Engine and Transmission Tech

Jim, yes-just now. Looks like something Pete Aardema would be involved in? I've read that "Zeus" heads,the god of hp.?, are the biggest in std. flow #'s for Lotus, but "Very" expensive. If I can make around 300 cfm. otta 907's, save save a ton-o cash. roverman.

Jim, Yes, just now. Looks like the work of Pete Aardema ? But Wait, for just a few $'s more...why not ploppem onna LS alum. block , or -OR, better-yet...a CADDY ? Kinda like a "Big Boy" Northstar ? roverman.

Art,240Sx/S14 heads look like a better fit. They have withstood 9000 RPM and 500 Hp turboed.4.4 bore spacing. Here are some pics:





Edited 1 time(s). Last edit at 02/08/2010 10:46PM by mgb260.

Jim, Thanks. Got 4.9L bore spacing ? ?

Art, Yes I do! By tape measure 4 3/8"(4.375) Probably 4.4 like Chevy. Head bolt pattern 3.5" up and down,4.5" left to right. Skinny heads, probably limited to stock heads. Porting, polishing ,gasket match,larger unshrouded valves.

At the risk of repeating, os. valves are: int. 1.450",.280" stem x 4.479 oal. and 67 grms. exh.: 1.282",.280" stem 4.479 oal. and 60 grms. I would like to speak to a skilled, "port shop", with personal experience with this head, that woun't feel compelled to charge $1,500 per head ? Maybe I'm out of touch ? I mean, bare/used, "Zeus" head starts at $2,100 ? roverman

Ahh it's right here 8-/

It looks as thought there is room to move the head bolt holes on the head
in 1/2" on each side
There would probably have to be some welding involved to get the cam towers to seal.
I don't know if the new holes would hit water
but if that isn't a problem , or an easily fixed problem I would think that this
would be a much better solution than adding a deck and sleeves.
I don't have a head so I'm basing all this on online photos but I'm ready to start the project :-)

Yeah, That does look like there is room. Is that a Duratec or Lotus head? Duratec has only 4.02 bore spacing.



Edited 2 time(s). Last edit at 02/19/2010 05:39PM by mgb260.

Sorry if this has been asked and answered, but how do you deal with the fact that one of the two heads will have the intake and exhaust on the wrong side? The ports aren't symmetric, nor are the valves the same size, so I wouldn't think you could easily swap intake and exhaust.

Gentlemen, please read,"all" the threads. Justin, you want to move ea. head bolt/boss, inward .531"/ea.? Much more work than deck. Billet cams must be made, preferably "LS" firing order. Heads and towers invert, side/side, or "Medusa",(snakes-on-top). Good Luck, roverman.

"Yeah, That does look like there is room. Is that a Duratec or Lotus head? Duratec has only 4.02 bore spacing."
No it's a 907 head without the cam towers to illustrate that there is room to move the head bolt holes on the head without hitting anything mechanical. I don't know if the moved holes will hit water and if they do if it's workable. I'm arm chair engineering, I have no 907 heads to look at but a wealth of 215 blocks.
Art, short of adding a deck plate and sleeving, one couldn't move the cylinder head bolts on the block deck...correct? Not having a head to compare I'm probably missing something important. If moving the head bolt holes in .531" on the head to match the rover block is indeed workable what else would make it a requirement to use a deck plate on the block to use the 907 heads?

Justin, and all, anyone considering this conversion, should get a new/used, 907 head gasket. That's when those "agonizing re-appraisals", set-in. Plenty of folks have went as far as "plopping" a pair of 907's on a Rover block. To date, as far as I know, that's as far as it got ! No Pete Aardema, but "maybe" Rover ? Unless one were to run "lots" of external lines,coolant, oil press/drainage, welding will be mandatory! What's the most expendable/changable item,(including developement labor), block or heads ? You move the bolt holes in the head, now what head gasket? Not Rover ! Making (4) billet cams is mandatory! (8) sleeves that woun't "sink", in the block is mandatory! Scratch- built,intake and exhaust system, mandatory! Pretty serious project, for even the most skilled. Do you feel lucky ? roverman.

Yep I spent some time looking at photos of the head gaskets and realized this was way beyond my capabilities. It looks like even with a deck plate and new liners there will be coolant flow problems under the exhaust ports, that is there will be no flow at all unless external lines are run and so on. Good luck to those brave souls who move forward with this project.

Well technically you can just have a head gasket made:

[www.cometic.com]

Any thinkness too. I was seriously considering this before my experimentation with the piston recess thing I did on my heads. I do still think the deck plate is probably necessary but it's worth fleshing out any ideas. Cooling under the exhaust ports is a good point...

What I was getting at was not that the head gaskets are different, one could bang out a copper head gasket if need be but that the 907 heads appear to be a bit wider than the rover deck, and that being said there would be no block under the 907 exhaust port coolant passages even with a deck plate unless external lines were run.
Why didn't Lotus figure this out first so our or Arts job would be easier :-)

Justin and clan, doesn't, "halft" to be Art's job. Any one else ? Rumor was Rover, had (2) , 32 v engines/cars and (1) was destroyed on "Autobaun" ? Makes for great print, but weak on supporting evidence. Primary purpose of periperal or deck adapter plates, is not to seal compression, Rover deck will do, but to properly transfer/"angle", feed and drain oil and coolant, with-out external lines. Fewer external lines on anything, to me, is fewer potential leaks. roverman.

AND you were looking at something like 750 thou for the plate thickness, right? So you could mill channels for the drain back and water ports in the top.

I know this is a long shot but would any one know where I could find technical drawings and dimensions for a 907/912 head and a Rover head?

Nic' and clan, using 2 pc. peripheral plates, they could be thicker with no effect on deck height. Angled holes for proper distribution. 2 pc would waste less material and allow step/mitre fitting to block.roverman.

I like that idea. So you mean that some of the deckplate would be below deck, right?. This is probably a bad idea but just tossing it out there: what about milling down the block deck like 120 thou or something to tune the plate position/thickness? Could end up with a pretzel block I suppose...