B30A Head porting for low-end power

[dl242gt]

If you shop overseas it's like shopping at Summitracing for domestic speed parts. There are many vendors of custom pars for our cars. Just that darn shipping. Well at least we don't have to pay VAT.

[Petey]

Originally Posted by OttoB

Stock valve springs (yellow label = Gulmärkta) are ok, just check pressure and installation length.

More edit. I used my old springs from 1972. They were completely ok. But new ones are cheap as soap

Are the springs exactly the same between the B20 and B30?
I can get some yellow label springs from Brookhouse for £5 and it says suitable for B20
They also sell springs that look identical but are double the price and says suitable for B30
However if you look on VP, they sell springs that say suitable for B20 and B30 so I'm confused on who is right and who isn't

Also, what's everyone's opinions on those kits for cutting 3 angle valve seats by hand?

[spock345]

Originally Posted by Petey

Are the springs exactly the same between the B20 and B30?
I can get some yellow label springs from Brookhouse for £5 and it says suitable for B20
They also sell springs that look identical but are double the price and says suitable for B30
However if you look on VP, they sell springs that say suitable for B20 and B30 so I'm confused on who is right and who isn't

Also, what's everyone's opinions on those kits for cutting 3 angle valve seats by hand?

They should be the same. If you look on IPD They have part 418737 for the B18/20 and B30. The part where it gets interesting is when you look at variants of the B30 and B20. The B20E/F and B30E/F get the 418737 spring in IPD and VP's catalogs. But in VP's catalog the B30A gets spring 403717, which is shared with the B4B and B16 family of motors for whatever reason.

The high performance spring kits VP sells are all 418737.

My guess is that you have three tiers of OEM valve springs here. The older singles (403717), newer single springs (418737), and finally aftermarket double springs for those who really want to rev out the motors. Although from what I've read the doubles need modified spring seats and put more pressure on the cam. The cam oiling being a weakness on the OHV redblocks, hence why these motors can wipe out lobes.

I'd just get whatever the equivalent to part number 418737 is. Although I bet someone else has more real world experience with this other than just staring at catalogs.

Get the three angle job done by a machinist. You need precision to have that valve seal right. It is a pretty standard cylinder head improvement.

[gsellstr]

I'd bet there's some difference due to the stem size change as well, later heads had larger valve stems.

[JohnMc]

Originally Posted by spock345

The cam oiling being a weakness on the OHV redblocks, hence why these motors can wipe out lobes.

Indeed. If you look at the way the motors work, there's really practically no direct oiling for the cam lobes. The lifters are not directly fed oil, they just get some of the drainage from the rocker shaft oiling, so I doubt much leaks past them down onto the lobes. And some of the oil draining down out of the head can land on the cam in between the lobes, not sure how much good that does. About the only way I think they get oiled is through windage, oil droplets flying around the engine.

In other words, use an oil with plenty of zinc/ZDDP additive.

[Petey]

Thanks for the help, I'll go with the B20 yellow band standard springs then in that case.

Been looking into the head gasket situation regarding the larger pistons and although I have the part numbers, there are no such gaskets on the Cometic website and even a google search only brings up the forum post itself. I've contacted Cometic so waiting on what they have to say

[142 guy]

I didn't see it mentioned. When you get your multi angle valve job done you will want to have hardened inserts installed on the exhaust ports for use with unleaded gas - unless that has already been done. From the factory, your B20A would not have been set up to deal with un leaded gasoline.

With the engine out of the car, plan for replacement of the front and rear felt crank seals with more modern neoprene lip seals.

If you are doing a complete head job, ITM used to make nice bronze valve guides, part number VG 933 BR and VG 934BR. You will want new exhaust guides after you clean up the top of the exhaust port. If you search you can still find suppliers. Rock Auto had them; but, you had to search using the vendor page rather than by car model. The only down side is that you have to order them in packs of four.

Plan for replacement of the lifters - they are a known problem area for the original design. I think the Isky lifters fit the B30. Definitely stick with OEM springs if you are going with a K cam. You don't need the additional lifter / cam wear associated with a higher spring rate.

[hiperfauto]

I agree with all of the above except for the front and rear crank seals. All B30's come with neoprene crank seals from the factory.

FYI, Isky lifters are just Chevy solid (non hydraulic) lifters but they're shorter than the stock lifters so they require longer push rods.

[JohnMc]

They sort of got a reputation as good replacements in that 1980's period when it seemed like OEM Volvo lifters were crappy junk that would fail and wipe out a cam lobe with little reason. The Isky's fit, were a bit better at not crapping out prematurely.

Not really a performance item in any possible way.

[spock345]

Originally Posted by 142 guy

If you are doing a complete head job, ITM used to make nice bronze valve guides, part number VG 933 BR and VG 934BR. You will want new exhaust guides after you clean up the top of the exhaust port. If you search you can still find suppliers. Rock Auto had them; but, you had to search using the vendor page rather than by car model. The only down side is that you have to order them in packs of four.

Is there any major advantage to going with bronze valve guides over the regular ones? I see the bronze ones mentioned a lot on this forum, usually in reference to OHC motors, but haven't seen an explanation of why.

[OttoB]

Originally Posted by JohnMc

They sort of got a reputation as good replacements in that 1980's period when it seemed like OEM Volvo lifters were crappy junk that would fail and wipe out a cam lobe with little reason. The Isky's fit, were a bit better at not crapping out prematurely.

Not really a performance item in any possible way.

There was some development during 73-74 with new material from Wizeman-Mahle. At least new material for camshaft was much better and could be heat threated. Much better than precious cast. Lifters were something "double chromed".

My papers give 39,9 mm installion length with 29 kg for Yellow label valve springs.

[culberro]

Originally Posted by spock345

Is there any major advantage to going with bronze valve guides over the regular ones? I see the bronze ones mentioned a lot on this forum, usually in reference to OHC motors, but haven't seen an explanation of why.

Bronze guides transfer heat faster, and are slightly sacrificial for when things go bad. Downside is they don’t last as long. Instead of 150-200k, you might get 50-100k miles. I’m not entirely sure on the mileage, but I haven’t had a head I’ve rebuilt hit 100k miles yet

Most OEMs still use cast iron guides, more specifically sintered iron guides with a small amount of bronze/copper/nickel/aluminum.

I don’t have a problem with iron guides when done correctly.

[spock345]

Originally Posted by culberro

Bronze guides transfer heat faster, and are slightly sacrificial for when things go bad. Downside is they don’t last as long. Instead of 150-200k, you might get 50-100k miles. I’m not entirely sure on the mileage, but I haven’t had a head I’ve rebuilt hit 100k miles yet

Most OEMs still use cast iron guides, more specifically sintered iron guides with a small amount of bronze/copper/nickel/aluminum.

I don’t have a problem with iron guides when done correctly.

So if one was rebuilding a head for a street motor like what OP is doing what would you recommend? Looking at VP's parts list there only seems to be a $1 difference between OEM and bronze (I think what they label as "RACE" is bronze). So choosing based on cost is kind of pointless.

[142 guy]

Agreed that none of my suggestions would enhance power output.

The comment on lifters was focused on 'if they are original they need to be replaced'. The Isky are a known good replacement; but, I have heard that the revised / later Volvo OEM lifters do not have the same wear issues as the original lifters. The bronze valve guides are a 'nice to have' if you need new guides and can get the ITM guides. The ITM guides were around $4-5 each from Rock Auto, so no more expensive than OEM guides. If the OP was going to remove the restriction in the exhaust port around the guide I would expect that they might be installing new guides.

The up-side to bronze guides, aside from the better lubricity of bronze is that bronze is a better conductor of heat than iron. On the exhaust valve, the valve is cooled primarily through contact between the valve head and valve seat with secondary cooling through the valve stem - guide interface. Hence the importance of making sure that you don't skimp on valve lash if you want to avoid burnt valves. When you go to a multi angle valve job you reduce the contact area between the back of the valve head and the valve seat which reduces the heat transfer at that point so improving the heat transfer through the valve stem - guide interface can help make up for that. Bronze guides on an OHC engine would be more of a 'thing' because the turbo motors are already using sodium filled exhaust valves to increase heat transfer from the valve head to the valve stem - guide interface.

As I recall, bronze has a higher coefficient of expansion than iron so they need to be fitted with a cold clearance that is greater than an iron guide to get the same running clearance. Otherwise, get your engine really hot and the stems may gall the guides. If you don't have a machinist who is knowledgeable about fitting bronze guides, better off to stick with the OEM iron guides.

[culberro]

I'd use cast iron guides for a b30 lo-po DD.
I'd also check the rocker pattern on the valve tip and adjust it as needed. They are all over the place from the factory.

[142 guy]

Originally Posted by culberro

I'd also check the rocker pattern on the valve tip and adjust it as needed. They are all over the place from the factory.

Are you talking about the variability in the rocker ratios? I know that uneven wear on the rocker shoe can alter the rocker ratio; but, I thought a lot of the rocker ratio variability was baked into fabrication issues. When I rebuilt my engine the machinist fabricated a fixture to allow him to grind the shoes to remove the groove and create a consistent curvature on the rocker face; however, on assembly I measured all the actual valve lifts with a dial gauge and I still had variability between the valves (or my brand new cam had some casting issues).

Various internet sources (for what that is worth) had suggested that if you wanted equal rocker ratios you had to source a bunch of salvage rockers, fix the profiles and then test them to determine the actual ratios and then mix and match to get equal ratios. Were you able to alter the ratios by machining to contact shoe or are you just talking about doing the mix and match thing? Given the measure - mix - match hassle I figure that if you really want equal rocker ratios you might be better off trying a set of YellaTerra's roller rockers for the B20 (and I think B30). I don't know how good they are; but, they do appear to actually deliver them as opposed to that 'other source'.

[culberro]

I was talking about the pad contact patch and how it rubs on the valve stem.
Stock ones have different sweep profiles and side loading issues. I also have the tooling for grinding the rocker shoe, and it's very eye-opening how far they are off from the factory.
On a head I did for a local, we ended up using 0.080" thick lash caps on the tips of the valves to get the rocker sweep to a narrow profile that was positioned correctly on the valve tip. You can also have shims made that go under the rocker shaft pedestals and adjust the contact patch that was as well.

The rocker ratio is another variable with these engines, but I haven't measured them to see what they are.

[Janspeed]

Originally Posted by spock345

I'd just not really touch the ports but just crank the compression up a bit and throw in the cam. Polishing up stuff looks nice but for the effort I don't see it doing much.

The B30A made 145hp in its early guise with 9.3:1 compression and a C cam. The later B30E made 175hp with the same cam but 10:1 compression. Although I am not sure if they saw the same valve size change the B20's did when they got fuel injection (B20E/F got bigger valves and a bigger cam than the B20A/B/D). Tight squish to help mitigate knocking and higher compression with that K cam should do nicely.

175hp isn't bad. A 1970's BMW M30 3.0L inline6 on carbs made 180hp and the injected version 200hp, i had the carbed version and if tuned correctly (jets, carb synchronisation) it would be nice and torquey. Plenty fast enough to get you into serious trouble.

As for porting, the B30 volvo head i believe is made of cast iron so it will be a PIG to port. You really do need carbide tools. Nothing like a modern alu head. 40 years ago i did it on a cast iron Ford Pinto OHC head. No thank you, way too much work for not enough gain. never again.