Mike K's '79 242 Barn Car Revival

[Stiggy Pop]

Can you tell me the height of the stock bucket without a shim compared to that 1.023" height?

I have to see if I still have a complete stock head loose in the shed, I had the same thought (also wanted a stock bucket and shim to bring to the machine shop for reference). If I can find one tonight I will post it up.

 

[dbarton]

Yeah. It took a few hundred miles for that jam to occur each time. Strange that it took that long. I was sorry that happened to him, but relieved it didn't happen to me.
Dave

 

[DavoS40]

My RSI head has the same buckets but has lash caps instead, have bounced it off hard rev limiter at 7k without issues so far. Are the shims varying thicknesses on yours? The lash caps in mine all have the same effective thickness.

I emailed SuperTech a few months ago about getting 8mm lash caps in varying thicknesses, but they said they only offered varying thicknesses on the 8mm shim versions (not the lash caps). Maybe you'll get a different story if you talk to them on the phone though. At the time I was looking into swapping in a different camshaft, so I needed some slightly thicker caps at two sizes to get the clearances correct.

 

[Stiggy Pop]

Dave B - wasn't able to easily get a stock bucket in hand. I might dig into a spare block this weekend to get the data point. If anyone else has easy access and knows how to measure things properly I'd definitely appreciate an assist!

My RSI head has the same buckets but has lash caps instead, have bounced it off hard rev limiter at 7k without issues so far. Are the shims varying thicknesses on yours? The lash caps in mine all have the same effective thickness.

I emailed SuperTech a few months ago about getting 8mm lash caps in varying thicknesses, but they said they only offered varying thicknesses on the 8mm shim versions (not the lash caps). Maybe you'll get a different story if you talk to them on the phone though. At the time I was looking into swapping in a different camshaft, so I needed some slightly thicker caps at two sizes to get the clearances correct.

Thanks for weighing in. You might have misinterpreted my last post, as it sounds like you and I have the same setup - I only have lash caps and buckets as well, no shims. I did not have a mic to measure the effective thickness, but we measured overall height of the shim (inclusive of shoulder) and found some small variations which we took as an indication the lash caps were ground to adjust clearances. Don't know that for sure, but there's no other way to adjust lash with the way it's set up.

Last night we pulled valves from the effected #1. Both the intake and exhaust had sharp edges rolled up on the top edge of each keeper groove, such that we had to file/dremel it smooth in order to pass it through the guide. The valve tips looked good and were not deformed. I've made the decision that I will not be re-using the valves. Other than the sharp edges on the valve everything looks OK.

this is what I have for valves

stock comparison

Below is what I was able to get for data points last night. Anyone got any of the blanks available??

I spoke with Larry's and like the 'vibe' from them as a shop. They're alert, interested, taking the time to listen etc. They did give me a gentle caution that their shop rate for custom work is $145/hr and I might want to do as much research and procurement as possible before bringing the head down. I'm going to take that advice and set about getting as much of this understood and planned as possible ourselves.

- First step is to get on the valves. Will make calls to Ferrea today and see where that takes me.
- I'm thinking we should try to get the buckets figured out and in hand ourselves if possible, and save the shop time. I have to do some research to see if it's really just a matter of buying a different set of buckets from Supertech made for shims as you guys are saying (and hopefully I can get some big mix bag of little 8mm shims?)
- There's a formula in here for the valve springs that we don't have, and the cam is a factor in that equation and I have jack **** for cam data.
- Thought for me right now is get valves in hand, buckets in hand, shims in hand, then get it all down to the shop so they can spec it all out, spec the cam, figure out springs with me and bring it all home.

I'm finding some positive in all of this. I bought the head complete and just put it on, now I have to build it out and as a result will have a much better understanding of the general principles and also what I'm working with. I'll have more confidence in the setup, and i'm hoping something that is even better performing.

And on the side burner we have the turbo. Again a similar thing, I just bought the Holset and ran it. It was "good enough". I want to move on to something that's been thought out to be part of this system, and better matched to the car and it's purpose. I have a lot of research to do here, and I think I'd like to get a turbo in my hands by next month to start planning that work out.

Lot of money coming, and not really a reinvestment in the car I was planning on. BUT I think it's really going to make a difference and I'm excited to get into it.

All that said if I do all this and lay the money out and the stupid thing blows up I'm parting it out and buying a ****ing 911

 

[Stiggy Pop]

I had a very productive lunch break, ran out to our local machine shop to have them weigh in on the head as well. Good conversation and lots of food for thought.

He agreed with Culberro that the triple groove keeper VW si valves are a poor design, and he is using the more modern single groove VW valve in a variety of applications. He said if he were to do the work for me he advised I get my buckets and shims decided and sourced, then he would get valves made to spec (Manley is their go-to). He was adamant that if he were in my position the unknown factor of the cam would be a problem. I'll pay ransom money for RSI T3 cam grind specs...

I'm going to poke at you guys a bit as to why you're pushing to get rid of the lash caps? I see lash caps of varying thickness listed on the Supertech website, so I don't see what I stand to gain by going to a recess and a flat shim. We looked at the lash cap on the valve in the shop and he said it was a good fit, and there were no inherent issues with the caps or their relationship with the valve stem. My opinion at this point is that my issue was due to the valve springs and insufficient pressures. The lash cap hung the valve open, but it did so because I was floating or bouncing the valve enough to ALLOW it to dislodge. With proper spring pressure and proper lash it's effectively impossible for the lash cap to become dislodged in this way (I think). I'm all ears, but this is what I'm seeing with my two eyes. I have no attachment to either setup, but I want to spend my money wisely and where it's needed. I'm looking at the recess and shim as the inverse of a lash cap, so what's to prevent the exact same thing from happening except it's just a shim popping out instead of a lash cap?

SO I think I have a game plan. I'm going to decide on the buckets, source them, and then go down the path of procuring valves. I'll then work with one of the two machine shops on the assembly and spring combination. This is where my local guy has heartburn over the lack of cam info, as he wants that information to determine what springs to use.

- The supertech buckets I have in hand are the same height as a stock volvo bucket
- the supertech buckets are considerably lighter than stock
- has anyone run custom Manley's in their car?
- does ANYONE out there have real grind info on the RSI cam?

sure I'll lose some of your interest but I'll keep documenting this process out for posterity

 

[RvolvoR]

I had a very productive lunch break, ran out to our local machine shop to have them weigh in on the head as well. Good conversation and lots of food for thought.

He agreed with Culberro that the triple groove keeper VW si valves are a poor design, and he is using the more modern single groove VW valve in a variety of applications. He said if he were to do the work for me he advised I get my buckets and shims decided and sourced, then he would get valves made to spec (Manley is their go-to). He was adamant that if he were in my position the unknown factor of the cam would be a problem. I'll pay ransom money for RSI T3 cam grind specs...

I'm going to poke at you guys a bit as to why you're pushing to get rid of the lash caps? I see lash caps of varying thickness listed on the Supertech website, so I don't see what I stand to gain by going to a recess and a flat shim. We looked at the lash cap on the valve in the shop and he said it was a good fit, and there were no inherent issues with the caps or their relationship with the valve stem. My opinion at this point is that my issue was due to the valve springs and insufficient pressures. The lash cap hung the valve open, but it did so because I was floating or bouncing the valve enough to ALLOW it to dislodge. With proper spring pressure and proper lash it's effectively impossible for the lash cap to become dislodged in this way (I think). I'm all ears, but this is what I'm seeing with my two eyes. I have no attachment to either setup, but I want to spend my money wisely and where it's needed. I'm looking at the recess and shim as the inverse of a lash cap, so what's to prevent the exact same thing from happening except it's just a shim popping out instead of a lash cap?

SO I think I have a game plan. I'm going to decide on the buckets, source them, and then go down the path of procuring valves. I'll then work with one of the two machine shops on the assembly and spring combination. This is where my local guy has heartburn over the lack of cam info, as he wants that information to determine what springs to use.

- The supertech buckets I have in hand are the same height as a stock volvo bucket
- the supertech buckets are considerably lighter than stock
- has anyone run custom Manley's in their car?
- does ANYONE out there have real grind info on the RSI cam?

sure I'll lose some of your interest but I'll keep documenting this process out for posterity

The only info I have is some generic specs for it and I am working off of slightly hazy memories as well.

12.5mm of lift, 240 @ .050" duration, 107 LSA.

Also, I am pushing to get rid of the lash caps as I have seen this exact issue before with the same parts and the solution which worked was to use the puck style shims of proper thickness rather than lash caps. Furthermore, you also get a lot more variety in shim thicknesses using them rather than the 2 different thicknesses of lash caps you can get.

 

[Stiggy Pop]

The only info I have is some generic specs for it and I am working off of slightly hazy memories as well.

12.5mm of lift, 240 @ .050" duration, 107 LSA.

Also, I am pushing to get rid of the lash caps as I have seen this exact issue before with the same parts and the solution which worked was to use the puck style shims of proper thickness rather than lash caps. Furthermore, you also get a lot more variety in shim thicknesses using them rather than the 2 different thicknesses of lash caps you can get.

Gracias, that's a start!

10-4 on the lash caps. I definitely take the firsthand experience as valuable, just trying to understand this as thoroughly as I can, and understand why I'm making the various decisions.

Senior talked with a friend of his who races BMW's and got a name of someone at Supertech, so have some phone calls to make.

 

[RvolvoR]

Also, I look at high revving OEM setups and what they use...none use lash caps really (my Ducati did, but that also is a desmo setup so it doesn't count). BMWs all use puck style shims for the M motors, the lexus ISF uses different thickness buckets, all high performance (moto-x/enduro racing/Japanese 4 cylinders which spin to a brazillion RPM) bikes use puck style shims (aside from older KTM RFS motors which use eccentrics).

 

[Stiggy Pop]

My friend at the shop during lunch referenced Subaru as using varying bucket thicknesses as well (not that that is a high revving application). I have pretty limited experience here (my dirt bikes are two strokes..) so I'm learning learning learning.

 

[RvolvoR]

2T bikes don't give me the engine braking I like on a supermoto track....plus, Husaberg's motto was "4 stroke force" anyways.

 

[dbarton]

- The supertech buckets I have in hand are the same height as a stock volvo bucket

Ok. This tells me you DON'T have the same Supertech buckets that I had, since mine were shorter. So I would not be concerned with the potential issue I brought up.

- the supertech buckets are considerably lighter than stock

And of course one of the major benefits of using this type of cam follower. Less valvetrain weight that can be controller by lighter springs than a heavier valvetrain.

The other major benefit is a wider flat friction surface area on the top of the bucket than the stock bucket with a shim, since the stock bucket usable top friction surface is reduced by the recess wall. That wider top provides more surface for a high lift cam if desired, that would otherwise be limited by the smaller top surface.
Dave B

 

[culberro]

Going with shim under bucket should be pretty easy, you'll just have to either find a spring retainer that has the provisions to hold the shim, or have some made.
There are a lot of motorcycle engines that use shim under, and the shim kits are relatively inexpensive from Hot Cams and other suppliers (usually around $100).

Can you switch out to the VW double valve springs? Ran them on the rally car to 8k with a k-cam and never lost a stock type shim...
You can also shim the current valve spring to increase the "seat pressure" and spring force, but this has limits wrt to cam lift.

 

[Stiggy Pop]

Going with shim under bucket should be pretty easy, you'll just have to either find a spring retainer that has the provisions to hold the shim, or have some made.
There are a lot of motorcycle engines that use shim under, and the shim kits are relatively inexpensive from Hot Cams and other suppliers (usually around $100).

Can you switch out to the VW double valve springs? Ran them on the rally car to 8k with a k-cam and never lost a stock type shim...
You can also shim the current valve spring to increase the "seat pressure" and spring force, but this has limits wrt to cam lift.

At this point the world is my oyster. I?d like to manage costs but I?m in it, so all decisions and options are open.

Yeah machinist said same on just shimming up the springs (he called it ?standing on the springs? which was a new term to learn)

I started talking with Shoestring on here about potentially coming out to measure valve events on the stage 3 cam. Might provide some good data points for the spring considerations

 

[Stiggy Pop]

We've now spoken with a couple machine shops, read a LOT, and spent a few lunch breaks together doing napkin math and talking theory. We then called Ferrea yesterday afternoon and had an EXCELLENT conversation with one of their tech guys, John Verburg. It was a shockingly good phone call actually, John spent probably 45m on the phone with us talking specifics, theory, manufacturing, supply chain... it was great. He also listened and paid attention to what I was telling him happened, what the setup was etc. Very impressed, and the talk helped connect a lot of dots in my head around my new learning on valvetrain.

John offered me what I was really looking for, which is someone who understands all of the engineering we are working to understand and is interested in a data-driven solution. Another way to put that is we are really good at over thinking and over engineering the hell out of things, and John is willing to nerd out with us about it instead of just telling us to throw more spring at it.

At face value John thought my spring pressures made sense (90 closed, 205 open). The part of the convo that really interested me was his explanation of spring harmonics and the follow on discussion about valve speed, bounce and stresses experienced particularly when hitting a rev limiter. He was big on spring material and also getting the spring to within a couple mm of coil bind to reduce harmonics (we also started talking double springs etc.). One thing I feel pretty sure of is that RSI did not put this much thought into it when they put this thing together.. I think my failure mode was the valve bouncing off the seat during the violent spark cut. Root cause likely a combination of improper spring for the application and excessive lash on the #1 exhaust valve.

I'm going to be sending a pair of 'stacks' to Ferrea (valve, spring seat, spring, retainer, keepers) for evaluation. I'll be working with John on a custom package solution built around what we determine we want for valves, no half measures. It seems like a good possibility that all of that stack might change, but will reuse parts where it makes sense. TBD if the actual head work (seats and guides) was good and I don't need to re-do that. I might get into the guides anyways depending on what we end up with for valve stem size compared to what I had.

No one really picked up on it but my first measurement had the intake valve .013" longer than the exhaust, which makes no sense. I'm going to drop another pair of valves tonight and see how those measure out. Will be interesting to find if that's the exhaust being beaten down, the intake length being a mistake, or perhaps the intake valve being cut LONGER to compensate for the seat being in the wrong place.

Should get my valves off to Ferrea tomorrow, and they said it should only take a couple weeks to spec out the package. It's not going to be the cheapest option, but I think it's the best path.

FYI Ferrea does not have any stock or reference data for old Volvo's - it's all custom work.

 

[RvolvoR]

they should have something... they will be custom one-offs for price and availability, but we (well, pat actually) sent them a complete slice of a 530 head a few years ago for them to design the valves. Furthermore, its been a bit of a known that, while they work, the VW springs are not really right for the application.

I also missed the part about excessive lash on #1...that definitely did not help the situation.

 

[Stiggy Pop]

they should have something... they will be custom one-offs for price and availability, but we (well, pat actually) sent them a complete slice of a 530 head a few years ago for them to design the valves. Furthermore, its been a bit of a known that, while they work, the VW springs are not really right for the application.

I also missed the part about excessive lash on #1...that definitely did not help the situation.

Not sure, but the guy I spoke with knew Volvo's well and the head I was describing (they have a guy on staff who drags a wagon, evidently) and he said they've got nothing on the books. Could be a disconnect there or they binned it?

I'm making a bit of an assumption on #1, since it was jammed when pulled I could not measure a lash there. But I found others where lash had grown since last check and would need shimming, not a big leap to think #1 was in the same boat. Worth noting I checked lash about 1200 miles ago and #1exh was around .018" which I accepted.

Should end up with a pretty legit setup after all this, at least. Have to see how things price out and see where I can afford to get fancy on materials.

 

[Stiggy Pop]

I emptied out the head tonight. Some data is below. All of the intake valves are slightly longer than the exhausts which doesn't make a lot of sense. need to understand it before I set up Ferrea.

The tip of the exhaust valve on #2 had the same smile impression as the terminal #1 exhaust had from the lash cap. I believe that was my first occurrence when I got the car going again, and I might have just gotten a lucky bounce.

Here's what one of the RSI springs looks like at installed height of ~1.714" (something like that, from memory)

and at full lift from the stage 3 cam. Certainly not the 1-2mm from coil bind I talked about with Ferrea.

On the side I'm reading forums about turbos (subaru and mistubishi guys change turbos like tires it seems). I'm in familiar territory where what I WANT to do is very expensive, but I don't want to half-do it. So it's going to be a whole lot of something or nothing at all.

I still don't know where the boost went before the head crapped out. We played around with the wastegate and boost controller and the system works. Thought you guys might get a kick out of the stack of adapters to kludge this together it worked!

<iframe width="560" height="315" src="https://www.youtube.com/embed/l-UmC6YKimE" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

I also stripped the interior because I've had some plans in mind I'd really like to see through

 

[RvolvoR]

you should probably pick up one of these guys if you are going to mess with stuff yourself:
https://www.summitracing.com/parts/...MI1MqiwrPx3wIVyh6tBh0JCAaoEAQYASABEgI5WPD_BwE

 

[Stiggy Pop]

you should probably pick up one of these guys if you are going to mess with stuff yourself:
https://www.summitracing.com/parts/...MI1MqiwrPx3wIVyh6tBh0JCAaoEAQYASABEgI5WPD_BwE

Yeah I could have used one of those tonight!

 

[mikezohsix]

you should probably pick up one of these guys if you are going to mess with stuff yourself:
https://www.summitracing.com/parts/...MI1MqiwrPx3wIVyh6tBh0JCAaoEAQYASABEgI5WPD_BwE

Yeah I could have used one of those tonight!

There's one sitting on the shelf from me doing my heads the first time. It's in the box with all the valve tools - didn't think of it last night.
Can play with it when we degree the cam.

On the variable intake valve length,
wonder if it's where the seat is cut on the valve that is the variable. The next thing to check is if they ground the tips of the valves, which you could check by measuring from the top land of the keeper to the tip. If the numbers are different, then RSI did something even I wouldn't consider.