Modifying my 1600 engine

[zetecspit]

The background is that I inherited a Vitesse 1600 from a friend about 3 years ago. Lovely car, the best driving herald/vitesse I have driven, from the sense it felt good. 

There were a few issues. Starting with bodywork, which will need some tidying, but that can wait, it is cosmetic. My kids were going to be using it, and so after nearly 60 years the car got a pair of seatbelts fitted, along with MX5 seats. (amazingly these are a perfect match for the matador red interior). The gearbox was a 3 synchro, so that has been swapped for a 4 syncro, diff swapped to a 3.89 and front brakes are now type 16. 

Next is the engine. In the 1980s it was fitted with strombergs, but Jon (my friend) had fitted the original solex thingies. Hmmm....

So I have just started to see if I can tweak the engine up in power and driveability without anything too dramatic.

Saturday saw the Solex carbs and manifolds off. Next was the head, then the timing cover, swiftly followed by the cam. 

First thing was to check teh mk2 Vitesse cam I had would work, so that was inserted and indeed, it rotates freely. Result.

Next I took a look at the head, which is the later, better, 1600 head. I then looked at the head gasket which was shim steel. It felt very thick, and after a poke, it seperated. There were 2 gaskets fitted. Most odd I thought. The head and the block looked "dirty" as if there was something going on with the gaskets, but no burning/deteriotion around the "fire rings".

I then cleaned the piston tops, lo and behold, +60 pistons. 

Now to the techy part. I want the head skimmed to give a CR of 9.5 and this is my thinking.

Std bore size is 66.75mm  Plus 60 will take that to 68.25mm Stroke is 76mm.

Those figures give a cylinder cc of 278cc  (1668cc total)

From Vizard, CR = (cyl.vol +c)/c where c is combustion chamber total volume

That leads to a required total volume of 32.7cc

Vizard suggest 4.5cc for the head gasket. He uses the same figure for the 2 litre cars, so I am assuming (ouch) it is for a composite gasket which I would like to use. 

That leads to a combustion chamber volume of 28.2cc 

Does that all sound right, or have I lost the plot?

 

[JohnD]

Clive,

While I completely agree with your wish to raise the compression, and think you will see an improvement (albeit small) in performance, your calculations are correct, but theoretical!  A better approach is to measure the volumes concerned, so may I humbly recommend my article    How To Raise The Compression Ratio, Safely And Effectively. - Technical Articles & Reviews - Sideways Technologies ? 
 

John 

 

Edited January 20 by JohnD

[zetecspit]

I have a syringe here to measure the combsution chamber volume, and a bit of clear acrylic. 

What I don't have is a composite gasket to measure. If anybody has a used one to measure, that would be handy. 

I have measured the area of the combusytion chamber using a bit of graph paper and a greasy finger, then counting squares (3 times to make sure it is correct!)

What I am slightly worried about is that all 1600 gaskets are shim steel. With 7/16 studs I have had advice to use a mk2 gasket with extra holes (as sold by Witor). I am assuming the extra cylinder diameter of the 2L cylinders won't be a problem. 

As to power, it is more about driiveability. Even Mr Pearson said that any cam, even a mk1 saloon etc, was a better cam than the 1600 one and a mk2 vitesse cam was a good choice. Hoping to be at around 90bhp when all is done, significantly more than the 70 with the solexes and std cam. (a std 1600 with strombergs was allegedly 84bhp, so hoping cam/CR will give a few extra ponies plus rev more freely, which is what the 1600 is so good at)

Edited January 20 by zetecspit

[JumpingFrog]

I've only encountered a shim gasket once, on an early 1200. IIRC the workshop manual suggests to coat them in Wellseal, which is quite nasty (IMO) brown stuff, might explain a dirty appearance? Another option might be to get a custom head gasket made, but I don't think that will be cheap.

Watching with interest, always been a little curious about the 1600 engine.

Edited January 20 by JumpingFrog

[Nick Jones]

IIRC the composite gaskets squash to about 0.020”. May have one hung on the wall. Will try to look later (at work now).

The brown gunge will be Wellseal. Good luck getting that off!

[zetecspit]

Wellseal (or whatever) is off. But it was also some oily/sooty type deposits. So the gaskets appeared to be leaking a little, but hadn't blown. A shame he used 2 gaskets, a single one would have been a bit better in terms of compression, but Jon was a superb mechanic. (he built a couple of the masterclass winners at Stafford back in the 90s, not bodywork, but assembly/mechanical work etc. you just couldn't fault. He once "fixed" my Toledo carbs, got it going like a rocket, without actually starting the car. Pure witchcraft...)

[Steve 13-60]

My other classic is a 1976 Hillman Imp, which is in storage ready for rebuild once the Herald is finished. Anyroadup, there's a guy called Andy Ward who has a YouTube channel...Shrigley Tube TV.....

He is into modifying imp engines and is well worth a watch. He recommends measuring the volume with the head on and fill to the bottom of the plug hole.

[Steve 13-60]

I really fancy one of his long rod, motorbike pistoned 1040cc motors.......will be fun seeing if I can get capital expenditure approval for that!

[zetecspit]

2 hours ago, Steve 13-60 said:

He recommends measuring the volume with the head on and fill to the bottom of the plug hole.

I can't see how that would work on the Triumph engine, the combustion chambe wouldn't be full at that point.

[Escadrille Ecosse]

Clive, your calculations look fine to me too and you have the necessary to measure the existing chamber volume so you can calculate how much you need to skim. Just do the measure by the perspex and syringe method. Plug an valves in place.

Just remember (sorry I know you know this) that the bit you'll be skimming doesn't have the ramp by the plug hole so the skim will be the required volume reduction divided by the area of your greasy graph paper.

The the 2L gasket should be fine as there is plenty of 'land' around the cyclinders for it to seal on. I had a note of the gasket thickness somewhere but damned if I can find it. We can trust Mr Jones to have a suitable prototype for measuring

The 2L Mk2 cam is a honey for a road car, especially with a revvy engine like the 1600 I would expect.

However, I have just seen the picture you have posted. I take it that is not the head from the 1600? It is cracked between the valve seats which is a 'bad thing'

Edited January 20 by Escadrille Ecosse

[JohnD]

Nasty crack between the valve seats! ( Colin got in first!)

That method might be useful with a recessed piston face, or in Triumph with the domed pistons, but it's easy to measure a recess in the other way, using the cover plate, or to measure the dome by putting the cover over the piston in the bore.   And the devil to clean up afterwards!

John

PS I tell you the dome volume in my article!

Edited January 20 by JohnD

[zetecspit]

Fret not, it was just a pic I found to illustrate the plug hole issue.

The 1600 head I am using is the later type, so does have ramped sections like this pic

[Escadrille Ecosse]

Good stuff Clive. That is much more reassuring although I did think you would be on top of this

[Nick Jones]

Looks like a mk2 head chamber to me - so suspect library photo only! Clive’s not going to be missing/ignoring an unplanned feature like that now is he?

Have just ventured to the workshop and established that I appear to have lost the used gasket that I remembered hanging up…..

I have consulted the archives and looked on my excel CR calcs spreadsheet which shows that I’ve been using 0.75mm thickness giving a gasket volume of 3.36ccs.

[Escadrille Ecosse]

1 minute ago, Nick Jones said:

Clive’s not going to be missing/ignoring an unplanned feature like that now is he?

I didn't think so and suspected from the valve ports it was, hence my tentative query, but better safe than sorry

Given today's 'disappointments' I'm in check everything mode...

[zetecspit]

12 hours ago, Nick Jones said:

I have consulted the archives and looked on my excel CR calcs spreadsheet which shows that I’ve been using 0.75mm thickness giving a gasket volume of 3.36ccs.

That makes sense, and the nominal vizard 4.5cc including piston clearance seems about right. 

Yes, the actual head needs a good going at with a scraper to the valves, some hard deposits on there. I also need to find my valve spring compressor, not used that for a very long time. I am hopeful guides are good, and I may for expediency just get the skim done and see how long the lead memory lasts. I may just get lucky, and I need to remember this car is not going to be thrashed mercilessly. I just want it to feel a bit quicker and livlier. The std 1600 is very very tame.

[JohnD]

" just get the skim done and see how long the lead memory lasts"   A skim need not include valve seat recutting, which is where the lead memory resides.  

[Nick Jones]

1 hour ago, zetecspit said:

am hopeful guides are good, and I may for expediency just get the skim done and see how long the lead memory lasts. I may just get lucky

Would probably be my approach. Chris’s 1300 Spit engine had this treatment and lasted 10k (with some fast road thrashing) even though I did grind the valves seats fairly hard to remove the worst of the pitting. If recession does start it can be kept at bay with additives and cure is the same as prevention anyway.

I’m applying the same logic to the GT6 (no problems yet but only 4k in) and previously successfully applied on the Vitesse.

[Mark]

17 hours ago, Steve 13-60 said:

My other classic is a 1976 Hillman Imp, which is in storage ready for rebuild once the Herald is finished. Anyroadup, there's a guy called Andy Ward who has a YouTube channel...Shrigley Tube TV.....

I've whatched every episode of Shrigley Tube, new video uploaded every Sunday night at 7pm, not to be missed. Its got me hankering after an imp, ginetta g15, or imp based rear engine kit car, but got enough Triumphs to deal with at present.

[ahebron]

Loving this.
Its not often we see a 1600 thread let alone modifying one.
Please keep it going.
I managed to get a NOS bare head for a 1600 a few years back.
Not that I need it but I have a spare short block as well.

[thebrookster]

5 hours ago, ahebron said:

Its not often we see a 1600 thread let alone modifying one.

True that! I'll put my hands up and admit that when I first saw this thread and that it was by Clive, I assumed it was another Zetec engine 😁

[zetecspit]

Update. After mush faffing and indecision, I have come up with the following plan:

Head is off at the machine shop. For a 40thou skim, which should give a CR of 9.5 give or take (depends on gasket thickness, hence the give or take bit)

Having asked about unleaded conversions, the cost would have been significant so that will get tackled if/when needed.

I need a set of followers, the small ones. Hoping Stoneleigh will be productive.

Chris Witor will be getting an order for 7/16 stud/bolt set and his special head gasket (A mk2 gasket, but with the extra holes punched for the early engines) and followers if I don't find any.

I have machined teh original fan spacer down to MK2 vitesse size, 5/8, as they are totally unavailable. Even Dave P at canleys doesn't have any among his piles of old stuff. I can then use a mk2 plastic fan to replace the original fan (which is missing half one ali blade. Causes vibration at about 5k)

A propshaft is at Feltham being "fixed" After finding one new prop from Wins is the cause of vibration, and upon investigation it is from the "powertune" group, which is not encouraging. The one I am having done is an OE non od prop, so the large diameter tube. Being shortened, new UJs and balanced. Fingers crossed it will be a good'un

I need to strip the 2 pairs 1600 stromberg carbs I have, and build up a "best" pair. I have a large buscuit tin of carb parts that came with the car, and I am hoping that will supply the expensive stuff (having heard about Nicks carbs and costs!)

Apart from that, I need to find the tin full of core plugs, again came with the car, or buy a set. Plus a stainless bypass pipe as the original was rather thin. 

The other thing I would like to find is a moulded carpet set to replace the rather worn and ill fitting "stitched" set. Needs to be red, and I am too tight to buy from the main suppliers unless a very good discount is available. Will I get lucky? 

In other news, I have received a pack of 3 bluetooth gizmos, so I can use a basic/cheap power amp hidden away and get music off my phone, The bluetooth bits cost £2.50 each, and I have a couple of amps. One is working in the dolly, and acceptable quality. The amp in that is a bit small despite being labelled 500Watt. 5 is more likely. I will try one of the other amps, see if that is better. 

 

[JohnD]

Zetec

"Having asked about unleaded conversions, the cost would have been significant so that will get tackled if/when needed."

It's just six exhaust valve seats bored out and the rings shrunk in.   Would that really multiply the cost?  Now's the time to do it, if ever you want to, while the head is off and being worked on!

John

[Nick Jones]

28 minutes ago, JohnD said:

It's just six exhaust valve seats bored out and the rings shrunk in.

And seats recut….. usually they want to change the guides too, and recut the inlets and grind them all in. £250 minimum!

If the seats are good at the moment and no grinding needed then they’ll last probably 20 - 30k as they are with the option to extend using additive.

[zetecspit]

34 minutes ago, JohnD said:

Zetec

"Having asked about unleaded conversions, the cost would have been significant so that will get tackled if/when needed."

It's just six exhaust valve seats bored out and the rings shrunk in.   Would that really multiply the cost?  Now's the time to do it, if ever you want to, while the head is off and being worked on!

John

£50+vat a seat! That is £300, before additional work. 

The total would have been £500, essentially a recon head (so cheaper than going to any of the suppliers who are all about £600)

Skim is £70+VAT. A light lap of the valves and I hope to get a good few years or longer before new seats required.