Blown Head Gasket on 440 EX

[iride440ex]

Hi all I am New here but had a question about a blown head gasket on my 440 EX. Did the gasket blow because of the head bolt threads being pulled or the bolt stretching I have heard many different stories and ended up ordering the stud bolts from TC racing and will be drilling and tapping my cylinder from 10mm to 12mm holes Tom at TC said the bolts won't stretch but the threads will pull.
Thanks
Tony

[MIKE400EX]

Was it a steel shim gasket or one of the composite type?

Welcome to EX Riders!!!:macho

[iride440ex]

It was a composite type gasket

[MIKE400EX]

Food for thought >>> Composite gaskets, like the Cometic ones, MUST be retorqued after a few complete heat cycles. It would also be wise to not load the motor hard before the head is retorqued. Not every composite gasket needs to be retorqued, but every one I know of for the 400EX does.

[buckeye400ex]

The guy that's doing my 440 (Treadway in Zanesville, Ohio) said that a lot of head gaskets blow because of the sleeve being improperly installed and slips below being level with the block.

Just one engine builder's opinion. Makes sense to me.

[Dune Surfer]

I asked a lot of engine builders when mine kept blowing. You are on the right track with the new studs. get a metal gasket and take it to 40lbs.

[TEAMPHIL]

I would recommend using a metal head gasket and torquing the head to the standard honda recommended torque 33lbs. Give sparks a call and ask for the XR400 gasket, its .025 instead of .030. We do several kits a month and haven't seen a blown head gasket yet with the stock studs.



2001 TRX400EX

JE 440 kit with .025 metal head gasket
Hot cam stage 2
Porting
CHM SYSTEM P4R exhaust
Dyno jet kit

[iride440ex]

I checked the sleeve and it is flush with the cylinder and I did order the metal head gasket hopefully I can get it put back together this weekend. It's a real bummer when you are running up china wall in Glamis and find out you blew a head gasket.
Thanks for all the info.
Tony

[MIKE400EX]

Teamphil, your shop is using OEM XR400 gaskets on a 440 bore? J/C
I recently took apart a 440 that the machine shop didn't even machine the top of the cylinder and sleeve flush. The shop told the owner that the oil leak was because he overheated it and cracked the head!:huh

[quadman21]

This is just my .02 cents worth, Did you have your cylinder decked? If you didn't than your not at a true 11:1 compression and there would be no reason your bolts would have stretched. I've been through the same scenario. I finally bought a new cylinder form honda and had the 440 sleeve installed before I put my studs in. I would remove the studs yourself and clean the threads thourohly before re-installing the studs. Some machinists don't clean up the threads as well as others. I have had no trouble since with my stock studs.

[TrX465]

just wait until u have to o-ring your cylinder head!!!!!!;)

[oynot400]

A steel head gasket should help you out. What compression are you running? I have a 463 (426 bore, stroked 6mm) :devil I am running 13:1 compression. Knock on wood but, I have not had a problem with head bolts. I talked with Mike at For Dirt Only. He says that when you put the head studs back in after the sleeve replacement. The manual is either wrong or it is confusing. What happens is the studs get over torqued and pull the treads out of the jug. :( Alumimuin and fine tread do not work well together when they are over tighten. It acts like a drill.
Over sized head bolts are not a bad idea, but putting in a Helicoil sould work also.
Good luck and welcome to the site.......:D

[Nate]

I don't know how you built your engine, but I have heard stories about people with 440's having trouble with the stock rod stretching and blowing head gaskets. Just something to keep in mind if you are running a stock rod.

[Sandragggen]

I had a problem with head gasket on my 14:1 465. Was planning to o ring but Sparks set me up with a shim gasket. Same type that they run on their Raptors. So far no problems.

[iride440ex]

Well I took the cylinder off to install the new bigger studs and found out that my piston is cracked (Wiseco 89mm 11:1) is there any pistons better than Wiseco? also does anybody have a good picture of there stock connecting rod/crank. I looked at mine and it looks like it got hot around were the rod connects to the crank (on the cast not the journal) but the rod is within specs no signs of heat stress on the rod. I thought maybe this was from being assembled at the factory. If not I guess I am going to have to replace the crank And it won't be stock. Does anybody have a price on a stroker crank with a better rod set up and were is the best place to buy one.
Thanks
Tony

[roostu]

You could get a ROSS piston. I have a few buddies with tehm and they havent had any problems with them. I woudl also have your studs checked, it is very common for them to get pulled out.

~Roost-U

Tony,

Dont get yourself too excited about a small discoloring on the crank, remember these things do heat up a lot, and hey your pistons cracked allready anyhow :)

I have had little to no problems with the cometic 3 piece metal gasket. The little is a very small leak on the side of the timming chain that doesnt appear to have any effect on the cyl pressure and is from a slightly off cyl face.

Make sure you check the mating parts of the cyl and head for any burrs or warping cause they just have to be 100% flat or the gaskets wont seal 100%.

I do understand your thinking into the new stroker crank and rod etc cause I have decided if I get even one little excuse I am gonna go that route also.


Hey its good to see some old faces here especially the ones (you know who you are lol) who helped me out last year with my 440 woes, now just what ever happened to Matt Fischer?

Oh yea the Ross pistons are as good or better than any so check them out.

Problem with a lot of the mfg's is they are not selling the needed bore sizes on the 440 to the public and are locked into the mail order people (This is why JE now suks).

Though I have used their two stroke pistons wiseco's four stroke piston just dont impress me. I may be biased in that most of the 440's pumping out 9:1 comp were wiseco's.

[MIKE400EX]

What part of the piston cracked? Assuming it was in the piston top, since you noticed it when replacing the head gasket, it could well have been due to detonation or preignition. That would also explain the blown head gasket. Good thing you found it before it was "fatal"!

[iride440ex]

I decided to pull the cylinder off to install the studs and saw the hair line crack on the skirt of the piston (intake side) Not on top, the bore looks good. So a little bit of blue color on the crank casting is ok? and where can I get a ross piston, I heard they were on back orderso it takes a while to get them. nobody has a pic of there stock crank? also I did buy the 3 piece stainless Cometic gasket to go back in.
Thanks Guy's
Tony

[MIKE400EX]

If the "blue" is somewhat around the crank pin (rod journal) area that's OK. I'm sure Honda heats them up to press the pin/crank together. Check the bore dimension, particularily at the bottom of the jug. Too much clearance there, or again preignition/detonation, can cause skirts to crack (piston skirts!).

[iride440ex]

Hey Thanks MIKE400EX I was kinda worried about the crank but like I said everything is tight and smooth on the rod, and I will Mic the bore to see if it is to tight. Were is the best place to get a Ross Piston?

[MIKE400EX]

You can get them directly from ROSS: rosspistons.com
I know their custom piston orders require a minimum of 4 pcs., but that shouldn't be a custom job. If you already decked the cylinder to raise/correct the c.r., you might want to just slap in another Wiseco. In order to not have a clearance issue, and/or too much compression. Pistons don't normally crack on the skirt unless they were subjected to abusive shock, in which case ANY brand would have probably failed.

[iride440ex]

I don't think the cylinder has been decked but I believe I have 52 thousandths clearance between piston and valves.

[MIKE400EX]

Thats not much at all. You wouldn't want to deck it if you only have .052" clearance now. How did you measure that anyhow?

[TIGER72]

WHO MAKES THE BEST METAL GASKETS, AND WHERE CAN I PURCHASE SOME? ALSO, I NEED TO KNOW WHICH BRAND OF HARDENED ROCKERS IS BEST.(?) I'M GETTING READY TO DO SOME MODS, AND THE INFORMATION IN THIS THREAD HAS HELPED ALREADY, THANKS!!!!

[iride440ex]

The guy that did the motor originally said thats what the clearance was I can't be sure, but I am building it this time.

[MIKE400EX]

IRIDE440EX,
Put the piston back on, without the rings, bolt the jug down (don't forget the base gasket, and measure the deck height. If it's around .030" then chances are the cylinder has not been decked to correct the compression ratio. Maybe just decked to give a good gasket seal. If it's around "0" or so, then it was decked, you will need to know this when ordering another piston, ie.... a J&E or Ross will probably not work (too far up or out of the bore). It doesn't make sense that you only have .052" piston to valve clearance with an "un-decked" Wiseco 440. If it's indeed true, I don't think you would have any/enough if you replaced the piston w/a Ross or J&E piece. That needs to be checked also. From what I gather, this only applies to WISECO 440's.
Good Luck!

and where can I get a ross piston, I heard they were on back orderso it takes a while to get them.

Ross like many other mfg's in this industry do sell direct, but unless you are looking at multiple pistons etc you would get a better price from C&D.

What I have done in the past is simply check all the numbers and if the mfg wasnt giving any great discounts I would just get it from the dealer (C&D) This way you can avoid multiple freight charges, save a few dollars and help out a small business by giving them your business etc.

There have been some instances where the mfg likes the big mail order dealers and sells a lot of their products thru WB or PU etc and there is an opportunity to save more than a few dollars buying these from the smaller dealer etc.

[TEAMPHIL]

mike400ex, we use a xr400 head gasket that has been bored to the 440 size. we use the xr400 gasket because it thinner. Give sparks a call or xr"s only. They should have them in stock.

Who's "boring" those gaskets :) :rolleyes: :devil

[MIKE400EX]

Interesting idea about the gaskets! I measured an OEM XR gasket and if you bored 4mm out of it, you'll be into the sealing ring!?! Oh well, if it works go for it! (But do check it first):confused2

[TEAMPHIL]

xr only and sparks racing offers metal head gaskets for the 440. Ask for the xr440 head gasket though, its thinner than the trx440. you can bore a stock gasket but i recommend going through sparks or xr's only. its faster and easier. It works great, no blown head gaskets in any of our installations.

Its starting to sound like the 3 piece cometic to me :confused:

[TEAMPHIL]

we've tried the cometic gaskets and they don't work. The sparks gasket is identical to the stock gasket but sized for the 440. Use this gasket torqued to the standard 33 ft lbs. and you won't have any problems. 5-6 440 kits a month and haven't had any problems yet.