Tonight we decided to remove the old 6 cylinder and trial fit the V12. well as our luck has it it fits, but not well. The engine is on a 10 degree angle backward. In order to lower the front of the engine I have three options. I just need to know which is the best option. option A ; cut the firewall back 7 inches, this will allow me to get the front crank pulley behind the front crossmember and lower it down the correct amount. option B ; cut out the front member to lower the engine. option C; leave it as is just don't know if it will be ok run the engine like that, everything does fit exhaust clears, rad clears. so what would you guys do ?
yup, cut the firewall/floor 10 degree crankshaft angle is too much--3 is more like it. the stock front crossmember has a notch in it stock for the factory lower pulley, and, while I have heard of guys cutting the notch bigger, I've never felt it necessary.
If it gets the back of the engine past the firewall, I'd think twice about cutting that much out. You're likely to run into issues servicing the engine later. If it is only the triangular "humps" common on the old mopar firewalls, by all means get rid of them. What would you be giving up by notching/removing that front crossmember?
Cars up here in canada have to p*** a government inspection before they can be licensed and insured, by notching out the crossmember i do run the risk of not being able to p*** no matter how good my welding is, it might have to have a engineers stamp. Which would cost a pretty penny. That's the only downfall of cutting out the front crossmember.
I'd be contemplating grafting in the center section of a firewall from a late model rear wheel drive van just to have the ready made removable under dash access panel.
Another vote for 'fixing' the firewall. A removeable section is necessary if there are maintenance items to deal with. Oh yeah, post some pics. .
Need pics before I can say anthing. How are your welding skills? Butching a fire wall is never nice. Uncle Rocky
How in the heck is the "government" gonna know you cut the firewall? or put a new front suspension in?
NONSENSE! Cut away! Sheet metal is easy. Why does everyone ***ume that professional car safety inspectors, VIN inspector, or cops, etc. are ignorant or stupid? In my direct experience, they are anything but.
I've cut out the firewall and set the engine back as far as i'm comfortable with i really don't want to cut out the pinch weld . It's still not back enough so i've decided to cut out the crossmember also that way i can see the timing marks on the balancer.
heres a silly one but it works well. cut out the firewall and use a wheelbarrow to patch.. they look good and will have all the depth you might need... or you could do what some people do.. lengthen the front end... that would make it real odd...
I would tweak the crossmember. You can reinforce it so that it is stronger than stock. It will not be fun working on that engine with one and a half cylinders buried under the firewall. The stock Plymouth front cross member has a lot of metal in all the wrong places for a swap like this. Or, of course, swap in a Jag IFS. That would be more work but would solve many problems at once.
Don't forget that on the Jag V12 you check the timing from the bottom. It is a sign of trust setting the timing on those cars - 3000 rpm; you must really trust the person with their foot on the gas while you are upside down underneath that beast spinning at 3000 rpm trying to see the timing marks.
yeah its getting cut the person on the gas will be my wife so better trust her ill post some pics later
"Cars up here in canada have to p*** a government inspection before they can be licensed and insured, by notching out the crossmember i do run the risk of not being able to p*** no matter how good my welding is, it might have to have a engineers stamp. Which would cost a pretty penny. That's the only downfall of cutting out the front crossmember." Dont live in Man but have done lots of safety inspections in Ontario. Make sure the welding is professional looking (No bubble gum welds as we used to call them )and the cross member is finished and painted. And DON"T ask the inpsection guy if it is OK. In other words make sure it is done well enouf that it looks stock. Don
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