Pinky II

[algirdas]

Dear Geoff:

I think Robie the Robot is correct on this one. In torquing bolts, you should not put the torque wrench back on to "check" to see if it is properly torqued. I was taught that if you were not sure if you torqued the head properly, that you should loosen the head bolts half a turn and then come up onto the torque setting in 5 lbs increments (i.e. 65 lbs., 70 lbs., 75 lbs. and finally 80 lbs.) and being sure to follow the torque pattern.

If the head bolt is properly torqued at, say, 80 lbs., your hitting it again with a torque wrench set at 80 lbs. will result in it being torqued to more than 80 lbs. Perhaps not much more, but nevertheless more than 80 lbs.

I would also check the holes in the block that the head bolts thread into. Often times, when you yank the head, coolant, oil and other crap fall into those holes and fill them up. Then when you lubricate the threads on the head bolt, it simply adds to the potential for hydraulic lock. I blow them out with compressed air and then clean them well with brake cleaner and long cotton swabs. If the engine is out of the car, I turn it upside down and clean them out in that position.

Sincerely,

Algirdas

[Doc Fizzix]

when I discussed this same issue with Robie he was telling me that he would crack them loose and then re-torque, I do not have the balls to do that

I am no engine guru, but that has got to be wrong. There's no way it could get tighter on its own--only looser. Thus you only need to check the torque wrench on it to be sure it's tight. And the reason why is how the bolts are designed to stretch just a tad, and usually only supposed to stretch ONCE and if you retorque them they can break. Just blabbering anyway . . . .

Doug, Im with ya

I guess my wording did not translate correctly. What I was trying to say was that I agree with you and I would never try to "bust loose" an already torqued head bolt. I don't think Robie was saying that the bolts get tighter, what he said to me on the phone was that he likes to back them off a bit and then reset them (scary stuff). Like I said in my posting, I do not have the "balls" to do that. I was always taught that you should check to see that they are tight but NOT loosen and then re-tighten. I agree with you Doug but I was posting the question only because I wanted to make sure I was not missing something since what Robie told me sounded strange.

[Doug]

not trying to start any pissing, just throwing in the caution flag.

you have to take into account the type of head, type of bolt, etc. With all the boost we push, our engines go way over 10:1 compression--can't remember the last time I calculated the compression ratio with 15lb boost it was 12 or 13:1

why not email Hethel and ask them about what they recommend on their bolts and engines??

[GeoffSmith]

Algirdas, at least we agree about hydraulic lock but I would never slacken off a head bolt, especially after running the engine for any length of time.

Don't forget that torquing a bolt is a pretty crude method anyway and that if your wrench releases at a given torque, it shouldn't turn the bolt, no matter how many times you do it.

Monty, you couldn't have misread your torque wrench could you, and applied 58N.m instead of 58lb.ft? That could explain your extra ¼ turn.

Geoff

[Monty]

Monty, you couldn't have misread your torque wrench could you, and applied 58N.m instead of 58lb.ft? That could explain your extra ¼ turn.

Geoff

Nope, and it was Nm`s i used

[Doc Fizzix]

Monty

If you have the bolts out, can you tell if they stretched? I have a couple new ones around that I can measure, try to measure the length of one of yours and we will compare. I am thinking maybe your bolts have stretched

[Dico]

Nearly £70 for a set of bolts from Lotus. Thats just a joke!

[Doug]

Nearly £70 for a set of bolts from Lotus. Thats just a joke!

well, the you'd feel good buying some ARP bolts for less . . .

just gotta figure out the specs on them and order up.

[Monty]

Monty

If you have the bolts out, can you tell if they stretched? I have a couple new ones around that I can measure, try to measure the length of one of yours and we will compare. I am thinking maybe your bolts have stretched

Doc, thats a good idea. i`ll have the head bolts out tomorrow. PM me u`r measurements when u get chance and i will compare.

Cheers
Jay

[Doug]

better use some digital calipers or your measurement error may be more than the stretch

[algirdas]

Dear Doug:

Or a bolt stretch gauge if you can get one long enough for a head bolt.

Rule of thumb on a rod bolt is .001 inch of stretch and into the waste heap it goes. Not sure if the same applies to head bolts because of the lack of oscillating stresses.

Sincerely,

Algirdas

[Monty]

Got the head of today and the gasket is knackered
I assume the damaged was caused by gasket compressing and the head bolts becoming lose so the gasket wasn`t sealed and the combustion gases getting in between and doing the damage.

The question is have the bolts stretched, but the manual has no mention of replacing them or what type of bolt they are
Head bolts from SJ`s

CYLINDER HEAD BOLT A100E6189S EACH 5.04

Need 10, = £50.40 + vat= £59.22 + postage

The head is going of to be pressure tested and skimmed on monday, just hope the head is fine.

Edited:
Next door neighbour works on aircraft and measured the bolts for me with digital calipers:-
Bolt length 101.55mm (not including the head), but was difficult to get an accurate measurement as the end of the bolt isn`t flat.
Bolt length up to the the 1st faint thread mark 74.27mm. (not including the head)
Full bolt 113.9mm including the head.
There was very little difference in the shaft diameter.

[chris.t]

Thats in a shocking state monty its gone all over the place

[GeoffSmith]

Thats in a shocking state monty its gone all over the place

Told you it would be a big hole! I think that, for whatever reason, all the bolts have been undertorqued. I think it highlights the importance of re-checking after warming up and after a few hundred miles; I always do the former but usually forget the latter.

[ESM]

Sorry to hear about all this misfortune Monty

I too have a kmckmc set that I'm looking at slightly nervously now...

[kmckmc]

Hi guys,

I follow this thread closely as I also fitted the "kmckmc" head gasket. My engine is working fine for the past 2500+ km.

Is what Monty facing a head gasket related problem or cylinder head bolts related one? I do not know much about engine. Please advise.

I know I have been distributing those gasket sets for some time. I thought they are made with good quality materials at a reasonable price. The vendor will remove that washer/insert on the head gasket before he packages the gasket sets in the future. He was surprised to learn about that washer/insert issue from me as he had sold many many sets to Japan and Africa. Please comment so that I could give end-users feedback to the vendor.


Cheers,

[Monty]

Micheal,

Not 100% sure, but think it`s more down to not re-checking the headbolts after use (even thou i went by the manual) and maybe the gasket u supply compress more than the lotus/isuzu type

Yourself and DaPinky have fitted this gasket and had no problems, i did 250 miles and it was fine until the trackday

[Doc Fizzix]

Micheal,

Not 100% sure, but think it's more down to not re-checking the headbolts after use (even thou i went by the manual) and maybe the gasket u supply compress more than the lotus/isuzu type

Yourself and DaPinky have fitted this gasket and had no problems, i did 250 miles and it was fine until the trackday

The answer will come down the line from what happens with other who use the kmckmc gasket. If they have the same problem then I think the gasket is the problem, if not, Monty needs a new torque wrench, I am betting on the later

[Doug]

yes, get new studs and nuts and torque wrench and don't drink until after you're done

[chris.t]

Monty would it possible to check you're wrench against some others to see if it is torquing correctly? That would at least rule out or confirm one of the possibilities.