Twin Cam engine rebuild

[SimonP66]

Hi All,

Happy New Year! I just wanted to start off the year with a question that doesn't seem to have been anbswered recently (not according to the archives anyway!).
My S2 is in need on an engine rebuild so that it can pass the MOT. It smokes quite badly and won't pass in it's current state. I've had someone who knows what he's doing do an leak down test on it and it's looking like rings rather than valve guides.
At the moment I can't afford to spend loads on it but want to get the car passing the MOT. Any ideas for a reliable but cheap engine builder?
I was tempted to do it myslef as i'm reasonably technically minded but have never done an engine before and don't want to make my first mistake on the twink!

Thanks for any help!

[bcmc33]

I was tempted to do it myslef as i'm reasonably technically minded but have never done an engine before and don't want to make my first mistake on the twink!

Don't hesitate - do it yourself, it's the only way to learn.

Where are you? My engine is almost in pieces if you want to come and look to see what it's all about. I can delay taking the crank, conrods and pistons out and we could do that together.

[ftsoft]

Hi All,

Happy New Year! I just wanted to start off the year with a question that doesn't seem to have been anbswered recently (not according to the archives anyway!).
My S2 is in need on an engine rebuild so that it can pass the MOT. It smokes quite badly and won't pass in it's current state. I've had someone who knows what he's doing do an leak down test on it and it's looking like rings rather than valve guides.
At the moment I can't afford to spend loads on it but want to get the car passing the MOT. Any ideas for a reliable but cheap engine builder?
I was tempted to do it myslef as i'm reasonably technically minded but have never done an engine before and don't want to make my first mistake on the twink!

Thanks for any help!

I just got my engine back from a rebuild. I agree that if you have the tools and space, doing it yourself would be good. I've done this in the past (early 70's), but don't have the energy or resources now. I was tempted, because I thought that I only needed a water pump, but as my mechanic got into it, we found rings, rods and mains, broken camshaft, warped head (and blown head gasket of course), leaking Weber float, plus much more. It was expensive to have it done, but if you have enough miles, you will likely find a number of problems that will take some time to address also. If you have the time go for it, just be aware that it might escalate on you. I've always done all of my own work on the car (66 S2), but these problems were a little out my league.

Frank

[gerrym]

Simon, your friend's leak-down test is indicating rings: for a Twincam, this is likely to mean restoring worn bores rather than just replacing rings. You run the risk of the rings not sealing, breaking against a wear "land" at the top of the cylinders etc.

You should really steel yourself for a bottom end rebuild. Strip down and measure and then figure out what needs to be machined, versus what oversize components you will be fitting.

Good news is that so long as your engine has not suffered many earlier rebores, the bottom end is pretty straightforward.

Regards

Gerry

[pauljones]

i know you don't want to spend too much,but if you do need rings,then consider a re-bore out to a safe size and speak to QED about oversize cast piston and ring sets.

i was considering this as an option for a number of reasons,but am going all steel in a 711m block now.

i have no connection with the above,it just seems that it may solve your problem,and if done then you gain more capacity,and higher compression all be it a small one.

Paul

[Allison]

Hi - do engine rebuilds come cheap and if they do are they worthwhile? On the assumption that you don't want to do it too often and on the basis that the engine is the heart of the car (no engine, no car) - get it done by someone who knows their stuff. You were suggesting broken rings which means a rebore and new pistons etc; you didn't mention oil pressure but that might be a regrind of the crank.
If you're in the east of England you could get a quote from Brian Randall on 01359 251888; he's on the Norfolk/Suffolk border near Diss. He did our S3 S/E in September - and the engine's fine (just the rest got a bit smashed up in the Casablanca Rally in November!).
You can always increase the insurance value on the basis of the professional rebuild!

Peter

[Roy Gillett]

Hi Simon,

Having recently done my own rebuild on a Twin cam for my +2, I don't think there is such a thing as a cheap rebuild on a T/C. With QED refurbishing the head and doing the rest of the work myself I spent almost exactly ?3000 on mine and that is without a rebore (but with new pistons - its a long story!) . That said with the Miles Wilkins book and the workshop manual to hand its not too difficult, and I hadn't rebuilt an engine for about 30 years.

Once you open it up, however, I bet you find more wrong with it than you expect. If it has been together for long enough for significant bore / ring wear then other bits will be tired. On mine the jackshaft (the old Ford camshaft) was cracked through for example and the alloy of the head was significantly corroded aft of cylinder 4.

Do it once and do it well.

I am quite close to you over the boarder in Surrey (Wallington) so if you want a chat or to see my (now) spare engine that is out and which I am about to pull apart and examine then I am happy to make contact.

Good luck,

Roy

[david.g.chapman]

You could have a chat with Gosnay's Engineering on the A12 Eastern Avenue in Essex. They gave me a quote for a Twinc bottom end re-build of ?800-?900 in 2004, if you give them the engine - I can't remember the details of the quote (parts extra or not).

I have not used them for many years, but they have been around since 1930.

Dave Chapman.

[sinkyb17]

Hi Simon,

From what you initially posted it seems you do not want to get into a complicated or costly engine rebuild (in fact if your only problem was high levels of smoke and as long as you did not have any serious noises or low oil pressure then a limited rebuild is maybe all that is needed). You have to consider why you have worn or broken rings (indicated from your leakdown test). There can be many reasons for rings problems but by far the most common are caused by high mileage and high engine temperatures and the cyclic effects of rise and fall in temps (resulting in the tension going from the rings hence smoke). A limited engine rebuild is possible by yourself (although I would recomend purchasing the Miles Wilkins engine book for reference) The crucial point of the whole exercise is determining how much wear has taken place in the bores. The measurement of the bores is a must as it will determine the limit of your rebuild. As rule of thumb wear of up to 0.006" (6 thousands of an inch) can be accomodated by new rings provided the pistons are not badly worn. If high engine temperatures are suspected then those issues have to be investigated fully. I have rebuilt engines with those wear dimensions using only Rings, Bearing Shells, Seals & Gaskets, and one is still running 20yrs later and 40,000mls. Believe me it can be done by yourself for a fraction of the price as the labour is probably going to be in the region of ?600 - ?900 for a limited amount of work.

Best of luck

Dave.

[Bruce Crowthorne]

Bear in mind that the bottom end is basically a Ford Anglia! (Well I supose a Consul to be more exact) and the technology is 1950s.
It really is comparatively simple stuff, and doesn't take long.

You can pile on costs by doing "nice to have" jobs like hardened valve seat inserts, but a basic bottom end rebuild is well within an amatuer's capabilities!
I did mine 2 years ago and it's still going strong!

I can't think of anything special that you will need in the way of tools - just a torque wrench.

Go on - think of the satisfaction you will have when it is done.....
Bruce

[john.p.clegg]

the valve spring compressor is an unusual item to get round the intake runners..

John

[SJ Lambert]

Is there a specification range of the "Thickness of the Jackshaft Head", or in other words the thickness of the material from the front of the thrust bearing/bottom/back side of the head of the jackshaft to the mounting surface of the jackshaft sprocket?

In other words, what is the range of thickness of material in front of the bearing in order to get good alignment of the sprocket with the camshaft and crank sprockets?

BTW, I think I know, but I'd like confirmation from others who are definitely in the know - the question arises out of modifications made to the standard set up in order to run a tacho drive off the nose of the jackshaft.

Cheers

Thanks - James.

[SJ Lambert]

The standard FoMoCo late model jackshaft head measures 700 thou and gives good sprocket alignment to the crank in the example I'm looking at right now.