Can you reharden a softened alloy head? One of my spares (reconditioned and in the cupboard!) is on the soft side but still in spec. Everyone has spare heads in their cupboards I'm sure.
Two new racecars in NZ
- Thread starter Frans
- Start date
Not that I know of, but if a metallurgist could chime in about now, that'd be good
I have never had the opportunity to see nor hear my car down the straight at any track. This video from a friend gave me the view. It sounds so quiet from here.
Very short clips but hope you enjoy it as much as I do.
Regards, Frans.
Very short clips but hope you enjoy it as much as I do.
Regards, Frans.
I can't answer your question but I should point out that the Rolls Royce engine factory produced it's aluminium V8 blocks years before they were to be used and they were stored outside on pallets to "weather" before any machining at all was commenced, as confirmed by my father who worked in the foundry services business back in the UK.
That was for stress relieving. It is said that when building their F1 engines (M12/13, 1400HP out of 2000cc) in the early sixties BMW used M10 engine blocks that had been out in the rain for years to relieve stress form casting. Mechanics told stories about taking a leak on them every now and then.
Not sure about heat treatment. I think you may need to add something or other in the furnace to re-harden something that went soft.
Not sure about heat treatment. I think you may need to add something or other in the furnace to re-harden something that went soft.
I am of the belief that hardening of NEW alloy heads can be achieved by heat soaking the head for 8 hours at 250C but I am unsure about rehardening an old head.
This article kind of confirms this https://www.otto-junker.com/en/prod...systems-for-cylinder-heads-and-engine-blocks/
An oven could be made from a covered BBG similar to this.
This article kind of confirms this https://www.otto-junker.com/en/prod...systems-for-cylinder-heads-and-engine-blocks/
An oven could be made from a covered BBG similar to this.
Hi, I know it's not the "real thing', but can a R5 G/Alpine head be fitted to the R8G block?
Henry
Henry
How interesting. Thanks.
Henry,
Yes, that is very possible, but you would need the head, rocker shaft, push rods, intake manifold etc to make a start. Probably better to buy a whole motor to strip what you need.
Some photos.
Yes, that is very possible, but you would need the head, rocker shaft, push rods, intake manifold etc to make a start. Probably better to buy a whole motor to strip what you need.
Some photos.
There have been some tests done on a 5G based motor here in the UK with some startling results. A 1550 was built using Salv Sacco's parts and cam choice, but was put together with a standard 5G head to facilitate some development work on the Dyno. The result was 154 BHP showing 100bhp/litre from a standard head. My own 1550 had the largest valves that would fit in the head (Lotus/Ford bits with 7mm wasted stem in nimonic stainless) and was pretty state of the art in every sense, it produced 112 bhp/litre and it was not cheap! You must accept that although the standard head is startling in performance terms it won't last being revved to 8000 rpm, so the light trick valvetrain bits are more about reliability than power
Every day is a schoolday.
Every day is a schoolday.
The R8 Gordini driven by "Captain" Peter Janson as part of the Victorious Renault Australia Rally Championship Team winners back in the early '70's was unusual in that it had a 10,000 rpm Jaeger Tachometer fitted instead of the 8,000 rpm unit found on the other two factory entered R8G's. Whether it had something to do with the ultra low ratio diff that he always ran or whether it was something to confuse the Japanese Mitsubishi and Datsun entrants I couldn't say!
Hi
Franz has provided an entertaining and instructive commentary on his racing and exquisite preparations. I guess it had to end but on a happier higher note would have been nice. Good luck with the new engine.
Some thoughts on the old head from someone who has done some metallurgy in the distant past. Who knows what the alloy was when new, but as it has been expensively welded a couple of times I guess the alloy is a bit variable over the face. Also the thickness is variable too and the face is not as thick as when new ! So while various grades of alloy are heat treatable as per this article it would be hard to say how good that would resolve the problem but could allow the ageing to settle before any finish skim.
http://www.heat-treat-doctor.com/documents/Aluminum Castings.pdf
But possibly an angled skim to remove the obvious dips would give a nice head that could be used on a road car for a bit of fun rather than the continuous hammering for racing
Those stories of ageing castings make good reading and built up some myths for the punters but ageing can be achieved by low temperature heat treatment in a shorter time. However by definition ageing can be achieved by "age" and some thermal cycling out in the sun and cold but pissing on them and the like is just a good story IMHO !
Good luck what ever way you go. The Forum may not be here to hear your story in the future
Jaahn
Franz has provided an entertaining and instructive commentary on his racing and exquisite preparations. I guess it had to end but on a happier higher note would have been nice. Good luck with the new engine.
Some thoughts on the old head from someone who has done some metallurgy in the distant past. Who knows what the alloy was when new, but as it has been expensively welded a couple of times I guess the alloy is a bit variable over the face. Also the thickness is variable too and the face is not as thick as when new ! So while various grades of alloy are heat treatable as per this article it would be hard to say how good that would resolve the problem but could allow the ageing to settle before any finish skim.
http://www.heat-treat-doctor.com/documents/Aluminum Castings.pdf
But possibly an angled skim to remove the obvious dips would give a nice head that could be used on a road car for a bit of fun rather than the continuous hammering for racing
Those stories of ageing castings make good reading and built up some myths for the punters but ageing can be achieved by low temperature heat treatment in a shorter time. However by definition ageing can be achieved by "age" and some thermal cycling out in the sun and cold but pissing on them and the like is just a good story IMHO !
Good luck what ever way you go. The Forum may not be here to hear your story in the future
Jaahn
I remember on My HNC course one of the lecturers talking about burying a casting in the ground over the winter to normalise it and then finish machining it. He was talking about Iron and not Alloy though.
Frans,
I think the cheapest is still the head and rocker gear from UK/Eu, and if you want to go strong all round is use a Virage/1400 block and crank, same as the R5G/A but not blue printed treatment. The R12V is big crank with R16TS bearings. All sorts of possibilities.
Seeing "dauphproto" is on the thead he may know of some parts, at a decent price. ???? Apart from his spares on the shelf ???
Ray
I think the cheapest is still the head and rocker gear from UK/Eu, and if you want to go strong all round is use a Virage/1400 block and crank, same as the R5G/A but not blue printed treatment. The R12V is big crank with R16TS bearings. All sorts of possibilities.
Seeing "dauphproto" is on the thead he may know of some parts, at a decent price. ???? Apart from his spares on the shelf ???
Ray
Ray. The shelf is empty I'm afraid, and 5A/G engine bits are getting very expensive, as well as hard to find. Time marches on and the parts we could find as virtual scrap are not in general circulation. Frans Loved the short vids. Funny how all Sierra/Cleon motors sound similar...
Hi,
I have 2 heads at the engineering shop now. The one is from the dry-sump motor and the other is my spare that needs quite a bit of work on.
The dry sump is the one that will go in for this season. I have started some substantial work on it (again).
Regards, Frans.
I have 2 heads at the engineering shop now. The one is from the dry-sump motor and the other is my spare that needs quite a bit of work on.
The dry sump is the one that will go in for this season. I have started some substantial work on it (again).
Regards, Frans.
So what do I do now??
I got the one head back from the engineering shop. This is the spare head I had that should go on the wet sump motor to replace the head that has gone soft. It is so good that without increasing the volume to lower the Compression Ratio it turns out to be too low.
I have just done a cc check and it will be 12.07:1 if I fit it as is. The old head started life on the race car at 12.4:1 and in the end, 11 years later, I couldn't get it lower than 12.6:1. Do I take it in and get it skimmed more to up the CR? It will be such a waste to do that with a good head. The no.2 combustion chamber has got some pit marks from a previous repair and I thought that I would have to take that material away to lower the CR, but now I can't. Those chambers are still for the 74.5mm bore and I hoped to take the ridge away because the new bore is 77mm.
Then, if all works out to my plan, this will become the spare engine and the dry-sump will become the no.1 engine.
Decisions, decisions.....what do you think should I do?
Frans.
I got the one head back from the engineering shop. This is the spare head I had that should go on the wet sump motor to replace the head that has gone soft. It is so good that without increasing the volume to lower the Compression Ratio it turns out to be too low.
I have just done a cc check and it will be 12.07:1 if I fit it as is. The old head started life on the race car at 12.4:1 and in the end, 11 years later, I couldn't get it lower than 12.6:1. Do I take it in and get it skimmed more to up the CR? It will be such a waste to do that with a good head. The no.2 combustion chamber has got some pit marks from a previous repair and I thought that I would have to take that material away to lower the CR, but now I can't. Those chambers are still for the 74.5mm bore and I hoped to take the ridge away because the new bore is 77mm.
Then, if all works out to my plan, this will become the spare engine and the dry-sump will become the no.1 engine.
Decisions, decisions.....what do you think should I do?
Frans.
