DOHC swap

[richter888]

Ok to start i have an 89 mustang with an 87' tcoupe engine. I have tons of mods that i dont even feel like typing. I was reading the article on merkurtech.com about the b234f head conversion. I am gathering supplies to do this swap, but ran into a small bump in my process of choosing exactly what to do.

What i plan on doing is grabbing myself a 2.3turbo block(since the turbo oil return line is already drilled) a b234f head(which i found one at a pull-your-own yard THANK GOD!)with assorted pieces(intake). Also a 2.5 crank

My big question is that i want to use a 2.5 crank and rod rotating assembly using the cp pistons. If the information on www.therangerstation.com/forums/showthread.php?t=9 is correct then the stroke+rod length difference between the 2.3 and 2.5 is .528". The problem is that the piston pin height only changes by .3275! That leaves and xtra .2005 left on the table! Unless im missing something this would cause an issue. Unless the deck height of the block is higher or piston height from the pin is different then i need some more in depth info. I must be missing something and would like some clarification. And most of all, is it even feasible? Should i stick to the 2.3 rotating assembly?

This will take a long time to create and this is merely the beginning. I think it will take anywhere from 4months to 10months to complete.(due mainly because of money). Any other useful info is appreciated.

Other mods is relocating oil filter and oil cooler. I hope i dont sound too much like an idiot. I'll have a competent machine shop do much of the assembly, so don't worry about me putting the internals together! Thanks!

[Stinger]

If you order our CP volvo head pistons, they will come with the correct pin height to match your combo. I've never found the 2.5 crank to be "worth it" from a hp/dollar standpoint though.

You should look into doing the swap by modding the block rather than the head, seems to be much easier that way.

[richter888]

Is there a major difference between the 2.3 and 2.5 crank other than the stroke? Mainly concerning reliability. I know on the 2.5 cranks the main journal diameter is smaller. What about the rods as well? When you mean by modding the block you mean simply bore, hone, decked, bearings, so on and so forth? Correct me if im wrong, but im unsure as to what you meant by simply modding the block instead of the head. Is the dohc setup not worth the time and money?

[Stinger]

The 2.3 and 2.5 cranks are both plenty strong. Rod bearing diameter is the same.

I mean don't mod the head (welded on aluminum block, drilled holes, filled holes, etc.) and instead mod the deck surface to line up with the head (plug a few of the holes in the block).

I can't define worth for you. In general I think it is only "worth it" for individuals capable of doing all of the fabrication work (including header and intake manifold) themselves.

[richter888]

You make a very good point. I have no way of obtaining the material to do the fabrication myself and paying someone else to do the work is way out of my pay. I believe a 2.5 single came motor is by best bet for its simplicity and cost.

Anyway i have bad news. I was driving the car back to my home and without realizing my oil pressure gauge had dropped to zero. I didn't realize it until i started hearing noises i didn't want to hear. So far i think only the top end has suffered. Checked oil and it was extremely low. Leak is unknown but car does smoke blue a tad at start up and under heavy throttle. Motor came out of a 105000 mile tcoupe!

I find myself very disgruntled by this whole car and i may also leave the 2.3 turbo world and cross to the 5.0 world. I have found it hard to even keep up with a factory 5.0 car even when the 2.3 ran somewhat right. I have spent well over $2300 on this project alone(that's just engine parts! let alone all the xtra things i bought like the center mount header($235) and the t3/t4 turbo that cost me $550!). A good friend of mine said for that kind of money he could have built me a very fun 5.0 motor that would leave a lot of cars in its wake considering all the other modifications to my car alone! Gas mileage is hardly a concern since i barely drive but a couple miles a day!

I'd love to continue trying to make a 4 banger turbo a street terror, but it just isn't happening. The cost is too much. I know the power output from these motors can be extreme, but i think i'm gonna give it up.

[turbo23240sx]

I though the same way when my distributor gear stripped and blew my new exhaust to pieces. I am now glad i stuck with the 2.3, just ran 13.80 @100mph with 18psi and completely stock 2.3 in my stang. I just switched to a holset and upped the boost and now i feel it will run 12.70 @112-115mph, then the large valves and cam will come for an 11 second 30mpg street car for a total of approx $1,500.0 in the engine.

[Stinger]

Aug 5, 2009 18:40:40 GMT -5 @richter888 said:

You make a very good point. I have no way of obtaining the material to do the fabrication myself and paying someone else to do the work is way out of my pay. I believe a 2.5 single came motor is by best bet for its simplicity and cost.

Anyway i have bad news. I was driving the car back to my home and without realizing my oil pressure gauge had dropped to zero. I didn't realize it until i started hearing noises i didn't want to hear. So far i think only the top end has suffered. Checked oil and it was extremely low. Leak is unknown but car does smoke blue a tad at start up and under heavy throttle. Motor came out of a 105000 mile tcoupe!

I find myself very disgruntled by this whole car and i may also leave the 2.3 turbo world and cross to the 5.0 world. I have found it hard to even keep up with a factory 5.0 car even when the 2.3 ran somewhat right. I have spent well over $2300 on this project alone(that's just engine parts! let alone all the xtra things i bought like the center mount header($235) and the t3/t4 turbo that cost me $550!). A good friend of mine said for that kind of money he could have built me a very fun 5.0 motor that would leave a lot of cars in its wake considering all the other modifications to my car alone! Gas mileage is hardly a concern since i barely drive but a couple miles a day!

I'd love to continue trying to make a 4 banger turbo a street terror, but it just isn't happening. The cost is too much. I know the power output from these motors can be extreme, but i think i'm gonna give it up.

Sorry to hear that. That's why I always advise to run the stock engines with bolt ons until you get near the hp limit of the stock used shortblock. Saves a couple thousand dollars of initial costs that then can be used on other items (a means of tuning for example).