: Big Serts installation



roebigd
03-14-06, 10:14 AM
I am currently repairing a northstar engine for a customer that the original inserts have pulled out of.
I ordered the Big Sert Kit to repair this block , Has anyone epoxied the Big Serts into place instead of using the loctite?
I am thinking this may lock the big serts in better and take up any extra space around the threads and save the block
Any ideas ?
Thanks Dennis

Ranger
03-14-06, 10:54 AM
I have never done it but FWIW, I would not do anything not recommended by the FSM. Never heard of a timsert pulling unless it was not installed properly. I'd install as recommended. Just my $0.02.

zonie77
03-14-06, 11:34 AM
I'd run it by timesert.

The loctite acts almost like superglue. There have been 1 or maybe 2 times someone said the timesert didn't hold and they thought the metal in the block was the problem. Apparently the timesert had metal stuck to it. This would seem that either the block wasn't totally cleaned, the loctite wasn't applied evenly, or the block really had a bad spot. There was a request to watch the shavings as you drilled/tapped the heads for differences. This is going back aways.

What did you see with the old timeserts? Metal stuck to them or just loose? If loose I'd wonder how good a job of cleaning the threads was done.

sts96
03-15-06, 03:23 PM
I have pulled timeserts out on 2 N* blocks the metal came out on the outside threads of the timeserts. followed the directions to the letter. have not tried big serts as the cost of big serts was to high to take the chance of another pull out replaced both engines with used ones they are running GREAT. also gave me lots of extra parts. 1 engine was 2000. the other was1500 both without exchange
sts96

zonie77
03-15-06, 03:56 PM
sts96, you might be one I was thinking of.

chevelle
03-17-06, 02:21 PM
I am currently repairing a northstar engine for a customer that the original inserts have pulled out of.
I ordered the Big Sert Kit to repair this block , Has anyone epoxied the Big Serts into place instead of using the loctite?
I am thinking this may lock the big serts in better and take up any extra space around the threads and save the block
Any ideas ?
Thanks Dennis

Use the bigserts and forget the epoxy. The loctite helps prevent the bigsert from unscrewing itself out of the block if the head bolts are ever removed again but really doesn't add any strength to the joint. There isn't any epoxy on this planet that is strong enough to influence the strength of the bigsert in the block material. Waste of time and money to try it.

The only timeserts that I have seen "pull out" of a block were either incorrectly installed or were the standard length timeserts...not the longer timeserts specifically for the Northstar. The longer timeserts made specifically for the Northstar head bolts MUST be used as well as the special installation kit for those inserts. Many people see "timesert" and assume that they are all the same. Or, they try to cut costs by using the standard timesert kit, not the one for the Northstar head bolts specifically. Those would not pull out in my experience....especially twice for one person in two different engines. I have also seen several cases of helicoils pulling out from a previous repair. Helicoils are NOT strong enough for this joint and are a guranteed failure. People see the helicoil pull out, assume they are the "same" as the special timeserts and figure that the joint is not repairable.

There are specific bigserts for the Northstar head bolt joint as well. Make sure and use those as they are longer than the conventional bigserts that timesert markets.

sts96
03-18-06, 08:49 AM
I can verify that the correct timeserts installed by timeserts directions will pull out of a soft block. in my case it was only 1 insert in each block as good as timeserts are they will not hold in severely overheated blocks. I have used timeserts on main bearing and other repairs with no problem and like the product but good as they are I found 2 engines abused beyond repair this was not a fault of timesert which is a top quality tool. the question should be
how badly has the engine been overheated and for how long the driver ( not the owner) drove the car 70-80 miles 4 times after the dic said shut down for overheat then returned the car and said it had a problem. sts96

chevelle
03-18-06, 02:02 PM
Did you install the timeserts that you observed "pull out"....??...so that you KNOW they were installed correctly and such?

I have seen correctly installed timeserts withstand some incredible loads without pulling out of the Northstar block. I would suspect that if one pulls out that there was something to do with the intallation of the insert or the installation of the head bolt during the repair.

Zorb750
03-18-06, 04:52 PM
You ALWAYS timesert all bolts.

sts96
03-18-06, 08:07 PM
Yes I installed the timeserts with a brand new n* kit.The serts that pulled came out with the outside threads full of block they gave on the next to last tightening pass, any n* head bolt is under high stress when tight. if you feel a little funny give on the last pass or so you may have a pulled unit it will fail the gasket later. I think this is a block problem, not sure if a bigsert will repair it. sts96

parts68
03-19-06, 09:08 PM
I have not done this but just wonder why head bolt studs wouldnt be better.
When using a stud it is installed at normal torque and the threads on upper end are the threads that take all the abuse of torquing.

Zorb750
03-19-06, 09:28 PM
You're still putting force against the threads. The twisting of them is nothing of consequence. Anyway, how do you know how much to tighten them?

Ranger
03-19-06, 10:04 PM
I have not done this but just wonder why head bolt studs wouldnt be better.
When using a stud it is installed at normal torque and the threads on upper end are the threads that take all the abuse of torquing.
That battle has been fought before and it was a doosey. :want:

Loose screw
03-20-06, 01:53 AM
Epoxy is great stuff especially steal filled slow cure epoxy - very strong but give it a surface it can interlock into like a threaded hole not just a smooth hole. But it has it's limits. I have used it a on several head bolt thrads that have stripped out but drilling out most of the damage metal and cutting shallow new threads into the block and then epoxy in a stud instead of a bolt - it does work and it does last. These were not northstar engines.

The problem using epoxy is that it is much thicker than red lock tite and doesn't want to stay in the threads during assembly. You have to apply a thin coat to both threads but even then if you have a good tight fit without extra clearance any epoxy used must be a freshly manufactured batch and the long setting type to assure it is thin. I use a steal filled epoxy to help repair a damaged northstar main bearing thread hole that the Time-sert fit was way too loosely. But I wouldn't recomend epoxy for a normal fitting sert - there clearance is a little tight for that and the epoxy can end up pushed or scraped out at the bottom or all out the top and not in between the messing threads where is can do some good. If you do try epoxy there is one other problem to consider that I experienced. The smart boy at Time-sert have a very fine product and it works well. But the installing tool is designed to do two jobs in one. It must screw the sert in and after that expand the bottom of the sert. The sert install tool fits into the sert and will apply a turning force to the sert while you install it only up to a ceratin point (it is designed to stop turning the sert once the sert has been screwed in and doesn't want to turn any more because it has contacted the seat created by the step drill bit) once it become harder for the install tool to screw the sert in, it will instead screw it self into the sert (as designed) and out the bottom, expand the bottom end of the sert into the threads of the block binding it in. If the epoxy or any other material or problem occurs that causes too much resistances for the sert to screw into the block easily the insert tool will start to screw into the sert and start to expand it creating even more resistance and the problem get worse and worse with the end result of the sert not being all the way in - not good!

To solve this problem you can take a spare sert and grind the bottom off a few threads (I can't remember how much) and screw it on the install tool upside down and let it act as a stop. Apply a little grease to the contacting lips of both serts so they will seperate from each other easily when you back the tool out. Then screw the sert on the tool (the sert acting as a stop should only let the sert to be installed screw on the tool half way) then you can install the sert until it seats and back out the tool. Then hold the "stop sert" with plyers (you don't care about those threads) and unscrew it off. You then take the install tool without the stop sert on it add a drop of oil to the bottom few threads and screw it in until it goes through the bottom of the sert in the block and finish the second step by expanding bottom into the threads of the block.

Always make sure the bottom of the hole is empty (blow and flush out if necessary) otherwise you wil cause a hydrolic pressure that can crack the block. Installing a sert does not take a lot of force!

I would prefer Time-sert to supply two tools instead of the 2 in 1 install tool and make the sert fit just a little tighter. But I understand their reasons and appreciate their quality control that makes it possible. But there is one compromise in doing so I have noticed from doing all the head bolt threads and all the mains (and that is alot of serts) on one very sick engine - the clearance between the sert and the newly cut threads in the block are not as close as I would like. The reason is as I stated above that no extra resistance can occure for the install tool to work right. And as the serts are very long and not polished smooth the fit could not be very tight as any imperfection would cause the sert to jam and result in an improper install.

I should mention even though I had a very sick engine and had to do several unconventional things, all the sert have held well for almost a year of very fun everyday frequent full throttle driving :thumbsup:

I would save epoxy for large clearances fills and repair - use a metal filled slow cure epoxy they are stronger and easier to work with. You can speed the cure but slightly warming it.

But I would recomend instead of using the red locktite (which is a great product for tight clearances threads) another product may be even better for the long slightly looser fit of the time-serts for the northstar. Permatex make a product called "Bearing Mount" #20297 used to lock bearings shaft that have become worn, it is strong stuff and fill gaps 0.005 to 0.020 in fully curse in 2 hours and is good to +300f it is thin enough to get it into and stay in the small gaps but will also fill and strengthen the bigger gaps. It is a Methacrylate Ester. On other nut and bolt with tight fits I use the locktite.