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Join Date: Sep 2008
Location: San Diego, CA
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2.7L Top End, Advice Needed

Hi guys, long-time lurker who is now doing a top-end on a "mystery" 2.7L that came with my 914/6 conversion project. My engine experience consists of three Type 4 914 engine builds, no 6-cyl experience. But I have a copy of Wayne's book.

Quick background, the engine came on a pallet with a stalled 914/6 project. I assembled the car and the engine ran well enough on Webers although it smoked on every start-up and leaked oil between the heads and cam carriers (right onto the exhaust - ouch!). So the engine came back out and I've now stripped it down to the short block.

Damage report: Heads have relatively new valve guides but most of the valves are out-of-spec. Engine had been sitting for years so valve guide seals suspect. P&C clearance measured at 6 thou. Cam lobes show pitting. Luckily case deck is flat and case savers have previously been installed. Head stud and through-bolt torques were all good upon disassembly.

Progress: Heads are now rebuilt to stock specs along with cam carriers and chain housings.

But now I am looking for the advice of the community. The goal is to rebuild this engine on a budget with the end-goal being a fun weekend canyon carver.

My Alusil jugs are shot (pistons are OK). I have leads on good used Alusil or Nikasil jugs in the $500-600 range. Also, I could have EBS coat my jugs (Nikasil) for $1000.

If I went Nikasil, I could probably find used matching Mahle pistons for a couple hundred. Or JE 9.5:1 for about $1000.

Since I need to re-do my cams anyways, I am tempted to get the JE pistons and match that with a more spirited cam grind than the CIS pistons would allow. But this path adds to the cost. Is the performance increase with this combo compared to CIS pistons and SC-grind cam significant? If it's a minor bump-up I'll probably save the grand but I'd like to hear from those who have gone down this path.

One other question: after tapping out the wristpins to remove the pistons, one of the rods now grabs slightly on the crank. In other words the rod no longer drops under its own weight. I never had this issue on the Type 4 engines. Should I now buy a set of rod bearings/bolts/nuts for this one rod? Can you confirm the rod bearing can be swapped without splitting the case?

Thanks guys and I look forward to sharing the built with you all. Will do Carrera tensioners and oil line restrictors, please let me know of any other important mods while I'm in there.

See a pic below of the engine before major disassembly.

Cheers,
Brent



Last edited by wertygrog; 06-04-2017 at 09:58 PM..
Old 06-04-2017, 09:56 PM
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Join Date: Jan 2004
Location: Upstate NY
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Most important is the case lay shaft through stud. Make sure there's an insert in that stud.
Once the case is closed up you can't fix it. Well I should say it can be done but it's a nightmare from what I've heard. If that stud starts to pull upon torquing you'll be sorry and apart the case comes once again.

I had my 2.7 case all done up by Ollie's machine. It's not cheap but a piece of mind that it's done right.

I had my case line boarded standard, case mating surface machined, same with the cylinder base,
case savers for the head studs, and the lay shaft through stud.

With the rod issue that you have, I would take it apart to look at it. The rod bolts can't be re-used so you'll have to buy a new pr. If you plan on taking all the rods off you may want to upgrade the rod bolts if the budget allows it. On the rod bearings keep an eye out where they are made. There was some bad batches going around a while ago so not sure if that got squared away by the manufacturer.

There's a few things that I wouldn't do that are in Wayne's book. One of them is putting silicone sealant on the case through bolts. Do your homework before you close up your case. Make sure you use the proper sealants in the right places. Henry sells a kit with all that you need.

Last edited by Luke M; 06-05-2017 at 11:51 AM..
Old 06-05-2017, 11:42 AM
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Looks like you have the solid tensioners mod in there too. In a nutshell, they don't account for thermal expansion. Stretches the chain and could lead to wearing the case in an oval though that's rare.

Following your build with interest as I've decided to rebuild my 2.7 as well.

What kind of intake did that motor come with?
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Old 06-05-2017, 01:14 PM
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Following as well. I have mine in long block form sitting on the engine stand.
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Old 06-05-2017, 05:43 PM
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Hi guys, thanks for the responses. I don't intend on splitting the case as the engine came apart for other reasons. At the advice of Motor Works in San Diego I re-torqued all of the through-bolts to factory spec and confirmed that the crank still turns easily. Also, the deck is still flat. According to them this means the case is good and there's no need to split it (it had been apart recently for case savers etc. apparently).

The induction for this engine is Weber 40IDTP carbs on Porsche manifolds. Will be going through these this summer as well.

I think what I'm going to do is have the jugs Nikasil'd through EBS and get a set of JE 9.5:1 pistons. Along with 911E cam grind. This is definitely scope creep with respect to my original intentions but I don't think I'll regret it.
Old 06-05-2017, 08:09 PM
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Well guys, I removed the rod mentioned in my first post that had a little drag.

The rod bearing was completely shot. Deep scratches and copper-like backing material showing through. Also scratches on the crank journal.

My dreams of not splitting the case have been shattered. Will finish splitting the case tonight and report back with the damage report. Pray for my soul...and wallet!
Old 06-07-2017, 07:59 PM
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So I split the case last night. The good news is that the wasted rod bearing was the only really bad bearing. I caught it in time before it destroyed the rest of the engine, by sheer luck. See pic below of the bad bearing. The other rod bearings and the main bearings didn't look like this. I did notice that this bearing does not sit snugly in the rod. It's curled in a bit instead of curled out slightly like a typical bearing which would friction fit into the rod. Kinda hard to explain but definitely something going on here. I will be sending the case, crank, and rods to my machine shop to figure out where I stand.

The oil pump has 4 ribs. Should I take it apart to clean and rebuild? Do the gaskets etc. come in the normal engine rebuild gasket kit?

Cheers,
Brent



Old 06-08-2017, 08:07 PM
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