Page 1 of 2

SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 9:16 pm
by Surgeonasst222
Well I just bought a 92 RS and it had some engine problems, there is a oil leak somewhere... I didn't look into that cuz I know the top end is bad. I was going to get that rebuilt for like $300 but someone kind of talked me into saving up for a full engine rebuild now that's about $1900.

While I was looking for more people that rebuild engines, and I found a guy that will replace my engine for another engine that is from a junk yard and try to get it with low miles. This would cost me $300-$500... So I used to have a 94 RS with a DOHC, I don't know the differences and thought maybe I could that engine instead.

So I have many questions here as I am a noob to this stuff.

1. Should I just do the top end rebuild?
2. Should I save for the full rebuild?
3. Should I just get a different engine with low miles from a junk yard?
4. If I should do number 3, should I get the same engine or a DOHC engine?
5. Is that even possible, if so what are the advantages if I do?
6. Is there even a difference between the 2?

Thanks in advance,

Kegan

Re: SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 9:40 pm
by kulluminati777
if i was in your shoes i would do number 3 and get the a DOHC 4cyl with a tad bit more power....

Re: SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 9:50 pm
by Surgeonasst222
kulluminati777 wrote:if i was in your shoes i would do number 3 and get the a DOHC 4cyl with a tad bit more power....
As I have a SOHC now can they just pop out that one and pop in a DOHC with no problems? I don't want to put in hundreds more just for stuff to work.

Thanks,

Re: SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 9:53 pm
by kulluminati777
im 99.9999% sure the only thing extra you would need would be the ECU but im a V6. I would wait until i 4cyl guy gets online and comments to pull the trigger

Re: SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 9:57 pm
by Savin
Swap in a BP engine. Its plug-n-play for the SOHC engine. To swap to the DOHC B6, you'd have to change the whole engine harness as well.

Re: SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 10:07 pm
by kulluminati777
oh i thought the BP was DOHC?

Re: SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 10:38 pm
by Savin
The BP is DOHC. But it uses a VAF like the SOHC B6 whereas the DOHC B6 uses a MAF.

There's other differences I'm sure. But the BP is the engine you want if you're going to swap. There is much info about the swap in the 4cyl FAQ and peoples' worklogs.

Re: SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 10:44 pm
by Surgeonasst222
Savin wrote:The BP is DOHC. But it uses a VAF like the SOHC B6 whereas the DOHC B6 uses a MAF.

There's other differences I'm sure. But the BP is the engine you want if you're going to swap. There is much info about the swap in the 4cyl FAQ and peoples' worklogs.
Lol ok I said noob here so what do I need to ask for when I go to this guy and point me at a work log that talks about this and I will be happy man! I don't really want this to be a hassle, I want this not to be a big deal. Is the SOHC really that much of a dog I will hate myself for not doing this other DOHC? Like I said I just want to plug and play, if I want to bump up to this bp DOHC how much extra money am I talking here.

Thanks much Savin

Re: SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 10:51 pm
by Surgeonasst222
Double post sry :(

:s

Re: SOHC Vs. DOHC??? Some question...

Posted: February 20th, 2013, 11:10 pm
by Savin
SOHC B6 - 88hp
DOHC BP - 130hp

If the engine is from a junkyard or where ever, then it should cost about the same (plus the bp computer and matching VAF) those both plug right in though.

Read this: http://www.mx-3.com/phpBB3/viewtopic.php?f=3&t=38979 It'll give you a ton of info.

Re: SOHC Vs. DOHC??? Some question...

Posted: February 21st, 2013, 2:02 am
by RobMinhas
That thread is a little difficult to go through without a decent amount of car knowledge so I'll try to give you some help here.

What you'll need:

A Mazda/Ford BP engine(90-94 Mazda Protege with the DOHC and 90-93 Ford Escort GT, Im not 100percent sure on the years for the Escort though).
BP VAF from the same car the engine came from.
BP ECU from the same car you pulled the engine from

That's it, you don't need any harness bits or anything, pull out, stuff in, bolt up and plug in. Any mechanic worth their salt can do this swap.

Id reccomend doing the timing belt and water pump as well as replace the clutch since those jobs are incredibly easy when the engines out.

A guide i used when I researched my swap(other then picking at Mi|<es brain) was this site here:

http://www.clubprotege.com/wil/tech/b-s ... wapfaq.htm

Re: SOHC Vs. DOHC??? Some question...

Posted: February 21st, 2013, 7:42 pm
by Surgeonasst222
RobMinhas wrote:That thread is a little difficult to go through without a decent amount of car knowledge so I'll try to give you some help here.

What you'll need:

A Mazda/Ford BP engine(90-94 Mazda Protege with the DOHC and 90-93 Ford Escort GT, Im not 100percent sure on the years for the Escort though).
BP VAF from the same car the engine came from.
BP ECU from the same car you pulled the engine from

That's it, you don't need any harness bits or anything, pull out, stuff in, bolt up and plug in. Any mechanic worth their salt can do this swap.

Id reccomend doing the timing belt and water pump as well as replace the clutch since those jobs are incredibly easy when the engines out.

A guide i used when I researched my swap(other then picking at Mi|<es brain) was this site here:

http://www.clubprotege.com/wil/tech/b-s ... wapfaq.htm
Thanks man you answered some of the questions I had after reading that long thread! Also I want to try and do this swap by myself it is the main reason I got this car was to learn more how to do car stuff and I think this sounds pretty easy for swapping a engine... I will also look at doing both of those things while I am in there.

My last question is most of what I was reading in there seemed to be for manual tranny. I have a automatic tranny is there any differences that I need to be aware of and should I do a flush and filter change while the engine is out?

When it turns spring I start a work log on all of this... When I start... My house doesn't have a garage and my dad has spare space so it will go there when spring comes!

Thanks guys for the help!!!

Re: SOHC Vs. DOHC??? Some question...

Posted: February 21st, 2013, 7:51 pm
by RobMinhas
It's supposed to be stupidly easy to do the swap assuming you don't run into seized/broken bolts. Borrow a hoist and you should be set, helps to have some buddies who can help wrench.

As far as auto trans....I really don't know if the auto from the b6 will bolt up to the bp, I would imagine it does but I don't know for sure.

Re: SOHC Vs. DOHC??? Some question...

Posted: February 21st, 2013, 8:42 pm
by Savin
It'll bolt up fine. ...but it won't last long if you drive the car hard. The auto transmissions in these cars aren't exactly strong. They barely manage to handle stock power.

Re: SOHC Vs. DOHC??? Some question...

Posted: February 22nd, 2013, 6:17 am
by Surgeonasst222
Savin wrote:It'll bolt up fine. ...but it won't last long if you drive the car hard. The auto transmissions in these cars aren't exactly strong. They barely manage to handle stock power.
Ok sounds great at least I know it works! Also car only has 79k on it with only one owner before me and besides the engine it is in good shape... The inside is dirty but a solid weekend of cleaning will do her good. Need some new seats thoe. Guy was a college kid, doubt he had the money or the time to deal with it.

I will plan on this in the spring!

Thanks again guys!