807/TS DD, Auto-X, Hill-Climb build.

[Richard48Y]

It occurs to me that I may have been posting some of my questions to the wrong sub-forum.
They may be more appropriate here?
1970 S2, 807/TS DD, Auto-X, Hill-Climb build.

An enhanced performance street car/occasional mild competition build.
807 engine with TS head, Weber 40's, headers, and whatever other tricks I may add on a limited budget.
It will be a DD in summer out here in rural Nevada.
No intent to subject it to city traffic unless I go to a weekend car show, and that would never be the Hot August Nights jam-up.

Most discussion at this site seems to be related to Lotus/Ford TC engines.
I see a few Renault powered cars being raced so hopefully I may bounce some of my questions off this sub-forum.

While I am not chasing max HP I am very interested in reliability/long engine life mods.
So far the most interesting I have found mention of are.
1. Undercutting the camshaft so that the followers do not hit the casting when on the cam heel.
2. Reducing excess oil flow to the cam for more oil pressure to the crankshaft.
3. Discussion of valve spring pressures.
4. Cutting a 4mm deep relief around the circumference of the cylinder top for a more positive head-gasket seal.

My own musings have me chasing after Beehive valve springs and cryogenic or TiN treatment of cam followers, camshaft, cylinders, and maybe even the crankshaft.

TiN turns out to be very expensive but Cryo is relatively cheap.
Cannot do much more with the Beehive springs goal until I get the cam back from Delta Cams.
I shipped it to them a couple of days ago so they should have it Friday.
They will contact me with their assessment for repair and grinds they offer.
If Delta are able to provide excellent service we may want to make note of that somewhere.
I was originally going to buy a Cat Cams camshaft but Euro 550 and shipping, plus the language barrier made that infeasible.
I believe that Delta will be half the cost, possible less.

My Wossner forged pistons are 77.8 mm for 1595cc.
I expect to have to shave the tops to bring compression down a little.

I have been corresponding with Salv Sacco a bit and bought the pistons from him.
Salv states that the Max Speeding rods have improved from their early days and are now very good.

More as it occurs, suggestions welcome.

[Richard48Y]

I was going to add some PDF's regards new metal treatments but the files are too large.
MS2, Metal Ion implantation, Moly DiSulphide.
I can email them to anyone who is interested.
Claims are some pretty amazing results for HP gains and increased component life.

[Richard48Y]

A bit of information not easily found for TS type heads.
Original thickness/height top to bottom.
Nominal height 93.5mm. (3.681102")
Minimum repair height 93mm. (3.661417")

This can be used to find out if the head has been milled in the past and how much.
Seems milling the head also throws off valve-train geometry.
So head milling is not a good means of raising compression.

[GavinT]

Seems milling the head also throws off valve-train geometry.

It depends.
The valve train between the lifters and valves remains unchanged because they're all contained in the head.
The part that can change is the relationship between the cam (in the block) and the lifters. That's what adjustable cam sprockets are for. 

[Richard48Y]

My minor victory of the day is finding that my head is .0073" thicker than "Nominal". 
This should mean it has never been cut.

I have a lot of notes and comments scattered around the forum.
Tonight I hope to complete my email to Delta Cams.
I also intend to gather much of this information up and post it here after it is organized.

[Richard48Y]

What I sent to Delta Cams as reference for my new grind.

This may be what I have now?
The 807-12 and the Euro 17TS-844 engine (cooking versions of ~125HP) used a valve timing of 40/72/72/40.
Valve lift: Inlet - 9.6mm; Ex. 9.5mm
This is off a photocopy from Franco-American Imports in the early 80's, it's was sourced out of the Renault racing manual for 12/15/17. picture below.

7701452043 - R12G
Inlet Valves
opens BTDC 40 deg
closes ABDC 72 deg
Exhaust Valve
opens BBDC 72 deg
closes ATDC 40 deg

There was also a more competition oriented cam that some guys are running on the street.
7700524884 - 1600cc Racing
Inlet Valves
opens BTDC 53 deg
closes ABDC 83 deg
Exhaust Valve
opens BBDC 83 deg
closes ATDC 53 deg

From the UK Renault engine expert, Salv Sacco.
A lobe profile that gives 290 – 296 duration somewhere close to these dimensions – (at cam lobe not at valve)
Total lobe height 0.285 – 0.290” lift
54 degrees from peak - .070” - .075”
If that can be ground at 108 LCA and using a theoretical rocker ratio of 1.52:1 and a valve clearance of .015” you should see something very close to these figures:-
Total valve lift = 0.425” Lift at TDC = 0.099”
Set cam timing to show either an equal lift on both inlet and exhaust at TDC, or with .005” - .010” more on inlet than exhaust.
I find this gives a smooth idle, really strong mid-range with a 7K peak.
Start line RPM I guess would be around 4500RPM
All the above is based on what I have used and it works for me!

Most of the folk I have conversed with feel this one is too much for the street.
http://www.catcams.com/products/camshafts/datasheet.aspx?ENGINE_id=194&CAMSETUP_id=752&Language=english

                                intake                       exhaust
camshaft data:
lash ramp:                0.40mm0                  .40mm
duration @ 0.1mm:   :280°                        :280°
duration @ 1.0mm    : 236°                        :236°
valve lift                   : 10.00mm                 :10.00mm
cam lift                    : 6.25mm                    :6.25mm
lobe angle                : 110°                         :110°
timing @ 1.0mm       : 8° / 48°                    :48° / 8°
valve lift @ TDC        : 2.15mm                    :2.15mm

[jbcollier]

Sal knows these engines inside and out.  I would always go with his recommendations.

[Mecky]

Hi Richard,

I'm now building my second engine of this type, which you also have. I'm wondering that you are talking about small budget, but use forged Wössner pistons with Ø77,8 mm bore. They are high end. It's almost a pity that you want to machine them for lower compression ratio. There is also another set of competition pistons available for that bore. These were used by works-supported Renault Formula Renault Europe teams in the 70s. Renault supplied a tuning kit back in the day, which was called the 160 HP kit (SAE horsepower, but nonetheless). I used to have a set of those to spare (picture attached), but gave them away a week ago, because I want to take it one step further with my engine and go for the Wössner pistons with high compression. I'm aiming for 12:1, but my engine has the 318° cat cams shaft with adjustable chain wheel and double valve springs. So not at all driveable on the road.

I have also had good experience with the 310° cam shaft. This brings a huge torque from 4500 RPM onwoards, but not maximum HP at high revs. The 310° is still not useable on the road.

A bit of information not easily found for TS type heads.
Original thickness/height top to bottom.
Nominal height 93.5mm. (3.681102")
Minimum repair height 93mm. (3.661417")

This can be used to find out if the head has been milled in the past and how much.
Seems milling the head also throws off valve-train geometry.
So head milling is not a good means of raising compression.

Do you know, why the minimum repair height is set to 93 mm? My racing head is already well below that and supplies good power. Of course, the combustion chamber is machined in order to fit the high compression pistons. But if the crimp endge in the cylinder head chamber is adjusted to the piston height, it should be no problem to go below 93 mm or is there a danger of cutting into oil or water channels, when doing more plane milling? I have now four cylinder heads and want to modify a second one to full race spec. Maybe even further than the first one, which was a bit more towards safety with compression ratio of 11,5:1.

I love the cylindre head configuration, which is shown attached. It is very high compression, but for 1800 cc. Looks beautiful. Built by JL Engineering. I will take that as a role model for my build.

[Richard48Y]

I had a lot of difficulty getting an intelligible response from the French companies regards piston specification. I really never did get a clear answer.
I would have been satisfied with the "160 HP" pistons if I had been able to determine the part number and availability.

The Wossner's I bought from Salv Sacco were still much less expensive than having a custom set made.
I am running them as supplied since I feel the undercut of the dome does not allow removing material from the top.
Since this is to be a "Hot" street driven car I may have to pay for race fuel, or mix in some AV100LL to prevent pinking.

As some on the site have said cutting the head does not alter the components which attach to it but can throw off the geometry of the push-rods/cam timing.
Since you have the adjustable cam wheel you should be able to correct your cam timing.

Cam cores are very difficult to obtain in the US so I have sent mine out to be reworked. One lobe was very porous at the nose.
Once it has been welded I will get it reground.
I am still trying to determine the profile but will probably go with Salv's recommendation.
I am also taking note of the cam-heel side interference issue.
This may not occur with the billet CAT cams.

[GavinT]

Do you know, why the minimum repair height is set to 93 mm? My racing head is already well below that and supplies good power. Of course, the combustion chamber is machined in order to fit the high compression pistons. But if the crimp endge in the cylinder head chamber is adjusted to the piston height, it should be no problem to go below 93 mm or is there a danger of cutting into oil or water channels, when doing more plane milling? I have now four cylinder heads and want to modify a second one to full race spec. Maybe even further than the first one, which was a bit more towards safety with compression ratio of 11,5:1.

Hi Stefan,

The minimum head thickness is set by the factory and is intended as a reference point within a retail Renault service environment.  It more relates to customer cars & warranties etc. I expect all manufacturers would have something similar.
Once you go beyond that, understandably, you're on your own as far as the factory is concerned – it's a statement as to the limitation of their liability.

On the other hand, I expect we've all seen some seriously shaved & modified heads. Motor engineers may find this acceptable but with some caveats, conditions and agreement from the customer.
For instance, there's the cam and lifter relationship. Also, it's possible the dizzy base may need to be shimmed as it gets closer to they drive gear. We know that removing material from the combustion chamber comes close to the water jacket - lots of things like this.

I once bought a Renault crossflow F2 engine and the owner said he'd blown it up more times than I'd had hot dinners. I laughed and thought that was a pretty funny anecdote but he wasn't looking to make some sort of warranty claim.
Incidentally, that head measures at 92.8mm.

That JL Engineering head is very pretty.

Interesting . . your Formula Renault Europe pistons are a very similar style to the Renault Sport pistons used in the 1800cc Alpine rally cars (pic below). We often see Gordini style pistons with a different pronounced bulbous hump in the middle.
Do yours also have the "FTV' marking? I'm not familiar with the brand so perhaps it is no more.

[Richard48Y]

It occurs to me that since the cam followers are inclined in relation to the cam thinning the head moves them a fraction from the original factory geometry.
Probably not enough to be a major issue but does it affect their "Spin"?

Bumpy pistons, yep.
Wossner's.

[GavinT]

I guess what happens is the lifters are effective lowered into the cam well.
Hmmm . . can't see it affecting the spin significantly because the lowering still retains the same axial relationship between lifter and cam lobe – happy to be educated.

One thing that comes to mind is whether the lifters run out of 'upwards' travel when the head is shaved. Probably not difficult to relieve the lower entrance to the lifter bores.
Perhaps other thing might be a need to either shorten the pushrods or look at shorter rocker adjustment screws.
I've never seen comment on either of the above so presumably it's OK, but still worth checking.

[Richard48Y]

For myself I am happy to find my head is uncut. 
I do intend to grab a set of the Ti. valve spring keepers that are available unless the cost is just crazy.
Looked into Ti. valves from Ferrea and found they are not interested in small volume sales.
My current intakes are 42mm but the faces are worn to concave.
I may have found a less expensive Ti. valve maker but am still unsure of their use in a street engine.
Discussions of coatings and special valve seats come up regards them, more $$$.

I am still looking at getting my cam Cryo treated, my lifter faces and rocker tips plated with ?
Also still trying to find a set of beehive springs with the lowest working spring pressure. For that I need to know my cam specs and valve weights.
I spoke to one engine builder who tried beehive springs in his TS race engine.
He said they were too stiff so wiped the cam.
That was several years ago and since I know beehive springs are now used in everything from Chevy LS to sport-bikes suitable springs should be available.
My hope is that significant reduction in valve train mass will increase component life.
I am surprised the racers have not already found answers to these questions.

[Mecky]

Do you know, why the minimum repair height is set to 93 mm? My racing head is already well below that and supplies good power. Of course, the combustion chamber is machined in order to fit the high compression pistons. But if the crimp endge in the cylinder head chamber is adjusted to the piston height, it should be no problem to go below 93 mm or is there a danger of cutting into oil or water channels, when doing more plane milling? I have now four cylinder heads and want to modify a second one to full race spec. Maybe even further than the first one, which was a bit more towards safety with compression ratio of 11,5:1.

Hi Stefan,

The minimum head thickness is set by the factory and is intended as a reference point within a retail Renault service environment.  It more relates to customer cars & warranties etc. I expect all manufacturers would have something similar.
Once you go beyond that, understandably, you're on your own as far as the factory is concerned – it's a statement as to the limitation of their liability.

On the other hand, I expect we've all seen some seriously shaved & modified heads. Motor engineers may find this acceptable but with some caveats, conditions and agreement from the customer.
For instance, there's the cam and lifter relationship. Also, it's possible the dizzy base may need to be shimmed as it gets closer to they drive gear. We know that removing material from the combustion chamber comes close to the water jacket - lots of things like this.

I once bought a Renault crossflow F2 engine and the owner said he'd blown it up more times than I'd had hot dinners. I laughed and thought that was a pretty funny anecdote but he wasn't looking to make some sort of warranty claim.
Incidentally, that head measures at 92.8mm.

That JL Engineering head is very pretty.

Interesting . . your Formula Renault Europe pistons are a very similar style to the Renault Sport pistons used in the 1800cc Alpine rally cars (pic below). We often see Gordini style pistons with a different pronounced bulbous hump in the middle.
Do yours also have the "FTV' marking? I'm not familiar with the brand so perhaps it is no more.

Hi Gavin, the pistons I used to have didn't have any inscription, just the diameter figure, which is 77,8 in my case, and an arrow pointing towards the exhaust side of the piston. The pistons were not forged, but cast, I think.

@Richard, I love the look of the fresh Wössner pistons. Going to purchase them soon, too. I will go for the Ø42/35,35 mm valves. This is the famous Mignotet configuration. Marc Mignotet was the engine guru, who developed and tested the Alpine rallye and racing engines. I heard that this guy had the engine dyno next to his house and fine-tuned all the works Alpine engines there. I was thinking about using bigger valves, but if the guy from Alpines engine department, who slept next to the dyno, found this as the most effective way to make horsepower and torque, I go for it, too.

My dream would be to achieve around 172 HP from the engine, which I read on some occasions should be possible from that engine in a best-case scenario at 7200 or 7500 RPM. The torque figure of 192 Nm (of course a bit lower in the rev range) was also something that I read should be possible, if everything works out perfectly. There's a lot of wishful thinking involved, but as long as I reach 160 HP, I'll be happy.

[GavinT]

What I know about beehive springs could be scratched on the back of an aspirin with a crowbar – or even conventional springs for that matter.

And I thought they were supposed to allow lower seat pressure?
Still interesting and I reckon you're right in that there should be something suitable around – same for Ti retainers. Worth pursuing methinks.

Around these parts, most folk default to using the set up recommended by Collier's in Sydney. Collier's were part of the Oz R12G rally effort back in the day. The R12G springs were prone to breaking so they developed longer springs which meant machining the valve spring seats deeper to accomodate. I put Paul Z on the old Yahoo list onto them and I believe he's happy.

The French vendors now seem to offer 43mm valves instead of the older 42.1mm ones.
Some 'enthusiasts' offer 44mm valves but with offset valve guides.
Some time ago I did a quick experiment with a Nissan 45mm valve (pic below) . . and they're problematic, though the length is OK and could likely be reshaped to a suitable size.