let's talk dohcs

Right all, I'm building a boosted dohc. 234. I'm wondering what common problems if any there are with these? I know a high rpm can bend your valves, and **** can get hot internally, but say I've got a squirter block, 230 Pistons, the correct injectors and ford Mustang valve springs, what else could I do in the way of reliability? Looking for around 270 ponies, as the drivetrain (with some abuse) can typically only take around 300. What's this delete kit I hear of where it takes a sprocet/cog out of the system or something? Also what's more reliable, hydraulic or sprung (if exists) tensioner? Cheers for your help chaps.

If you're putting a 16V head on a b230 block, yout can't use either style tensioner. because on the B234, the tensioner mounts on the block, and on the B230 the tensioner mounts on the head. So with the B230 block and the B234 head there's no tensioner anywhere. Yoshifab has a great adapter though, uses Volvo parts of various types (tensioner, idler, t-belt itself) and is a slam dunk solution for that issue. It's neither sprung or hydraulic thout - you twist the center of the tensioner around to tighten and then clamp it in place.

What sort of drivetrain do you have? A Volvo manual trans won't handle that sort of HP, and an AW70 will be sweating bullets. AW71 with accumulator mod might handle it (not very familiar with the automatics).

What sort of car are you putting this in? The B234 intake is rather bulky, and by reputation doesn't work that well in boosted applications - the with end cylinders getting fed less air than the centers.

And on the off chance your squirter block is a B234 block that you plan on putting b230 pistons into (assuming you mean B230FT pistons for the dish and lower comrpession ratio) then:
1) You'd need to carve some valve reliefs into the B230Ft pistons. Some have run without, some have run with incorrectly sized reliefs on the intake side (which would have hit if they'd ever been used), but the safety margin is razor thin between nothing and bent valves. Reliefs give you some more room for valve timing errors/experimentation. But still, they don't really help if the t-belt breaks. That still mangles stuff regardless.
2) You may be talking about removal of the balance shafts and their associated drive belt. Sometimes that belt fails, and the bits of broken belt get in the way of the timing belt, and then everything crunches. Easy as can be to just not install that belt, slightly more difficult to remove the balance shafts themselves and drill/tap/plug the oil feeds in the block for their bearings.

Yes a 234 block and the balance shaft was the one I was talking about. It's going into a volvo 360. With 2 CT12 turbos off a friends supra. I am talking 230 FT Pistons and had completely forgot about valve reliefs (cheers for reminding me) and I will be looking at a custom FFP for intake. I will have the 234 Pistons so will get the reliefs cut to match them regarding depth, even though I will be running the dish, for extra precautions. I just don't want this motor to break really. Dohcs are so bloody hard to find over here, I finally got one and I don't want to destroy the thing. He says adding two turbos.

The dish and the valve reliefs are in different parts of the piston (mostly).

Main risk to the head is from a broken or slipped timing belt. The turbos will likely blow up the bottom end if you lean on it too hard or make a few tuning mistakes along the way.

Which brings up... H-beam rods? Forged pistons instead of OEM cast? The H-beams are quite a bit stronger than the stock rods, even the stronger 13MM rods. When people blow up engines, it's very often due to a rod breaking from the abuse. Next, forged pistons. They have the ability to bend and yield when subjected to detonation. As I've found out (hah... ). Bending vs. breaking is the difference between the car coming up a bit lame (low compression, lots of blow by, maybe some knocking noises) after some hooning and some iffy tuning, vs. the cast pistons breaking and everything blowing up.

If OEM never get twin turbos to work right---and only put them on to make some Japanese/Hong Kong/Singapore rich boy get a stiffy when he looks at the badge on the boot----why would you want to make so much trouble for yourself?
Particularly for such modest output---which we know can be done in a n.a. car with a little work---probably less work in the case of a little bugger like that 360.....and then maybe the gearbox might last in it.

(I know even in nice cars (240) with the steering stuff, even normal turbo is a pain---can't imagine it being easy in one of those..)

Turbo is supposed to be "the easy way" to increase TORQUE
But it alwaus costs something..
N.a. around here is for 99% unknown territory...
But I think the costs are same, just spent in different areas.

JohnMc said:

The dish and the valve reliefs are in different parts of the piston (mostly).

Main risk to the head is from a broken or slipped timing belt. The turbos will likely blow up the bottom end if you lean on it too hard or make a few tuning mistakes along the way.

Which brings up... H-beam rods? Forged pistons instead of OEM cast? The H-beams are quite a bit stronger than the stock rods, even the stronger 13MM rods. When people blow up engines, it's very often due to a rod breaking from the abuse. Next, forged pistons. They have the ability to bend and yield when subjected to detonation. As I've found out (hah... ). Bending vs. breaking is the difference between the car coming up a bit lame (low compression, lots of blow by, maybe some knocking noises) after some hooning and some iffy tuning, vs. the cast pistons breaking and everything blowing up.

Click to expand...

Agreed.
And my rods are the best.. Longest and strongest.
And they are in now 3 or 4 ex-works Volvo Group A touring cars---including the best one in Australia---formerly Dick Prince's car --now having been sold.

Maybe you're thinking about the balance shaft delete? There's no kit per-se, but the process is pretty simple.

With each balance shaft removed there's a small feed port and a larger drain port below it. I just boogered up the feed port with my MIG welder. I plugged the drain port with a 240 wheel stud that I cut the threaded portion off of and some epoxy.

Block is upside down in this pic.


Remember that the stock balance shaft crank pulley should be kept in place to maintain proper stackup.

The timing belt pulleys on B234s are kinda weak. You should consider getting a billet steel one. KLRacing has them.

The first-gen oil pump pulleys are also a point of failure. Here's a comparison pic showing the difference (newer on top):


I don't have the part number for the newer pulley, but it superceeded the old one, so finding it at the dealer shouldn't be hard. It's also recommended to upgrade the bolt to a 12.9 and overtorque it slightly.

The B204FT came from the factory with a windage tray that bolts on to a B234. The part number is 3531227.

Why twins? Because it hasn't been done very often, it's unique. I'm not sure what H beams were came in, not sure what year this 234 block is either. Wasn't planning on forged anything tbh. The car will be run on either 95 or 98 octane fuel, which is our higher side, but I didn't think 270 would be an issue with the stock Pistons, but had thought about the rods. I've done my research, and if I want to push it past 270-300, and the rear end fails, Porsche 924 or 944 rear end is a suitable match to replace the factory train. What's the pricing on a billet belt pulley? And off what would I find a newer oil pump pulleys? Dealers want the earth for everything here. 800 nzd for a head gasket, by itself.

Karl Buchka said:

Maybe you're thinking about the balance shaft delete? There's no kit per-se, but the process is pretty simple.

With each balance shaft removed there's a small feed port and a larger drain port below it. I just boogered up the feed port with my MIG welder. I plugged the drain port with a 240 wheel stud that I cut the threaded portion off of and some epoxy.

Block is upside down in this pic.

Remember that the stock balance shaft crank pulley should be kept in place to maintain proper stackup.

The timing belt pulleys on B234s are kinda weak. You should consider getting a billet steel one. KLRacing has them.

The first-gen oil pump pulleys are also a point of failure. Here's a comparison pic showing the difference (newer on top):

I don't have the part number for the newer pulley, but it superceeded the old one, so finding it at the dealer shouldn't be hard. It's also recommended to upgrade the bolt to a 12.9 and overtorque it slightly.

The B204FT came from the factory with a windage tray that bolts on to a B234. The part number is 3531227.

Click to expand...

Updated pulley part number: 9135112

49,50$, IIRC.

I plugged returns with 16mm freeze plugs and dab of RTV, feed port on intake side with M12 bolt, exhaust side M6 grub. I like the idea of being able to return shafts at some point, though no one ever is going to, so your method rocks.

But something tells me he's 13 and isn't going to do this any time soon.

nordmaschine said:

Updated pulley part number: 9135112

49,50$, IIRC.

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And it's made from Mother Volvo's finest Unobtanium.

When an Aussie <strike>stealer</strike> dealer wanted $190 AUD + GST for one (and a 50% deposit up front before ordering it, if you please!) he told me there was one left in a German warehouse. I decided to try elsewhere, only to find that a chap on this board got the very last one from that same warehouse in Germany several months ago.

logan360 said:

Why twins? Because it hasn't been done very often,

it's unique..

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The time and money and I'll say it ( you're NZer, so I'm going to assume you aren't the typical, babied since birth, never had the word NO spoken to him, insecure American whiner who regards ANY and ALL words posed as a question or not enthusiastically supporting any whim idea as an life and ego threatening attack)--wasted effort you will dump into the not so unique idea of twin turbos, you could buy some decent internal parts---pistons and rods---and have a motor that will work and work really really well with ZERO or ONE turbo..

The ego stimulating "belief" that some idea is unique, and that is a reason to do anything is a bad sign.. A sign of something not very well thought out..And things not thought out means things probably will never get finished...

Here, you may be pissed, but this is a good guideline on builds, engines or whole cars:

"A good plan today, violently executed, is better than a perfect plan tomorrow"..

That is, of course, presuming you want to one day DRIVE the car and impress yourself---or if you want to wank off over it for years and get the adulation of all the whole Intra-web...

Personally, I like pounding on cars--and the work part is a neccasary evil to be able to DRIVE them...
But what the stuff do I know, Fred?

What John said... Picture*1000

bgpzfm142 said:

And it's made from Mother Volvo's finest Unobtanium.

When an Aussie <strike>stealer</strike> dealer wanted $190 AUD + GST for one (and a 50% deposit up front before ordering it, if you please!) he told me there was one left in a German warehouse. I decided to try elsewhere, only to find that a chap on this board got the very last one from that same warehouse in Germany several months ago.

Click to expand...

I was that chap.

I got another one some two months ago, actually.

Hate me please.

Listen to what John is saying. It will save you a lot of expense and allow you to put that money into building the engine right. I could get one of those gears machined up for you if you need it.

nordmaschine said:

What John said... Picture*1000
I was that chap.

I got another one some two months ago, actually.

Hate me please.

Click to expand...

Is it time for a colourful metaphor? Hate? Nah, but perhaps a while back I'd have expressed a wee bit of teeth-gnashing, green-tinged envy. Ah, well, things worked out well in the end anyway - it was a good excuse to buy another complete B234 for spares which popped up at a reasonable price.

Anyway, fellow Antipodean with a 360, I agree with what John said so much that I'm placing an order next week with him for rods, CP pistons, and a pair of his Suupa Bitchin' steel flywheels next week, when a certain long-awaited cheque clears. (Would've placed my order earlier, but the USD to Aussie peso exchange rate isn't going back to its glory days like I'd hoped it would). Doing these things properly the first time means they only have to be done once.

If memory serves, space is hardly the final frontier in a 360's engine bay at the best of times. A 16V head will eat a lot of the little it has. Which makes The Outside Agitator's point about avoiding over-complication for the sake of being unique even more prudent.

BTW logan360, what have you considered using in the camshafts department?

bgpzfm142 said:

Is it time for a colourful metaphor? Hate? Nah, but perhaps a while back I'd have expressed a wee bit of teeth-gnashing, green-tinged envy. Ah, well, things worked out well in the end anyway - it was a good excuse to buy another complete B234 for spares which popped up at a reasonable price.

Anyway, fellow Antipodean with a 360, I agree with what John said so much that I'm placing an order next week with him for rods, CP pistons, and a pair of his Suupa Bitchin' steel flywheels next week, when a certain long-awaited cheque clears. (Would've placed my order earlier, but the USD to Aussie peso exchange rate isn't going back to its glory days like I'd hoped it would). Doing these things properly the first time means they only have to be done once.

If memory serves, space is hardly the final frontier in a 360's engine bay at the best of times. A 16V head will eat a lot of the little it has. Which makes The Outside Agitator's point about avoiding over-complication for the sake of being unique even more prudent.

BTW logan360, what have you considered using in the camshafts department?

Click to expand...

Oi Fred, you going be going turbo or gonna be Abbey Normal and go for a 16v on ITBs and rev it up?
What sorta octane in yer fuel-- No, the CAR's fuel ya silly bastid!

John V said:

Oi Fred, you going be going turbo or gonna be Abbey Normal and go for a 16v on ITBs and rev it up?

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Can't be Abbey, since I'm not of the religious right. It shalt be a jurbo (just the one), running about 8:1 static within a 1st oversize B230 bore. Torque to be obtained via mucho gusto from a suitable snail. IOW, big boost, low static compression. I'm aiming for about 300 lb/ft (or 405 Nm as we say) so the T5 won't break. 142s are light, so it should go okay.

What sorta octane in yer fuel-- No, the CAR's fuel ya silly bastid!

Click to expand...

What they flog over here as 98, which is 98 RON. E85 can be got, but not easily around where I live... and I don't feel like emptying a tank primarily for the purpose of refilling it (thus interfering with time better suited to personal octane intake). So I foresee the need for water injection.... for the car!

So... how many real moneys do you require for -
- a set of suitable rods
- a set of CP pistons with valve reliefs in them, and rings
- a Suupa Bitchin' steel flywheel?

bgpzfm142 said:

Can't be Abbey, since I'm not of the religious right. It shalt be a jurbo (just the one), running about 8:1 static within a 1st oversize B230 bore. Torque to be obtained via mucho gusto from a suitable snail. IOW, big boost, low static compression. I'm aiming for about 300 lb/ft (or 405 Nm as we say) so the T5 won't break. 142s are light, so it should go okay.



What they flog over here as 98, which is 98 RON. E85 can be got, but not easily around where I live... and I don't feel like emptying a tank primarily for the purpose of refilling it (thus interfering with time better suited to personal octane intake). So I foresee the need for water injection.... for the car!

So... how many real moneys do you require for -
- a set of suitable rods
- a set of CP pistons with valve reliefs in them, and rings
- a Suupa Bitchin' steel flywheel?

Click to expand...

Sounds like a well thought out plan...I've written a number of times about the 'orrible effect of these miserable turbo inlet restrictors rally maniacs have to contend with and how once the size reached 34mm restrictor and the poor motors would not really make any poop above maybe 5200 rpm, everybody fingered out if they won't rev, bugger revving and make the mid-range torque monsters with really high static compression, eye popping compressor ratios, and loadsa boost--like 3 bar...or so
And it came to pass that some engines were happy to do 10+ comp and 3 bar and some were a constant fight...the key element in which were happy was they all had bores no more than 86mm. And those that were unhappy were those--like YBG Cosworth in those Frods and EJ20 in Sub-a-rat which have 90,8mm and 92mm respectively... Those two were limited to about "9,1 to 9,15 comp--and I mean it" said a WRC engine builder/tuner guy in beautiful Essex FORD COUNTRY!!!! FREEDOM!!!!
(geezas spossed to be a Scot but we know better, eh)


I asked this famous guy "Oi what about us poor sods wif 96mm bores, eh squire?"
He said "Bugger me 96mm wot da fuq? I'd say no more than 8:1 if you intend on givin it fun amount of boost and then flogging the beast..And min 98 okt, too"

Interestingly, since you mentioned Ford and rally, when Ford switched from the tarted up CVH with a pretty 16v head to the REALLY nice Duratec all alloy thing--which has 87.5mm bore, for WRC they sleeved the thing to 85mm and corrected stroke to 88--which just so happens to be the old Misterbitchy 4G63 Evobitchi motor--a paragon of power..and happy to make 3 bar--and gobs of the desirable ft/lbs..

So a set of pistons complete---and just for the sake of the rings I advise going 96,5mm not Volvos whacked out 96,3---wif dish and reliefs and round wire locks---not the gross disgusting flat circlips or Spiro-loc junk pins etc is ---as far as I know---$720.

Set of rods with big manly 7/16" rod bolts......$400

Balanced steel flywheel with a variety of pressure plate patterns for affordable pressure plates,............$340

And post would be probabaly around $130-140..

And I know you have greedy parasitical bastids who want to squeeze every penny from ya --having sent a fair number of things down there and we can discuss via email ways to keep them happy..Never lie to a bureaucrat bastid when half the truth will do.

John, you seem to be wasting your time, from a quick read it looks like the OP has no intention on upgrading the internals....

Perhaps afraid of doing any real engine work or wants to invest all his money on things people see when he opens his hood? (or is it bonnet over there?)

Mueller said:

John, you seem to be wasting your time, from a quick read it looks like the OP has no intention on upgrading the internals....

Perhaps afraid of doing any real engine work or wants to invest all his money on things people see when he opens his hood? (or is it bonnet over there?)

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Well I said I saw what I call certain 'markers' in the NZ guys words that means itsa high chance its all a wank-fest..

But the Lurker-to-poster ratio round these parts is pretty high, so discussion I hope benefits those other guys, the ones who want to actually drive their cars..

Can't win 'em all.