4.6 gets the green light !

cobraboy

Well-Known Member
#1
Having made the front bonnet slam panel a removable item a couple of weeks ago time was pressing on to beat the oncoming cold weather and a hand operation, so the 4.6 install was go..........
3.5 ready to come out.
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Removed
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Side by side to allow transfer of ancillaries
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4.6 built up
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hooked up for lift
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Installed, and nearly ready to light up.
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Initially I thought that I would bung on a pair of 2" HS8 carbs as an easy way to keep the car stock in case I wanted to revert back to the HIF6 thus keeping the linkages intact.
It was not easy, pretty much everything is affected by the change. New throttle linkage at the carbs, choke or enrichment for starting yet to be finalised, rocker covers modified to clear jets, air box elbows need extending, blah blah blah.
The motor is built with 10.0:1 CR, fast road cam, mildy flowed heads, 2" HS8 on ported manifold, 3500s ex manifolds, 2" straight through system.

I have a plan for starting enrichment which I will play with when I have it running, I will drop the jets manually to start it.
I will run Evans coolant with zero pressure so just need to fill up and fit the distributor after bringing up oil pressure. Start up this coming weekend is the plan.
 
#2
cool, watching this, i have a 4.6 in mind myself and was pondering a pair HS8's, although i think the inlet manifold is actually a bigger restriction than the HIF6,s, so pondering making up a trianglar shaped adapter to allow twin su's on a 4 barrel manifold
 

cobraboy

Well-Known Member
#3
The inlet manifold I used seems to have a taller centre section than the HIF6 one, the tower height is the same, but the distance between the casting around the tower and the top of the tower is shorter, so looking through the opened up carb mount holes it looked quite big inside. I don't know what it came from.
I have an Offenhauser 4bbl intake and may use it in the future, but am keen to try the bigger SU's first.
 

cobraboy

Well-Known Member
#6
Looks really smart. I Guess With Your special bonnet, the carbs will fit undeneath?
Hey Barten
I have carefully measured the height of the dashpot caps up from the valley gasket on both engines and the HS8 are only about a 1/2" higher, so I think they will clear the uncut bonnet area anyway.
I shall be testing with plasticine on the carb tops and gently lowering the bonnet bit by bit in case my measurements are out.
 

quattro

Well-Known Member
#7
When I fitted the EFI, I placed a piece of gaffa tape, upside down on top of the plenum, then carefully lowered the bonnet, then lifted it again and it was still there, then actually closed it fully, until it clicked. When I opened it again, the gaffa tape was stuck to the bonnet felt, so I knew I had run out of space. It only needed 1/4" so pretty close.

That engine should give it some grunt :)
 

cobraboy

Well-Known Member
#8
Thanks
I set my expansion tank using plasticine it aint half handy.
I spoke with Quaife today regarding the grunt situation, am going to send them pics of diff shafts to see what can be done.
 
#9
Thanks
I set my expansion tank using plasticine it aint half handy.
I spoke with Quaife today regarding the grunt situation, am going to send them pics of diff shafts to see what can be done.
as im considering doing same myself and possibly building a second car to race i could well be interested in adding to any order you might make, it coudl make financially more viable
 
#15
I have quite a few pics of a Jag install if that helps. I don't want to go that route at the moment
im considering building a car for a spot of classic racing, where regulations dictate using a P6 diff assembly, which is why im interested in uprated bits, i suspect there are quite a few owners out there that would be interested in up rateing the diff but not fitting something totally alien
 

cobraboy

Well-Known Member
#17
After a long day fiddling, fettling, and praying to the v8 God I went and turned the key, it coughed first time :)
Second time it only bloody started :D
Holding firmly onto a wooden desk as I type, I do not have anything in the drip tray underneath ;)
 
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