Cause for bubbles in the filler tank and overheating?

TB2 · Post by **TB2** » Thu Jul 21, 2011 7:52 pm

Today I managed to get the head of. To my surprise, the head gasket is intact and I'm not sure what the problem is. Here are a couple of pictures. Do they tell a story?

It's okay though, a couple of the other seals (exhaust manifold for example) are leaking oil so changing everything doesn't hurt. Though I am a bit disheartened. If I put everything back together and I still have the problems, that would suck.

I'll see that I can get the head pressure tested...

toddao · Post by **toddao** » Thu Jul 21, 2011 7:57 pm

Carl wrote

I'll see that I can get the head pressure tested...

would be the logical step. I had a cracked head on the TRD .
Nice pics by the way - don't feel bad, think of all the new things you've learnt and you had the guts to take it on. I'm sure you'll get it sorted.

Oscar · Post by **Oscar** » Thu Jul 21, 2011 8:37 pm

You star. As Todd said, you had the guts to do it. I gave up on mine. Well done.

Brian · Post by **Brian** » Thu Jul 21, 2011 9:03 pm

Clean up the head surface, be very carefull not to damage the face.

Straight edge diagonally across the head surface, use feeler gauges to check for irregularities.

Inspect, with the aid of a strong light and magnifying glass, where the fire rings on the gasket mark the head, for any blow by marks. Also the ali between the inlet and exhaust valves for hairline cracks.

Good luck

Post by **docchevron** » Fri Jul 22, 2011 2:51 am

that head has been decked before, by an idiot.
there's milling marks all over it, alloy heads should have a new stone used them everytime.
Judging by the whitening on the carbon it's clear there's been water ingress.
Worth checking the block very carefully down the bores, they can and do go porous.

citronut · Post by **citronut** » Fri Jul 22, 2011 8:58 am

that head needs to be firstly presure tested, then if ok the head needs to be skimmed,

the block doesnt look to good either, give the matting surface of the block a good clean up without scouring it in the slightest,
then post more picy's of that,

what i call No. 1 cylinder (cam belt end ) looks the worst block and head face, there is also evidence on the gasket, and there is sign's of blow by on No. 4 also,

regards malcolm

TB2 · Post by **TB2** » Sun Jul 24, 2011 3:01 pm

How are you guys getting the head that shiny clean without using something more effective than 'a blunt soft instrument' as haynes is suggesting? This is the best I got with alcohol, a soft cloth and a plastic dough scraper:

Click to enlarge

What on earth is that hole just next to the leftmost swirlchamber??

I think I found a crack in one of the swirl chambers:

citronut · Post by **citronut** » Sun Jul 24, 2011 3:42 pm

the only way to get the head like Brian's images is to have it skimmed,

but i have never seen a hole in the combustion area like in you picky's,

i think you either need to get that welded up by a compatent alloy welder, or get another head,

the ricaro inserts are quite oftten cracked but im reliably informed this is ok,

if you do get that hole welded up i would still have the head presure tested before skimming,

regards malcolm

TB2 · Post by **TB2** » Sun Jul 24, 2011 6:54 pm

Thanks for the information Malcolm.

I'll bring the cylinder head to an expert tomorrow morning.

Still, here are a few more pictures and questions...

The inside of the inlet manifold is quite greasy. Especially the pipe closest to the inlet (cambelt side) is really oily, reaching into the valves. Is this normal? What could cause this?

Here the difference in oiliness is very obvious, between the inlets:

So much gunk on the middle inlets!

Here's the inside of one of the cylinders...

citronut · Post by **citronut** » Sun Jul 24, 2011 8:44 pm

is the oilyest port from the cylinder were the hole is in the combustion area,

otherwise it could be a valve stem giude or seal,

it realy is best to get the head presure testted before spending any other money on that head,

regards malcolm

Post by **docchevron** » Sun Jul 24, 2011 11:50 pm

the hole in number 4 is there for a reason.
If you look at the top side of the head you;'ll find a bolt in it, directly above the hole. It's so you can remove the bolt and use a guage to find TDC.

citronut · Post by **citronut** » Mon Jul 25, 2011 8:00 am

very strange as i have never seen this on all the heads i have had off

although it dont look like a coroded hole,

regards malcolm

TB2 · Post by **TB2** » Mon Jul 25, 2011 2:55 pm

docchevron wrote:the hole in number 4 is there for a reason.
If you look at the top side of the head you;'ll find a bolt in it, directly above the hole. It's so you can remove the bolt and use a guage to find TDC.

Oh interesting.

I left the head with an engine specialist. He looked at it and told me that it's generally in good shape, but he will contact me if he finds any problems with it. He will remove the swirl chambers, skim the head and then refit the swirl chambers with the correct protrusion. The crack in the swirl chamber is indeed no problem.

He did however also say that they rarely pressure test alloy heads because A) the cracks would only show at operating temperature and B) they can usually be seen with the bare eye. I guess I'll trust him, the shop looked really professional.

Post by **docchevron** » Tue Jul 26, 2011 12:56 am

said holes been on every one of the 400 odd XUD heads I've overhauled..

Thats not strictley true about cracks only being evident at operating temp though.. A pressure test will show up any cracks, even those that cant be seen!

Post by **mat_fenwick** » Tue Jul 26, 2011 9:49 am

I'm nowhere as experienced as the good Doctor, but I'll also add that on the only time I've had a head fail a pressure test, I couldn't see a crack.

Interestingly, I've done a head swap where the head pressure tested OK, but the pressurisation remained afterwards, as did oil/water mixing. The head looked to be a recent (new looking) replacement so I suspected the problem lay elsewhere in the block - in the end we ditched the engine and replaced it with one kindly supplied by David R.