this is a really odd set of problems that me and my friend ran into last night installing his new motor. he has a 92 dx that was a sohc. the first time we did this swap we ran into all kinds of problems(trans mount brackets, wiring harness, slave cylinder.....). well when we got done putting this motor in it started missing and smoking. this motor only lasted 3 months. come to find out it had cracked exhaust valves int the #1,#3 and the #4 was already broken and had no compression. after 3 months it finally broke the #1,and #3 exhaust valve. so we found this great deal for a 94 dohc for $450 with only 47,000 miles. we just got done installing it today and it works great. now to the odd stuff. when we got a better look at the exhaust manny right before we installed it we found out that it wouldn't work. for some reason it came with a factory header. it is a shorty header and doesn't even have a place for a o2 sensor. i guess it must be int the down pipe that didn't come with ours. as far as i know they didn't make a factory header for the 1.8l dohc. the other odd thing was with the firing order. we had to use our distributor out of the 92 dohc that we just removed. when installing the distributor with the motor at top dead center the rotor didn't line up with the #1. we had to move all the wires over one to the right. but besides this every thing worked out great. i'm thinking that there might be either a different cap for a 94 vs. 92 or maybe a distributor. but i'm really lost on the exhaust. it even has a part #bpe1 stamped on the sheild. any thoughts?

 

ok dohc parts will not work with the sohc parts...

there was no difference between a 92 and 94 motor sohc vs sohc, or dohc vs dohc

and can you sum up your post?? Currently it makes little to no sense. the head is 16 valve therefor there are 2 valves per side, ie. 2 exaust valves and 2 intake valves per cyl. so your post make no sense what so ever.

how about we simplify and clairify your post

 

94 had a different exhaust manifold style (supposedly preferable to the 90-93s), although I was not aware that it wouldn't bolt up, that's kind of strange.

94 also had true 9.0:1 pistons. The earlier years were said to actually be 8.8:1 despite the specs.

 

well to tell you the truth sohc parts will work on a dohc. it just depends on what part you are trying to use. to clear this up, this is the 3rd motor. sohc was removed and replace with a 92 dohc motor and trans. that motor broke 3 exhaust valves. it broke one of the two exhaust valves on the #1,#3,#4 cylinder. i hope thats alittle clearer.

 

found out from mazda that they used a factory header on a 94 protege lx with an auto trans only. they only used it for one year. it will bolt up to all 90-94 proteges with dohc but you have to change the down pipe. the down pipe is different and thats where the o2 mounts. and on the firing order issue, found out that there wasn't any difference between any of the years for the cap or the distributor. its really not a big deal. the car runs great. its just odd that we had to move the firing order. so now instead of being 1,3,4,2 we are 2,4,3,1.