Head gasket progress

[Sardonicus]

adam quantrill said:

Cheers I already have the replacements - two row ones made by Elring Klinger (recommended by Martin). Here's a piccie (please ignore the greasy thumb prints...):



Also bear in mind that the other side is the same as the one I just took off, and there have been no problems there so far...

Elring OE are the bks FACT

[adam quantrill]

Hopefully that's a good thing!! ;^)

Latest is I detected two more shagged threads on this head - one I know about on the inlet and a new one on the exhaust.

As per a previous "engineering mod" on the exhaust I have tapped them out to M10, then I can put in M10 studding, and an M10 nut then clamps the parts together. The previous stripped thread was detected about 6 years ago and I took this approach and it works really well. And it's cheap, to boot!

The nut is undone first then the studding is removed when working on the exhaust. This means that the studding is screwed in/out with no force on the threads.

[ferlin]

adam quantrill said:

Cheers I already have the replacements - two row ones made by Elring Klinger (recommended by Martin). Here's a piccie (please ignore the greasy thumb prints...):



Also bear in mind that the other side is the same as the one I just took off, and there have been no problems there so far...

It would be worth measuring the thickness of new one and comparing it to the old one.
But really you should just change the pair and do both sides Adam because next month the other side may just fail too and you will be back to square one. It failed for an unknown reason which makes it even more important to do the pair.

[adam quantrill]

I have been looking at the gasket again and put it back on the head while I offered up the refurbed head up to check the studs will go in OK.

While it was sitting there the problem became very apparent - the sealing ring on that piston has distorted outwards too. I believe it's due to inadequate re-torquing on that row of studs.

I don't think the other side will necessarily fail because it's been there two years now. Besides to do that side I have to remove the supercharger which is a pile more work. With infinite time I would do both sides but I don't think the extra effort is necessary, and I always have the option to do that if needed while leaving the offside alone, at a later date.

[Number 7]

What figure are you torqueing them to Adam? From distant memory, mine are done to 70ft lbs.

[adam quantrill]

THe standard as per the ARP instructions, which is 40, then 60, then 80-lbf all done in the usual tightening sequence.

Then after a bit of use, re-torque to 80lbf.

The fine (upper) threads and the washer must be lubricated, too.

[adam quantrill]

Ratchets set to "do up" and it's going back together!

The head is on and just needs its final 80lbf torquing.

Just going through the seed tray putting back volts, and a few nuts - it's a good way to organise the bits.

[Boosted LS1]

It takes a lot of force to distort a gasket fire ring so I'd put it down to detonation but maybe over a period of time. If it was just a clamping issue the gasket wouldn't be distorted as the pressure would be released around the gasket imo.

[adam quantrill]

Possible I suppose - the outer cylinders run a little leaner do they not? Maybe it was a by product of the "cutting out" syndrome I had, when the fuel starved it had a couple of too-lean detonations? As I have since fixed that, maybe it won't recur. Time will tell.

[V8 Fettler]

RPi mention issues with "> poor fuel distribution and weak mixtures eventually cause detonation <" with regards to supercharging an RV8.

Don't know how it will eventually cause detonation, surely if the conditions are right for detonation then it will occur instantaneously. Looks like you'll need an AFR sensor in each of your headers Adam!

[adam quantrill]

Yeah just to recap a little - before the previous re-gasketing I had smooth (!) acceleration but eventually the coolant burping became intolerable.

After a while after the overhaul I started getting this "cutting out" problem where the engine would cut out if I pulled out to overtake. Turns out that was the fuel pre-filter clogged and the pipe from there collapsing under vacuum. Each time it cut out the fuel would be starved but I guess not immediately, it would take a few injector cycles to use up the exiting rail pressure, so it must have run lean.

There is a clear warning on the DPR installation sheet - any misfire and contact DPR - so I guess Dennis must have been well aware of the potential outcomes.

Maybe I need an AFR at every exhaust port! ;^)

[mrzigazaga]

adam quantrill said:

Maybe I need an AFR at every exhaust port! ;^)

And good quality gaskets all round and ideally an up-to-date ignition system....Detonation happens a lot quicker in a supercharged engine and can be catastrophic , Mechanical systems were "adequate" but they do struggle to keep on top of things...Any weaknesses anywhere and the blower WILL find it!....Are you sure that only replacing a head gasket on one side is advisable?..If you have a composite gasket on one side and the brothers grim on the other then surely the CR will be lower in only one head?....I might be talking twaddle ...Or i might not......

[V8 Fettler]

mrzigazaga said:

adam quantrill said:

Maybe I need an AFR at every exhaust port! ;^)

And good quality gaskets all round and ideally an up-to-date ignition system....Detonation happens a lot quicker in a supercharged engine and can be catastrophic , Mechanical systems were "adequate" but they do struggle to keep on top of things...Any weaknesses anywhere and the blower WILL find it!....Are you sure that only replacing a head gasket on one side is advisable?..If you have a composite gasket on one side and the brothers grim on the other then surely the CR will be lower in only one head?....I might be talking twaddle ...Or i might not......

It will be close enough! Probably

[adam quantrill]

Both sides are composite! (And have been since before I got the car) I'm not that silly. The only question is what the exact compressed thickness is of each side is, I think I can estimate this from the old gasket which has compressed and uncompressed regions, and a new unused gasket.

I did try asking the gasket manufacturers about this but they couldn't even come up with an uncompressed specification (poor show really.)

[mrzigazaga]

adam quantrill said:

The only question is what the exact compressed thickness is of each side is, I think I can estimate this from the old gasket which has compressed and uncompressed regions, and a new unused gasket.

I did try asking the gasket manufacturers about this but they couldn't even come up with an uncompressed specification (poor show really.)

Was this the one from Grimmers?....As said it will probably be fine but i thought i would ask...You don't want to be doing the other side in a couple of months time!!

[Sardonicus]

adam quantrill said:

Both sides are composite! (And have been since before I got the car) I'm not that silly. The only question is what the exact compressed thickness is of each side is, I think I can estimate this from the old gasket which has compressed and uncompressed regions, and a new unused gasket.

I did try asking the gasket manufacturers about this but they couldn't even come up with an uncompressed specification (poor show really.)

Elring are 1.3mm new and 1.26/1.28 used after 100k + miles cant vouch for pattern compo's but the last set I measured were 1.3mm again but cant vouch for the above Elring staying tolerence after mileage covered for the cost involved I see no point in using anything for a stock to a warmed over rebuild than Elring, at £13 ea a no brainer IMO there are even guys using moderate rates of NOS and various forced induction with no issues using Elring and have been for some time .... whats not to get?

[Boosted LS1]

adam quantrill said:

Both sides are composite! (And have been since before I got the car) I'm not that silly. The only question is what the exact compressed thickness is of each side is, I think I can estimate this from the old gasket which has compressed and uncompressed regions, and a new unused gasket.

I did try asking the gasket manufacturers about this but they couldn't even come up with an uncompressed specification (poor show really.)

You can measure a gasket with a micrometer if it's off the car. The one that's on the car can be measured with feeler guages. .040-045" is quite common for compressed composites. The factory rover 4.6 gaskets are the best ones I've come across.

[rev-erend]

I believe some after market ECU's use an EGT probe to throw in extra fuel if they see excessive temps..

Talking of that - fired mine up on Saturday and the exhaust manifolds went past red almost to opaque .. until we moved the timing a bit.

[adam quantrill]

Nice one Rev - the beast breathes again...

While people are revealing technical data, do Elring also specify the roughness of the head/block surfaces? (I have heard it doesn't do to have them too smooth...)

These later composites also seem to have little prickles all over them in the dark grey areas, which come out and bite into the head side. I guess that helps to stop things moving about.

[V8 Fettler]

Good to read it's up and running (is that what the breathing bit means?). How many hours?

Edit: Ah, you mean Rev's car