Lotus Elan

What Happened To My Engine?

PostPost by: Greg Foster » Mon May 16, 2005 2:28 am

I feel for you as I know all too well the same feeling. My s130 did the same thing at a FATT day at Summit Point last October. Chewed up the head a little, knocked a hole in #4 piston . I looked the engine over and found the P.O. had reground the cams to 405s.had deepened the spring seats , milled about .030 off the head and another .020 off the block which was sleeved and then bored .040. on and on all in need of total rebuild. I am processing a kent block to see about a stroker and saving the 701m block for later. I figure about $4.000 in basic materials and another $2500 in shop time plus my own labor. I have heard the cost of replacing the engine with a 2liter Z tech is significantly cheaper and will just about bolt up the same plus extra HP without trying.
I spoke with Quantum Mechanics regarding the T9 5 speed conversion the sell. I think for about $2500 to 2900. Tele# 203-459-9612. Kit comes with an adapter, trans, and driveshaft.
Good Luck
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'72 +2 S130
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PostPost by: types26/36 » Mon May 16, 2005 8:02 am

<!--QuoteBegin-type26owner+May 14 2005, 03:23 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (type26owner @ May 14 2005, 03:23 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin-->
If you need to remove valve guides or seats let me know and I'll tell how it's done the trick, no fuss or bother way..[/quote]
Do you have another method different from the one detailed in the Lotus manual?
if so I would be interested in hearing about it.
Rgds Brian
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PostPost by: type26owner » Mon May 16, 2005 1:52 pm

Hey Brian,
The manual's way is definitely the wrong way to proceed. What I'm going to tell you is the way the professionals that know their trade do it.

The seats are removed first by tack welding in two places 180 degrees apart by a mig or tig welder, the valve to the valve seat. The valve has flats ground on both sides on a belt sander about 3mm into the sealing surface and that's where the tack welds go. The welding is done quickly so the aluminum is not melted. Just quick pulse of heat is all that is needed. The seat is removed by tapping on the stem of the valve with a hammer. By tack welding onto the seat it shrinks it down when it cools so much so it nearly will fall out of the head. Total time of an experienced guy is ten minutes of effort to remove all 8 seats.

The guides are the items that will destroy the head if not removed by the following method. From the cylinder side use a 7/16" counterbore that has a 5/16" pilot in a handheld electric drill motor. The replaceable pilot type counterbores are too weak and break off a lot. Buy or have ground a solid piloted type of counterbore. If you can't then purchase lots of the pilots because you'll break about two off on every guide to be removed. That silicon bronze is tough stuff. The depth of the counterbore hole should be to the far end flush with the bottom of the pocket for the valve spring. Now stick a drift shaft into the hole so it contacts the face in the guide and tap it out. It will also be quite loose and it will not be necessary to tap very hard. What this does is relieve most of the wall thickness of the guide which makes it strong and hold itself firmly in place by the interference fit. Making the wall thin makes it weak. Also by tapping on the face at the far end it pulls the guide out. By pulling on the guide it stretches the metal so it collapses in diameter a tiny bit. The guides will come out without any aluminum stuck on to them normally. Be sure to spray some penetrating lubricant onto the guides before hammering on them and remove any hard carbon deposits. This takes a little longer because machining the bronze is slow since it's tough stuff. 30 minutes is about right to complete this task.

Beware of the ones that are clueless. My buddy had his aluminum Maserati heads destroyed by an idiot just recently done by the manual way. The guides mushroomed out from being pounded on and opened up the bores in the head by at least 0.25mm. Then the guy realized he'd screwed up so without asking he knurled the guides and when that didn't work he just epozied the guides into the heads. My buddy got screwed on that deal.
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