....Cylinder head gasket continuation.....pictures now..

[type26owner]

There is closure here since I too think it was impact damage. The scratch marks of the sander of some kind can be seen clearly in the hemisphere area of the latest picture. Whew, another bullet dodged there berni.

That's the good news, the bad news is the intake valve seating surface is recessed by a chunk. From the looks of it you'll need to have it replaced since the seat edge is below the aluminum already. The original guides look to be still in there too. The bronze guides are far superior but so hard that a reamed finished hole commonly produces a spiral twist in the bore and that's bad. Bronze guides must be honed to size to get a straight bore so choose the repair shop accordingly. Rohan & John, do you guys agree?

Berni, you can check the quality of the valve seating surfaces quickly when you pick the head up by shining a bright flashlight in the ports and looking for any light leaks all around the valve. The bluing paste is the other way it's done to make sure both surfaces have the needed contact area for cooling.

Have them remove the guides by my method only or a lunkhead will destroy your head.

[rgh0]

Keith

I agree that their are better materials than the original cast iron and that machining of these requires special techniques to accurately get the correct clearance which is critical

I have copper-nickel-silicon guides from the Elan Factory in my cylinder heads. If you look at their web site in technical information you can see the guides and the fitting instructions.

Aluminum-bronze guides are also an alternative especially for a road engine.

Rohan

[berni29]

Thank you again for all the help.

I have been trying to find Keith's instructions for guide fitting in the archive but cannot seem to. I learnt quite a bit while looking though! If anyone (Keith you would be best I guess!) point me in the right direction please). I will have a look at the Elan Factory information as well. I just bought some new valve springs from QED. ?20 they charged which seems very reasonable. I have my yearly drive to North Wales coming up at the end of March, so I am going to lap the valves, change the springs and hope for the best. I will have the whole engine out as soon as I get back and then sort things properly. I have a cunning plan to kill most of my Lotus related issues with a single stone!

Many thanks

Berni

[Dave-M]

Quote:: I have a cunning plan to kill most of my Lotus related issues with a single stone! ::Quote

Bernie, Buying a Mondeo are we?
Regards
Dave-M

[purplepete]

berni,we all covet something like that spring tester,but you can do a fair enough job of it with a valvespring compressor,and a pair of bathroom scales,or some other such heath-robinson type of thing.definately go with the idea of grinding your valves in(test with pencil)personally,i'd use a tube of hylomar on the head gasket-gives a good seal,and holds the bugger in place!even if you buy new valvesprings,you'll still need to measure them.good luck.

peter.

[berni29]

Hi There

I will definitely be using some sort of head gasket sealant. I know that in the land of unintended consequences anything can happen, but that cannot be a bad idea for a man in my situation can it? On the cunning plan front my thinking went like this.....I was going to get a Zetec chassis from Spyder and do a Zetec with standard suspension (cannot live with the wheels sticking out/ride height thing) and sell my used galvanised chassis, and eventually sell my current green plus 2 which has a standard Spyder chassis. While doing that I was going to fuel inject the green car to get me part of the way there as it were. Now I think that it might be better to build up the galvanised chassis with my polybushed suspension of my old yellow car and other decent bits, and then plonk (sound easy) the green body on along with the engine on that and use the standard Spyder chassis from the green car for the basis of my Zetec car. That way I can continue to use the green car, have minimal outlay and use the maximum number of bits in house.

Tra - lahhh!

Berni

[john.p.clegg]

Could I suggest Wellseal for the head gasket

John

[marcfuller]

I am not sure what is special about Wellseal, but Wilkins wrote to use only Wellseal or nothing on the head gasket.

[carrierdave]

Hi Berni,
If you use Wellseal (as I do) make sure that once you have applied it you leave it to dry for at least 30 minuts before assembling the parts.

This just ensures that the Wellseal stays between the head and the block and allows the solvent to flash off. Otherwise the Wellseal gets queezed out as soon as you do up the bolts.

Also torque it up at 20, 40 and then 60lbs/2in2 and do it over an hour; this just ensures that there is gradual even pressure applied and any squeezing out of the Wellseal is taken up by the next torque. Then finish with a final torque to the correct pressure.

I have done it this way on the last two occasions and never had a problem.

Good luck
David

[rgh0]

Berni

Keiths method to remove and refit valve guides was as follows.

1. Drill using a pilot guided drill from the bottom of the guide to just before the locating clip groove at the top of the guide. Reduce the wall thickness of the guide by the maximum amount you are confident of drilling without going though the wall.

2. Use a drift the diameter of the pilot drill to tap the guide out from the bottom. The drift seats on the lip where the pilot drill stopped. This pulls the guide out of its hole easily as it stretches and shrinks the guide diameter as it pulls.

3. Refitting per Lotus directions by warming head and chilling guides and then ream correctly to match valve steam diameter.

Rohan

[berni29]

Thank you all again for the help. It is really good to be able to approach the job with the benefit of prior knowledge and experience rather than learning the hard way!

Berni