7m issues... (owners fault)....

[Supraguy7M]

So I recently rebuilt my 7mgte top end. I didn't pull the motor put of the car, and I threw a metal gasket in it. The hks 1.2 mil gasket to b exact. I've got a lot of money into other parts in the car.. my chassis clean..

Anyways I took my car out for the first time the other day, and the temp came up a bit, quite a bit before red so I didn't worry. I thought it was air in the system. So I brought it home and parked it. Today I changed my thermostat just in case, and took it for a ride. I let it idle for probally 45 miniutes, and the temp didn't move one bit. So I took it for a ride down the road. Just cruising, I wanted to see what it was like in boost.(it never boosted the last time I drove it) it hit 10 psi off my 11psi wastegate, and the temp started coming up... Then it came back down a bit, and went up again...and this time hung out until it was about to hit red, and I shut it down.. brought it home, and there it sits..

Its only got 16mi on it since the rebuild.. I let it come up to temp, then I shut it down and let it cool the first run, so the gasket would seat.. could I have a tuning issue? Factory rad not big enough? Clutch fan seems to b doing just fine, or do I have to pull the head again and put my other composite head gasket in..? Any help would b nice.. thanks agian guys..

 

[3p141592654]

what prep work did you do on the block for the MLS gasket?

 

[Supraguy7M]

I cleaned it, made it shine. But never had it machined. Stupid question but the radiator being factory wouldn't do it would it? Im boosting more with the same amount of coolant flow as stock. I'm just grasping at straws here.

 

[Supraguy7M]

I dont think my gauge is accurate..

 

[Suprapowaz!(2)]

I didn't pull the motor put of the car, and I threw a metal gasket in it.

I cleaned it, made it shine. But never had it machined.

That may have something to do with your MLS not seating properly. Have you done a compression, leakdown, combustion leak detector test?

 

[Supraguy7M]

No I haven't. I don't lose any coolant. When it idles its 100% normal temp. My oil is clear, no milky residue. And my plugs are a lil on the black side.

 

[Supraguy7M]

I'm thinking it could b my stock single core radiator. It's fine at idle, until its under load, and the temp creeps up. It doesn't shoot up. If I back off on the throttle it won't cool, but it won't get any higher.

 

[Backlash2032]

No, its probably your mls gasket not sealing because you didn't do the proper prep work.

Sent from my HTC Droid DNA

 

[supraguy@aol]

If you lose absolutely no coolant, and it doesn't fill up the overflow bottle, you >might< have a cooling system issue.
I had temp spikes in the summer, any time i turned on the ac. It would run fine without. I upgraded the rad, and problem solved. Question- do you have the stock fan clutch? If so i would check it.

 

[JDMMA70]

My car did the exact same thing only I was pushing coolant into the overflow tank. Almost everyone here said BHG, me and Kai had a long think about it. Came to the conclusion my radiator was at fault. Replaced the radiator and boom problem solved. As far as prep work goes after reading Reg Reimers article on MHG it stated that as long as thr block surface was flat and verified (straight edge), then you could prep the surface via lapping. Anyways that's my. 02 cents.

 

[Supraguy7M]

I straight edged it with feeler gauges and it checked out. I'm not loosing coolant at all (check again later). I'm still running my stock rad/fan but I have no shrouds installed. None for the fan, or under the car. Not sure if that matters. I'm jut hoping its not the gasket, although I have a felpro head gasket if needed..

 

[Corkey723]

Try testing the radiator cap, could be an issue with it also. The shrouds will make a bit of a difference, but if its really hot out ~90, this could cause it to run a bit hot.

 

[supraguy@aol]

I would check under the oil cap to make sure that no coolant got into the oil, but again, i would check the fan clutch to make sure it works. No fan shroud would not cause overheating in an otherwise healthy cooling system, but if you had a marginal fan clutch or radiator, then it would exacerbate the heat exchange process to where it could be an issue.

 

[grimreaper]

was a machinist straight edge used? You wont find these on the shelf locally. $100 bucks or so online is the usual option.

Even the use of scotch bright and 2000+ sand paper will remove more than enough metal to waffle the deck. A lapping plate larger than the deck is the only option I would consider by hand.

True story, first machine shop I stopped by years back said a straight edge from the hardware store would work just fine. Old timer in the shop started ranting about using a fine grit sand paper to clean the surface before use and how everybody over pays etc.. I brought my machinist straight edge to compare to their hardware store special. Theirs looked like a noodle and fluctuated severally every few inches.. Worst part, they were using it as their shop straight edge!

 

[Dirgle]

I straight edged it with feeler gauges and it checked out. I'm not loosing coolant at all (check again later). I'm still running my stock rad/fan but I have no shrouds installed. None for the fan, or under the car. Not sure if that matters. I'm jut hoping its not the gasket, although I have a felpro head gasket if needed..

Look, the reason it's recommended that the block be removed to be machined in preparation for a MHG is for two reasons. To ensure a straight surface with a proper roughness average. Both are very important since the distance between cylinders is so small on the 7M. With so little material you need to give the gasket the best possible chance to seal. Keeping the surface straight and not microscopically uneven while polishing for the proper RA, while keeping polishing compound from getting down where it shouldn't be, while the engine is in the car is nearly impossible. Doing so will cause the engine's reliability to go down, while causing the likelihood of future(though possibly not immediate) BHG to go way up.

Then there is the peace of mind factor. Everytime the engine does something funny you're immediately going wonder if the lack of prep work finally caught up to you.

Now you have said that the issue was owners fault, and understand what you failed to do. But you are still trying to justify it by saying that this was ok and this is ok, so this could be ok. Even if it is ok now, at some point in the future it will not be. Not by any fault of the 7M but because the proper prep work was not performed.

To JDMMA70's point, people have gone the lapping block route with success. But you have to be meticulous in your perp work leading up to the lapping. And the you have to be even more cautious in your cleanup up the engine after the fact. I can think of very few ways to destroy bearings quicker than metal infused diamond lapping compound getting down to the oil pan. And after all that work it is almost simpler to take the block out and send it in.

To your original point, it may be a BHG or it may not. Honestly it's hard to confirm or deny based upon available info. Cooling system issue? possible, I've seen worn or shot radiator caps display similar symptoms. I've seen corroded gasket sealing surfaces at the radiator opening, make even brand new caps malfunction. BHG? also possible, and there are test to rule that out. There are a number of things it could be, so you need to start troubleshooting to narrow them down. Check the radiator cap, pressure test the cooling system, compression, leakdown, combustion leak detector test(as stated by suprapowaz!).

But even if you go through all this and determine that it is something other than a BHG and fix it, there is still the issue of peace of mind, which I consider to be invaluable. So if I were in your shoes I would start saving up to preform a proper build, with the proper machine work on the engine you have or a spare you can get.

 

[Supraguy7M]

I'll start troubleshooting :/ I had a feeling I should have done it right.. Not rush it.. But I rushed my build and potentially screwed myself. The piece of mind would b nice, and I wanna properly built motor, to make power, and b reliable. Which I should have thought about. Thanks everyone. If I figure it out and it happens to b my hg, could I use a composite gasket to finish out the season? (I need it as my daily for work, some asshole took out my truck)..

 

[Dirgle]

A good composite HG is very compliant, with proper torque values, and will probably last you for many many miles. I did 16psi daily for 40,000 miles without issue.

 

[Supraguy7M]

Well so far its not looking like a headgasket. It seems like a cooling system issue. Half my rad is ice cold after it has been sitting, while the other side is blistering hot. I'm not losing coolant. More trouble shooting to come though.

 

[7M4EVR]

I straight edged it with feeler gauges..

How does that work?

 

[Scooter7M]

Well so far its not looking like a headgasket. It seems like a cooling system issue. Half my rad is ice cold after it has been sitting, while the other side is blistering hot. I'm not losing coolant. More trouble shooting to come though.

Pull the radiator and flush it. What do you have to lose?