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Ford dohc - bad as people say.
emwmarine - 1/9/12 at 06:23 PM

I am planing to put a zetec in my Dax but then had a sudden thought about maybe the Ford DOHC.


It would have some advantages:

- I already have a stainless 4 2 1 and it wouldn't need a cat and be easier on emissions.

- The Rush part built chassis I bought had mounts for the DOHC.

The downsides are people say it is a bit rough and can't be tuned.


Is this right? Surely I could take the head to my friendly chap at Sabreheads. Presumably I could fit bike throttle bodies on it ?


Does anyone know anything about these engines?

r1_pete - 1/9/12 at 06:41 PM

Heads are prone to cracking, and warping.

Quite a heavy lump.

I was going to use one, but gave it away and went Zetec.

Xtreme Kermit - 1/9/12 at 06:59 PM

When people say it can't be tuned, I think it's more a lack of available aftermarket off the shelf tuning parts.

It's much easier to pick an engine with good aftermarket support.

Go zetec. You know it makes sense.

big_wasa - 1/9/12 at 07:09 PM

Bits are dear, I would go with the 16v rs2000 dohc engine over the 8 valve. But then again zetec's are so cheap and easy

Fatgadget - 1/9/12 at 07:09 PM

Why not if its for nish?Cant be that much heavier than a Pinto No?

steve m - 1/9/12 at 07:18 PM

Its very heavy, and as said, crap.
unless its all you have, stick somthing better in, as you will only regret it later

jollygreengiant - 1/9/12 at 07:41 PM

Timing chains tend to let go at 80 - 100k miles. Most of the time the result of this is the block is a write of due to the chain cracking the front main bearing cap.

The chain is cheap, but the hydraulic tensioner is dear and use ONCE only.

Lack of tuning parts.

8 valves instead of 16.

Heavy.

About the only thing going for it is that it is relatively easily replaced with a Z-tec.

Oh and did I mention that the heads tend to crack for a hobby.

mark chandler - 1/9/12 at 07:42 PM

Being easy on immisions is a big plus (as this is then for the life of the car), ford used them for a few years and you have it with the bits to run so why not?

After you have passed SVA you want an upgrade then what's the extra costs, redoing engine mounts, coolant hoses and fiddling with an exhaust manifold?

Go for it....

chillis - 1/9/12 at 09:21 PM

No not really, depends what you want.
If you want something tuneable later then there are better and cheaper, if you want a sturdy and reliable unit then theres a lot to recommend them. As mentioned they are heavy but no heavier than a pinto.
16v RS2000 engine is by far the best to use- 150hp stock and the same torque as a 2.8l V6 Capri.
Bike carbs and megajolt. overall cheaper than a pinto these days. Again cams are no more expensive than say vauxhall red top.
Cam chains can fail but my RS did over 125000 miles on the same chain and was in quite good condition when i stripped the engine. Chain and tensioner no more than the cost of a black top belt kit.
You could build with the 8v then fit a 16v engine later.

britishtrident - 2/9/12 at 06:04 AM

Because the valves and valves lift are so much larger with any old school 8v DOHC hemi head engine you are going to have to keep very strictly within the rev limit as if valve bounce occurs the valves are much more likely to end up crashing into each other or the piston.
The 16v version is essential designed to be built using as much of the 8v tooling as possible so is old school in design.

With other more recent 16v engines the valves are lighter smaller with correspondingly less lift and on modern 16 valve because the included angle of the valves to each other is less then the odds of damaging contact between the valves is less.

The timing chain issue has already been mentioned.
Another specific Sierra DOHC concerrns the connecting rod little end which has been known to fail when higher mileage engines are subject to hard use, ISTR Forrd beefed up the con rod in production.



[Edited on 2/9/12 by britishtrident]

ali f27 - 2/9/12 at 07:14 AM

Well mark used one in the first car he built 2.3 16 valve scorpio balancer shafts removed on modified honda throttle bodies made 200bhp and went like stink nothing wrong with it at all cannot understand why people dont like it lot of sh..t talked no heavier than any cast engine

MikeRJ - 2/9/12 at 10:05 AM

quote:
Originally posted by ali f27
Well mark used one in the first car he built 2.3 16 valve scorpio balancer shafts removed on modified honda throttle bodies made 200bhp and went like stink nothing wrong with it at all cannot understand why people dont like it lot of sh..t talked no heavier than any cast engine


That's not the crappy old 8v DOHC engine though, at least the 16v version has the benefit of some power. And yes they are heavier than a lot of cast iron engines, the Zetec E is lighter for starters!

rusty nuts - 2/9/12 at 10:21 AM

If it was that good an engine then Ford would have used it for a lot longer than they did . A head gasket set alone cost's more than a decent Zetec

jollygreengiant - 2/9/12 at 02:14 PM

quote:
Originally posted by ali f27
at all cannot understand why people dont like it lot of sh..t talked no heavier than any cast engine


EDIT BIT.

For those hard of reading, I am a time served mechanic and MOT tester (although I have been out of garages now for 8 years ish). I speak ONLY from experience of REAL world faults, repairs, servicing. When someone asks a specific question, i.e. Ford DOHC I personally take this to mean the 8 Valve DOHC and NO other, NOT the 16V units in either 2.0L OR 2.3L versions. I know that a lot of the contributors on this queery have and DO speak from EXPERIENCE and not as suggested or implied from somewhere else. Advice was sought and learned advice was given.
So please DO NOT try be-little-ing peolpe(s) comments.

END OF EDIT BIT

Lets just say that, those of us who earned a living working on them have a BIT of an idea as to WHAT we ARE talking about.
As said DOHC = 8 valve DOHC, came in either Carb or Injection models. It does not refer to ANY other variant be it 16V or higher capacity.

Oh and the hydraulic lifters usually rattled like complete and utter so and so's (sounds like the engine is falling appart) for up to an hour (or longer) even when the revs were raised to 2000rpm, after a rebuild. Appart that is, from the one time when a customer was standing beside me and I warned him about the rattle before I did the first start up with him standing beside me.

[Edited on 2/9/12 by jollygreengiant]

chillis - 2/9/12 at 02:29 PM

Ah the usual load of cr@p from those who have obviously had nothing to do with this engine and just puke up the rubbish they've heard down the pub!
A close look at the 16v head shows it to be very similar to the BDA head and the much loved vauxhall 16v.
Mountune were getting over 200bhp with nothing more than pistons and cams and running to over 8000rev/min with a stock bottom end!
16v was designed to make maximun use of 8v parts - as are many an engine including the sierra cossy engine and the BOA/BOB!
The engine is not cheap to tune - few engines are these days, true there isn't so much available to tune them with, but what there is isn't any more expensive that would be the case for Zetec, Duratec or Vaux. 16v.
8v engine, the valves will NOT contact the piston or each other at valve bounce, this is the same for any engine. (do you know what valve bounce is?)
From my notes I see the DOHC is 1.3kg lighter than a pinto and 100gk lighter than an Essex V6 (the 8v is just 5bhp less than the essex V6!)
The DOHC engine in one variant or another was used from 1989 to 2007 - 18years. The zetec 1992 to 2004 - 12 years.

emwmarine - 2/9/12 at 03:08 PM

So if I get one and run it with bike carbs and megajolt.

Maybe get sabreheads to do a mini porting job on the head, how much power is it likely to give?

The zetec gives 130 ish in a tin top and when put in a kitcar with decent induction and bike throttle bodies gives 170 ish bhp.

If the DOHC gives 115 ish with its standard induction am I likely to get 150 ish+ with the above?


p.s. does anyone have one?

mcerd1 - 3/9/12 at 08:04 AM

quote:
Originally posted by chillis
16v was designed to make maximun use of 8v parts - as are many an engine including the sierra cossy engine and the BOA/BOB!
but being a 16v engine that started life as 8v doesn't automaticaly make it good.

besided the cossie YB is based on the already much loved pinto and I don't think it wasn't even the first 16v pinto at that (see warrior 16v's - not sure when they first appeared exactlly, but I'm fairly sure it was pre-YB)

(BOA/BOB's worked well enough, but the have there own issues and aren't exactly light weight)
quote:
Originally posted by chillisFrom my notes I see the DOHC is 1.3kg lighter than a pinto and 100gk lighter than an Essex V6 (the 8v is just 5bhp less than the essex V6!)

The Essex is hardly a fair comparison it dates from the mid 1960's and always had a reputation for low power to weight (I've got one of these in my scimitar)

quote:
Originally posted by chillisThe DOHC engine in one variant or another was used from 1989 to 2007 - 18years. The zetec 1992 to 2004 - 12 years.

Yes, but that covers several versions of the engine, mostly in low production volume cars - how many zetec E or zetec SE's were sold in the same time ?
By the same logic Kent engines in various forms were in production for 43 years from 1959 till 2002 (i.e. kent, X-flow, valencia, HCS, Endura E), but your hardly going to tell me that the ford KA had the same engine as the Anglia are you….

mcerd1 - 3/9/12 at 08:07 AM

quote:
Originally posted by emwmarine
p.s. does anyone have one?

next door to me has (last time i checked) a complete granny with a 2.0 DOHC 8v - he's got an old e class now so I doubt it'll ever move again - I could ask if you really wanted it

britishtrident - 3/9/12 at 11:31 AM

quote:
Originally posted by chillis
Ah the usual load of cr@p from those who have obviously had nothing to do with this engine and just puke up the rubbish they've heard down the pub!
A close look at the 16v head shows it to be very similar to the BDA head and the much loved vauxhall 16v.
Mountune were getting over 200bhp with nothing more than pistons and cams and running to over 8000rev/min with a stock bottom end!
16v was designed to make maximun use of 8v parts - as are many an engine including the sierra cossy engine and the BOA/BOB!
The engine is not cheap to tune - few engines are these days, true there isn't so much available to tune them with, but what there is isn't any more expensive that would be the case for Zetec, Duratec or Vaux. 16v.
8v engine, the valves will NOT contact the piston or each other at valve bounce, this is the same for any engine. (do you know what valve bounce is?)
From my notes I see the DOHC is 1.3kg lighter than a pinto and 100gk lighter than an Essex V6 (the 8v is just 5bhp less than the essex V6!)
The DOHC engine in one variant or another was used from 1989 to 2007 - 18years. The zetec 1992 to 2004 - 12 years.



Do you actually know where the bonnet catch is on a car ?
I have spent too many hours of my life untangling bent valves and rebuilding the heads on various types of DOHC engine because the drivers downshifted too early or got the wrong gear on down changes, two valve DOHC hemi headed engines are unforgiving -- just ask ask owner of a Lotus-Ford Twincam engine.

emwmarine - 3/9/12 at 03:20 PM

Thanks everyone.

Decided what to do - taking the zetec route.

However will try to find a pre-95 zetec.

gallons perminute - 3/9/12 at 03:57 PM

I have used the 2L 16v Engines in various cars that I have built and found them to be ok if kept standard ie 150 bhp. Mountune got lots of power out of this engine when used in the Works RS2000s in period. I managed over 200bhp replicating what they did but found that pistons were the weak link.

I still have some RS2000 16v parts tucked away including a complete engine, spare heads, blocks, cams, cranks, rods, various sumps ( including a dry sump kit) , competition cams and fancy exhaust manifold if anyone is interested.

Paul W - 15/9/12 at 03:46 PM

u2u sent re rs2000 stuff

chillis - 15/9/12 at 05:49 PM

quote:
Originally posted by britishtrident
quote:
Originally posted by chillis
Ah the usual load of cr@p from those who have obviously had nothing to do with this engine and just puke up the rubbish they've heard down the pub!
A close look at the 16v head shows it to be very similar to the BDA head and the much loved vauxhall 16v.
Mountune were getting over 200bhp with nothing more than pistons and cams and running to over 8000rev/min with a stock bottom end!
16v was designed to make maximun use of 8v parts - as are many an engine including the sierra cossy engine and the BOA/BOB!
The engine is not cheap to tune - few engines are these days, true there isn't so much available to tune them with, but what there is isn't any more expensive that would be the case for Zetec, Duratec or Vaux. 16v.
8v engine, the valves will NOT contact the piston or each other at valve bounce, this is the same for any engine. (do you know what valve bounce is?)
From my notes I see the DOHC is 1.3kg lighter than a pinto and 100gk lighter than an Essex V6 (the 8v is just 5bhp less than the essex V6!)
The DOHC engine in one variant or another was used from 1989 to 2007 - 18years. The zetec 1992 to 2004 - 12 years.



Do you actually know where the bonnet catch is on a car ?
I have spent too many hours of my life untangling bent valves and rebuilding the heads on various types of DOHC engine because the drivers downshifted too early or got the wrong gear on down changes, two valve DOHC hemi headed engines are unforgiving -- just ask ask owner of a Lotus-Ford Twincam engine.


Do You

Any engine will break if its abused - not sure how you can suggest I know nothing because you had to repair the actions of morons!
I had quite a bit to do with the development of this engine.

gallons perminute - 15/9/12 at 07:09 PM

Chillis. We had lots of issues with the pistons. The lands between the rings in particular burnt away. Any idea why? Ford had CR issues at the time of production and reduced the CR with a thicker head gasket as a stop gap before altering the heads. Why was this? It has a smashing head, as good as a BDG etc but the bottom end is so heavy and seems over engineered compared to other engines about at the time. Do you have any idea why they went the way they did on the block? It always seems strange that they went with a chain drive rather than a belt. Any idea why?

The Galaxy 2.3 with the idlers in the sump is a brute of a thing. Were the shafts added because there was serious vibration issues? I used that engine in a minimilist sports car and it went well although the extra weight was and change to the induction plenum ment we had to re design the chassis.


GPM

chillis - 15/9/12 at 10:59 PM

quote:
Originally posted by gallons perminute
Chillis. We had lots of issues with the pistons. The lands between the rings in particular burnt away. Any idea why? Ford had CR issues at the time of production and reduced the CR with a thicker head gasket as a stop gap before altering the heads. Why was this? It has a smashing head, as good as a BDG etc but the bottom end is so heavy and seems over engineered compared to other engines about at the time. Do you have any idea why they went the way they did on the block? It always seems strange that they went with a chain drive rather than a belt. Any idea why?

The Galaxy 2.3 with the idlers in the sump is a brute of a thing. Were the shafts added because there was serious vibration issues? I used that engine in a minimilist sports car and it went well although the extra weight was and change to the induction plenum ment we had to re design the chassis.


GPM


Which version? I did encounter issues with the 2.3 piston lands but then we were doing pre ignition surveys at the time -most engines don't like full power at +8 degress of advance over base on a top limit CR engine.
Chain drive is considered more accurate than belt drive, the duratec is chain drive, the latest vauxhalls are as well.
Yes the engine does seem heavy but it was meant as a pinto replacement and is no heavier.
As for the vibration issues they were a bit over exagurated. We had to put them in the transit version only because there was some contract between ford and cosworth who made the ballance shaft kits! They cost more than the transit van profit margin and for the first time since the transit launched in 1967 it made a loss
The dohc performed better in its durab. sign off tests than everyones beloved zetec. The black top (cost down) zetec has chocolate pistons as well and cronic cooling issues. (they came back to haunt us on the RS focus)

emwmarine - 16/9/12 at 08:55 AM

quote:
Originally posted by chillis
quote:
Originally posted by gallons perminute
Chillis. We had lots of issues with the pistons. The lands between the rings in particular burnt away. Any idea why? Ford had CR issues at the time of production and reduced the CR with a thicker head gasket as a stop gap before altering the heads. Why was this? It has a smashing head, as good as a BDG etc but the bottom end is so heavy and seems over engineered compared to other engines about at the time. Do you have any idea why they went the way they did on the block? It always seems strange that they went with a chain drive rather than a belt. Any idea why?

The Galaxy 2.3 with the idlers in the sump is a brute of a thing. Were the shafts added because there was serious vibration issues? I used that engine in a minimilist sports car and it went well although the extra weight was and change to the induction plenum ment we had to re design the chassis.


GPM


Which version? I did encounter issues with the 2.3 piston lands but then we were doing pre ignition surveys at the time -most engines don't like full power at +8 degress of advance over base on a top limit CR engine.
Chain drive is considered more accurate than belt drive, the duratec is chain drive, the latest vauxhalls are as well.
Yes the engine does seem heavy but it was meant as a pinto replacement and is no heavier.
As for the vibration issues they were a bit over exagurated. We had to put them in the transit version only because there was some contract between ford and cosworth who made the ballance shaft kits! They cost more than the transit van profit margin and for the first time since the transit launched in 1967 it made a loss
The dohc performed better in its durab. sign off tests than everyones beloved zetec. The black top (cost down) zetec has chocolate pistons as well and cronic cooling issues. (they came back to haunt us on the RS focus)


What made me decide to stick with the Zetec was talking to the people at DJ who said that the vibration seemed to cause more exhaust breakages than on any other engine they had installed into the Rush. Now I know that could be down to installation but it I will bite the bullet and get a cat put in my exhaust and get ECU etc.

At least I should have 160 bhp out of the box.

gallons perminute - 16/9/12 at 10:05 AM

Chillis,

Thanks for the info. We used RS2000 engines. We tried for a similiar spec as the Escort rally cars but although we got good power we did not manage good levels of reliability.

I am not an engine man and picked this engine because it was easier and cheaper to source gearbox adaptors than get new ones cast. With hindsight it was a big mistake because the XE became the norm and we were left behind.

GPM