Topic: Time to build it! Got a few questions

[chardrc]

I Still have my stock throttle body (just the lower part with the throttle plate. Send me a PM and we can figure out shipping and cost.

[grumpygy]

http://4bangerjp.com/forums/index.php/topic,4044.0.html

[Jeffy]

http://4bangerjp.com/forums/index.php/topic,4044.0.html

They're talking about the TBI engines.

[bigal389]

Pm sent.

[bigal389]

I have a few questions on cams! The cam profile that was recommended By Geoege at Clay Smith Cams is as follows:

Advertised Duration  :264
  •Duration at .050" : 214
  •Lobe Separation :  110
  •Valve Lift based on Rocker Ratio
  •1.5    .450
  •1.6    .480
  •1.75  .525

My question is: Will this be too much lift with 1.6 ratio for the stock springs, will I have coil bind at .480 lift? Geoerge said he didn't think I would need to upgrade the valve train unless I planned on running at high rpms  which I don't. Hopefully with this cam, a bump in compression, porting and a bore throttle body and spacer my little 4 banger will really wake up!
Thanks, Al

[bigal389]

Ok I got the throttle body and spacer from Chardrc, I am planning on getting it bored as soon as I can. Also i plan on using the butterfly from a 1987 4.0 low output which has a 52 mm throttle body, this will be easier to cut down than a larger butterfly. After thinking about it for a few days I will keep the compression below 10:1, I am just going to clean up the mating surfaces on the head and block, I figure the final cr will end up between 9:5 and 9:8 depending on how much I have to bore the block. i will install the cam from Clay Smith Cams, port match, port and polish and add a cai and exhaust. I figure with all of this it should give it a nice little kick in the pants. I won't be able to get started until after the first of Nov. but I will  keep you all posted once the work begins.
Al

[chardrc]

Can't wait to read about the results. Do not forget to take pictures. 

[sharpxmen]

remember you'll have to pay more for gas with that CR

[bigal389]

Yeah I know but keeping it below 10:1 should help with the octane that it needs. When you bore the throttle body was enough material left to take it to 52 mm or was 50 the max? I ask because I haven't had a chance to measure yet and if I can take it to 52 it will save a little work on the butterfly.
Thanks, Al

[sharpxmen]

Yeah I know but keeping it below 10:1 should help with the octane that it needs. When you bore the throttle body was enough material left to take it to 52 mm or was 50 the max? I ask because I haven't had a chance to measure yet and if I can take it to 52 it will save a little work on the butterfly.
Thanks, Al

honestly i think i bored as much as i could safely do it, you can probably sqeeze another mm in there but keep in mind that is cast so it is not perfectly concentric with the outside diameter to begin with so you will end up with some areas that are thinner (which would be your limit). You'll have to make a jig for the butterfly, it has to be machined round with the butterfly at an angle, otherwise you risk of having too much air bleeding around it.

[bigal389]

Thanks I was kinda stumped on the butterfly part but now I see exactly what to do. I'll let you know how it turns out.
Al

[dwtaylorpdx]

I have the Hesco RVOB cam for the 4cyl, its a Clay Smith when it arrives... :)
http://www.hesco.us/products/7735/cylinder-heads/167924/rvob4-25l-camshaft Note the warnings on the page....
My builder machined the spring pockets on the head to keep the springs from binding, If I recall it needed about .050.

I did new springs. stock rocker arms. 4.0 adjustable timing set. (Gets rid of tensioner)

There actually are several different pistons used in the 2.5 when my builder got to looking into it if I recall the post 95 pistons were similar to  a hyperutectic and came coated.. This was to prevent the piston slap the jeeps had issues with from the factory.. I've got 85K on mine and good so far.

Cheers
Dave

[sharpxmen]

how does the non-tensioner timing chain adjust? (i replaced mine including the tensioner and that piece of plastic is prone to fail so i'm interested in this one for future reference).

[bigal389]

How does it perform with the RVOB cam? The cam I'm looking at is similar to it. I'm also interested in the adjustable timing set, got any info on it?
Al

[sharpxmen]

how does the non-tensioner timing chain adjust? (i replaced mine including the tensioner and that piece of plastic is prone to fail so i'm interested in this one for future reference).

nevermind, it adjusts the timing offset not the chain. in the end I don't know what's worse, using the plastic tensioner or having one without it like the 6 cylinder, I wish someone would have come up with a better design for the tensioner itself.