Did someone throw a boat anchor behind my car at 4500?

[Jimmy]

OK, Jimmy is banned from this thread.

[malcolmr18zoy]

Well I would have expected your dwell to reduce at high revs, but if you have that much dwell, you're probably not having a spark problem. The timing variation at high revs won't make a huge difference either.
You don't have to pull the cylinder head off to check the valve timing, but you do need a degree disc and a dial indicator.
Malcolm

[max71]

Thanks Malcolm. That eliminates those.

I do have a dial indicator and a degree wheel.

[Jimmy]

Gary, since I'm not allowed to use this part of the forum, could you please take careful notes of your current cam timing before changing anything, then PM me the numbers?
Maximum torque at 2,250 rpm sounds absolutely perfect for a street MGB, so I'd like to copy your setup one day.

[max71]

Just got back from a run. Brick wall at 5000 as usual. I had someone in the car and I wasn't able to pull the choke. Its kind of scary when it hits 5000 like its at redline and its going to do something bad if I push it past it.

I'll go pull the air cleaners now unless I have to meet someone. I'll report back on that. I'm kind of losing hope on this one.

While Steve doesn't want a tach that reads past 5000 I remember how this car drove and it was a blast. Now its like your parents put a rev limiter on the whole thing. Sucks.

[max71]

Tough to do a run in Santa Monica. Anyway ZERO change with the air cleaners off.

I give up. I don't think its needles because its not struggling as much as hitting a wall. I don't know what went wrong with this build. Its thoroughly depressing.

[malcolmr18zoy]

I don't like camshafts that require a stepped key to operate properly, but is it possible that you installed the stepped key the wrong way round?
Malcolm

[max71]

I asked Dave Anton about this and he said with a 2 degree key it wouldn't make much of a difference and definitely not what I'm seeing. All performance cams needs either adjustable vernier gears or an offset key, right?

[malcolmr18zoy]

Wrong. If the cam grinder knows what he is doing, he grinds the cams so that it works with the manufacturers timing marks.
Malcolm

[max71]

I don't know. All the cams except the Huffaker cam require cam timing. I don't know why. You would know more about why they decided the advance was necessary. I'm above my head in all this.

Anyway, I give up.

[malcolmr18zoy]

Gary, I think they're giving you mixed signals. If they're saying you have to use a stepped key to advance the cam timing two degrees for proper results, but if you install it the wrong way round and retard the timing by four degrees that will make no difference, What do you think?
Malcolm

[max71]

I was only repeating was Dave Anton said when I asked him that very question.

To recap. We did the math and I ordered a 3 and 4 degree key. Our math was wrong because this number was way past 103º. So I then ordered a 2 degree key and we installed it both ways to make sure. One was showed BTDC and the other was ATDC 103º. At least with two knuckle heads reading Vizard's book on how to do it and carefully trying to do the math.

According to the cam maker it would change the power band moving it up or down but it shouldn't hit a brick wall like its doing. I'm getting very nervous at this point to even try to push it beyond 5000 because its such a wall it feels like I'll do damage.

Again this is one of those Why the hell didn't I do it when the engine was out and sitting on Steve's floor for a week. A) Steve didn't know anymore than me B) I didn't know about you at the time or I would've covered your cost to come out and verify.

A Northern CA racer I contacted said the bounce I get in the timing mark could be crappy chain tensioners coming out of India at the moment. He said he uses a Jag tensioner which takes 10 seconds to modify to work. That's just a side note.

[Jimmy]

(Perhaps because I'm retarded, but I still don't quite get the 206 degree difference between two degrees advanced and 2 degrees retarded.)

[Steve Simmons]

Wait, so now it's 5000 where it drops off, not 4500? Then what you're saying is that the car doesn't perform well at RPMs beyond your peak HP and torque. Why would you ever want to rev that high when you will only be losing power and acceleration anyway?

Your car pulls strong and runs well, or at least it did the two times I drove it. If it were me, I'd be thrilled to have the power band so low. In fact I spent a helluva lot of money to get mine that low.

I do understand wanting to figure out what goes wrong at very high RPMS, but you should never be over 5K RPMs anyway based on the dyno sheet, so I'd treat this as more of an investigative project than a repair. That's just me though.

While Steve doesn't want a tach that reads past 5000 I remember how this car drove and it was a blast. Now its like your parents put a rev limiter on the whole thing.

My tachs do go over 5,000 RPM, thank you very much. Putting the drop-off issue aside, it sounds to me like you have a well designed cam but it isn't to your liking. Maybe you should change it out for a mild race cam that puts torque and power in the higher RPM range. Personally I hate that because it makes the car more difficult to drive on the road. But everyone has a different preference. Again, this is putting the drop-off aside as this now seems to be a secondary issue.

[malcolmr18zoy]

Hi Steve,
I'm in your camp there. High revs in order to get the maximum power out of an engine usually mean sacrificing torque in the mid range. For a street car, mid range torque is king. If you have a flat torque curve, you don't nee to rev the engine to go faster, you just change gear and save destroying your engine. No matter what you do, you still won't achieve maximum revs in 4th overdive, so why even bother.
Malcolm

[max71]

First, I confused Jimmy's comment with you. He said he didn't want a tach that goes over 5K.

All I want is for the cam to perform to spec. I've posted the specs two or three times. Its why I bought the cam. I didn't want a more powerful cam because power comes on too late to make it a fun daily driver.

The power band per spec is perfect 1200-6200. What more could you want in a street car?

The Huffaker cam had more lift but only on the intake. The Huffaker cam went from as I recall 1500-6500. But it didn't it effortlessly. Now the VP-11 does it very well too but is not performing to spec. The manufacturer said its not performing to spec, another engine builder who the manufacturer respects said its not performing to spec. Dave Anton's dyno guy said there was something seriously wrong after doing the run. Sean Brown thinks the dyno numbers are crazy... are we getting the right picture?

I had numerous conversations with Dave Anton on what cam to choose and I kept explaining daily driver, needs to idle, love canyons and twisties. We agreed on the VP-11. After he measured the Huffaker cam he said it was far closer to the VP-11 than the VP-12 and I agreed.

Anyway, its been a 3.5 year frustration and I just give up. I don't know why wanting it to perform to spec is such a horrendous thing. I'll consider 5000 as the new 6000 and forget it.

[Steve Simmons]

From what I gather from your comments, you want to be able to rev the engine as high as possible to get power. That's why I suggested you might like a more aggressive cam better.

The power band per spec is perfect 1200-6200. What more could you want in a street car?

I've never heard of a power band that wide, or that flat, in an MGB. I don't see how you could possibly create any real power at 1200 RPM. Weird.

[malcolmr18zoy]

Is your tachometer accuarate?
Malcolm

[max71]

Steve. Those are the specs. Speak to Dave Anton.
Malcolm. I had the tach checked and he said it was slightly off on the low end and accurate on the top end. At one point I meant to put Steve Snap-on on the car.

Regarding the title of this post. Its begins to stumbled at 4500 and hits the wall at 5000. Agreed it acts like the dyno numbers but it shouldn't do that. That head is not breathing right at the higher RPMs. That's exactly what the Dave Anton's dyno guy said. Well, Huffaker then Sean Brown. It should be breathing right. His opinion is its the wrong cam for the head. But I don't want a hot cam. Arrrrgh. Forget it. I'm sick of the topic.

Just close the thread.

[malcolmr18zoy]

No!! You've got us all hot and heavy on this subject, then you just want to drop it?
Is it anything to do with the fact that your engine used to be loose as a goose, and now it's tight?
Malcolm

[max71]

No the engine wasn't rebored just re-ringed (twice). Its had plenty of miles to break in bearings and such. Having owned this car my entire adult life I've never, ever experienced this.

I'm just sick of it. Steve's comment set me off. I sunk so much money into this engine only to re-do, re-do, re-do. I'm just tired of it. Steve feels I'm nuts for not being happy with the power band. I know what the car with its Huffaker bits has and can do. Many people who drove the car in the past even commented it was the fastest and smoothest to redline MGB they ever drove. That included mechanics.

In my opinion the headwork is now wasted. A stock 18V engine is famous for not going beyond 5000 yet all my bits are dialed in and all I get is a stock 18V? An engine is not supposed to go backwards when you redo it.

I have plenty of stress and I'm tired of chasing things. I'm chasing so many things that never gave me a problem before the rebuild I don't know why it would be a problem after. Things like Grose jets, float height, exhaust and on and on worked fine with the old set up.

The car clearly would have to be turned over to an expert because I haven't a clue. No one understands it even the race driver up north, Basil, whom even Steve respects. They all say it shouldn't be happening but it is and does.

I just don't want to chase any of it anymore. I'll set the carbs, clean the filters and forget it.

[Steve Simmons]

My apologies if I came off the wrong way - I certainly didn't mean anything negative. Reading my post from earlier, I can see how my wording could be taken as saying to ignore the problem. This was not my intent! I'm just seeing this as two separate issues now instead of one. The first issue is that your car won't redline as high as before it was rebuilt and reconfigured. The second issue is that the power band isn't what you want, although your statement above confused me because it seems you're happy with how wide and flat it is.

To me, it doesn't matter where redline is so long as the engine performs the way I want it to. It sounds like you have the power band you want, but still want it to rev really high. I guess I'm just unclear on what your priority is, and what you're trying to accomplish with the power up high. Not that I'll be any real help with that anyway, I just wanted to understand what you're after in case I can offer any suggestions. As far as the other issue (dropping off) I've run out of ideas!

Regardless, I'd suggest taking a step back from the whole thing for a spell because the car is reliable and performs quite well exactly how it is, so there is no reason why solving this problem should be stressful or a major priority. I'd just enjoy the huge power band and not rev to 5K since there's no power up there anyway. Then deal with the high rev stuff a tiny piece at a time, as more of a fun problem solving project.

[malcolmr18zoy]

Hry Gary,
You've posed a problem for all of us, and we've all chipped in with our opinions, and given it a lot of thought. It does seem a little harsh to say that you're sick of this forum, and drop us all because we haven't been able to come up with the answer. I've given this problem a lot of thought, but still don't have the complete picture. Was your engine really rattley before you freshened it up? Did it perform as you liked it before you freshened it up?
Malcolm

[max71]

Did I use the words "I'm sick of this forum"?

I don't think so. I said I'm sick of this engine. I absolutely respect and I hope show it by thanking people when they have constructive opinions. Closing the thread to me just means I'm just tired of the whole process. I thought sending the head to Sean Brown would solve all of it. Even though he corrected many things the Burbank Speed Shop did wrong it didn't help. Who knows what else that shop did wrong if they can't even figure out where the intake and exhaust guides go? (they reversed them).

I'll provide some gory details so everyone understands why I'm sick of this engine:

Had a local person assemble it after all the machine work was done by what I was told as being the best speed shop in L.A.

Read up on everything to make sure I bedded in the cam right and searched out the right oil with the right amount of ZDDP and added some additive for good measure.

After initial bedding in of the cam ALL the freeze plugs blew out and I almost lost the entire engine.

After fixing that I could never get it to perform and even drove out to APT for them to look. Dave wasn't there and his assistant was and it was just a waste of time and money - no fix.

Did a compression test at 500 miles and one cylinder was down a ton. One of the members of this board and an excellent mechanic, Joe Siam, allowed me to pull the head and pan in his shop. We found the rings were in up-side-down and so many other mistakes I can't or don't want to remember. We also found ALL of the chambers in the head leaked like crazy. Send it back to the speed shop and they just fixed one chamber. We had to re-ring the whole engine.

Sent the carbs to be redone by some guy in the midwest who totally screwed them up and insisted he knows what he's doing and sent me a letter from someone loving his work. I sent the carbs to someone I know back east and he said they were completely screwed up and redid them. Although as I just found out this week he didn't set the float height correctly. Or even close to correctly.

Replaced the coil twice within 30K miles. Tried three different types of ignition wires and three different caps. Built a electronic ignition and tried that. Tried different condensers. Sent the dizzy back to be curved exactly how Dave Anton suggested then sent it back again a couple weeks ago to be verified.

And the list goes on and on and on for 3.5 years including going through 2 defective clutches, sending the head out for a third time this time to someone who knows what they are doing and they had to replace EVERYTHING the speed shop did.

I've beat my head against the wall for 3.5 years. I was hoping there was a simple fix as usually there is. In this case I do not believe there is. So I'm throwing in the towel.

I'm really angry that in the beginning when I talked to Joe Huffaker and he agreed to do the engine I didn't send it to him. I told my wife and she insisted as I taught her which is Do it right the first time. It may be more expensive but it will be cheaper in the long run. I've essentially paid to have this engine done twice and its still not working. Again, Malcolm had I known about you I would've given it to you or I should've given it to Joe Siam. The reason I wanted to Huffaker is because they did the most flawless engine I ever had in the car even though they only did the top end. Twenty years after Huffaker I had the engine redone by the most respected MG shop here in L.A. (finally had to deal with the bottom end) and their machine shop made a mistake and instead of skimming the block they decked it to ZERO deck height. The solution by this respected shop? They put on TWO head gaskets. They did call and tell me about the mistake but wanted me to pay for all the machining for a new block if and when they could find one. This is a daily driver. I couldn't wait and already spent $3K with them just to do the bottom end. THAT's why I wanted and should've sent the engine to Huffaker this time.

Steve, I don't know why wanting the cam to perform in spec is so wrong? Everyone one else from APT to associated people say it should but it doesn't. Would you be happy if you bought a TV that got 100 channels and stopped at 90? I can spool the analogy to anything but I don't think people are happy when they spend a lot of money and try to do everything proper, not cut corners, and the product doesn't deliver - yet, everyone else who bought says theirs is fine.

Its gotten better in that I couldn't go past 4500 before and while it bogs down I can get to 5000 and the wall is so obvious its not going to go past it. So why continue the thread? Its a problem that needs much more serious investigating that spells $$ and I don't have any to throw at this engine any more. The triple clutch thing burned me out as it is....

It is no disrespect to the board. Its just compounded frustration that I never acted on my gut. When that engine was sitting on Steve's floor my gut told me to check the cam timing and Steve and I discussed it as mentioned above. As Steve explained well it works and he hadn't done cam timing either and I thought whatever Sean was doing it would fix it.

Sean did do good work and it is smoother from 3500-4500. I don't want to give the impression his work isn't satisfactory.

So I give up and won't participate in this thread. I think we've narrowed it down enough to know its not something simple and that engine is not coming out again.

[Steve Simmons]

Just to be clear, I never said that it's wrong to want the engine to work correctly. I did state that I fully understand wanting to fix the high end problem, and I would also want it corrected if it was my engine! As noted In my last couple posts I was addressing what I now see as two problems - power band and drop-off. My comments only said that the power band sound amazingly wide, which you also seemed to agree with, and that the high-RPM issue shouldn't be a major concern since it isn't hurting anything and is beyond where the engine should be running with its current power band. If you don't like the power band how it is then my last comment is moot, but as noted I'm unclear what you're after since you stated how much you like the power band but also want it to rev higher. Sound like I'm either misinterpreting what you said or missing the point trying to be made. No worries.

I agree it's frustrating to fight a problem for so long, and you've spent a helluva lot of time and brain power on it in the past few weeks. If it were me I'd just take a break from it for a while.