Fresh 260 (Low Compression)

[Johnfoister]

Hi guys. I am new to these boards and have been reading and see that you all are a wealth of information. I am an Independent Auto Repair shop owner. My 87 2.4 efi <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-comhttp://forums.screamandfly.com/forums/ /><st1:City w:st=bridgeport</st1:City> bass motor blew head gasket and eroded away top of cylinder. I got on here and began looking for a 2.5 260 to buy. Found one in <st1:State w:st="on">New Jersey</st1:State> that had a fresh rebuild and never fired. Drove to Jersey from <st1:City w:st="on">Cincinnati</st1:City>. Went to check compression and starter was bad, pulled heads and everything looked good. Owner had receipts for new pistons from Jay Smith (top pinned and teflon coated, light wrist pins), Jim Ruck 2 new sleeves with block decked, and receipts for crank work from the folks in CA. Had receipts from local guy for the rings, bearings gaskets and labor for rebuilding. I pay the owner and drive home. When I get home I put heads back on and replace starter. Compression test shows 100lbs on all 6 cylinders. I plan to do a leak down and see if there is ring leakage, but I doubt it would have same ring leakage on all six cylinders. Mechanic who assembled noted on repair bill that he set ring end gap.
I have tried two different compression gauges and made sure battery charged and cranking speed was correct. I opened butterfly and made little difference.
What is normal compression on a stock 260?
I plan to use motor on my same bass boat for fishing that I had my 2.4 bp on.
Any ideas will be greatly appreciated.

[Johnfoister]

I also sqiurted some oil in each cylinder with no real improvement in readings. ????

[Greg Moss]

Check compression after it's been run. Compression depends on which heads that are on it. After it's run and seats the rings it should come up. The lowest compression heads should be around 130 - 135.

[Greg Moss]

I would ever file the ends of the rings on a 2 stoke because it tightens the fit on the locator pin causing problems.

[YELLOWSS]

brand new rings will have more comp than that right away. did you put new head gaskets on? ring end gaps should be checked. wizards are on the money. never seen a bad set from them. make sure the comp gauge is sealing against the head. i have seen that give a low number. i live in cincy where exactly are you located at?

roy

[HStream1]

Fire that puppy up and let it idle on and off for about 1 1/2 hrs Lightly cracking the throttle ocassionally to help seat the rings. Monitor everything for the first 15 minutes or so Water pressure, temp etc. After the first 15 pull the plugs and do a inspect. If everything looks good fire it up again.That compression should come up once the block heats up and the rings have seated. Use conventional 2 stroke oil for break in (no synthetic). Keep us posted & good Luck!!:thumbsup:

[tlwjkw]

What kinda rings are they? Were they made for tha top pin or did "HE" make 'em fit tha top pin?.............Should make more than that even never fired.

[Johnfoister]

My auto repair shop is Johns Auto Service in Fairfield. My cell number is 513-314-6762. My experience tells me there should not be much if any increase in compression after running engine if everything is correct to start with.
I have tried to reach the gentleman that did the teardown and assembly, but he runs a Marine business in Jersey and is very busy with Memorial Day approaching. You guys on the east coast may know of him, it is George at Fuller's Marine and Machine.
The pistons came from Jay Smith but the rings I can't find on any invoices. Do pistons from Jay come with rings? They were purchased on 08/08/2007. No part number, just says "set of JSRE racing pistons". I know the date on this purchase is 2 years ago. The seller said engine went down in 2006 and he collected parts for the next year and engine was assembled in 2008 and then just sat in his garge till now. In 2008 did Jay sell wizard or wiseco racing pistons?
Roy, I can see top ring end gap and looks about right. Thanks for your thoughts guys, I am real interested as a tech to find out whats up with this.

[captglm]

If its a brand new rebuild with no break in or hours on it follow HStream1 advice. let the rings seat! then check compression and leak down.

[TheRickster]

Stock heads on a 260 will put cranking compression at sea level around 130ish.. What is the altitude where you are?

Rick

[HStream1]

Try what I suggested. If Things don't come into play then I would Seriousely question the rebuild.:confused:

[olmo40]

Leakdown % is the only way to be sure sure .Considering the compression all the same ,you may need to cc the heads and check the gaskets , as a starting point .What everyone above has said is good advice .

[Jay Smith]

I've sold Wizards for years and the set comes with TiN coated or Chrome faced rings. A stock 2.5 260 has 130 ish if healthy. If the guy is having to file the the end gaps something is weird. With a 3 .500" bore the end gap on a known new Wizard ring is .016" -.018" ....The only reason a ring end gap must be altered is if the bore is too tight... A top pin type piston ring can be filed with no ill effects to the engine.Again if the bores were stock they would be Nicom /Nik and would be at 3.500" or BIGGER due to wear , this would make the end gap wider than our speck. I find for every .001" a ring end gap is too large equals to the bore size being 3.14 thousanths or Pi larger than standard......100 lbs cranking is way to low UNLESS this motor has 41 cc heads which it could very well have. 2.5 have several vintage heads ( CC's ) from 37- 41 CC your motor might have a set of 41 cc heads and that might be the low compression issue...

Good luck,
Jay

[tlwjkw]

THATS why I ask about tha rings. even 41's are gonna be more than a hundred..........

[mercace]

We assembled the engine over 15 months ago. The pistons came from Jay ( wizards ) and everything the owner told you was true. We used every thing that was supplied by the owner. The heads where not cc'ed by us.The ring end gaps where @.018 when installed. The head gaskets where off the 2.5 champ engine as told to use by Jim Ruck. The customer took the powerhead to install on the boat. He made several appointments to have the timing set, engine fired up, broke in and dynoed. None of the appointments where kept. We usually never let an engine leave without beeing checked. If the engine does not have proper compression and leakdown, we would find the problem and repair it. It is not uncommon for us to pull the heads and tweak the cylinder bores to improve leakdown. I would run the engine to seat the rings and recheck. If compression does not improve, I will cc your heads and correct it for you. Sorry for not getting to you on the phone, but we have well over 200 boats to commision this time of year. Thanks George Fuller

[YELLOWSS]

he is about 600' above sea level. who knows what heads are on it now. pull them and cc them. does the hone job look great and new?????

[Johnfoister]

George, thanks for your reply. I am a very meticulous individual like yourself and others. I am just alittle anixous to get back to doing some fishing. But something is amiss with the compression and I needed some information to determine the proper direction to go. I was so impressed this evening when Jay Smith called me to offer any help he could give me over the phone. George, Jay said that the pistons the owner purchased could have had TiN coated or Chrome faced rings. I know it has been over a year ago that you did the work, but do you recall which rings were used? If they were TiN coated then maybe there is some ring leakage that will improve after running. I believe at this point I want to get the heads cc'ed and then I will know for sure how much compression to expect. I would like to call you when the Holiday is over and chat about the engine, let me know when a good time would be or just call me when you have time. 513-314-6762.

Thanks
John

[Johnfoister]

he is about 600' above sea level. who knows what heads are on it now. pull them and cc them. does the hone job look great and new?????

Yes, looks perfect. Just what you would expect from Jim Ruck.

[captglm]

Fire that thing up seat the rings and go fishing! I heard they was hittin spinner baits in the back of creeks at Alum Creek and 6 pound cove has fish near the back. try blue worms on the lay downs up river on Delaware reservoir, small crank bait are working on the drops in Deer Creek, the Ohio river on Pool #1 has fish in the mouth of the creeks on wood, Lake Erie has smallies around the rocks at bass island and off the shoals on the east side of puttin bay in 10' of water. Indian lake still has a few spawners in the canals, you can catch them on trick worms and sinko's. Try crank baits on the bluffs on the east side of the big O river near the Columbus zoo. Good luck

GM ><>

[mercace]

Hi John, I don't remember what rings are in it. Sorry. One more thing befoere you go out, Set the timing pointer and check the timing. As I said, He never brought it back to be checked and tuned. Have a great holiday weekend......George I don't think they where chrome rings the more I think about it.