what is the gasket compressed thickness? if it's .045 compressed x2 is .090, and then subtract .025 to get .065 total thickness... that'll lower the compression a bit I'd say.... personally, I'd see about getting a bigger starter for it..

 

I forgot to mention that we tried another starter with the same results and that is about the only starter available. All we can get is a regular head gasket and until the head is removed and the gasket thickness checked I don't know what the thickness will be, at .045 it looks as if you and I are thinking about the same thing however. I guess what I was really asking is would two head gaskets be OK from a reliability standpoint or would there be problems with them blowing out? Warping the head maybe?

 

Could you consider putting a compression release on the motor..We have them on the big singles that are used in motorcycle racing..without one your leg is just not strong enough to start one of those things..

Sam

 

maybe a battery with some higher cranking amps would help if there is room.... the compression relase is a good idea too if possible.

 

You can make a gasket from copper or aluminum sheet in the correct thickness if required, it will take some work with a drill and file to make a nice one. Glad to hear your helping a young rodder out, nice job!

 

Always heard that using two gaskets doesn't work but have never tired it. Is it using a 12 volt system? I think Interstate batteries used to sell an 8 volt battery for the old tractors etc and you could hook 2 together for 16 volts if there's room. I have a buddy that runs his old 6 volt Chevy pickup with a 12 volt battery. With a car you have to make sure you protect the gauges but the starter doesn't seem to mind it. 175 psi cranking. Wow, that's better than a lot of car engines lol

 

What do you think will, the double gasket work?

Doubling the gaskets isn't the best idea, IMHO. Possibly they're available in a variety of thicknesses.

You could use dead soft Cu stock to make up the difference of what was milled off of the head, along w/a standard gasket.

Brass shim stock is also available as is Al, but are somewhat stiff as compared to DS copper, so conforms less.

Don't hesitate to use some sealant between the shim surfaces.

 

Got into this thing today and the old gasket measures about .040, hard to tell exactly but that seems to be really close. I have the two gaskets and as of right now we probably will give that a shot because if one (or both) fails it will not be totally unexpected and we will just try something else. I am looking at just making a new gasket from the soft Copper of the right thickness, doesn't look hard to do at all. I found the Copper sheet in various thicknesses at Enco so it would just be a matter of determining what thickness we will need.

Thanks everyone for the thoughts on this.

 

What gauge are the starter cables? I'm thinking 6 gauge at best. With that compression you might just try a heavy gauge jumper cable set to see if it cranks over then. I would suggest using at least 4 gauge cable if it does.

 

Boosting the volts just a little bit will certainly help. Put a battery charger set on "boost" on it and try cranking it. Bet that will whirl it over pretty good. Also if its just the head you milled, you could just get another head. I've found OHC honda heads on ebay for 30 or 40 dollars, briggs is probably similar. Might be better than trying to mess around with the old one trying to get something to work.

 

Two head gaskets will work as long as they are not composite gaskets, they must be solid copper or aluminum. You could also get the starter rewired to handle the higher compression.

Vince

 

Well as the old saying goes "back to the drawing board" We already have a gasket failure with less than 1 hour on the engine (they were composite gaskets). At this point the Copper gasket will probably be the way to go however while I had the head off I thought about checking the volume of the chamber and the cylinder at TDC, which actually looks to be zero at TDC with what appears to be nearly a zero deck height, to determine the compression ratio. After doing that I could mill out some excess material in the chamber maybe and drop the compression down to a normal level with just a regular gasket, maybe anyway?

 

possibly... cylinder heads arn't expensive tho.

 

When I was a kid I milled my cart engine's head an unknown amount. It was plenty though, I discovered that the valves were hitting the head( side valve of course). I remedied it by machining pockets above the valves. I might suggest this to lower compression some...it might help flow as well. Flat head Fords benefit from similar machining as well as relieveing the block. Relieveing it would also help lower compression. I would avoid 2 head gaskets, it gives one more area for leakage.

 

Unless I'm mistaken, the engine in question is an OHV.

I believe a soft Cu shim gasket along w/an OEM composite gasket would be the way to go, but maybe machining the combustion chamber is easier for you.

 

Yes it is an OHV, I don't have it torn back down yet but I plan to take a serious look at removing material from the Combustion chamber.

 

Yes it is an OHV, I don't have it torn back down yet but I plan to take a serious look at removing material from the Combustion chamber.

My mistake, but the comments about 2 head gaskets is still the same. Removing combustion chamber material is a good way to aproach it, also if the piston has enough head thickness a little there would help too. I doubt that you would have too take much. If the cylinder is removable, an extra gasket or spacer under it would accomplish a similar reduction..Most industrial engines have little or no advancing of the ignition, so it probably has most of the advance on full time. If the reduction of material in the conbustion chamber doesn't help, you might consider an initial retard device that you can switch over after it lights.

 

Yes it is an OHV, I don't have it torn back down yet but I plan to take a serious look at removing material from the Combustion chamber.

What (if anything) did you do to compensate for the change in the valve train geometry when you milled the head initially?

I know there are different p-rods available for some of the Briggs engines, but the one you have- I'm not too sure.

Getting the head back to where it was originally will restore the geometry back to what it was to start with.

Last I've got to say on it AFA "shim it". LOL

 

What (if anything) did you do to compensate for the change in the valve train geometry when you milled the head initially?

I just adjusted the valves to specs and there did not seem to be any problems. I know what you are talking about with the change in geometry but I was assuming (very dangerous word there!) that what I took off the head would not change the rocker angle enough to matter much, maybe I was wrong?

 

what I took off the head would not change the rocker angle enough to matter much, maybe I was wrong?

Prob. not, I'm guessing that at the RPM the engine sees, the geometry isn't as critical as it would be at elevated engine speeds.

I was more curious than anything- in case I ever wanted to go mower racin'!