Engine build for the S1 - Done

[cabc26b]

Its taken a year or so to get critical mass. Spring/Summer of 2010 Might just be when this ?lan returns to service after being in mothballs since 1984 ?

What?s been done to date ?

First decision was to keep the integrity of the original MK1 motor numbered to the car ? I figured the best way to do this was to use a low mileage donor motor ( another piece that has been in mothballs since the 80?s

I dismantled the engine and send off the head 9 months ago with instructions to make the most out it while keeping to the letter on FIA regs - Headwork was done by Omnitech , numbers look pretty good ? keeping the valves small allow me to run more lift than my 1.65? motor ( .510 vs .46/.47 intake?s) Head ships this week !

Bottom end is just back from the machine shop ? all that?s been done is to bore the cylinders to match the new JE pistons. Also had the small end of the Carrillo rods clearanced for the pins . Next step is to trail fit the crank ( stock stroke) and fit pistons to check the deck. If the block needs work then its off to the machine shop - We will also check the clearance on the rods /block , sometimes you have to chamfer the block b/c Carrillo?s are wider than the stock rods. Yes, I know my rods and crank are illegal for FIA - The iron crank and 125E rods will be kept just in case it ever comes to that.

I will attempt to keep this thread going through the dyno test on the motor - I still have decisions to make , so, i would like to keep this thread interactive so please feel free to jump in with opinions , prior experience ,facts and tricks of the trade . Who knows we may end up capturing a good reservoir of twin cam tribal knowledge.

George

[gjz30075]

George, it all looks good but I'm wondering about the main caps. Are those the ones you're going to use? If so, I'm wondering why you didn't go with the bigger caps found on later TCs and 1600s? But....maybe that's not an issue?
Just wondering.....

Greg Z
'72 Sprint

[rgh0]

Looks like a nice engine is coming together

What revs are you plannning to run ? - are the original round main bearing caps an FIA requirement as they start to get marginal up around 8000 rpm I believe. Do most FIA racers replace them ??

cheers Rohan

[gino1]

Hi George,
Your doing exactly what I'm doing with the same makes of parts except for the main bearing caps. I will be using an L block I found with LA stamped on it and some machined steel main caps to take the higher revs.
Farndon also do some FIA legal main caps that look just the same as the ones you have.
My mate in Italy, Montanari who specialises in racing Twin cams, uses all FIA legal stuff from Farndon (GAF) and revs to 9000 RPM without problems.

Gino Milano
Italy.

[cabc26b]

Gents ,

Thanks for the pointer on the caps , The Jury is out for the time being. I asked this question going in " do you want me to order the steel caps" , answer was not necessarily , If we have to line bore , then the new caps will be uprated.

On FIA compliance I am hoping Dag or Andy will pipe up as I have heard both the use of clever copies and only oem ( could also be moot as the crank and rods are not fia legal) .

However , we are not thinking that the engine will be rev'd like my non-compliant engine with billet caps and 12 bolt crank & dry sump that routinely saw 9000 RPM - The way this one works , it may be pointless to venture beyond 8000-

Thinking I may want to revisit - but have never been steered wrong by the guy who I use for this stuff -

Keep the comments and suggestions coming - I'll report back with findings and updates on my end.

George

[Dag-Henning]

Looks good indeed. Yes, the round caps are a FIA requirement in "pre -65" , as well as 4 bolt crank. According to App-K of the rules , only caps made by Classic Motorsport Ltd. ( I do no know them...) are legal. and they are supposed to carry a number " 95.1" . There is a Swiss manufacturer as well of round caps in EN 19 material, that are widely used.
Again, they are not listed , but "everyone " use them. "If they look right, they are legal......" .
Furthermore, I see you have "full flow" of oil to the head.....Has the item of restrictor in the passage been discussed on this forum before ??

Dag

[GrUmPyBoDgEr]

Hi,
I'm not an FIA racer but have followed Historic Motor Sport in GB for some while.
Not being an FIA racer I'm prepared to say that I've not heard of anyone demanding that a Competitors engine be stripped to ensure accordance with the "Rules".
Uppermost in Historic categories is good racing & the preservation of Historic Machinery.
You have a nice Crank & rods that won't break too quickly but Twincam Blocks etc. are getting scarce.
A set of steel Main Bearing Caps with the required Line Bore would keep you car on the track without endangering it as much.
I've known of much greater "hidden" changes to Historic Race Engines.
That's Life!


If anyone considers this posting "Riske" I'll willingly Delete.
John

[Dag-Henning]

Well John, you are of course right..... - rules are one thing, what goes is another..... I know TCs that run with "billet" caps in FIA events, and the risk belongs entirely to the owner. I do wish no engine would be opened up, but last year's Goodwood Revival required all Minis to present themselves for scruteneering with head off block......

Dag

[batfish]

Hi George

As Dag says the caps are specified. However the specialist building my race engine told me last November that he could not get them from that scource and so he had some made to the correct spec. They look to me to be machined to the correct shape from steel billet and possibly not strictly legal.

Regards
Andy

[cabc26b]

This thread is turning out exactly as I hoped -

Thanks to Dag, Andy and John for also weighing in - Now, I need certain back channel contributors to go public so there is a single repository .

Ok so on the subject of main caps, 1st , no one is arguing that the steel ones are stronger. The engine guys I am using during this process agree that steel is stronger as well. However neither can recall a stock one failing . In addition they both are recalcitrant to take a really nice block and send it off for unnecessary line-boring. John said if i really wanted to, go find some 711M caps and fit the best set so that only a hone is necessary , btw he said these never failed when used in FAtl engines ( I think these are were the billet caps were rule of thumb )

SO,
Can any one add more data on the stock caps - ie, they absolutely fail at a given rev range, I used them and they broke trashing my engine at XXXX RPM. does a fully counter weighted crank help or hurt ?

a data point on when the race engine formula change over occurred and why -

data points on machine shops making a mess of the refit of new caps.

Let me know , in the mean time I will go get a third ( maybe fourth) opinion here in NA.

George

[GrUmPyBoDgEr]

This thread is turning out exactly as I hoped -

Thanks to Dag, Andy and John for also weighing in - Now, I need certain back channel contributors to go public so there is a single repository .

Ok so on the subject of main caps, 1st , no one is arguing that the steel ones are stronger. The engine guys I am using during this process agree that steel is stronger as well. However neither can recall a stock one failing . In addition they both are recalcitrant to take a really nice block and send it off for unnecessary line-boring. John said if i really wanted to, go find some 711M caps and fit the best set so that only a hone is necessary , btw he said these never failed when used in FAtl engines ( I think these are were the billet caps were rule of thumb )

SO,
Can any one add more data on the stock caps - ie, they absolutely fail at a given rev range, I used them and they broke trashing my engine at XXXX RPM. does a fully counter weighted crank help or hurt ?



a data point on when the race engine formula change over occurred and why -

data points on machine shops making a mess of the refit of new caps.

Let me know , in the mean time I will go get a third ( maybe fourth) opinion here in NA.

George

My goodness, you do use some strange Phrases.
Do I understand from your 1st Sentence that you expect the Racers to tell the World what's inside their Engines, that's a great sense of humour you have there

Nevertheless good luck with your rebuild & rely on your own conscience George.
Having reached the extent of my Knowledge, I'm out of here.
Cheers
John

[cabc26b]

My goodness, you do use some strange Phrases.
Do I understand from your 1st Sentence that you expect the Racers to tell the World what's inside their Engines, that's a great sense of humour you have there

Hi John,

Nope, not looking for anybody to open the kimono so to speak ( is this what you would consider strange or is this an example of Riske ? ) . The reason behind asking questions in the thread is I want to tap into any insight that is available and then look for the best way forward - an example of this would be Rohan's post on ports awhile back - I saw the McCoy work and it coincided Ingram's Hiatus ( great prior experience with tony BTW ) so I went with McCoy. This lead to a discussion on doing an FIA head. I am taking every opportunity to examine the status quo

I took the comments on main caps and went back to examine the pros and cons of the round vs Square , billet vs round steel vs iron - we are working up a plan now based on me asking not to use the rounds ( what exactly is wrong with the rounds other than no one uses them is still an open item).

G

[GrUmPyBoDgEr]

Sorry but I'm going to have to back down here.
My Twincam experience ended 30 years ago; back then "the Boys in the know" advised me to use Steel Main Caps which was not a problem then because Twincams weren't classed as Historic.
This Folk Lore has just been handed down as being the thing one should or must do.
The Racers on here will know what the probability is of an old round Iron Cap breaking.
Having seen all of the nice shiny bits your putting into your rebuild I would not hesitate at uprating the Caps to best Spec.
It would be such a shame if a Cap let go & caused all of those expensive bits to go Bang

The main point is that the Scrutineers will only start to want to look inside your Engine if you start winning everything, is there much chance of that happening?

Cheers
John

[dusty]

The main point is that the Scrutineers will only start to want to look inside your Engine if you start winning everything, is there much chance of that happening?

Cheers
John

Or if they read this thread

[GrUmPyBoDgEr]

The main point is that the Scrutineers will only start to want to look inside your Engine if you start winning everything, is there much chance of that happening?

Cheers
John

Or if they read this thread

Dusty,
I think they know what goes on.
A Nod's as good as a Wink provided everyone has a good time.
It's not as though there's big Prize Money to be won in Historic Racing or?
As previously stated, I'm not a Racer & everything I've written here is mere assumption & cannot be regarded in anyway to be factual.

Cheers
John