Neil Haughey
New member
Wow thanks for the update Pat, always great to hear what you guys are up to with your boundary pushing race car.
Competition success for the Transaxle continuing.
- Thread starter 333pg333
- Start date
George Elliott
New member
Patrick,
this is a great thread title, and as others have said, I also enjoy reading about your cutting edge development work.
Really sorry to hear about that last session and the issues. Its painful to read in places, and no doubt 100 times worse to live. Have to admire your frank description of the whole thing. Doing the 5 why's it would appear to be a balance/harmonic root cause? Can I ask you to confirm if my understanding of the following is right pls?
Crank - knife edged heavily ?
Flywheel - lightened? by much?
Balance shafts - Deleted?
Front pulley - Not S2 spec harmonic pulley?
all part of a high rev 3.1 litre 8 valve unit.
were the Crank/Rods/Fly-Wheel properly balanced as an assembly?
On the new engine, help me with the "wider ellipse" term?
You have proved what the 952 can do, and will no doubt add to those achievements in future.
I'm having doubts about anything over 2.7 or 2.8 litres these days. There seems to be huge challenges in getting a rounded package in the really big capacity M44/52, with reliability. Look forward to what your 2.5 will achieve
thanks again for the update
good luck
George
944t
this is a great thread title, and as others have said, I also enjoy reading about your cutting edge development work.
Really sorry to hear about that last session and the issues. Its painful to read in places, and no doubt 100 times worse to live. Have to admire your frank description of the whole thing. Doing the 5 why's it would appear to be a balance/harmonic root cause? Can I ask you to confirm if my understanding of the following is right pls?
Crank - knife edged heavily ?
Flywheel - lightened? by much?
Balance shafts - Deleted?
Front pulley - Not S2 spec harmonic pulley?
all part of a high rev 3.1 litre 8 valve unit.
were the Crank/Rods/Fly-Wheel properly balanced as an assembly?
On the new engine, help me with the "wider ellipse" term?
You have proved what the 952 can do, and will no doubt add to those achievements in future.
I'm having doubts about anything over 2.7 or 2.8 litres these days. There seems to be huge challenges in getting a rounded package in the really big capacity M44/52, with reliability. Look forward to what your 2.5 will achieve
thanks again for the update
good luck
George
944t
Thanks guys. I really don't have any remarkable qualities as a human but for some odd reason I've persisted with this platform. Some sort of unreachable quest it seems. There are many things I'd change if I could wind the clock back, but we could all say this no doubt. [
]
George
I don't see a real issue with the bigger bore motors but that would somewhat depend on the intended use. For a fast GT coupe that sees the occasional trackday I wouldn't hesitate to continue with the increased capacity...provided it was put together avoiding some of the usual pitfalls. With a race car that is seeing extended periods of higher boost and rpms then it's possible to rethink the bore size. On the 16v motor we have been discussing dropping the capacity down to a 2.2 - 2.4ltr motor but this is on a totally one off type of build. I really think the main problems with pushing these motors is the near 30 year old Alu blocks/heads and the spacing of our main studs. They are so wide apart compared to many other 4 bangers. Challenging to keep the seal in place. We feel that the copper gasket / bronze sealing rings have worked, but with this new motor we anticipate having to boost more so that will be put to the test.
I can post a ton of pics of all the parts but it's not so user friendly in this forum and takes time while I'm sitting at work, so I will describe as best as possible.
-Crank: I bought this many years ago via Chris White in the US. Apparently it was sent to LR for medium lightening but came back fully knifed. I don't have the weight of that crank but take it for granted that there were many lbs shed. We've had this sitting in the shop now for a little while and the few experienced builders that have happened by all point to that as being the likely culprit.
I supplied it to my builder in the US and this was to go into a larger bore street/club motor so perhaps he wasn't overly concerned. In retrospect it would have been better had he made a call on this crank when the motor became more race than street...however...
-Rods: Were also supplied by Chris White. They were Arrow rods which you know are of good quality. The pistons were forged CP and yes they were balanced.
-Flywheel: Is lightened stock. Can't recall the weight but a few lbs off stock.
-B/shafts: Stock. NOT deleted. Seems to be polarising opinion on these for a race car but I think unless you build a motor from ground up, it is probably not worth the risk of deleting them. I know there are a few people that have had success without them but I don't believe the cons outweigh the pros as such. We didn't have an S2 pulley/dampener. This time we've sourced one from the US that from RS barn. In the 16v motor I would source something even better.
My feeling is that with the dampener and stronger crank, plus lighter parts we should go a long way to 'curing' the ugly harmonics that beset the last motor. In terms of the 'ellipse' I referenced, I mean that with the longer rods/shorter throw plus the smaller / lighter wrist pins which are located higher in the piston, the motion of the new setup vs stock specifications should be less aggressive inside the bore. The piston won't 'fall over' as much at the top and in general should provide a smoother engine. Bear in mind, I'm not an engineer so my description is probably pretty poor! The builder/engineer sent me quite a technical email but I lost my phone and that email so I can't find the info. A more specified list of the parts below.
NA Block
Doweled Girdle
Line bore checked
Polished internally
Deck plate fitted
Steel liners fitted and honed to 102.00mm
Race prepped Bearings
Bull nosed Crankshaft with narrowed journals, balanced to new Piston and Rod weights
Carrillo Rods, increased CCL to suit shorter Piston Comp height
CP lightweight boxed strutted Pistons with DLC pins, gas ported for low tension ring set
Piston Oiling Valves fitted
9/16" ARP head studs with 12 point nuts
Updated for late tensioner assy
NA 2V Cylinder head
Ported both sides
49.00mm x 5/16" Intake Valves
43.500mm x 5/16" Exhaust Valves
Ampco 45 valve seats
Ampco 45 valve guides
PD race valve springs
PD Titanium Valve Spring Retainers
PD Titanium Valve Locks
Stainless Exhaust studs
Machined for stepped head washers
PD stepped head washers
Arrow solid Cam Followers
PD Camshaft
Modified cam housing
8v head results on flowbench at 28" test pressure
Lift - Intake - Exhaust
0.050 47 26
0.100 82 59
0.150 114 92
0.200 141 111
0.250 163 133
0.300 187 151
0.350 212 171
0.400 235 182
0.450 257 192
0.500 265 200
0.550 273 206
0.600 279 211
"This head keeps flowing. The cam lifts are 0.595 and 0.526". So disregard
the flow numbers above these lifts. But it shows this head does not go into
choke even up to 0.600" lift. The exhaust goes sonic even on the bench so I
know the velocity is high. You can hear it crack!"
]George
I don't see a real issue with the bigger bore motors but that would somewhat depend on the intended use. For a fast GT coupe that sees the occasional trackday I wouldn't hesitate to continue with the increased capacity...provided it was put together avoiding some of the usual pitfalls. With a race car that is seeing extended periods of higher boost and rpms then it's possible to rethink the bore size. On the 16v motor we have been discussing dropping the capacity down to a 2.2 - 2.4ltr motor but this is on a totally one off type of build. I really think the main problems with pushing these motors is the near 30 year old Alu blocks/heads and the spacing of our main studs. They are so wide apart compared to many other 4 bangers. Challenging to keep the seal in place. We feel that the copper gasket / bronze sealing rings have worked, but with this new motor we anticipate having to boost more so that will be put to the test.
I can post a ton of pics of all the parts but it's not so user friendly in this forum and takes time while I'm sitting at work, so I will describe as best as possible.
-Crank: I bought this many years ago via Chris White in the US. Apparently it was sent to LR for medium lightening but came back fully knifed. I don't have the weight of that crank but take it for granted that there were many lbs shed. We've had this sitting in the shop now for a little while and the few experienced builders that have happened by all point to that as being the likely culprit.
I supplied it to my builder in the US and this was to go into a larger bore street/club motor so perhaps he wasn't overly concerned. In retrospect it would have been better had he made a call on this crank when the motor became more race than street...however...
-Rods: Were also supplied by Chris White. They were Arrow rods which you know are of good quality. The pistons were forged CP and yes they were balanced.
-Flywheel: Is lightened stock. Can't recall the weight but a few lbs off stock.
-B/shafts: Stock. NOT deleted. Seems to be polarising opinion on these for a race car but I think unless you build a motor from ground up, it is probably not worth the risk of deleting them. I know there are a few people that have had success without them but I don't believe the cons outweigh the pros as such. We didn't have an S2 pulley/dampener. This time we've sourced one from the US that from RS barn. In the 16v motor I would source something even better.
My feeling is that with the dampener and stronger crank, plus lighter parts we should go a long way to 'curing' the ugly harmonics that beset the last motor. In terms of the 'ellipse' I referenced, I mean that with the longer rods/shorter throw plus the smaller / lighter wrist pins which are located higher in the piston, the motion of the new setup vs stock specifications should be less aggressive inside the bore. The piston won't 'fall over' as much at the top and in general should provide a smoother engine. Bear in mind, I'm not an engineer so my description is probably pretty poor! The builder/engineer sent me quite a technical email but I lost my phone and that email so I can't find the info. A more specified list of the parts below.
NA Block
Doweled Girdle
Line bore checked
Polished internally
Deck plate fitted
Steel liners fitted and honed to 102.00mm
Race prepped Bearings
Bull nosed Crankshaft with narrowed journals, balanced to new Piston and Rod weights
Carrillo Rods, increased CCL to suit shorter Piston Comp height
CP lightweight boxed strutted Pistons with DLC pins, gas ported for low tension ring set
Piston Oiling Valves fitted
9/16" ARP head studs with 12 point nuts
Updated for late tensioner assy
NA 2V Cylinder head
Ported both sides
49.00mm x 5/16" Intake Valves
43.500mm x 5/16" Exhaust Valves
Ampco 45 valve seats
Ampco 45 valve guides
PD race valve springs
PD Titanium Valve Spring Retainers
PD Titanium Valve Locks
Stainless Exhaust studs
Machined for stepped head washers
PD stepped head washers
Arrow solid Cam Followers
PD Camshaft
Modified cam housing
8v head results on flowbench at 28" test pressure
Lift - Intake - Exhaust
0.050 47 26
0.100 82 59
0.150 114 92
0.200 141 111
0.250 163 133
0.300 187 151
0.350 212 171
0.400 235 182
0.450 257 192
0.500 265 200
0.550 273 206
0.600 279 211
"This head keeps flowing. The cam lifts are 0.595 and 0.526". So disregard
the flow numbers above these lifts. But it shows this head does not go into
choke even up to 0.600" lift. The exhaust goes sonic even on the bench so I
know the velocity is high. You can hear it crack!"
Won't that be a novel idea Thom! Thanks for the positivity. Partly through resignation and also through a better understanding of the stresses associated, I always expect failure nowadays. I'm hopeful that we won't need crazy boost but just the size of the ports and cam make me feel like it's going to need it just to get things moving along.
TTM
Well-known member
With a very aggressive camshaft and much-ported head you may be able to run this large turbo in its sweet spot (between 1.5 and 2 bar of boost) considering the static CR of 9:1.
The intake manifold at this point remains to me the sensitive point for the engine, considering the size of head ports.
The dual plenum manifold like you mentioned the other day could be a good solution as you could package the large bellmouths needed in a large but not too wide secondary plenum (Corleone style) and add a smaller primary plenum over the turbo.
Food for thought.
The intake manifold at this point remains to me the sensitive point for the engine, considering the size of head ports.
The dual plenum manifold like you mentioned the other day could be a good solution as you could package the large bellmouths needed in a large but not too wide secondary plenum (Corleone style) and add a smaller primary plenum over the turbo.
Food for thought.
George Elliott
New member
Thanks for the info Patrick, very informative as always.
There is project ongoing here, and it has swayed from big capacity to sleeved down 2.2, then to 2.0litre steel block (924 turbo) high boost, and then came full circle to 2.5 litre, Darton Sleeve, dual scroll, Augtronic ECU, 8 Valve.
I look forward to seeing it and when done that thread will be revived.
Keep up the good work
George
944t
There is project ongoing here, and it has swayed from big capacity to sleeved down 2.2, then to 2.0litre steel block (924 turbo) high boost, and then came full circle to 2.5 litre, Darton Sleeve, dual scroll, Augtronic ECU, 8 Valve.
I look forward to seeing it and when done that thread will be revived.
Keep up the good work
George
944t
I was looking at something similar in pre made options Thom but they all seem to come with that 'perpendicular' orientation rather than parallel. I from what I've read/heard, those dual plenum setups were mostly used on cars with restrictors on them. In any case we will see what we can make and what will fit.
George, I have also thought about the 924 block. Had some reasonably serious discussions about a billet block too. There were a few people interested but a longer term project. I'd certainly be interested to read more about your project. What sort of ETA?
George, I have also thought about the 924 block. Had some reasonably serious discussions about a billet block too. There were a few people interested but a longer term project. I'd certainly be interested to read more about your project. What sort of ETA?
George Elliott
New member
That requires bravery Pat,
if you wanted to go the Custom Cast route, Crossthwaite & Gardner were at Techno this year, and they are a real eyeopener to speak to. A UK firm, you probably have come across them, thats where things like Auto Unions get revived to hand crafted perfection using the original processes. Really good McLaren grade stuff.
Ask them for a block, they would not blink, maybe reply "Aluminium or Magnesium"? All comes at a cost I guess.
ETA, [
][] lets all post our eta's some day......Its a project my lad started while at college locally, he seem's to just have an interest in turbo's. Then Augtronic in England whet his appetite further, and the sales people in Turbo Dynamics /Garrett were most helpful with dual scroll......the headers suit it [
]Its a massive subject which I struggle to understand in that depth
There is a plan which covers the next 12 months approx.....
He will update us all, don"t worry
George
944t
We 'think' we can get away with the stock block but it may be a case of good/bad luck depending on the metallurgical integrity of whatever stock block is chosen to modify. To note, much of our opposition are in much more modern cars and boosting to 35psi+ so we're behind the 8-ball to start in many ways George.
Oh, and I didn't really answer one of your questions from above. Essentially, yes, we believe that the severely knifed crank was the reason we had all our issues. We've discovered one or two possible mitigating circumstances but it get's purely theoretical.
If, and it's a pretty big if, we finish the 16v motor, it will have a custom Arrow crank and rods plus a lot of quite different custom parts on it such as one piece cnc'd pan/girdle that would connect to the block via a tongue and groove type attachment. Lock in the crank being the objective.
Would certainly enjoy reading about your Son's project. It sounds very interesting and should yield some great results I'd imagine. Definitely keep us in the loop with that one!
Oh, and I didn't really answer one of your questions from above. Essentially, yes, we believe that the severely knifed crank was the reason we had all our issues. We've discovered one or two possible mitigating circumstances but it get's purely theoretical.
If, and it's a pretty big if, we finish the 16v motor, it will have a custom Arrow crank and rods plus a lot of quite different custom parts on it such as one piece cnc'd pan/girdle that would connect to the block via a tongue and groove type attachment. Lock in the crank being the objective.
Would certainly enjoy reading about your Son's project. It sounds very interesting and should yield some great results I'd imagine. Definitely keep us in the loop with that one!
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