M20 rebuild, replace, or let it ride...

[Matty-CT]

Hello all,

I'm new to the forum as of today. I've been following the forum, though, since late August when I picked up a 1987 325ic on Craigslist. I'm no mechanic, by any stretch, but I've been gung-ho on getting my car operational. I'll make the back story really brief and then get to my questions.

Bought the car billed as for parts or restoration; has 175K miles. Seller intended to restore it but never did. Sat in his garage for a year unregistered. Claimed it most likely had a blown head gasket. I flatbedded it home and got it started. Lots of white smoke out of the tailpipe. Sounded like all the cylinders were firing but there was a good amount of valve clicking. I have a short iphone video of it. I have since bought the Bentley manual and have been since seriously upgrading my toolbox!

So, I know it needs all new belts and service items like pumps, etc, and certainly needs a head gasket (at the minimum.) I finally got the head off and out of the car this past weekend. Today I took it to a local, highly reputable engine shop - Carlquist Engines in Watertown, CT. They do high performance race car builds and the like. They will clean, test, and machine head, and rebuild if necessary.

The main question is about the block. After removing the head there was a bit of coolant pooled in the four middle cylinders. The optimist in me was pleased to see that the coolant hadn't drained past the rings which makes me think that the rings are tight. Since the engine was at TDC, cylinders 1 and 6 were up. Pistons in 1 and 6 have black carbon all over them as well as the matching head areas. The remaining 4 cylinders have some crud in them (from coolant I assume) and rust/corrosion on the valve faces. Also there's a little corrosion on those cylinder walls near the top.

The engine shop thinks I should pull the whole engine, have it bored, and get new pistons, etc. I'm not so sure I want to put 2-4K (or more?) into the engine. All I want is a classic car for tooling around aimlessly in the summer. So, my question is: Should I go great guns and have the engine rebuilt, look for an engine to swap, or just have the head reconditioned, clean up the gunk on the block as is, reinstall with new gaskets and roll the dice?

Thanks for any advice! First post!

Matt

[digger]

what do you actually want from the engine?

it would be crazy to get new pistons and keep the engine as a low compression B25. you can build a high compression stroker engine for not much more.

maybe you could do new rings and a hone only so reuse pistons? i imagine it would be cheaper to swap a running engine though.

[GillesBigCowboy]

Rebuilding the engine would probably give you great peace of mind, a sense of satisfaction, and the most years of trouble-free running, but obviously it will co$t you.

I have never rebuilt an engine (I am hoping to do so in future), but I have swapped a used engine with manual tranny into a formerly auto, and I am trying to do it again (you can pick up a decent used m20 with tranny attached for less than $500), so that is certainly your most economical, and easiest option (in the short term).

The tool investments are a slippery slope... into nirvana.

[redlightpete]

Unfortunately cracked heads are more common than blown head gaskets on stock m20s. If the head test shows it's cracked, you may just want to get a used motor. Then you can drive the car while you build your big stroker motor!

[Matty-CT]

Thanks for the input. I'm still waiting on the machine shop regarding the state of the head. I bought the car for $600 so I haven't spent a ridiculous amount of money on it. Sure, I've bought a few hundred bucks worth of tools, jacks, manuals, and supplies, but I would have bought that stuff no matter what car I bought.

Here's a short video of the car at idle. I was so stoked when I got it started because it wasn't running at all when I bought it! Lots of white smoke. Hopefully it's just a head gasket but I'll know soon enough!



I'm not ordering any engine replacement parts until I hear back about the head. No point, I guess. Any thoughts?

[Wanganstyle]

Clean the cylinders and the crud off the pistons, soak them with oil for a few days.

Borrow/buy/rent a leak down tester and air compressor
Build a block off plate for a single cylinder with 4 holes to bolt to head and a rubber sheet to seal; thread a hole for leak down tester.

You can then test the leak down of each cylinder individually and see if you need rings or not.


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[Matty-CT]

Hi all,

Since October I had a well-regarded engine shop rebuild the head. They pressure tested it, Magna-Fluxed it, machined it, replaced the exhaust valves, valve guides, adjusted lash, cam seals, the whole nine yards to the tune of $1000. Ouch. After I got it back, I replaced head gasket, all other related gaskets, distributor cap and rotor, plugs, injectors, thermostat, all intake/exhaust studs and nuts, water pump, timing belt and tensioner pulley, all belts, fuel filter, oil, coolant, and ps fluid. I also drained the fuel tank of 2 year old gas. All parts were OEM i.e. Bosch, Mann, Contitech, etc.

However, I used a Victor Reinz head gasket and new VR head bolts. Not sure if that was a bad choice or immaterial. Months of Winter work. Never having worked on an engine before other than my lawn mower/snow blower, I got smarter (I think!) as I went along. I used the Bentley manual and all the forums and Youtube videos for help, as well as a little help from my friends.

So here's the problem... I'm getting a leak from the mating area of the head and block right around cylinders 3/4 (the middle) on driver's side. I can see liquid flowing down the side of the block. It wasn't doing this immediately after putting everything back together. Car's unregistered and I've put about a half mile on it up and down the street. Seems to idle "fine" yet, admittedly, the power doesn't seem so hot.

I didn't use a torque angle tool for the 90 degrees + 90 degrees. I lined up my big torque wrench perpendicularly to the block and then turned it 90 degrees until it was parallel.

Anyway, what options or avenues should I pursue at this point? Can I (hope against hope) put another 25 degrees on the bolts (in case I was short) or is that idiotic? Thanks for any and all ideas and advice!

Matt

[Matty-CT]

I have to add that I have really enjoyed the process. I was just getting ready to put the hood back on today when I noticed the coolant (?) leak. Very demoralizing.

[jd_e30]

M20 rebuild, replace, or let it ride...

Make sure it's not something simple first, before going to extreme measures. You seem intelligent and it's obvious you did your due diligence in researching everything. I doubt something like not using a torque angel tool is your problem. Perhaps try replacing head gasket with OE and ditch the VR? Make sure it's torqued correctly and in the right sequence... I could be under complicating and speaking out of my ass here, but I think this could be a simple fix. :dunno:

[Matty-CT]

Well, it doesn't say "Noobie" under my screen name for nothing. I started the car again. Put my finger on the flowing liquid to discover it's gasoline! Looking closer, it is flowing down from the newly rebuilt head which, being so nice and shiny compared to the block, didn't look wet. Turns out it's a leaky injector leaking from the fuel rail port. My goodness this is good news. Taking off the fuel rail is child's play, comparatively. Even for a noob!

[jd_e30]

There ya go! Like I said, usually something simple. Get all of the injectors rebuilt and flow tested!

[digger]

like everyone here my thought was that damn VR head gasket strikes again...its not a great quality gasket, next time look for either goetze or BMW. glad it was simple though fuel leaks are my biggest fear due to fire risk. lucky they leak to the cold side of the engine.....

[Vivek]

Sounds like the engine shop was trying to make some more money off you. I highly doubt you'd need a rebuilt engine. I think you have everything figured out and it should all be good now. Do a compression test if you'd like on the engine to get a feel for it's health, if you feel that it's down on power. However, with that VR gasket, you may end up needing to replace it.