Right back to where I started four years ago

[FarmyardPants]

julian64 said:

Replacing core plugs on this and giving the engine a dust over was much easier this way. Not a cerb, but equally loveable

I bet the induction on that sounds nice

[julian64]

FarmyardPants said:

julian64 said:

Replacing core plugs on this and giving the engine a dust over was much easier this way. Not a cerb, but equally loveable

I bet the induction on that sounds nice

If I knew what I was doing I'd record it to share. But yes, its similar to the Cerb in the fact that the faster it goes the better it sounds.

[ukkid35]

Definitive proof of HGF, this time. No obvious sign of failure last time.

Perhaps four years ago it was simply much earlier and less obvious to detect, this time I did run the car until it was losing 2 litres per lap of the Ring.





It was cylinder 2 that failed, here are my compression numbers from four years ago

1 235
3 225
5 235
7 260

2 255
4 260
6 245
8 245

So it is possible that pinking played a part, and it is also the where one the front 14mm head nuts has to work, and I had issues with the weld failing on the tool I used.

So perhaps this is a combination of factors:

Incorrect head nut torque
High compression and pinking
Overheating
Track use

I also have an oil leak from around cylinder 1 where oil feeds the head, and where the other 14mm nut is.

Bizarrely I am quite pleased to see that it is HGF, because at least I know that a new pair of gaskets will enable me to use the car again. Last time I was confused and annoyed when it continued to lose coolant after replacing the head gaskets.

This time I have decided to fork out for a new duplex cam chain, that and the much higher cost of gaskets means that my parts cost is now a quite significant sum at £400.

[ukkid35]

A couple of weeks ago I cleaned up the heads only to decide that they could not go back on without another skim. I really wanted to avoid that as I really don't think there's enough material to do another skim. But the area under the fire ring where the gaskets were leaking has causing significant damage, and ignoring it seemed like a fools paradise.





I took them to a truly eccentric outfit recommended by Charlie at SRR, and they seem to have done a reasonably minimalist job, but even so it's still cranking up the CR and making it even more difficult to refit the timing cover and injectors/fuel rail.

I'm bracing myself for more pinking and I'm planning another trip to Joolz for a remap.

However I need to put the car back together before I can get up to Chesterfield, and I have DN13 booked in just 17 days time. If I can get back to the Ring for DN13 it will be a real accomplishment.

[jammy_basturd]

I know you prefer to keep costs down, but for the sake of saving the cost of another rebuild further down the line, could you not either see if anyone has some second hand heads, or alternatively get a custom, thick head gasket made up, or a spacer?

[ukkid35]

jammy_basturd said:

I know you prefer to keep costs down, but for the sake of saving the cost of another rebuild further down the line, could you not either see if anyone has some second hand heads, or alternatively get a custom, thick head gasket made up, or a spacer?

James you are absolutely right. I should definitely try to get some custom gaskets made, or find some replacement heads. Either would be a very good idea, but I have sunk a fortune in to DN events this year, and although I had a brilliant time in the 928 when the T5WC failed on the way to the Ring in April, I don't really want go back in the elderly 230k mile Porsche again this year. So I need to have a working car again in a matter of days (and I absolutely prefer to keep costs down).

However, worst case scenario and the engine runs like a dog, where do I get custom gaskets? Who makes them - Cometic?

I think custom gaskets would be less impossible than finding replacement heads - I'm assuming they don't really exist unless you buy a whole engine from one of our favorite Northumberland based scrap merchants.

Just between you and me, I just trashed a new head gasket on Friday because I only seated one head before torquing it to spec. When I fitted the second head I realised that I'd used two incorrect size washers under the inner kaylocs - Noooooo!!!! That was a £140 mistake, luckily RG were open yesterday so I could go buy a replacement, but it still hurt. I've done this job before, so I really don't understand how I could >?:@ it up so badly, oh well - only engine timing to go (I hate that job even more).

[m4tti]

Do you know what the root cause of the HG failure was? (Sorry if already posted)

[Gazzab]

Andy at APM mentioned thicker gaskets to me once. I assume they are comtec (?).
On my car we had to take more meat off the heads and so to be safe we wired it and fitted copper gaskets. That was 2 yrs ago I guess and no problems.

[ukkid35]

Gazzab said:

Andy at APM mentioned thicker gaskets to me once. I assume they are comtec (?).
On my car we had to take more meat off the heads and so to be safe we wired it and fitted copper gaskets. That was 2 yrs ago I guess and no problems.

This is a £500 repair for me. If I have to do anything more esoteric I would need to hand over the engine to someone else and it becomes a £5k job, which is not an option. It would make more sense for me to buy a used engine and try to make use of that than go for a high end rebuild.

[ukkid35]

m4tti said:

Do you know what the root cause of the HG failure was? (Sorry if already posted)

ukkid35 said:

I have a theory about the cause of HGF, but it's just a guess, I'd be interested to hear other suggestions.

Firstly my car does pink briefly if I'm not gentle with the throttle around 2k. Joolz got rid of most of the pinking, but a little always remained, exacerbated by hot weather or traffic. I think this has probably weakened the HGs.

Secondly, I have run low on coolant several times for several different reasons. I had a rad leak and didn't realise. That was two years ago and probably the worst overheat, because I didn't believe the temp gauge (I'd only recently had it repaired and I assumed it had gone wrong again).

On another occasion my car dumped most of it's coolant through the expansion tank cap relief while in hideous traffic in Luxembourg. I think that was due to the temp sensor under-reading, and therefore failing to switch on the fans (it would show 70C while cruising using the diags).

Over the last couple of months it has simply being over-pressuring, and expelling coolant. I have replaced the temp sender, and thermostat, and expansion tank cap, and each time the symptoms got a bit better. Probably because each had been damaged due to the system overheating. Each time I hoped it had been cured, because I wouldn't loose much on a run, perhaps just a cup or two.

However, by the time I got to the Ring on Wednesday, it was using a litre per hour. By the end of the second day it was using 2 litres a lap.

I didn't let that stop me have a brilliant time, because it was no different to drive, other than a little harder to start, presumably because it was sucking coolant in to the cylinders when cooling.

I am really not looking forward to taking the heads off again. At least I know what I'm letting myself in for this time.

[ukkid35]

Pre and post skim pics of the HGF area (at somewhat different magnification)





Combustion chamber has been seriously mullered by the HGF compared with other cylinders (piston was nice and clean though).

[Flatdash]

Is there no possibility of restoring the block face with an aluminum spray and re-maching such as Dymet ? .. just an idea.

[Jhonno]

Glad to see this is progressing Paul.. I'll keep my fingers crossed you can make DN13.. Shame you didn't think of the thicker HG earlier, it wouldn't have been much more expense, but yielded a better result for you longer term.

[ukkid35]

Jhonno said:

Glad to see this is progressing Paul.. I'll keep my fingers crossed you can make DN13.. Shame you didn't think of the thicker HG earlier, it wouldn't have been much more expense, but yielded a better result for you longer term.

I could always add a button to the dash and then call it a Red Rose...

[Jhonno]

Must be somewhere near the right CR now..

[ukkid35]

I've decided to route the temp gauge capillary along the chassis rail rather than the water rail, far less scope for damage from vibration etc.

And I've tried to protect the passenger side from further damage from coolant escaping from the expansion tank overflow.

Edited by ukkid35 on Thursday 17th September 06:34

[ukkid35]

But the best thing I did was mark the cams before removing them





So I've been able to match the odd and even bank from just the odd bank TDC, which is massively reassuring. That does assume that the cam timing was right before the repair, but since I asked Andy at APM to check it for me I am confident that all is correct.

[a1rak]

Hi Paul Ace café meetings have been rained off so haven't seen much of you this summer. Before you re assemble the engine are you sure the liner height is spot on. It makes no difference if you have flat even heads if a liner has dropped. You need a good set engineers parallels put them across the liner and measure how much higher the liners are than the block walls. You ideally need around 6thou and they must all be even to within a few thou. You may find one has dropped or one has always been high from new. Either way it will wreck your gaskets.

[steve320ise]

Hi, how many miles did it do before the hg failed , and did you have the heads skimmed last time , the unskimmed photo looks very worn and the skimmed one looks like it could do with a little more off,Im on with mine and so not looking forward to it going again, just a note skimming the head is about surface finish as well as being flat, all the very best I will keep my fingers crossed for you, Cheers

[ukkid35]

a1rak said:

Hi Paul Ace café meetings have been rained off so haven't seen much of you this summer. Before you re assemble the engine are you sure the liner height is spot on. It makes no difference if you have flat even heads if a liner has dropped. You need a good set engineers parallels put them across the liner and measure how much higher the liners are than the block walls. You ideally need around 6thou and they must all be even to within a few thou. You may find one has dropped or one has always been high from new. Either way it will wreck your gaskets.

Thanks Paul, but the engine is all buttoned up now, so I will have to keep my fingers crossed about the liners. Fortunately this has been a relatively inexpensive repair albeit rather time consuming. If I had found the liner had slipped it would be an entirely different ball game, as I wouldn't be able to do anything about it myself, so it probably would end up being a full engine rebuild costing several thousand pounds, which really isn't an option. Hopefully the gasket will hold this time, and I'll managed to keep it from overheating again.