So I went and ruined my engine case.

jrmints · Post by **jrmints** » Thu Feb 02, 2012 11:31 pm

Hi all, it's been awhile.

I was working on restoring an '86 Spree 50, part of which included a big-bore kit. I put everything in just fine, but the bolts holding the head down to the engine case are now totally stripped/plugged up with parts of screws and, of course, I can't get any compression.

My first attempt to fix this was to drill out the part of the seized screws from the case--no dice. Maybe the drill bit I was using was too big, but I only managed to put neat little dents onto the remnants of the screws. So I did what any reasonable idiot would do, and tried to replace them with studs instead--I used a tap to try to clean up the threads in the case and put in long threaded rods, glued in by JB Weld. Looked okay, but had no compression either, and eventually I figured out that the the thing that covers the piston (piston case? head case? I don't know what it's called) didn't quite go in all the way, and didn't connect to the gasket. I tried pushing it in a little more--my JB weld masterpiece broke apart.

Now I'm wondering what I can do about this. It's probably beyond help, and I'd probably have to get a new engine case. I think this weekend I'll try to get the screw bits stuck in the case out with a really small drill, and maybe make the holes a little bit bigger, tap them, and try the stud idea again. Does this sound reasonable to any of you? Should I just give up and buy a new case?

I know all of the above was basically a tutorial in "what not to do with an engine", but I do want to hear what you guys think.

Carnie · Post by **Carnie** » Fri Feb 03, 2012 12:02 am

Postings pics is always a must for the most helpful and accurate replies.

Bear45-70 · Post by **Bear45-70** » Fri Feb 03, 2012 2:13 am

Ever hear of the term "a learning experience"? You never forget them.

Wheelman-111 · Post by **Wheelman-111** » Fri Feb 03, 2012 2:18 am

Greetings:

Agreed that pics would help.

First removal of broken head bolts from crankcase might require some Skee-yulls,and perhaps a Left-handed drill bit from a Specialty Tool store.
Punch with a pointed drift dead center on the remnants to keep the drill from skating, then drill away in Reverse. The end of the screw may spin out without additional action.

If not, insert Easy-Out tool and extract.

If the case threads are intact, new head bolts should thread right in. If not, thread inserts need to be installed. Stock head bolts (or studs) are 6mm.

If broken head bolts are to be avoided, get a Torque Wrench. Most of this stuff can be Googled for sources. The know-how to use them comes with Practice.

guen84 · Post by **guen84** » Fri Feb 03, 2012 8:47 am

put some penetrating oil on there. center punch then start w/ 1/16th drill pit and work your way up next 1/8 so and so on till you can get the proper easy out in there.. use a SHORT WHRENCH with easy out, they are easy to break. try a thread chaser, if not got some heli coils and retap larger. red locktite the coils in and done.. either way never a easy task might want to take to a machine shop save the headache and it might not cost much more than all the new stuff you may have to buy. after removal is done id make sure you clean the block out really good. not sure if them bolt holes go all the way thru the case.

basically what wheelman said with my extra 2 cents

jrmints · Post by **jrmints** » Fri Feb 03, 2012 8:49 am

Thanks for the input, everyone!

Here's a photo of one of the, er, problems. They all pretty much look like this

[edit: holy giant picture, batman]

And yeah, I do plan to open up the case to clean out all of the metal shavings.

reynoldston · Post by **reynoldston** » Fri Feb 03, 2012 10:11 am

It sure sounds like a mess to me. The part that sounds bad is the holes are full of screw parts. I don't know what kind of screws you are talking about but you will find that some self taping screws are harden. Now you have harden screws into aluminum. I don't have any idea how you would drill out something like that and I would make a bet a machine shop wouldn't touch it.

bakaracer · Post by **bakaracer** » Fri Feb 03, 2012 10:14 am

Yeah open the case up first,then use a small drill bit and smal easy out to try and get that out. If not you will have to drill it out by going 1 size up at a time on the drill bit till its out and helicoil it

guen84 · Post by **guen84** » Fri Feb 03, 2012 10:48 am

if you open the case up, some times you get lucky and when you are drilling the bolt threads out the back side..

dem0nk1d · Post by **dem0nk1d** » Fri Feb 03, 2012 12:35 pm

You're doing it wrong!

Here is my advice get someone to weld a steal nut over that busted head bolt. This will heat up the aluminum block, causing everything to expand which may loosen up the bolt just a tad, and once the nut is welded on it and cooled for a few mins. Bust it off.

No drilling, no mess. Since the block is aluminum you don't have to worry about it getting welded to the steel welding wire and steel nut.

Check my post a few years back... Tons of info. I would drill as a last resort.
http://www.hondaspree.net/phpBB3/viewto ... =1&t=12621

Bear45-70 · Post by **Bear45-70** » Fri Feb 03, 2012 12:45 pm

dem0nk1d wrote:You're doing it wrong!

Here is my advice get someone to weld a steal nut over that busted head bolt. This will heat up the aluminum block, causing everything to expand which may loosen up the bolt just a tad, and once the nut is welded on it and cooled for a few mins. Bust it off.

No drilling, no mess. Since the block is aluminum you don't have to worry about it getting welded to the steel welding wire and steel nut.

Check my post a few years back... Tons of info. I would drill as a last resort.
http://www.hondaspree.net/phpBB3/viewto ... =1&t=12621

Not everyone has easy access to a welder.

dem0nk1d · Post by **dem0nk1d** » Fri Feb 03, 2012 12:52 pm

Bear, this is true but there is always your local muff shop. Not talking strip clubs. Hmmmm then again "stripped bolts, and muff shops." the mind wonders.

The last time this happened to that's what i did. Cost me 5 bucks

speedy25 · Post by **speedy25** » Sat Feb 04, 2012 9:48 pm

From the picture you have two choices. New cases, or a LOT of work to repair the old ones. Besides your mess with the seized fasteners, you have also made a complete mess of the base gasket sealing surface. Your only recourse for repair is to remove the steel and have the cases welded, re-drilled and the gasket area resurfaced.

Either job will require complete disassembly of the cases.

Another used engine may be more economic in the long run.

-SP

Trafficjamz · Post by **Trafficjamz** » Sun Feb 05, 2012 1:12 am

speedy25 wrote:
Another used engine may be more economic in the long run.

-SP

I have a few extra spree cases if you wanna buy a new one.

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