Lotus Elan

New Owner '69 S4 - Unravelling the Mystery

PostPost by: jbeach » Tue Nov 11, 2014 2:47 pm

Hello All,

I'm in South Carolina and just purchased a '69 S4 from out west. So far I'm loving this car, the Elan community, and the whole Elan Experience.

The car has many needs and I'm wrestling them to the ground one at a time. Although this is my first post, I met some members at LOG 34 and they have already been a great help (you know who you are!).

My current project is getting the engine oil leaks under control. At this moment a local British car garage has the head off and is getting ready to do a valve job and replace the related gaskets, etc. The previous owner had this car for 25 years and during that time says he has not removed the head or gone into the engine.

Based on a few hand-written notes and a Dave Bean form with some valve measurements (all delivered with the car), it appears Dave Bean did some work on the engine during the 80s (two owners ago), but the previous owner doesn't know what was done and cannot identify the person from whom he purchased the car in '89. So I can't call that person to ask.

SOOOO, I'm trying to determine what exactly Dave Bean did with the engine. Was it just head work, or did he do a complete rebuild? I've called Ken at Dave Bean and he says Bean doesn't keep records back that far, so no help there.

It appears from some handwritten notes Bean at least may have replaced the cam with a Sprint cam and [i]possibly[i] did a "big valve" replacement. Here's a photo of the camshaft and I ask you to help me confirm it's a Sprint one:

IMG_0248.JPG and


I'm also trying to figure out whether the previous owner/Dave Bean went further into the engine, perhaps a total rebuild. The only clue I have is the pistons, which look like this:

IMG_0236.JPG and


You can see (I think) see "75mm" stamped at the front of the piston. The valve cutouts look rather large. Is this an original Elan piston or a replacement?

Finally (for this post anyway), the exhaust manifold has been changed. This is a federal S4, so originally had the cast manifold. But with this car the crossover has been removed and blocked at the Stromberg carburetors and the cast manifold was replaced with this tubular one. Can you help me identify it?

IMG_0252.JPG and


There are more mysteries, but that's certainly enough for my first post! If you're still awake and interested, please let me know what you think and if further information might be helpful. I have several other photos (numbers forged into the camshaft, photos of the valves, etc.) if that would help.

Many thanks!

John
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PostPost by: pharriso » Tue Nov 11, 2014 2:56 pm

Welcome John,

Your cams have 2 grooves on the front land so can be positively identified as Sprint Cams.

The 75mm marking on the piston is strange to me as the standard bore is 82.55mm.

The exhaust manifold change is common, could be one of many.

p.s. where are you in SC? I'm in Greenville every other week.
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PostPost by: Grizzly » Tue Nov 11, 2014 2:59 pm

I have some QED pistons in my +2s 130 that look identical but mine had been rebored so they have +0.020 stamped on the top. I may well be wrong but i was under the impression the Pistons match the big valve head.

As above Defiantly Sprint cams.

But i may be wrong but weren't all the Big valve head castings Webber of dellorto side drafts? but they could well have fitted new valves?
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PostPost by: Mazzini » Tue Nov 11, 2014 3:02 pm

Welcome to the forum!
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PostPost by: pharriso » Tue Nov 11, 2014 3:06 pm

Grizzly wrote:
But i may be wrong but weren't all the Big valve head castings Webber of dellorto side drafts? but they could well have fitted new valves?


In the UK yes, but all Federal Sprints had Strombergs.
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PostPost by: pharriso » Tue Nov 11, 2014 3:17 pm

Aha.... I think the 75 mm is referring to the stroke... Standard stroke is 72.75mm, if you look at your 2nd picture, you have a spacer plate attached to your engines front cover.

What is the Block part number... look under the exhaust manifold at the rear of the LHS of the block... is it 711M6015?... You may have what we call a stroker...
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PostPost by: john.p.clegg » Tue Nov 11, 2014 3:27 pm

That spacer looks thicker than norm...and an oil reducer fitted in the head feed...

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PostPost by: jbeach » Tue Nov 11, 2014 5:37 pm

I truly appreciate the feedback!

Phil, I'm in Columbia. We have a small place in the mountains just above Greenville. My plan is to spend as much time in that area with the Elan as possible. I would value your review of my car when we can arrange a rendezvous.

Your thoughts on identifying the pistons and block are very interesting. Here is a photo of numbers cast into the block on left, below the exhaust manifold:

IMG_0051.JPG and


I believe the number reads: 2737E6015 with the last character either "3" or "B"

There is indeed a spacer on top of the timing chain cover. I don't know enough about these engines yet to have noticed it. Here is a clear photo:

IMG_0235.JPG and


What does it all mean?

I have more photos if additional information will help.

Thank you!

John
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PostPost by: pharriso » Tue Nov 11, 2014 6:07 pm

jbeach wrote:I truly appreciate the feedback!

Phil, I'm in Columbia. We have a small place in the mountains just above Greenville. My plan is to spend as much time in that area with the Elan as possible. I would value your review of my car when we can arrange a rendezvous.

John


John, that would be fun.

I have PM'd Rohan to get his input on your modded engine. He is the resident expert....
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PostPost by: jbeach » Tue Nov 11, 2014 6:38 pm

Thanks, Phil. Having reviewed Rohan's many contributions to this forum, I know he is a true expert. I look forward to receiving Rohan's guidance on this and the many questions to come!
best,
John
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PostPost by: types26/36 » Tue Nov 11, 2014 6:44 pm

The 2737 block is the first of the 1600 X flow blocks (it pre-dates the 711 block) if it is using the standard Xflow crank it would have a stroke of 77.62mm. There are other crank/conrods available so even this is not definite although I would guess it is the Xflow crank by the spacer.
Dave Bean used to supply those oil restrictors (the small bronze plug) and I would guess he did the whole engine when converting to the tall block, the 2 rings denote it is/was sprint cams but that is not to say they have not been reground to some other spec.
You can usually get a good indication of the bore size by taking a vernier and measuring across the top of the bore.
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PostPost by: john.p.clegg » Tue Nov 11, 2014 7:12 pm

The tops of the pistons don't look " standard ",missing the " ring "...

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PostPost by: jbeach » Tue Nov 11, 2014 7:18 pm

Thanks Brian,

This is at once exciting, surprising, and shocking. I cannot imagine my previous owner having this car for 25 years and not knowing it has a 1600 "tall" block. He stated this was his 3rd Elan, so if that is true, he was definitely not an amateur. Still, stranger things have occurred and I'm very pleased if this turns out to be correct!

For what it's worth (and I don't know enough to know what it's worth) my previous owner removed an oil cooler that was on the car when he purchased it in 1989. The cooler and related piping were in a box in the trunk when I took delivery.

Again speaking from ignorance, but it surprises me that someone would have gone to the trouble and expense of replacing the block, cams, valves, etc., and kept the Strombergs. Thoughts?

Best,

John
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PostPost by: jbeach » Tue Nov 11, 2014 7:27 pm

Thanks John. I don't know what the "ring" is but based upon my limited knowledge, these pistons don't look standard to me either. The valve cutouts look a little too deep to me, but what do I know? Was there some difference between cast and forged pistons that might help solve the piston question?
best,
John
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PostPost by: types26/36 » Tue Nov 11, 2014 8:38 pm

Here is a Sprint piston to compare, yours appears to be flat compared to a slight raised centre portion on the Sprint piston. It could have been machined down to lower the CR or get the deck height correct.
That does not explain the 75mm mark though unless it was stamped again.... or maybe it was just a set of custom pistons?
I think the 75mm means 0.75mm which is basically 0.030" overbore (approx)
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