

The crank which was supposed to be 88mm is actually 86mm. Not very happy about this but no use crying about it. Pistons are 87mm items so will be up for sale very soon to fund new items to be able to take the 88mm crank.

In the photo of the rear main you can see on the right side of the seal the light brown section. This is where the flywheel has been rubbing on the seal because the seal hasn't been fitted deep enough into the block. This also means that the outer oil seal lip doesn't even touch the crank, as can be seen in the second photo, and there has been a leak because of this covering the back of the flywheel in oil.

The flywheel is showing signs of cracks on the friction surface and will possibly need to be replaced. I have another that I will have inspected.



The other head is still yet to be taken apart so no news about that. Hopefully over the next couple of weeks.
 

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That's very disappointing for you Cam, but doesn't surprise me. Good luck with your investigations.
 
Ive done a bit of ringing around this afternoon with no success so far. Will post findings asap.

Peter, have replied to your PM

Cam
 
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