TOPIC: Tower Of Power Rebuild

I have a 90hp 1978 tower of power that I am rebuilding , had low compression in one cylinder ,rings were stuck . Replacing all six sets of rings and honed the cylinders all still in tolerance . My question is there a way to install the pistons back into the block with out having the six special clamps?

Can be done but you will swear for an hour and not repeat yourself. Especially if you bust a ring and not know it!! Best is to take it to a dealer mechanic who has the compressors and offer him a case of beer to drop the crank in for you, most will be only too glad to do so. Pick a hot day and chill the beer first.

thanks for the advice , that's what I was thinking on doing.

Conrad (Milkdud) did an excellent tutorial (posted here somewhere) on this subject a while back, I can't imagine trying it without the proper ring compressors!

Found it! www.fiberglassics.com/glassic-forums/home/mercury-outpost/inline-6-piston-install-video#103696

Hi,
I finally got a set on ebayba few years ago but here is what I used to do, "a poor mans set up"
Get a standard adjustable ring compressor for a 4 inch auto size bore. Take it apart, you will cut the band into 1 inch wide and 1 to 1 1/2 inch long strips. You will need 12 pieces DEBURR the cut edges till smooth. The 1 1/2 direction should be in the curved direction of the band to help conform around the piston.
Using a hose clamp, clamp down two strips placed around the piston rings but not covering the rings above the piston pins, use plenty of two cycle oil this will help a lot to jiggle everything into position. Make sure ring gaps line up with the pins in the ring grooves. I usually have the top edge of the strips even with the top of the piston and center the hose clamp so some of the strip is showing above and below the clamp band. I tighten the clamp till the strips are tight on the skirt so the ring edge dia are now in line wth the skirt dia. Now lastly I take zip ties and apply them above and below the hose clamp, have the zip clamp portion in line with the piston pins, but opposed to each other. Do all 6 cyls this way and carefully remove the hose clamps so the zip ties are keeping the strips in place to compress the rings. There is a slight loss in compression of the rings which is fine, it helps when sliding the piston down through this home made clamp. Please note the taper of the bore helps guide and transition the compressed rings AND the strips to the bores when the time comes. You will find the strips want to lock into the bore just at the taper which helps a lot in aligning as you are sliding the Pistons down. Now you can start to jiggle the assembly down into the block like the book tells you and cut the zip ties as you go along.
It's still quite a fiddle, oil helps. There is a sweet spot in the initial compression of the rings, enough to get them to slide into the taper but not so much they really clamp the skirt. Check for a broken ring per book and be gentle things should slide in with a little pressure and wiggling any real force probably means a ring is hung up on the leading edge of the taper and you risk breaking one.
Also before starting de burr your inside port edges so a ring doesn't catch a burr there. I use my finger and a small piece of 320. Wash completely.
Good luck!!!
Randy

Thanks Randy your way seems to sound pretty good . I had already rolled one inch strips of .040 stainless steel at work and I was going to try with hose clamps but your way with the zip ties and 1 1/2in. lengths sound like I will give it a try .
Thanks

We wait with bated breath for your results.

Even with the correct tools, this is a critical procedure that leaves no room for error. Even armed with the correct ring compressors you won't know something is amiss until it is too late.
I wish you were closer. I'd help you out.
doc

on first attempt got the first 4 pistons in then popped the bands on the last 2 , had to take it back apart to reband , will try again tomorrow. Checked with a couple local marinas and nobody has the clamps , one had three clamps but did not want to take it on .

Second attempt went smoother than butter. If somebody was to try this I would recommend a dry run with old rings so you get everything right when you use new parts.
Things I learned
1.use a good lube I mixed alittle STP with 2cyl oil
2.coat pistons and bands with lots of oil
3.be sure zip ties are positioned to go into the block where the clearance for clamps is.
4.make sure piston one is bottom dead center
5.take your time do not rush
6.as the rings go into the cylinders cut the bands and remove the bands keep count as not to leave any in block
7. check through ports to make sure they all have spring.

Good job !!!!

Nicely done, but if you are going to do more of this sort of thing than I suggest you try and score a set of compressors.

Very cool!!
I've never tried it this way, but you sure make it look slick and easy!
Thanks for posting!
doc

Thanks Doc , Got the block all back together everything torqued and ready to bolt to the lower .Almost time to go to the cottage for three weeks so work will come to a halt . But time to play with the last two winter projects . Once back will bring the 65 G3 into the garage and get started on it. Will be looking for a rebuildable another bigger tower to rebuild . Thanks for the help.

Awesome job, I'll have to remember that for the 800FGS when it's time.

Bob