2.7 Rebuild – To bore or not to bore and other questions

[draw]

Originally Posted by snbush67

Nice build. Were the deck heights on each cylinder the same?

Thanks! The deck was machined by Ollie's, so I only measured the deck height for cylinder #1. For the 1-2-3 side, I put a straight edge across the tops of the cylinders to make sure they were at the same height. For the 4-5-6 side, I eyeballed the deck height on cylinder #4 compared to #1. Also used a straight edge to make sure they were at the same height. In retrospect, with the obsessive measuring I've done, I'm a little surprised I did it this way.

Originally Posted by Jesse911

This is a very nice build! Also all the photos and info are great as I will be rebuilding my engine soon too. Thanks!

What oil pump did you use btw?

Thanks! I used a GT3 oil pump...

Originally Posted by mikedsilva

Interesting.. never had a strud strip like that before....

I see you have those vertical marks in your barrels...

Yeah, the stud was a little surprising. The nut wasn't cross threaded either.

The vertical marks definitely gave me a bit of a scare when I pulled the heads off.

I think I've done everything correctly...checked all the clearances, ring gaps, ring orientation, deburred the rings, proper oiling on the rings, piston skirts and barrels. Not sure why these are showing up. They cannot be felt. I sent a picture to Mahle tech support to see what they think, but they haven't responded. Hopefully they're nothing serious...I guess I'll find out when I start it up!

[draw]

Time to install the chain housings and camshafts.

Dougherty Racing DC 43x-102 camshaft cleaned and ready to install...



Left side done...



Right side done...



Check for parallelism on the right side. Got within 0.03mm with three shims...



Started with three shims on the left hand side, but had to add a fourth. Hit the mark exactly. Probably helps that I replaced all of the sprockets with new...



Onward...

[snbush67]

I discovered vertical marks in my cylinders caused by wrong size oil rings during a rebuild. It looked exactly like what is showing in your pictures. I ended up pulling the cylinders off and deglazing them, I could not remove the vertical lines completely. After installing different rings I ended up with 5% leakdown after break in.

I think that your oil rings aren’t right.

[draw]

Originally Posted by snbush67

I discovered vertical marks in my cylinders caused by wrong size oil rings during a rebuild. It looked exactly like what is showing in your pictures. I ended up pulling the cylinders off and deglazing them, I could not remove the vertical lines completely. After installing different rings I ended up with 5% leakdown after break in.

I think that your oil rings aren’t right.

Thanks for sharing your experience!

I called MAHLE Motorsports today and spoke to Jason. He's the guy that's in a lot of their YouTube videos. Anyway, after speaking to him and emailing him pictures, he said that "the 'ghost' streaks you cannot catch your nail on are normal."

Since I can't catch a fingernail on these marks or feel them in any way, I'm crossing my fingers and moving forward...

[draw]

With the camshafts and chain housings installed, moved on to installing the sprockets...



Tried turning the engine over, but nope! Something is binding up. If this picture was at all legible, you'd see that the chain slipped off the intermediate shaft sprocket...



After realigning the chain, I rebuilt the idler arms using new sprockets and the upgraded arms from Supertec. This shaft was toast and had to be replaced...



Installed those along with some DIY dummy chain tensioners made from $10 in aluminum tubing and two M10 bolts and nuts...





Onward...

[draw]

Time for rocker arms, etc.

Checked all of the rocker shafts. Spec is 17.992mm to 18.000mm. Six of the shafts were out of spec and trashed. I'm trying my best to avoid any leaks...



My camshaft housings were pretty beat up and had some damage to the shaft bores before Ollie's refurbished them. For extra insurance, I'm using the TurboKraft rocker shaft locks and RSR seals. Rocker arms were refurbished by Dougherty Racing, I replaced the elephant foot adjusters and lock nuts with new, and freshly black oxided bolts by me...



#1 intake installed...



After buying an indicator with a 3/8" stem to fit in the Stomski Racing tool, I was able to set valve clearance to 0.10mm...



And on #1 exhaust...



With the rockers in and valve clearances set, I rotated the engine to verify all was good. Nope! The motor locked up after about 60 degrees of rotation.

Backwards...

[PeteKz]

Is your cam timing in the ballpark? If not, set that first.

[fabracadabra]

Do you mean that you were rotating the engine anti clockwise?
Just trying to understand.
I think the Dempsey book told me not to do that at this point.

I have really enjoyed following your build thus far.

[draw]

Originally Posted by PeteKz

Is your cam timing in the ballpark? If not, set that first.

Turns out it wasn't in the ballpark!

I was a little too rough when I roughed in the cams and was rotated about 15 degrees (clockwise) off from vertical. Yellow line shows where the dot on the cams was pointing, green line is where it should've been (adjusting for parallax). I'm assuming that when I turned the engine over, the valve was touching the piston and that's why it was locking up.

Originally Posted by fabracadabra

Do you mean that you were rotating the engine anti clockwise?
Just trying to understand.
I think the Dempsey book told me not to do that at this point.

I have really enjoyed following your build thus far.

No, I was rotating clockwise. The camshaft was so advanced (?) that the valve was out of time with the piston and was touching after about 60 degrees of crankshaft rotation. One drawback of the "bolt" style camshafts is that the washer covers up the dot on the end of the camshaft, so my mistake wasn't obvious until I took the bolt off to investigate.

Glad you're enjoying my build!

Onward...

[draw]

On to cam timing, rocker installation, valve clearances, and chain tensioners!!!

Rotate to TDC using my degree wheel as a reference. I cut the pointer to a sharp point and I line that up with the right side of the 0-degree hash. Not as good as the digital degree wheel, but I can get very close with pretty good consistency. And it was only $20...



The range on the DC43x-102 cams is 4.4 - 4.6mm. Got the left side set at 4.49mm...



After four attempts, I got the right side set at 4.53mm. It's basically just the "slop" in the pin hole the causing the difference between the two sides. I can't consistently hit a number after torquing. It's somewhat random. It's going to be hard for my OCD to live with, but I'm calling a 0.04mm difference good. Unless I shouldn't...



Timing done!



Got all the rockers installed and valve clearances set...





Rebuilt chain tensioners by Glenn Yee Motorsports installed...







Onward...

[mikedsilva]

that accuracy is pretty good. The engine won't be able to tell

I think OCD is a healthy quality for this part of the build.. I take vids of my cam timing.. here's one I did recently.. https://youtu.be/orQf6tUtC_s?si=iAY1miMHax-9iC29&t=565

[draw]

Originally Posted by mikedsilva

that accuracy is pretty good. The engine won't be able to tell

I think OCD is a healthy quality for this part of the build.. I take vids of my cam timing.. here's one I did recently.. https://youtu.be/orQf6tUtC_s?si=iAY1miMHax-9iC29&t=565

Thanks for sharing Mike, your videos are appreciated!

[draw]

Time to start closing things up...

Installed new M6 studs into the chain housings...



Applied Dykem to the chain housing "lid"...



Sand and repeat until flat...



And installed. I had Simo at SVAUTO vapor hone the magnesium housings and covers...



Onward...

[Henry Schmidt]

Absolutely beautiful work thus far. Unfortunately you overlooked a serious problem.
You installed a set of 47mm, 4 bearing cams in a set of early 47mm 4 journal housing but you didn't drill the housings to oil the 4th journal.
It an easy fix but if you ignore it, the cam will seize in the housing.
I posted a thread on the subject called "billet cams in 2.7 housings". Check it out.


https://forums.pelicanparts.com/911-engine-rebuilding-forum/1084118-billet-cams-2-7-cam-towers.html






BTW: nice looking idler arms

[draw]

Thanks for pointing that out Henry! Definitely a doofus move on my part!

From reading that post you linked to, and this other post of yours, it looks like I need to tear everything back down and remove the cam towers to be drilled out. Correct?

Do you still offer the service to convert them?

Originally Posted by Henry Schmidt

Interesting question.
The billet cam blanks are all the same. They just grind the journals down from 49mm to 47mm.
What makes this interesting is that most if not all 77 cam tower are 4 journal.
The casting are the same as the casting used for 78 SC. The difference is the cam bore is smaller (47mm vs 49mm) and the unused journal is not drilled for oiling.
To be clear, the 77, 2.7 engine uses a 3 journal cam but the housing has 4 journals.
The journal that would be free (unused) with a 3 journal cam is not drilled for oiling. If it was drilled there would be a loss of oil pressure do to the missing cam journal.
These cam towers (77 2.7) are cool because you can drill the housing to make it a 4 journal housing (good for high RPM/racing motors). In fact, if you use a 4 journal cam in a 77 cam tower you have to drill it for oiling or the cam will seize in the housing do to lack of oiling.
We cam convert them for you or you can drill and plug them yourself.
The way you can tell if you have a 47mm 4 journal cam tower is to count them or look to see if the cam tower has one un-drilled casting and one drilled.

Looks like I'll get my engine building "reps" in and another shot at perfecting my cam timing.

Waaaaaaay backwards!!!

[Henry Schmidt]

Yes, we can convert them for you.
Your cam towers look great but we have a complete restoration service for those who want it.
We can also convert 3 and 4 journal 47mm cam towers to 49mm.
After extensive deflection testing we have great confidence in the ability to use 3 journal cam housings on larger engines. The 49mm cams are incredibly stout.
That is not to say you should/can use 47mm cams on 3.0+ engines.
They don't work well.

[SlateBlueTarga]

I would be buying Henry a steak dinner right now if I were you! I hope he is looking over my shoulder when I finally go into mine.

John

[draw]

Originally Posted by Henry Schmidt

Yes, we can convert them for you.
Your cam towers look great but we have a complete restoration service for those who want it.
We can also convert 3 and 4 journal 47mm cam towers to 49mm.
After extensive deflection testing we have great confidence in the ability to use 3 journal cam housings on larger engines. The 49mm cams are incredibly stout.
That is not to say you should/can use 47mm cams on 3.0+ engines.
They don't work well.

After doing some investigating, I'm going to attempt the modification myself. Besides, it gives me the justification for buying a drill press, which I've needed over the years but never got around to getting.

Originally Posted by SlateBlueTarga

I would be buying Henry a steak dinner right now if I were you! I hope he is looking over my shoulder when I finally go into mine.

John

While not a steak dinner, I've been a patron of Henry's over the years. Everything has been top notch...idler arms, twin plug turbo valve covers, head studs, and more!

Also, thanks to this forum, including Henry, for looking over my shoulder during my rebuild. The main reason I've posted a million pictures of stupid stuff is, in case I make a doofus mistake, someone might catch it and point it out.

[draw]

Sometimes to go forwards, one must go backwards...

Took apart the "front end" of the engine, including the cams, sprockets, etc....



Removed the entire top end...



Back down to the cylinders...at least I get to use my fancy cylinder hold downs again...



I removed my timing degree wheel before I knew I'd be going down this road. This time around, I'm going to fashion something a little different...

Time for lots of cleaning!

Onward...

[draw]

But wait...time for another detour!

Noticed this "gouge" in the exhaust valve stem tip...



I decided to replace it with a new TRW valve...



Procured some prussian blue (hey, I'm Prussian, too!) to check how well the valve seats...



New valve made perfect contact with the seat. I'm skipping any valve lapping on this, especially since this practice is now frowned upon by most engine builders...



Put the springs and retainer back on...



Using a $20 valve spring compressor from Amazon, got the keepers in and done...



Unfortunately, it's about 120 degrees in my garage this time of year, so I get to spend very little time working on the engine.

Onward...