2.7/2.8 cam switcharoo

[b7_Andy]

**See post #50 for dynos comparing 2.7 and 2.8 cams**

So I know the 2.8 cam question has come up a thousand times, but my approach is a little different. So I'm doing a big service on my 2.8 A4 and I was going to pull the timing chain tensioners from my spare 2.7 motor and put them in my 2.8 because they have less miles and the 2.8 ones are starting to make noise (I'm going to put brand new tensioners in my 2.7 when I build it anyway). As I started reading some cam threads I came up with a new idea. What if I swap the 2.7 intake cams and tensioners into my A4 and then have the 2.8 cams to go into my 2.7 when I finally get around to building it? I figured this will save me some money down the road but I'm more worried about what happens when I put 2.7 cams in my 2.8 A4? I don't care about power as the car is already slow as shiz, but will it run well without retuning the thing? Also the 2.8 is a 1998 AHA, I think all the intake cams are the same though. If I do go this route, can I just swap intake cams over? Is there anything else I should swap over with the cams like bearing caps etc.? I'm sure someone with an A4 and S4 has done this before. I'd like to hear some opinions from people on this forum and decide whether it's worth it or not... I figure it's like getting a free set of 2.8 cams!

[Trb1]

It will just make a less efficient 2.8. What turbos are you going with? It wouldn't be worth it to have 2.8 cams on the street unless you throw some big boys on there.

[Bordom]

There was a thread on here where a user dropped in 2.8 cams with no tune revision and gained 30whp. Definitely gains to be had

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[b7_Andy]

It will just make a less efficient 2.8. What turbos are you going with? It wouldn't be worth it to have 2.8 cams on the street unless you throw some big boys on there.

I'm swapping it into a B7 so I told myself that if I'm going to go through all the time and trouble doing a swap, it better be the biggest and the baddest!

[b7_Andy]

There was a thread on here where a user dropped in 2.8 cams with no tune revision and gained 30whp. Definitely gains to be had

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Ya no doubt it's worth dropping in 2.8 cams. So will that mean -30hp in the B5 A4?

[Bordom]

Ya no doubt it's worth dropping in 2.8 cams. So will that mean -30hp in the B5 A4?

Lol who knows. I'd think it'd run a bit smoother, otherwise, not much change

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[b7_Andy]

Lol who knows. I'd think it'd run a bit smoother, otherwise, not much change

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But do you think everything will be timed correctly and it can run properly without a tune? If anything maybe I'll get better gas mileage lol

[Trb1]

But do you think everything will be timed correctly and it can run properly without a tune? If anything maybe I'll get better gas mileage lol

It will definitely be okay without a tune, and it will be timed correctly, yes. You can swap cams from the 2.8 into a 2.7, so it will be fine the other way around.

[Trb1]

There was a thread on here where a user dropped in 2.8 cams with no tune revision and gained 30whp. Definitely gains to be had

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I feel like that's completely taken out of context. I doubt it was on a k04 car or anything similar. Maybe 30 peak horsepower somewhere, but with a smaller powerband and a decrease in torque as a consequence.

[JVD]

I feel like that's completely taken out of context. I doubt it was on a k04 car or anything similar. Maybe 30 peak horsepower somewhere, but with a smaller powerband and a decrease in torque as a consequence.

Do we have data to support either argument?

[Bordom]

Do we have data to support either argument?

Don't remember the name of the thread, otherwise I'd link it

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[Trb1]

Do we have data to support either argument?

http://www.audizine.com/forum/showth...s-experimental

This is for 93 octane on k04s. The story is different for e85.

Edit: I just noticed that op said the 2.8 a4 is a 98. Isn't that a pre facelift car? I believe pre facelift 2.8s are 12v heads which have different internals.

Bordom, this might be the thread you're referring to. Without a tune a 605 car gained 14 at the wheels but lost wheel torque. A 770 car only gained 30 at the wheels after a retune. Those are much bigger turbos than k04s. :9 you would sacrifice street drivability on k04s for a minimal uptop gain. Completely not worth it. Once again, e85 is different.

[Bordom]

http://www.audizine.com/forum/showth...s-experimental

This is for 93 octane on k04s. The story is different for e85.

Edit: I just noticed that op said the 2.8 a4 is a 98. Isn't that a pre facelift car? I believe pre facelift 2.8s are 12v heads which have different internals.

Bordom, this might be the thread you're referring to. Without a tune a 605 car gained 14 at the wheels but lost wheel torque. A 770 car only gained 30 at the wheels after a retune. Those are much bigger turbos than k04s. :9 you would sacrifice street drivability on k04s for a minimal uptop gain. Completely not worth it. Once again, e85 is way different.

They are not. I used to own a 96 12v V6, and am quite familiar with the history of that motor. 98 model cars with the 12v motor are rare, less than a few.

98 is when the 30v came out, but also when the S4 debuted in Europe. The 30v was actually being used since 96.

The difference b/w pre/post face-lift 30v are oilers around the cams. That's pretty much it.

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[b7_Andy]

@Trb1 @Bordom
The car is a 30v 1998. I believe the camshafts are the same for all years of the 30v 2.8. So basically my goal is to get my 2.7 motor to rev high. That's why I think the 2.8 cams will help out, especially to flow enough for RS6 turbos. And I've got to believe with the A4 that it doesn't flow nearly enough to fully utilize the more aggressive 2.8 cam so I'd think with the stock tune having 2.7 cams wouldn't make my slow car much slower at all. If it did pick up a little more lower end and better fuel economy I'd take that! I obviously don't want to make my A4 a lot slower, but the bigger focus is the 2.7 engine. I need that bad boy to flow and rev high...


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[Trb1]

@Trb1 @Bordom
The car is a 30v 1998. I believe the camshafts are the same for all years of the 30v 2.8. So basically my goal is to get my 2.7 motor to rev high. That's why I think the 2.8 cams will help out, especially to flow enough for RS6 turbos. And I've got to believe with the A4 that it doesn't flow nearly enough to fully utilize the more aggressive 2.8 cam so I'd think with the stock tune having 2.7 cams wouldn't make my slow car much slower at all. If it did pick up a little more lower end and better fuel economy I'd take that! I obviously don't want to make my A4 a lot slower, but the bigger focus is the 2.7 engine. I need that bad boy to flow and rev high...


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Go and read the link through the link that I posted. There's some good info. You might benefit from 2.8 cams if you run rs6 turbos. You'll really benefit if you run e85 with 2.8 cams. Doug@frankenturbo commented on the link I posted saying that the reason for more aggressive cams in the US spec 2.8 is more likely for emissions purposes than performance.

Flyboy, on his website, has logs of e85, 2.8 cams and f21 turbos running 513+ whp. When generally f21s will run around 450-470 on e85 with stock cams.

Here's his link:
http://www.myaudis4.com/2015/11/06/big-power-ft21s/


Here's another link of 513 whp with e85, 2.8 cams, and f21s. 2.6 fats.
http://www.audizine.com/forum/showth...-E85-Rods-Cams

[AudiTechS4]

Do we have data to support either argument?

http://www.audizine.com/forum/showth...echs4+2.8+cams

here is the dyno sorry its so hard to see as they made the lines all the same color. but this was 1 week apart. 1 run was the bas 2 runs were the cams you can see the gains from the cams here. hp is the top curve - you can see they started to make more power and the cam change over killed them but they carry the power longer at higher rpm . you can see the cam change over in the 2 runs compared to the base. thiis was before a retune with the cams , we wanted to see what they would do just throwing them in there.

[Bordom]

I like what you posted. I always wanted to do reground 2.8 cams for a more aggressive profile.

Haven't found a place locally that can regrind them and machine spacers to put under the lifters to make up for the material they take off

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[landfill]

^^^Was just about to link to the auditechs4 thread.
You were running a k04 car if I remember correctly.
That's also 30whp before tuning the car for your mods.
People saying there's no benefit have not done the comparison
first hand. Just regurgitate BS read online.

[AudiTechS4]

this was actually on a stg2+ car . good old k03's

[landfill]

^^There you go even better.

[Trb1]

^^^Was just about to link to the auditechs4 thread.
You were running a k04 car if I remember correctly.
That's also 30whp before tuning the car for your mods.
People saying there's no benefit have not done the comparison
first hand. Just regurgitate BS read online.

I'm not saying that their isn't a benefit. A motor I put together for a friend running 605.2s is running 2.8 cams per my advice. I linked a few threads about the benefits of 2.8 cams. I'm just saying that on 93 and a smaller turbo setup, 2.8 cams wont be beneficial for street performance. You'll gain minimal horsepower at the cost of moving the power band to the right.

Sure, it could potentially increase power on paper, but so does slapping a gt30 on a 1.8t. It's a lot of power, but you're going to prison if you open it up and enjoy it to its full potential.

[Zba]

^^^Was just about to link to the auditechs4 thread.
You were running a k04 car if I remember correctly.
That's also 30whp before tuning the car for your mods.
People saying there's no benefit have not done the comparison
first hand. Just regurgitate BS read online.

I second the motion "regurgitate bs read online"

[b7_Andy]

Thanks everyone for your responses. I think I'm going to pull the trigger on the cam swap. So the next question is am I good to just swap cams, or is there any other parts in the head I should swap over?


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[landfill]

Take a look at your cam chain and chain tensioners while everything's apart.
That's all I can think of.

[b7_Andy]

Take a look at your cam chain and chain tensioners while everything's apart.
That's all I can think of.

I think I'm going to swap my 2.7 chain and tensioner over to the 2.8 because it has less miles. The 2.7 motor will be getting brand new ones.

[Trb1]

I second the motion "regurgitate bs read online"

Whatever. Sometimes this forum can be incredibly dense.

[b7_Andy]

I got the driver side cams and tensioner out. Going to remove the passenger ones today. Cams on the 2.7 look good, should be the same case on my 2.8 since the car has run really well but we will see. One question though, do I use any kind of sealant on the caps on the edges of the cylinder head? When I removed them it didn't seem like there was any sealant, but it seems weird that they wouldn't leak without sealant unless the surfaces were more than perfectly flat.

[b7_Andy]

So I got the intake cams out of the 2.7 and put the motor back in the corner. Will be swapping them into the 2.8 this week and putting the 2.8 cams in the 2.7 to save for later. I picked up some permatex anaerobic sealant to use for the cam caps at the edge of the head. I'm only sealing the caps that border the edge of the head, not all the bearing caps correct? I feel like that's a really dumb question but I've got to ask. Also I thought the torque for the cam caps was 88 in-lb but it seems like they were a little tighter than that. Can anyone confirm?


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[Trb1]

So I got the intake cams out of the 2.7 and put the motor back in the corner. Will be swapping them into the 2.8 this week and putting the 2.8 cams in the 2.7 to save for later. I picked up some permatex anaerobic sealant to use for the cam caps at the edge of the head. I'm only sealing the caps that border the edge of the head, not all the bearing caps correct? I feel like that's a really dumb question but I've got to ask. Also I thought the torque for the cam caps was 88 in-lb but it seems like they were a little tighter than that. Can anyone confirm?

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That's correct. Only at the ends, and only a little bit. Cam caps are 8 ft-lbs so 96 in-lbs

[b7_Andy]

Shit!
That's on the 2.8 intake cam. I guess that's what I should expect from cams with 177,000 miles on them? It didn't make a noticeable difference on my A4 but I'm not going to put them into a motor that might potentially make 600+hp. I know machine shops are pretty capable but could something like that be fixed? I'm not sure if machine shops polish cams or anything of that sort. Either way there's so many 2.8s in junkyards I'll eventually find a good set of cams. I'll still be putting the 2.7 cams in the 2.8 I think because they look to be in better shape. I will inspect that spot on the cam further when I get it out of the car but I think it's a good size chip. Well I'm done for the day, will be back to the garage in a few hours lol

[AudiTechS4]

well what does the lifter look like under that cam . if its fine i wouldn't worry too much . but if you can get another set easily then id probably go that route

[b7_Andy]

well what does the lifter look like under that cam . if its fine i wouldn't worry too much . but if you can get another set easily then id probably go that route

I'll get pictures of the lifter when I get the cam out later.

[b7_Andy]

Also Trb1 says the torque for the cam caps is 96 in-lbs. can anyone else confirm this? Everywhere else I find they're 88 in-lbs. I want to believe Trb1 because they did feel a little tighter, but still not 100% sure.


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[b7_Andy]

Anyone know how to swap the damn tensioner pads? Those bloody bastards seem pretty stuck lol. Should I just break the old ones off? Also the 2.8 intake cams look trash. There's small pitting and dimples all over them. A little bit of dry scuffing but not bad. I noticed my 98 doesn't have an oil level sensor so there's a good chance one of the previous owners ran it a bit low on oil. Oh well guess I'll look for another set of 2.8 cams at the junkyard. Or somehow source some 2.4 cams .


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[b7_Andy]

Figured out how to get the pads off. Just used a heat gun and then was able to pop them off. Also on my 2.8 I couldn't push any of the valve lifters down with my hand, but on my 2.7 I could push at least half of them in with my fingers. I plan on getting new valve springs and retainers anyway, but do you guys think it's like that because it's been out of the car so long and lost oil pressure, or is the valve train not so happy?


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[Trb1]

So I got the intake cams out of the 2.7 and put the motor back in the corner. Will be swapping them into the 2.8 this week and putting the 2.8 cams in the 2.7 to save for later. I picked up some permatex anaerobic sealant to use for the cam caps at the edge of the head. I'm only sealing the caps that border the edge of the head, not all the bearing caps correct? I feel like that's a really dumb question but I've got to ask. Also I thought the torque for the cam caps was 88 in-lb but it seems like they were a little tighter than that. Can anyone confirm?

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10 NM, so I suppose 7.3 ft lbs. it' not incredibly picky. I torqued mine to 8 ft lbs.

[Tiluleshpingen]

10 NM, so I suppose 7.3 ft lbs. it' not incredibly picky. I torqued mine to 8 ft lbs.

i have done mine 9 thru 11 NM .i think 8 is too little and with 12 i have broken a few bolts

[b7_Andy]

i have done mine 9 thru 11 NM .i think 8 is too little and with 12 i have broken a few bolts

I think he meant 8 ft-lb which is more like 11 Nm. On my 2.8 motor the bolts didn't seem super tight when I took them off so I torqued them all to the factory spec 10 Nm (88 in-lb). On my 2.7 motor they felt a little tighter so I think I'll do 11 Nm (97 in-lb) especially since I'll be revving a little higher.

[Tiluleshpingen]

Anyone know how to swap the damn tensioner pads? Those bloody bastards seem pretty stuck lol. Should I just break the old ones off? Also the 2.8 intake cams look trash. There's small pitting and dimples all over them. A little bit of dry scuffing but not bad. I noticed my 98 doesn't have an oil level sensor so there's a good chance one of the previous owners ran it a bit low on oil. Oh well guess I'll look for another set of 2.8 cams at the junkyard. Or somehow source some 2.4 cams .


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Whats so good on the 2.4 cams?

[b7_Andy]

Whats so good on the 2.4 cams?

I believe they have the most aggressive lift and duration.