Vantage V8 4.7 engine rebuild
#16
Wow, did not realize the 4.7L were square bore motors (bore/stroke same).... No wonder its such a well balanced motor. 91mm bore / stroke is already pretty aggressive, I don't think you really need to go any bigger than 4.7L to get stupid power. I don't see why 490+ isn't easily obtainable with more rpms and full free flowing exhaust & tune.
Based on these most recent V12 issues I have been hearing, that only makes the case for the later 4.7L Motors even stronger. I think that has confirmed my choice of Vantage S.
Based on these most recent V12 issues I have been hearing, that only makes the case for the later 4.7L Motors even stronger. I think that has confirmed my choice of Vantage S.
#17
Bamford Rose have the 4.7 to 450 BHP in GT4 spec & manifolds/cats, with the N400 intake and twin throttle inlet manifold they can get close to 490 BHP
They have also developed a 5.0 conversion get up to 550 BHP!
Who needs a V12.
You just need deep pockets
They have also developed a 5.0 conversion get up to 550 BHP!
Who needs a V12.
You just need deep pockets
#20
Wow, did not realize the 4.7L were square bore motors (bore/stroke same).... No wonder its such a well balanced motor. 91mm bore / stroke is already pretty aggressive, I don't think you really need to go any bigger than 4.7L to get stupid power. I don't see why 490+ isn't easily obtainable with more rpms and full free flowing exhaust & tune.
Based on these most recent V12 issues I have been hearing, that only makes the case for the later 4.7L Motors even stronger. I think that has confirmed my choice of Vantage S.
Based on these most recent V12 issues I have been hearing, that only makes the case for the later 4.7L Motors even stronger. I think that has confirmed my choice of Vantage S.
91mm bore being aggressive is a relative term and all depends how much parent material you have in the block to allow overboring or support the sleeve you have. Subaru 2.5L flat 4 engines have a 99.5mm bore stock. Going to 101mm on stock sleeves in those motors is not possible and not advised. On the other hand Nissan sr20(2.0L I4) has an 86mm bore and when sleeved can be safely bored to 90mm.
Overboring the 4.7L AM from 91mm to 93mm is possible with respect to bore spacing and material left for proper headgasket sealing but it is not possible with stock iron sleeves. So if you really wanted to do it you can but it is not easy or cheap since sleeving the block is required.
#21
Pictures of Tonis:
http://multimaticmotorsports.com/pho...ce-day-barber/
#22
As a guy who works on his own cars thats pretty cool you took on that project seeing there isn't many resources out there for these cars and most of the dealers pretty much laugh you off. I have never tried to rebuild an exotic engine but it seems odd that Aston did not include tolerances on any of the engine parts in the shop manual. Just out of curiosity what did the rebuild cost?
My friend recently fried an engine in his 997 Carrera S and asked me if I wanted to take a stab at it. I sources the complete 997 service manual and then same clearance and ring gap situation exists.... there are none.
This rebuild after all was said and done cost about $15,000. That includes all machining, custom parts, oem AM parts, and labor.
#23
Engine balance does not have a lot to do with a motor being square or oversquare. V8 engines are balanced with bob-weights. The weight of this bob-weight is calculated based on 100% of rotating and 50% reciprocating weight of engine components. Every time you change out for a heavier, or lighter, connecting rod or piston you have to rebalance the crankshaft.
91mm bore being aggressive is a relative term and all depends how much parent material you have in the block to allow overboring or support the sleeve you have. Subaru 2.5L flat 4 engines have a 99.5mm bore stock. Going to 101mm on stock sleeves in those motors is not possible and not advised. On the other hand Nissan sr20(2.0L I4) has an 86mm bore and when sleeved can be safely bored to 90mm.
Overboring the 4.7L AM from 91mm to 93mm is possible with respect to bore spacing and material left for proper headgasket sealing but it is not possible with stock iron sleeves. So if you really wanted to do it you can but it is not easy or cheap since sleeving the block is required.
91mm bore being aggressive is a relative term and all depends how much parent material you have in the block to allow overboring or support the sleeve you have. Subaru 2.5L flat 4 engines have a 99.5mm bore stock. Going to 101mm on stock sleeves in those motors is not possible and not advised. On the other hand Nissan sr20(2.0L I4) has an 86mm bore and when sleeved can be safely bored to 90mm.
Overboring the 4.7L AM from 91mm to 93mm is possible with respect to bore spacing and material left for proper headgasket sealing but it is not possible with stock iron sleeves. So if you really wanted to do it you can but it is not easy or cheap since sleeving the block is required.
By Well balanced I meant Balance of HP & TQ in the powerband, not the actual "balance" of the engine, that part is obvious lol.
#24
![hilarious](https://www.6speedonline.com/forums/images/smilies/smLach2.gif)
#26
![Wink](https://www.6speedonline.com/forums/images/smilies/wink.gif)
Not sure but I think BR use the same crank on their 4.3 to 4.7 GT conversion.
#29
I have to look back in my notes for details. I checked camshaft lift and total duration. I did not check camshaft opening and closing. Static numbers do not mean much on these motors anyway since the intake camshafts have timing phasers and the ECU constantly changes timing. If total duration, both seat-to-seat and at 0.050", is known then the diagnostic scan tool can be used to check camshaft timing at different engine RPM and loads. (at least I hope it can be).