Cylinder Head Refubishment -Who?

[englishmaninwales]

Pulled the CH this weekend to attend to the oil leak (torrent!!) from the CH/front cover joint and deal with the tight cam follower clearances.
On balance decided to have the CH checked, refurbished and there are some problems I need advice/sorting.
The question is who to entrust the work to? I am located in north Wales.
Vulcan, comes to mind but are miles away, any other suggestions (NW England or Midlands)? QED and Burton only really deal in spares.
Thanks
Malcolm

[DavidLB]

How about Paul Exon. he was QED engineer. very happy with the work he did for me
David

[promotor]

John Wilcox Engines.

(Wayne) Mitchell Competition Engines - Bridgnorth, Shropshire. He used to work for Millington Engines.

Oselli Engineering

[englishmaninwales]

Thanks for the suggestions.

Malcolm

[RichardHawkins]

Malcolm,

Whoever you use, make sure that they have the capability to do the work themselves, and don't simply sub contract to another company. The time spent sorting out bad work will make the time spent travelling to someone competent seem of no consequence.

I took my head to Coventry Boring and Metalling, and although I thought they were competent, the work was poor. After some difficulties Coventry Boring compensated me, and I went to Serdi UK in Uxbridge West London, and am very pleased.

Coventry Boring and Metalling was a strange experience. They had the facilities, and were working on some very expensive engines, they had a Bugatti engine in their workshop. Unfortunately there was something wrong with there quality assurance and management. They did not do all the things I had requested even though I had put my requirements in writing, and the men on the shop floor did not seem to know what I required.

Hopefully they have resolved these problems now.

Just a cautionary tale really.

Richard Hawkins

[512BB]

And well done you, Richard Hawkins, for highlighting a firm that carried out poor work, so that the next Lotus owner on here, does not have to suffer the same fate.

So few on here are prepared to stick there heads above the parapet, and name names, even when they have received crap service. So what happens, the next Lotus owner uses the same company and he receives the same crap service. But that could have been avoided, if some cojones were to be found.

After all, isn't that what forums are all about ? To praise the good firms, but also to point out the bad.

I think I shall take a shower. What a beautiful day.

Leslie

[JJDraper]

Last time I had my head examined (!) it was by Cylinder Head Services of Moulton, Northamptonshire.

http://www.cylinderheadservices.com/contact/

I took them the head, with valves & springs in place and they dismantled, cleaned all parts. Gave the head an examination and a very light skim, refaced the valves and seats (three angle, whatever that means) and reassembled it all ready to fit. Cost was around 240 quid, including tax. Family firm that seems to know what it is doing - familiar with the TC & came recommended by a well known Northampton Lotus specialist. I delivered & picked up the head myself, as I didn't trust anyone with it.... They also supplied new cam shells at trade price. I believe they also do welding if needed..

That was over 6 months ago & the engine has done around 3k miles and feels pretty strong.

Jeremy

[512BB]

Also heard good things about the above company, and from a different source, so thats a bit more conclusive.

But as far as 3 angled seats are concerned, I am sure I read that they are not desireable in a twin cam head, as they will make the head / engine run hotter, due to the angles causing a hot spot.

Perhaps someone more experienced in these matters than me would comment.

Leslie

[rgh0]

Multi angled seats help the port flow better at low valve lifts and can increase engine power. The downside is that it will typically reduce the width of the sealing face ( how much depending on how it is done) which can lead to more rapid deterioration of the sealing surface. This is particularly a problem with the exhaust valves as narrowing the valve seat reduces the cooling the valve gets when sitting on its seat each cycle, leading to hotter running exhaust valves and thus more likely hood of deterioration to the sealing face. It is less of a problem with inlet valves as they are cooled by the incoming fuel air mix in addition to cooling via contact with the seats

A race engine normally uses the narrowest possible valve seat and with multi-angle seats in the search for every last increment of port flow and power. Long term reliability is not the key objective.

Going to these extremes is not warranted in a road engine and it is best to stay with near the standard seat width if going with three angle seats which limits to some degree the gains in order not to compromise reliability. A good cylinder head machine shop should be able to advise on the best option for your particular application.

Given that the twincam exhaust port breaths very well there is no real need for seat modifications on the exhaust port and multi angle seats are really only a benefit worth considering on the inlet side especially for a road engine IMHO

cheers
Rohan

[dougal9887]

My cylinder head is with Agra Engineering in Dundee for guides, seats etc.
They have huge twin cam experience dating from the early '70s.
I arrived with my list of instructions!
I gave them the details of the build and the car's intended road use.
On the subject of exhaust valve seats, I requested 3 angles on inlet and 45deg on exhaust, they said that they preferred 3 angles on the exhaust also and the seat provided would be sufficiently wide to provide adequate cooling for longevity.
I also asked them to make up a short tube to take the place of a spring so that I could measure the fitted spring length for shimming. They asked if I was going to measure the individual springs loads to take that into account whilst shimming.
I handed the lot over to them!

Dougal.

[adigra]

I ended up having a poor experience with Exon, suggested above, although many others have had good work done by them. I could only guess why the work done on my engine was so poor, but I had to have the engine rebuilt again due to lack of quality control at Exon. I am happy to go on record regarding this as I have photographs of the issues. One of the pistons was fitted back to front, and none of them were skimmed to suit, so were touching the head. The oil return pipe also fell off and was being chewed by the crank. Combined with the fresh paint flaking off within 1000 miles, it's an understatement to say I was unimpressed.

The parts they supplied were top quality, but the assembly work carried out was poor.

[JJDraper]

Perhaps I should have asked more when I took the head in... A quick internet search on 'Three Angle Valve' produces a torrent of info.... Another thing to worry about. I knew it would provoke some discussion!

I will keep an eye on the valve clearances, but I suspect the shop knew what it was doing - they knew it was for a street engine and who recommended them - they have a reputation to keep. They do cylinder heads and not much else...

He did comment that the metal of the head was showing 'granular inclusions' which he said was common on older alloy heads - see the surface speckles in the pics. Valve seats look reasonably wide to me, but I am not annengineer of that sort.

Jeremy

[a d price]

My elan is in Kendrick motors Llangollen for some work. I am due to move house in the next two weeks so they are storing it for me.Dont know what their work is like but the owner has two elans of his own which must be a good sign. You could ask them for advice
Cheers a d price

[512BB]

Adi wrote: I ended up having a poor experience with Exon, suggested above, although many others have had good work done by them. I could only guess why the work done on my engine was so poor, but I had to have the engine rebuilt again due to lack of quality control at Exon. I am happy to go on record regarding this as I have photographs of the issues. One of the pistons was fitted back to front, and none of them were skimmed to suit, so were touching the head. The oil return pipe also fell off and was being chewed by the crank. Combined with the fresh paint flaking off within 1000 miles, it's an understatement to say I was unimpressed.

The parts they supplied were top quality, but the assembly work carried out was poor.

You see the problem as I see it, is that the main man at any of these firms, be it Exon, Smurf, et al, cannot do all the work, as I would think, they have to much for any one guy to do. So what happens? The spotty youth gets to dirty his hands on your beloved big valve head, and hey presto, he f..ks it up.

Its a nightmare senario, but all you can do it ask loads of questions BEFORE you entrust your work to a given firm. Don,t just go on reputation, as they are won and lost on the very last job. And if you are not completely satisfied with the answers to the questions you have posed, walk away.

And well done to Adi for bringing this sorry tale to our attention. Now people can make an informed decision about Exon. Not saying all their work is crap, as others have had a good experience there. But do not just go on past reputation.

And the forum seems to be working well. Anyone else care to bring to our attention engine firms, good or bad?

Leslie

[jono]

In support of Paul Exon.

He did a nice job on my head last year in fitting new bronze guides. It doesn't use a drop of oil (except for what leaks out of the sump and front cover due to my own dodgy work ) and he clearly got the reaming spot on.

I've got another TC head there for welding at the moment, and a Mini engine for machining, he's obviously flat out though as I am finding him difficult to contact for an update

I agree with Leslie though - the guy who built my engine originally was very well respected and experienced but made some fundamental errors, including in fitting the water pump - I'm thinking that the 'monkey' or sub contractor probably did those bits but perhaps I'm being too kind.

Jon