Head gasket failure

ChrisJC · Post by **ChrisJC** » Mon May 05, 2008 1:15 pm

Afternoon all,
3 weeks ago I fitted the 3.5 V8 in my van with some new composite head gaskets. I skimmed the heads & did all that stuff to make sure it all went together.

After this, it leaked oil. Imagine my surprise to find that the oil was leaking out on both sides of the engine between the head & block!

I decided that it must be an issue with the head gaskets, so this morning I removed both heads to see what was going on.

Both gaskets were saturated in oil. I also noticed that the gaskets didn't have any kind of extra sealing around the oil feed hole.

I measured the removed gasket, the fire ring was 1.2mm thick, the gasket itself was 1.05mm thick. This gives two probable leaks:
- From oil feed hole out into gasket area
- From valley, down block deck, and out

I have some new gaskets, so I measured them, and although the fire ring is thicker (as you'd expect), the gasket was exactly the same. So on the gasket I removed, it hadn't been compressed apart from around the fire ring. The gasket material was just touching the block & head.

I also notice that the 3.7inch bore head gaskets have a copper o-ring around the oil feed hole, whereas these 3.5inch more ones don't....

These are from Rimmer Bros, manufactured by 'Allmakes 4x4'

Has anybody else seen this?, or got any suggestions?
I don't want to reassemble and find I've not improved matters!

Thanks,

Chris.

ChrisJC · Post by **ChrisJC** » Mon May 05, 2008 1:33 pm

Some pics:

Oil mark between head & block:

Removed gasket - you can see the oily sheen covering it, and the lack of o-ring around the oil feed hole:

Brand new one of the same:

And a 3.7inch bore gasket in the same area:

Hmmm.....

Chris.

Post by **katanaman** » Mon May 05, 2008 3:08 pm

don't think comp gasket was ever a factory fit so I guess they are all after market gaskets. Why not just use proper steel gaskets and non stretch bolts? Give them a coat of wellseal if you like as well. Would there be any major problems fitting the larger bore ones? Failing all that and you really want to stick with comp gaskets then get some felpro ones. They cost a bit but they made them for the rover engine long before rover ever did.

ChrisJC · Post by **ChrisJC** » Mon May 05, 2008 4:24 pm

You might be right in that there may not be a genuine part from Land Rover. I'll have to look further into that angle...

I did think about using 3.7" bore gaskets, but the fire ring would seat on the ally block rather than the liner which might not be good.

If all else fails, I'll probably use the gaskets I've got, but with some sealant where I think it's necessary. I'll also check out Felpro.

Thanks,

Chris.

Post by **katanaman** » Mon May 05, 2008 4:38 pm

the fire ring will always seal against the alloy of the block. The liner just isnt thick enough to do anything else unless you use top hats. What might happen to the extra exposed alloy I have no idea though. Cant see it being any different to the heads mind you but that really is just a guess. I know real steel used to do felpro and have comp gaskets listed at £11.16 each but dont know who the supplier is anymore. Quick phone call should sort that out though, Even if they arent they will be able to tell you what they are like to see if they are better made or not.

ChrisJC · Post by **ChrisJC** » Mon May 05, 2008 4:43 pm

Thanks for that, you must have read my mind!, I was busy looking at the Federal Mogul site to find out who their UK distributors are for Fel-Pro!

Chris.

CastleMGBV8 · Post by **CastleMGBV8** » Mon May 05, 2008 7:26 pm

Chris,

Just a thought, but it sounds like the gaskets haven't actually torqued down correctly, could it be that the bolts are bottoming out in the threads or if you over lubricate the threads you can get hydraulic lock which will also give a false torque reading.

Kevin.

ChrisJC · Post by **ChrisJC** » Tue May 06, 2008 7:46 am

I cleared the bolt holes with an air-line to make sure I didn't get hydraulic lock when doing them up. They were lubricated with a copper type grease which was supplied with the head bolts. They were also the angle tightened ones, and they got the full 180 degrees.

Chris.

ChrisJC · Post by **ChrisJC** » Tue May 06, 2008 8:50 am

Are the head bolts supposed to be 10.9 grade?

Chris.

stevieturbo · Post by **stevieturbo** » Tue May 06, 2008 4:40 pm

If it was feasable to use a 4.0 or 4.6 gasket, I'd be doing that. They are composite, and excellent quality, as Payen make them.

I never had any gasket problems on my 4.6 TT with the Payen AY400 ( think thats the part number )

They werent expensive either from what I recall.

ChrisJC · Post by **ChrisJC** » Tue May 06, 2008 6:04 pm

I'm a bit reluctant to use 4.6 gaskets (I do have a pair), because the fire ring is bigger.

I've just done some more measuring up, and am still none the wiser:
- The dowels in the block are definitely shorter than the holes in the head
- All the bolts have at least 10mm clearance between the bottom of the bolt and the bottom of the hole in the block
- The deck is flat
- Dropping a head on without gasket, I can't get a feeler gauge in the gap
- All the head bolts I can find are 10.9, so I guess that's OK. They all seem to be from different vendors though, maybe I had some dodgy ones that stretched too much and didn't apply enough force.

I spoke to Holly at RPi this morning (very helpful I might add), and he confirmed that there were never any OEM gaskets. They use Buick gaskets from the US for their composite ones, complete with spare bolt holes.

I'm not happy until I've found a definite fault!, which I might not find!

CHris.

stevieturbo · Post by **stevieturbo** » Tue May 06, 2008 6:50 pm

ChrisJC wrote:I'm a bit reluctant to use 4.6 gaskets (I do have a pair), because the fire ring is bigger.

The gasket will still have a good, flat surface to seal on. That awkward squish band may not be ideal.....But the gaskets are excellent quality.

If all the other gaskets that are available are the same as the ones I used years ago from RS....well, they look crap. Although they must work for most people.

Really, as long as both surfaces are truly flat, it shouldnt be too difficult to make a gasket seal.
Look at the std tin gasket as an example. its so thin, it would never take up any irregularities, yet they work quite well.

Could your bolts be bottoming out ? not clamping the head properly etc ?

ChrisJC · Post by **ChrisJC** » Tue May 06, 2008 8:03 pm

The plot thickens. I decided that if the gasket is OK, then it must be the bolts.

So I knocked up a bolt tester. Basically it's a thick piece of ally tapped 7/16 BSW. Thick enough for the entire threaded portion of the bolt. Then a thick ally spacer to take up the shank of the bolt.

I screwed in the bolt, nipped it to 50lbft, then wound it around until it broke, and measured the max torque required to break it, and also the angle that it turned before it broke.

I tried two of the suspect bolts, and a number of other makes that I had lying around, including a non-stretch bolt.

They all maxed out at about 90-100lbft, but interestingly the two suspect bolts broke at 225degrees (which is only a tad more than the 180 you're supposed to do!), but all the others varied between 315degrees and 450degrees before breaking.

Now I know this isn't quite the same as a stress/strain graph!, but it tells me that the suspect bolts are not as strong as all the others. Whether this translates into less clamping force I don't know.....

Chris.

sidecar · Post by **sidecar** » Tue May 06, 2008 8:27 pm

ChrisJC wrote:The plot thickens. I decided that if the gasket is OK, then it must be the bolts.

So I knocked up a bolt tester. Basically it's a thick piece of ally tapped 7/16 BSW. Thick enough for the entire threaded portion of the bolt. Then a thick ally spacer to take up the shank of the bolt.

I screwed in the bolt, nipped it to 50lbft, then wound it around until it broke, and measured the max torque required to break it, and also the angle that it turned before it broke.

I tried two of the suspect bolts, and a number of other makes that I had lying around, including a non-stretch bolt.

They all maxed out at about 90-100lbft, but interestingly the two suspect bolts broke at 225degrees (which is only a tad more than the 180 you're supposed to do!), but all the others varied between 315degrees and 450degrees before breaking.

Now I know this isn't quite the same as a stress/strain graph!, but it tells me that the suspect bolts are not as strong as all the others. Whether this translates into less clamping force I don't know.....

Chris.

Chris,

That is a good set of tests that your carried out and rather worrying.

Infact I'm glad that I've fitted ARP studs!

You might want to consider going the same!

Pete

Post by **katanaman** » Wed May 07, 2008 12:57 pm

Were these bolts new that you tested? Stretch bolts are for the bin after they have been used once. I have seen loads of failed stretch bolts that have been used a second time. Not on Rover V8 right enough but a stretch bolt is a stretch bolt. Fit ARP studs and be done with it.