16v motor build up

[ZVOLV]

Ok, a couple of questions regarding my 16v head motor.


I have a complete b234 and it is already completely broken down. The head is at the shop already rebuilt. Now I got to decide on the block.

Is there any reason I shouldnt use the b234 block? I think dick prince mentioned they can have uneven cyl wall thickness. I am also planning on cheapskating it and reusing the b234 oil pump.

The pros i see of using the b234 block is that I dont need to source/fab a timing belt tensioner. It doesnt have an aux shaft to run the oil pump so there is less drag there.

Some of the cons: potentially weaker block (but i think a rod will bend/break first), gotta use b234 crossmember, and i got to thread some of the oil holes and plug other for turbo oil lines. No aux balance shafts for me.


Also, what will my cr be if I use turbo pistons with reliefs on that head? The combustion chamber is obviously different. Will the CR be increased with the b234 head?

I might go with a b230ft block, but then i gotta deal with custom tensioner and maybe a custom belt too. What are my options there? (regarding tensioners and belts) All i know of is the ovlov.net tensioner and I heard something about a mazda tensioner being fitted.

 

[MikeHardy]

http://mysite.wanadoo-members.co.uk/360s

ask this guy about the cam tensioner he did. he did the build up on a B230ET block. compression is bit higher as the 16V head is 50CC instead of the 53.7CC of 531 (530 51.7CC)

pics of his build up (no ads) it's in a 360 though

page 1
http://mysite.wanadoo-members.co.uk/360s/modifications360.html
page 2
http://mysite.wanadoo-members.co.uk/360s/modifications3602.html

 

[Forg]

Is there any reason I shouldnt use the b234 block? I think dick prince mentioned they can have uneven cyl wall thickness. I am also planning on cheapskating it and reusing the b234 oil pump.

IMHO, if you're cheapskating it enough to reuse the B234F pump, I wouldn't worry so much about cylinder wall thickness. Everything I've read has said it's really no different in any B23xxx of the same age ... the best block is indeed a late B230FT or FK (FK is the 940S "LPT" innit?), but it sounds like you wouldn't be forking-out for anything as exxy as that anyway?

ie. yes, it's potentially an issue; but I think you'd be spending a fair bit more to get around that potential problem.

 

[Unregistered]

B234 block and oil pump

I've mentioned before that after finally solving my engine problems (due to floating rods with large bore clearance forged pistons, and detecting and controlling detonation) I now consider the B234 block is pretty much the same as a B230 (provided you junk the balance shafts which contribute nothing to performance, and plug the balance shaft oil feed and return holes).
The B234 oil pump in the front alloy housing works fine provided you are careful sealing the suction tube from the oil strainer in the sump. It stops if you drop a cambelt, but then you also have lots of bent valves. When a cambelt lets go at any revs above idle you bend 16 valves every time! This is the source of most cheap 16V motors after all. Replacement OEM stainless B234F valves are pretty cheap from the Volvo internet shops - I got a set for about US20 each.
The B234 crossmember is identical to the B230, but with the addition of a pressed steel mounting for the left side engine mount. You can replace the full crossmember, or just cut the pressed steel thing off a B234 donor and weld it to your B230 crossmember if you don't want to dismantle your front suspension and steering rack.
One advantage of using a B234F bottom end is that you already have flycut pistons, and they all seem to have the 13mm rods. Just don't put big clearance forged pistons on those floating rods.
Dick Prince Ovlov.net

 

[the poi]

Kinda of an off question... whats the stock CR of a b234f?

 

[linuxman51]

10:1

 

[spongemonster]

hmm

So other than the compression ratio being a wee bit high for boosted applications the block may just be fine? Hmm well darn this complicates things a little but also makes them cheaper for me hehe. Now the only ways I really know of to change that compression ratio are to use dished pistons (I think) or to use a thicker head gasket. Any ideas?
James

 

[Forg]

I dislike the bodge of using a thicker head-gasket.

Can you get the inside of the head reshaped to have more volume, and lower CR? I don't know if that's possible or practical.

You might want to fit a set of forged pistons anyway, mightn't you?

 

[Hank Scorpio]

IMHO, if you're cheapskating it enough to reuse the B234F pump, I wouldn't worry so much about cylinder wall thickness. Everything I've read has said it's really no different in any B23xxx of the same age ... the best block is indeed a late B230FT or FK (FK is the 940S "LPT" innit?), but it sounds like you wouldn't be forking-out for anything as exxy as that anyway?

ie. yes, it's potentially an issue; but I think you'd be spending a fair bit more to get around that potential problem.

have you even SEEN a b234F. No reason to replace the pump imo too. Its external, it flows better than a b230 style pump, its not really anything that can wear out.

 

[linuxman51]

I dislike the bodge of using a thicker head-gasket.

Can you get the inside of the head reshaped to have more volume, and lower CR? I don't know if that's possible or practical.

You might want to fit a set of forged pistons anyway, mightn't you?

I wouldnt mess much with the chambers in the 16v head. any lower cr you'd want to do things to the pistons rather than expand the size of the head.

 

[Forg]

have you even SEEN a b234F. No reason to replace the pump imo too. Its external, it flows better than a b230 style pump, its not really anything that can wear out.

I was thinking more in terms of it having already done 15 year's worth of work ... if I were reco'ing an engine, I wouldn't be saving money in the oiling system. Maybe I'm just paranoid. If the oil was ever dirty, surely that could wear the innards of the pump?

I wouldnt mess much with the chambers in the 16v head. any lower cr you'd want to do things to the pistons rather than expand the size of the head.

Yeah, pistons aren't as expensive as they used to be either; and I can't imagine any sort of fiddling with the inside of the head that's done by someone who'll achieve a positive result would be any cheaper than a set of pistons. Thought it was worth asking though.

 

[ZVOLV]

Well, Volvo only wanted 400 something dollars for the oil pump.....

The whole fricking motor with manifolds and accesories only cost 250. I asked a volvo junkyard/repair guy about the oil pump and he said just clean it out and reuse it. I also bought a b234 crossmember and brake booster/master cyl since the booster looked low profile to fit the intake mani.

I like the idea of not running an aux shaft like the b230 does for the oil pump and dist on 240s.

My only question i guess is how to go about getting the reliefs cut into the pistons. I called a few shops here in SD, but I didnt get very far.

My other question is what else should I do when doing the rebuild? I am planning on just putting in new bearings and getting the crank inspected and ground if necessary. I am also going to get the bores checked and see what it is going to take to fit my b230ft pistons in there. I am planning on balancing it too. What other machining/inspections should be done?

So far i have spent: $250 on the motor, $60 on the xmember and brake stuff, $140 for timing belt and gaskets, $150 for a head rebuild. Now I need a shortblock rebuild, pistons/piston cutting, engine management, and a few other minor bits. Feel free to remind me of things i might forget. My list is only a page long right now....

 

[Captain Bondo]

Can't say I agree with Doug re the oil pump. At the very least buy the updated metal pulley. I would wager to say I see 16v's more frequently than most here and I can say for sure that those friggin things fly apart on a regular basis! There's a reason volvo recalled/updated the pulley.

 

[ZVOLV]

What does the upgraded pulley look like?

 

[MikeHardy]

looks like there is a new pullley. part number 9135112, thats a very recent number for a 88-91 engine and on the vadis pic it hasn't got the missing teeth like the old ones.

 

[towerymt]

Search the brickboard. I recall there being an oil pump pulley guide pin that likes to shear off and cause problems. It's been a while for me, so research it yourself for all the details.

 

[916volvosport]

heh.. have the pistons shaved down.. like talked about in the old school b21ft build up article.. that's lower compression

-patg

 

[linuxman51]

My only question i guess is how to go about getting the reliefs cut into the pistons. I called a few shops here in SD, but I didnt get very far.

either be really careful with a dremel or get a custom set of pistons, since it'll likely cost that much or more after procuring turbo pistons and getting em machined

 

[pbonsalb]

If you took a stock 16V piston to a machine shop along with one of your pistons, you could get an estimate on the cost and difficulty. The machine shop might well tell you to go home and take out your dremel if you want to save some money and are not putting a lot of expensive parts at risk. I have a Penta AQ171 on the engine stand and the valve reliefs do not look impossible for a careful DIY type to duplicate, though before I would try it, I would take that trip to the machine shop to ask.

Philip Bradley

 

[coldfusion21]

with the reliefs cut, does it make it a non-interference engine, or does it just prevent them from hitting even when everythings lined up?