Pre-HE or HE advice

(William) #1

Hello, I’m new to posting on this forum, I had some questions about HE and pre-HE v12’s. I am not sure if this is the right section to post in. Ok so I am planning on building a 5.3 with a 5 -speed for a series 1 XJ6 swap, I don’t need crazy power, but I would like to see around 300-320hp at the wheels , My question is, do you think it is worth trying to find a Pre-HE motor due to their potential to make more power, or can my power figures be achieved just as easily with the HE motor? Some details about what I plan to do, I am going to be running an MS2 V3.0 controlling fuel with bank fire and maybe ignition on wasted spark, I plan on putting either a Getrag or a Tremec 5-speed behind it. I am swapping it into a series 1 XJ6. Again sorry if this is not in the right section.

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #2

Possible with an H.E. but probably easier with a pre-H.E.

(William) #3

Excuse the newbie question, but would you be able to convert an HE to a Pre-HE motor down the road if I want to make more power? I am doing this on a little bit of a budget (i know, budgets and v12’s dont mix well) what would be most cost effective way to wake up either the HE or pre-he. Thanks!

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #4

There wouldn’t be any point to such a conversion. You’d be better off just swapping engines. The pistons, heads, and several other items are different.

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #5

Cams. You might be able to find an outfit that can regrind the original camshafts to your specification.

(William) #6

Ok, thanks for the info! I think that Its probably best to go pre-H.E. in the first place then. would be correct in saying that you can rev out the pre-h.e. motor higher i.e. 7500?

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #7

The problem with revving a Jaguar V12 to 7500 isn’t with the engine, it’s with the torque converter – but if you’re going with a 5-speed you won’t have a torque converter, so you’re good to go.

I recommend an aluminum flywheel with an iron friction face. The Jaguar steel flywheel is waaaay too heavy.

(William) #8

Ok, cool. It’s going to take a while for me to acquire all the parts (im still in college). but hopefully in a couple years time I will have it all together! thanks for the help and quick replies!