SE or Sprint cams in an old engine?

[el-saturn]

ebay has a lovely 11mil pair up for grabs (like mine) and if fun factor means something to ya, i'd take those - otherwise you just may enjoy originality which is also cool sandy: to old ta change!

[nigelrbfurness]

Nigel,
Thanks for that summary. I had a S130/5 and that pulled like a train with extra lifts at 2500 and 5000 rpm despite the extra weight. It felt like a bigger engine. I thought SE cams might have taken me a little way there but perhaps it's all in the gearing. After all, they dropped the Sprint to a 3.7 diff from 3.55 as fitted to the Super SE to emphasise the acceleration.

Yes, old as in 275,000 miles but still the original crank (showing 0.001" wear) while cams still look good and used to be run regularly to 6,500; the secret of long life is to warm the engine thoroughly and I fitted an oil temp gauge. Re-sleeve was ten years/33,000 miles ago and you've probably seen my recent thread on head bolts.

I think perhaps I'll rebuild as standard and then check the compression, which I haven't done recently. If that is good then changing the cams is not a big deal and I can always change back. I had hoped someone might respond about Sprint cams with virtually everything else standard but perhaps that's too much of a mis-match and the extra torque might damage the (old) drive train.

Bear in mind that the Sprint (D-type profile) cams first appeared with the Stromberg S/E engine with a slightly higher compression ratio and standard inlet valves. Allegedly this was to counteract the loss of power caused by switching to Strombergs from Webers. I've driven Stromberg S/E cars that go very well indeed, but the gearing is very significant for Weber engined cars due to the duration of the changeover point form idle jets to main jets. So perhaps that adds a little to what you are looking for.

[Quart Meg Miles]

Congratulations are due, I have just won the eBay auction for SE cams! I placed my bid while it was showing ?62, just seconds before limit time, but my link was slow and when the auction ended it was for ?75 so I assumed I'd missed it, having bid much higher. Then I got an email saying I'd won at ?75.55!

So if I'd bid ?1000 does it mean I would still only pay ?75.55? I don't understand it.

Thanks for everybody's advice and comments, I'll update later on how it performs.

[ericbushby]

Meg,
With ebay the winner pays their bid price or one increment over the second highest bid wichever is the lower.
The increment is decided by ebay and increases as the price increases.
So the underbidder must have bid one increment less than ?75.55.
If you had bid ?1000.00 then you would have still paid the same because you were the highest bidder.
If someone else decides to put in an equally silly bid to ensure they get it, then you may well have had to pay ?1000.00
A dangerous tactic!
Hope this explains it,
Eric in Burnley
S3SE DHC

[Quart Meg Miles]

Thanks Eric, I had assumed that is what had happened but it does seem a strange system; if you win with a bid you should have to pay what you bid. But I'm delighted!

Can you only make one bid per item? It does specify "Enter your maximum bid" suggesting that you can't respond to a higher one, making it a Dutch auction.

[ericbushby]

It is a similar system to leaving a bid with any auctioneer. It is his job to bid for you to purchase the lot on your behalf at the lowest price possible. He should not take pretend bids to run you up to your maximum, if he is a honest fellow.
On ebay you will be offered the option to increase your bid at any time,
Eric in Burnley

[Orsom Weels]

OK guys, What have I got then ? I have an early twincam, LP3489 LBA, four bolt crank, mk 1 head, all std valve sizes, un-skimmed & correct compression ratio, std Lotus spec'd 40 DCOE's & correct spec dizzy for std engine. The cam's have no groove or identifying marks, they give std cam valve timing & have a lift of .374/5. Given the info in MW's book, I had always assumed they were just Lotus std cams.

Do you know what base circle the cams have. That will tell you if they have probably been reground at some stage to a non original lift. 0.375 could never have been a standard production lift as you are just to close to valve spring bind

cheers
Rohan

I don't know what the base circle is, must confess I never thought to measure it. I did measure the lift as the lobes are noticeably taller than the SE cams I had sitting on the bench at the time, but also much skinnier, giving less duration. As said, they give as close to std valve timing for me to just assume that's what they were. Didn't do any other measurements or compare valve springs etc, but the head is actually on my +2 at the moment with those cams in & running on a pair of 151 dcoe's jetted & choked to std specs. It gives shed loads of low end power, very tractable & will tick over at 600 -700 rpm all day long. It does loose out at the top end, but I never really go there much nowadays. I have the correct B/V head needing a rebuild, but haven't got round to it, as much because I like the characteristics of the engine as is, as anything else. Guess I'll get to it one day, but there's always something else to do

QMM, congratulations on getting your cams, you have more luck than me, I've completely given up on ebay, everything I want, it seems the world & it's wife wants too. If it had been me, I suspect they'd have ended up closer to your ?1000 Can't remember the last thing I won, it was a good while ago now.

Regards, Tim

[ianf]

Steve and John,

I may need a water pump and head overhaul soon as well and based near Guildford would be interested in hearing how the work turns out.

Happy if you wish to pm me.

Cheers,

Ian

[Stevie-Heathie]

Hi there, I've no hesitation in recommending Max at MAX500 in Guildford, I'm very happy with the engine upgrade work he has competed on my S3. He also did some work on the clutch and brake systems, first class.

Best
Steve

See thread here:

lotus-twincam-f39/fast-road-twink-two-engine-builders-two-recommendations-t38789-15.html

[ianf]

Thanks Steve,

Thanks for your reply - I hadn't seen your update, sounds great and look forward to hearing the new dyno figure..

Cheers,

Ian